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  • The broken Promise of the Mobile Web

    - by Rick Strahl
    High end mobile devices have been with us now for almost 7 years and they have utterly transformed the way we access information. Mobile phones and smartphones that have access to the Internet and host smart applications are in the hands of a large percentage of the population of the world. In many places even very remote, cell phones and even smart phones are a common sight. I’ll never forget when I was in India in 2011 I was up in the Southern Indian mountains riding an elephant out of a tiny local village, with an elephant herder in front riding atop of the elephant in front of us. He was dressed in traditional garb with the loin wrap and head cloth/turban as did quite a few of the locals in this small out of the way and not so touristy village. So we’re slowly trundling along in the forest and he’s lazily using his stick to guide the elephant and… 10 minutes in he pulls out his cell phone from his sash and starts texting. In the middle of texting a huge pig jumps out from the side of the trail and he takes a picture running across our path in the jungle! So yeah, mobile technology is very pervasive and it’s reached into even very buried and unexpected parts of this world. Apps are still King Apps currently rule the roost when it comes to mobile devices and the applications that run on them. If there’s something that you need on your mobile device your first step usually is to look for an app, not use your browser. But native app development remains a pain in the butt, with the requirement to have to support 2 or 3 completely separate platforms. There are solutions that try to bridge that gap. Xamarin is on a tear at the moment, providing their cross-device toolkit to build applications using C#. While Xamarin tools are impressive – and also *very* expensive – they only address part of the development madness that is app development. There are still specific device integration isssues, dealing with the different developer programs, security and certificate setups and all that other noise that surrounds app development. There’s also PhoneGap/Cordova which provides a hybrid solution that involves creating local HTML/CSS/JavaScript based applications, and then packaging them to run in a specialized App container that can run on most mobile device platforms using a WebView interface. This allows for using of HTML technology, but it also still requires all the set up, configuration of APIs, security keys and certification and submission and deployment process just like native applications – you actually lose many of the benefits that  Web based apps bring. The big selling point of Cordova is that you get to use HTML have the ability to build your UI once for all platforms and run across all of them – but the rest of the app process remains in place. Apps can be a big pain to create and manage especially when we are talking about specialized or vertical business applications that aren’t geared at the mainstream market and that don’t fit the ‘store’ model. If you’re building a small intra department application you don’t want to deal with multiple device platforms and certification etc. for various public or corporate app stores. That model is simply not a good fit both from the development and deployment perspective. Even for commercial, big ticket apps, HTML as a UI platform offers many advantages over native, from write-once run-anywhere, to remote maintenance, single point of management and failure to having full control over the application as opposed to have the app store overloads censor you. In a lot of ways Web based HTML/CSS/JavaScript applications have so much potential for building better solutions based on existing Web technologies for the very same reasons a lot of content years ago moved off the desktop to the Web. To me the Web as a mobile platform makes perfect sense, but the reality of today’s Mobile Web unfortunately looks a little different… Where’s the Love for the Mobile Web? Yet here we are in the middle of 2014, nearly 7 years after the first iPhone was released and brought the promise of rich interactive information at your fingertips, and yet we still don’t really have a solid mobile Web platform. I know what you’re thinking: “But we have lots of HTML/JavaScript/CSS features that allows us to build nice mobile interfaces”. I agree to a point – it’s actually quite possible to build nice looking, rich and capable Web UI today. We have media queries to deal with varied display sizes, CSS transforms for smooth animations and transitions, tons of CSS improvements in CSS 3 that facilitate rich layout, a host of APIs geared towards mobile device features and lately even a number of JavaScript framework choices that facilitate development of multi-screen apps in a consistent manner. Personally I’ve been working a lot with AngularJs and heavily modified Bootstrap themes to build mobile first UIs and that’s been working very well to provide highly usable and attractive UI for typical mobile business applications. From the pure UI perspective things actually look very good. Not just about the UI But it’s not just about the UI - it’s also about integration with the mobile device. When it comes to putting all those pieces together into what amounts to a consolidated platform to build mobile Web applications, I think we still have a ways to go… there are a lot of missing pieces to make it all work together and integrate with the device more smoothly, and more importantly to make it work uniformly across the majority of devices. I think there are a number of reasons for this. Slow Standards Adoption HTML standards implementations and ratification has been dreadfully slow, and browser vendors all seem to pick and choose different pieces of the technology they implement. The end result is that we have a capable UI platform that’s missing some of the infrastructure pieces to make it whole on mobile devices. There’s lots of potential but what is lacking that final 10% to build truly compelling mobile applications that can compete favorably with native applications. Some of it is the fragmentation of browsers and the slow evolution of the mobile specific HTML APIs. A host of mobile standards exist but many of the standards are in the early review stage and they have been there stuck for long periods of time and seem to move at a glacial pace. Browser vendors seem even slower to implement them, and for good reason – non-ratified standards mean that implementations may change and vendor implementations tend to be experimental and  likely have to be changed later. Neither Vendors or developers are not keen on changing standards. This is the typical chicken and egg scenario, but without some forward momentum from some party we end up stuck in the mud. It seems that either the standards bodies or the vendors need to carry the torch forward and that doesn’t seem to be happening quickly enough. Mobile Device Integration just isn’t good enough Current standards are not far reaching enough to address a number of the use case scenarios necessary for many mobile applications. While not every application needs to have access to all mobile device features, almost every mobile application could benefit from some integration with other parts of the mobile device platform. Integration with GPS, phone, media, messaging, notifications, linking and contacts system are benefits that are unique to mobile applications and could be widely used, but are mostly (with the exception of GPS) inaccessible for Web based applications today. Unfortunately trying to do most of this today only with a mobile Web browser is a losing battle. Aside from PhoneGap/Cordova’s app centric model with its own custom API accessing mobile device features and the token exception of the GeoLocation API, most device integration features are not widely supported by the current crop of mobile browsers. For example there’s no usable messaging API that allows access to SMS or contacts from HTML. Even obvious components like the Media Capture API are only implemented partially by mobile devices. There are alternatives and workarounds for some of these interfaces by using browser specific code, but that’s might ugly and something that I thought we were trying to leave behind with newer browser standards. But it’s not quite working out that way. It’s utterly perplexing to me that mobile standards like Media Capture and Streams, Media Gallery Access, Responsive Images, Messaging API, Contacts Manager API have only minimal or no traction at all today. Keep in mind we’ve had mobile browsers for nearly 7 years now, and yet we still have to think about how to get access to an image from the image gallery or the camera on some devices? Heck Windows Phone IE Mobile just gained the ability to upload images recently in the Windows 8.1 Update – that’s feature that HTML has had for 20 years! These are simple concepts and common problems that should have been solved a long time ago. It’s extremely frustrating to see build 90% of a mobile Web app with relative ease and then hit a brick wall for the remaining 10%, which often can be show stoppers. The remaining 10% have to do with platform integration, browser differences and working around the limitations that browsers and ‘pinned’ applications impose on HTML applications. The maddening part is that these limitations seem arbitrary as they could easily work on all mobile platforms. For example, SMS has a URL Moniker interface that sort of works on Android, works badly with iOS (only works if the address is already in the contact list) and not at all on Windows Phone. There’s no reason this shouldn’t work universally using the same interface – after all all phones have supported SMS since before the year 2000! But, it doesn’t have to be this way Change can happen very quickly. Take the GeoLocation API for example. Geolocation has taken off at the very beginning of the mobile device era and today it works well, provides the necessary security (a big concern for many mobile APIs), and is supported by just about all major mobile and even desktop browsers today. It handles security concerns via prompts to avoid unwanted access which is a model that would work for most other device APIs in a similar fashion. One time approval and occasional re-approval if code changes or caches expire. Simple and only slightly intrusive. It all works well, even though GeoLocation actually has some physical limitations, such as representing the current location when no GPS device is present. Yet this is a solved problem, where other APIs that are conceptually much simpler to implement have failed to gain any traction at all. Technically none of these APIs should be a problem to implement, but it appears that the momentum is just not there. Inadequate Web Application Linking and Activation Another important piece of the puzzle missing is the integration of HTML based Web applications. Today HTML based applications are not first class citizens on mobile operating systems. When talking about HTML based content there’s a big difference between content and applications. Content is great for search engine discovery and plain browser usage. Content is usually accessed intermittently and permanent linking is not so critical for this type of content.  But applications have different needs. Applications need to be started up quickly and must be easily switchable to support a multi-tasking user workflow. Therefore, it’s pretty crucial that mobile Web apps are integrated into the underlying mobile OS and work with the standard task management features. Unfortunately this integration is not as smooth as it should be. It starts with actually trying to find mobile Web applications, to ‘installing’ them onto a phone in an easily accessible manner in a prominent position. The experience of discovering a Mobile Web ‘App’ and making it sticky is by no means as easy or satisfying. Today the way you’d go about this is: Open the browser Search for a Web Site in the browser with your search engine of choice Hope that you find the right site Hope that you actually find a site that works for your mobile device Click on the link and run the app in a fully chrome’d browser instance (read tiny surface area) Pin the app to the home screen (with all the limitations outline above) Hope you pointed at the right URL when you pinned Even for you and me as developers, there are a few steps in there that are painful and annoying, but think about the average user. First figuring out how to search for a specific site or URL? And then pinning the app and hopefully from the right location? You’ve probably lost more than half of your audience at that point. This experience sucks. For developers too this process is painful since app developers can’t control the shortcut creation directly. This problem often gets solved by crazy coding schemes, with annoying pop-ups that try to get people to create shortcuts via fancy animations that are both annoying and add overhead to each and every application that implements this sort of thing differently. And that’s not the end of it - getting the link onto the home screen with an application icon varies quite a bit between browsers. Apple’s non-standard meta tags are prominent and they work with iOS and Android (only more recent versions), but not on Windows Phone. Windows Phone instead requires you to create an actual screen or rather a partial screen be captured for a shortcut in the tile manager. Who had that brilliant idea I wonder? Surprisingly Chrome on recent Android versions seems to actually get it right – icons use pngs, pinning is easy and pinned applications properly behave like standalone apps and retain the browser’s active page state and content. Each of the platforms has a different way to specify icons (WP doesn’t allow you to use an icon image at all), and the most widely used interface in use today is a bunch of Apple specific meta tags that other browsers choose to support. The question is: Why is there no standard implementation for installing shortcuts across mobile platforms using an official format rather than a proprietary one? Then there’s iOS and the crazy way it treats home screen linked URLs using a crazy hybrid format that is neither as capable as a Web app running in Safari nor a WebView hosted application. Moving off the Web ‘app’ link when switching to another app actually causes the browser and preview it to ‘blank out’ the Web application in the Task View (see screenshot on the right). Then, when the ‘app’ is reactivated it ends up completely restarting the browser with the original link. This is crazy behavior that you can’t easily work around. In some situations you might be able to store the application state and restore it using LocalStorage, but for many scenarios that involve complex data sources (like say Google Maps) that’s not a possibility. The only reason for this screwed up behavior I can think of is that it is deliberate to make Web apps a pain in the butt to use and forcing users trough the App Store/PhoneGap/Cordova route. App linking and management is a very basic problem – something that we essentially have solved in every desktop browser – yet on mobile devices where it arguably matters a lot more to have easy access to web content we have to jump through hoops to have even a remotely decent linking/activation experience across browsers. Where’s the Money? It’s not surprising that device home screen integration and Mobile Web support in general is in such dismal shape – the mobile OS vendors benefit financially from App store sales and have little to gain from Web based applications that bypass the App store and the cash cow that it presents. On top of that, platform specific vendor lock-in of both end users and developers who have invested in hardware, apps and consumables is something that mobile platform vendors actually aspire to. Web based interfaces that are cross-platform are the anti-thesis of that and so again it’s no surprise that the mobile Web is on a struggling path. But – that may be changing. More and more we’re seeing operations shifting to services that are subscription based or otherwise collect money for usage, and that may drive more progress into the Web direction in the end . Nothing like the almighty dollar to drive innovation forward. Do we need a Mobile Web App Store? As much as I dislike moderated experiences in today’s massive App Stores, they do at least provide one single place to look for apps for your device. I think we could really use some sort of registry, that could provide something akin to an app store for mobile Web apps, to make it easier to actually find mobile applications. This could take the form of a specialized search engine, or maybe a more formal store/registry like structure. Something like apt-get/chocolatey for Web apps. It could be curated and provide at least some feedback and reviews that might help with the integrity of applications. Coupled to that could be a native application on each platform that would allow searching and browsing of the registry and then also handle installation in the form of providing the home screen linking, plus maybe an initial security configuration that determines what features are allowed access to for the app. I’m not holding my breath. In order for this sort of thing to take off and gain widespread appeal, a lot of coordination would be required. And in order to get enough traction it would have to come from a well known entity – a mobile Web app store from a no name source is unlikely to gain high enough usage numbers to make a difference. In a way this would eliminate some of the freedom of the Web, but of course this would also be an optional search path in addition to the standard open Web search mechanisms to find and access content today. Security Security is a big deal, and one of the perceived reasons why so many IT professionals appear to be willing to go back to the walled garden of deployed apps is that Apps are perceived as safe due to the official review and curation of the App stores. Curated stores are supposed to protect you from malware, illegal and misleading content. It doesn’t always work out that way and all the major vendors have had issues with security and the review process at some time or another. Security is critical, but I also think that Web applications in general pose less of a security threat than native applications, by nature of the sandboxed browser and JavaScript environments. Web applications run externally completely and in the HTML and JavaScript sandboxes, with only a very few controlled APIs allowing access to device specific features. And as discussed earlier – security for any device interaction can be granted the same for mobile applications through a Web browser, as they can for native applications either via explicit policies loaded from the Web, or via prompting as GeoLocation does today. Security is important, but it’s certainly solvable problem for Web applications even those that need to access device hardware. Security shouldn’t be a reason for Web apps to be an equal player in mobile applications. Apps are winning, but haven’t we been here before? So now we’re finding ourselves back in an era of installed app, rather than Web based and managed apps. Only it’s even worse today than with Desktop applications, in that the apps are going through a gatekeeper that charges a toll and censors what you can and can’t do in your apps. Frankly it’s a mystery to me why anybody would buy into this model and why it’s lasted this long when we’ve already been through this process. It’s crazy… It’s really a shame that this regression is happening. We have the technology to make mobile Web apps much more prominent, but yet we’re basically held back by what seems little more than bureaucracy, partisan bickering and self interest of the major parties involved. Back in the day of the desktop it was Internet Explorer’s 98+%  market shareholding back the Web from improvements for many years – now it’s the combined mobile OS market in control of the mobile browsers. If mobile Web apps were allowed to be treated the same as native apps with simple ways to install and run them consistently and persistently, that would go a long way to making mobile applications much more usable and seriously viable alternatives to native apps. But as it is mobile apps have a severe disadvantage in placement and operation. There are a few bright spots in all of this. Mozilla’s FireFoxOs is embracing the Web for it’s mobile OS by essentially building every app out of HTML and JavaScript based content. It supports both packaged and certified package modes (that can be put into the app store), and Open Web apps that are loaded and run completely off the Web and can also cache locally for offline operation using a manifest. Open Web apps are treated as full class citizens in FireFoxOS and run using the same mechanism as installed apps. Unfortunately FireFoxOs is getting a slow start with minimal device support and specifically targeting the low end market. We can hope that this approach will change and catch on with other vendors, but that’s also an uphill battle given the conflict of interest with platform lock in that it represents. Recent versions of Android also seem to be working reasonably well with mobile application integration onto the desktop and activation out of the box. Although it still uses the Apple meta tags to find icons and behavior settings, everything at least works as you would expect – icons to the desktop on pinning, WebView based full screen activation, and reliable application persistence as the browser/app is treated like a real application. Hopefully iOS will at some point provide this same level of rudimentary Web app support. What’s also interesting to me is that Microsoft hasn’t picked up on the obvious need for a solid Web App platform. Being a distant third in the mobile OS war, Microsoft certainly has nothing to lose and everything to gain by using fresh ideas and expanding into areas that the other major vendors are neglecting. But instead Microsoft is trying to beat the market leaders at their own game, fighting on their adversary’s terms instead of taking a new tack. Providing a kick ass mobile Web platform that takes the lead on some of the proposed mobile APIs would be something positive that Microsoft could do to improve its miserable position in the mobile device market. Where are we at with Mobile Web? It sure sounds like I’m really down on the Mobile Web, right? I’ve built a number of mobile apps in the last year and while overall result and response has been very positive to what we were able to accomplish in terms of UI, getting that final 10% that required device integration dialed was an absolute nightmare on every single one of them. Big compromises had to be made and some features were left out or had to be modified for some devices. In two cases we opted to go the Cordova route in order to get the integration we needed, along with the extra pain involved in that process. Unless you’re not integrating with device features and you don’t care deeply about a smooth integration with the mobile desktop, mobile Web development is fraught with frustration. So, yes I’m frustrated! But it’s not for lack of wanting the mobile Web to succeed. I am still a firm believer that we will eventually arrive a much more functional mobile Web platform that allows access to the most common device features in a sensible way. It wouldn't be difficult for device platform vendors to make Web based applications first class citizens on mobile devices. But unfortunately it looks like it will still be some time before this happens. So, what’s your experience building mobile Web apps? Are you finding similar issues? Just giving up on raw Web applications and building PhoneGap apps instead? Completely skipping the Web and going native? Leave a comment for discussion. Resources Rick Strahl on DotNet Rocks talking about Mobile Web© Rick Strahl, West Wind Technologies, 2005-2014Posted in HTML5  Mobile   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Scrum in 5 Minutes

    - by Stephen.Walther
    The goal of this blog entry is to explain the basic concepts of Scrum in less than five minutes. You learn how Scrum can help a team of developers to successfully complete a complex software project. Product Backlog and the Product Owner Imagine that you are part of a team which needs to create a new website – for example, an e-commerce website. You have an overwhelming amount of work to do. You need to build (or possibly buy) a shopping cart, install an SSL certificate, create a product catalog, create a Facebook page, and at least a hundred other things that you have not thought of yet. According to Scrum, the first thing you should do is create a list. Place the highest priority items at the top of the list and the lower priority items lower in the list. For example, creating the shopping cart and buying the domain name might be high priority items and creating a Facebook page might be a lower priority item. In Scrum, this list is called the Product Backlog. How do you prioritize the items in the Product Backlog? Different stakeholders in the project might have different priorities. Gary, your division VP, thinks that it is crucial that the e-commerce site has a mobile app. Sally, your direct manager, thinks taking advantage of new HTML5 features is much more important. Multiple people are pulling you in different directions. According to Scrum, it is important that you always designate one person, and only one person, as the Product Owner. The Product Owner is the person who decides what items should be added to the Product Backlog and the priority of the items in the Product Backlog. The Product Owner could be the customer who is paying the bills, the project manager who is responsible for delivering the project, or a customer representative. The critical point is that the Product Owner must always be a single person and that single person has absolute authority over the Product Backlog. Sprints and the Sprint Backlog So now the developer team has a prioritized list of items and they can start work. The team starts implementing the first item in the Backlog — the shopping cart — and the team is making good progress. Unfortunately, however, half-way through the work of implementing the shopping cart, the Product Owner changes his mind. The Product Owner decides that it is much more important to create the product catalog before the shopping cart. With some frustration, the team switches their developmental efforts to focus on implementing the product catalog. However, part way through completing this work, once again the Product Owner changes his mind about the highest priority item. Getting work done when priorities are constantly shifting is frustrating for the developer team and it results in lower productivity. At the same time, however, the Product Owner needs to have absolute authority over the priority of the items which need to get done. Scrum solves this conflict with the concept of Sprints. In Scrum, a developer team works in Sprints. At the beginning of a Sprint the developers and the Product Owner agree on the items from the backlog which they will complete during the Sprint. This subset of items from the Product Backlog becomes the Sprint Backlog. During the Sprint, the Product Owner is not allowed to change the items in the Sprint Backlog. In other words, the Product Owner cannot shift priorities on the developer team during the Sprint. Different teams use Sprints of different lengths such as one month Sprints, two-week Sprints, and one week Sprints. For high-stress, time critical projects, teams typically choose shorter sprints such as one week sprints. For more mature projects, longer one month sprints might be more appropriate. A team can pick whatever Sprint length makes sense for them just as long as the team is consistent. You should pick a Sprint length and stick with it. Daily Scrum During a Sprint, the developer team needs to have meetings to coordinate their work on completing the items in the Sprint Backlog. For example, the team needs to discuss who is working on what and whether any blocking issues have been discovered. Developers hate meetings (well, sane developers hate meetings). Meetings take developers away from their work of actually implementing stuff as opposed to talking about implementing stuff. However, a developer team which never has meetings and never coordinates their work also has problems. For example, Fred might get stuck on a programming problem for days and never reach out for help even though Tom (who sits in the cubicle next to him) has already solved the very same problem. Or, both Ted and Fred might have started working on the same item from the Sprint Backlog at the same time. In Scrum, these conflicting needs – limiting meetings but enabling team coordination – are resolved with the idea of the Daily Scrum. The Daily Scrum is a meeting for coordinating the work of the developer team which happens once a day. To keep the meeting short, each developer answers only the following three questions: 1. What have you done since yesterday? 2. What do you plan to do today? 3. Any impediments in your way? During the Daily Scrum, developers are not allowed to talk about issues with their cat, do demos of their latest work, or tell heroic stories of programming problems overcome. The meeting must be kept short — typically about 15 minutes. Issues which come up during the Daily Scrum should be discussed in separate meetings which do not involve the whole developer team. Stories and Tasks Items in the Product or Sprint Backlog – such as building a shopping cart or creating a Facebook page – are often referred to as User Stories or Stories. The Stories are created by the Product Owner and should represent some business need. Unlike the Product Owner, the developer team needs to think about how a Story should be implemented. At the beginning of a Sprint, the developer team takes the Stories from the Sprint Backlog and breaks the stories into tasks. For example, the developer team might take the Create a Shopping Cart story and break it into the following tasks: · Enable users to add and remote items from shopping cart · Persist the shopping cart to database between visits · Redirect user to checkout page when Checkout button is clicked During the Daily Scrum, members of the developer team volunteer to complete the tasks required to implement the next Story in the Sprint Backlog. When a developer talks about what he did yesterday or plans to do tomorrow then the developer should be referring to a task. Stories are owned by the Product Owner and a story is all about business value. In contrast, the tasks are owned by the developer team and a task is all about implementation details. A story might take several days or weeks to complete. A task is something which a developer can complete in less than a day. Some teams get lazy about breaking stories into tasks. Neglecting to break stories into tasks can lead to “Never Ending Stories” If you don’t break a story into tasks, then you can’t know how much of a story has actually been completed because you don’t have a clear idea about the implementation steps required to complete the story. Scrumboard During the Daily Scrum, the developer team uses a Scrumboard to coordinate their work. A Scrumboard contains a list of the stories for the current Sprint, the tasks associated with each Story, and the state of each task. The developer team uses the Scrumboard so everyone on the team can see, at a glance, what everyone is working on. As a developer works on a task, the task moves from state to state and the state of the task is updated on the Scrumboard. Common task states are ToDo, In Progress, and Done. Some teams include additional task states such as Needs Review or Needs Testing. Some teams use a physical Scrumboard. In that case, you use index cards to represent the stories and the tasks and you tack the index cards onto a physical board. Using a physical Scrumboard has several disadvantages. A physical Scrumboard does not work well with a distributed team – for example, it is hard to share the same physical Scrumboard between Boston and Seattle. Also, generating reports from a physical Scrumboard is more difficult than generating reports from an online Scrumboard. Estimating Stories and Tasks Stakeholders in a project, the people investing in a project, need to have an idea of how a project is progressing and when the project will be completed. For example, if you are investing in creating an e-commerce site, you need to know when the site can be launched. It is not enough to just say that “the project will be done when it is done” because the stakeholders almost certainly have a limited budget to devote to the project. The people investing in the project cannot determine the business value of the project unless they can have an estimate of how long it will take to complete the project. Developers hate to give estimates. The reason that developers hate to give estimates is that the estimates are almost always completely made up. For example, you really don’t know how long it takes to build a shopping cart until you finish building a shopping cart, and at that point, the estimate is no longer useful. The problem is that writing code is much more like Finding a Cure for Cancer than Building a Brick Wall. Building a brick wall is very straightforward. After you learn how to add one brick to a wall, you understand everything that is involved in adding a brick to a wall. There is no additional research required and no surprises. If, on the other hand, I assembled a team of scientists and asked them to find a cure for cancer, and estimate exactly how long it will take, they would have no idea. The problem is that there are too many unknowns. I don’t know how to cure cancer, I need to do a lot of research here, so I cannot even begin to estimate how long it will take. So developers hate to provide estimates, but the Product Owner and other product stakeholders, have a legitimate need for estimates. Scrum resolves this conflict by using the idea of Story Points. Different teams use different units to represent Story Points. For example, some teams use shirt sizes such as Small, Medium, Large, and X-Large. Some teams prefer to use Coffee Cup sizes such as Tall, Short, and Grande. Finally, some teams like to use numbers from the Fibonacci series. These alternative units are converted into a Story Point value. Regardless of the type of unit which you use to represent Story Points, the goal is the same. Instead of attempting to estimate a Story in hours (which is doomed to failure), you use a much less fine-grained measure of work. A developer team is much more likely to be able to estimate that a Story is Small or X-Large than the exact number of hours required to complete the story. So you can think of Story Points as a compromise between the needs of the Product Owner and the developer team. When a Sprint starts, the developer team devotes more time to thinking about the Stories in a Sprint and the developer team breaks the Stories into Tasks. In Scrum, you estimate the work required to complete a Story by using Story Points and you estimate the work required to complete a task by using hours. The difference between Stories and Tasks is that you don’t create a task until you are just about ready to start working on a task. A task is something that you should be able to create within a day, so you have a much better chance of providing an accurate estimate of the work required to complete a task than a story. Burndown Charts In Scrum, you use Burndown charts to represent the remaining work on a project. You use Release Burndown charts to represent the overall remaining work for a project and you use Sprint Burndown charts to represent the overall remaining work for a particular Sprint. You create a Release Burndown chart by calculating the remaining number of uncompleted Story Points for the entire Product Backlog every day. The vertical axis represents Story Points and the horizontal axis represents time. A Sprint Burndown chart is similar to a Release Burndown chart, but it focuses on the remaining work for a particular Sprint. There are two different types of Sprint Burndown charts. You can either represent the remaining work in a Sprint with Story Points or with task hours (the following image, taken from Wikipedia, uses hours). When each Product Backlog Story is completed, the Release Burndown chart slopes down. When each Story or task is completed, the Sprint Burndown chart slopes down. Burndown charts typically do not always slope down over time. As new work is added to the Product Backlog, the Release Burndown chart slopes up. If new tasks are discovered during a Sprint, the Sprint Burndown chart will also slope up. The purpose of a Burndown chart is to give you a way to track team progress over time. If, halfway through a Sprint, the Sprint Burndown chart is still climbing a hill then you know that you are in trouble. Team Velocity Stakeholders in a project always want more work done faster. For example, the Product Owner for the e-commerce site wants the website to launch before tomorrow. Developers tend to be overly optimistic. Rarely do developers acknowledge the physical limitations of reality. So Project stakeholders and the developer team often collude to delude themselves about how much work can be done and how quickly. Too many software projects begin in a state of optimism and end in frustration as deadlines zoom by. In Scrum, this problem is overcome by calculating a number called the Team Velocity. The Team Velocity is a measure of the average number of Story Points which a team has completed in previous Sprints. Knowing the Team Velocity is important during the Sprint Planning meeting when the Product Owner and the developer team work together to determine the number of stories which can be completed in the next Sprint. If you know the Team Velocity then you can avoid committing to do more work than the team has been able to accomplish in the past, and your team is much more likely to complete all of the work required for the next Sprint. Scrum Master There are three roles in Scrum: the Product Owner, the developer team, and the Scrum Master. I’v e already discussed the Product Owner. The Product Owner is the one and only person who maintains the Product Backlog and prioritizes the stories. I’ve also described the role of the developer team. The members of the developer team do the work of implementing the stories by breaking the stories into tasks. The final role, which I have not discussed, is the role of the Scrum Master. The Scrum Master is responsible for ensuring that the team is following the Scrum process. For example, the Scrum Master is responsible for making sure that there is a Daily Scrum meeting and that everyone answers the standard three questions. The Scrum Master is also responsible for removing (non-technical) impediments which the team might encounter. For example, if the team cannot start work until everyone installs the latest version of Microsoft Visual Studio then the Scrum Master has the responsibility of working with management to get the latest version of Visual Studio as quickly as possible. The Scrum Master can be a member of the developer team. Furthermore, different people can take on the role of the Scrum Master over time. The Scrum Master, however, cannot be the same person as the Product Owner. Using SonicAgile SonicAgile (SonicAgile.com) is an online tool which you can use to manage your projects using Scrum. You can use the SonicAgile Product Backlog to create a prioritized list of stories. You can estimate the size of the Stories using different Story Point units such as Shirt Sizes and Coffee Cup sizes. You can use SonicAgile during the Sprint Planning meeting to select the Stories that you want to complete during a particular Sprint. You can configure Sprints to be any length of time. SonicAgile calculates Team Velocity automatically and displays a warning when you add too many stories to a Sprint. In other words, it warns you when it thinks you are overcommitting in a Sprint. SonicAgile also includes a Scrumboard which displays the list of Stories selected for a Sprint and the tasks associated with each story. You can drag tasks from one task state to another. Finally, SonicAgile enables you to generate Release Burndown and Sprint Burndown charts. You can use these charts to view the progress of your team. To learn more about SonicAgile, visit SonicAgile.com. Summary In this post, I described many of the basic concepts of Scrum. You learned how a Product Owner uses a Product Backlog to create a prioritized list of tasks. I explained why work is completed in Sprints so the developer team can be more productive. I also explained how a developer team uses the daily scrum to coordinate their work. You learned how the developer team uses a Scrumboard to see, at a glance, who is working on what and the state of each task. I also discussed Burndown charts. You learned how you can use both Release and Sprint Burndown charts to track team progress in completing a project. Finally, I described the crucial role of the Scrum Master – the person who is responsible for ensuring that the rules of Scrum are being followed. My goal was not to describe all of the concepts of Scrum. This post was intended to be an introductory overview. For a comprehensive explanation of Scrum, I recommend reading Ken Schwaber’s book Agile Project Management with Scrum: http://www.amazon.com/Agile-Project-Management-Microsoft-Professional/dp/073561993X/ref=la_B001H6ODMC_1_1?ie=UTF8&qid=1345224000&sr=1-1

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  • How to find and fix performance problems in ORM powered applications

    - by FransBouma
    Once in a while we get requests about how to fix performance problems with our framework. As it comes down to following the same steps and looking into the same things every single time, I decided to write a blogpost about it instead, so more people can learn from this and solve performance problems in their O/R mapper powered applications. In some parts it's focused on LLBLGen Pro but it's also usable for other O/R mapping frameworks, as the vast majority of performance problems in O/R mapper powered applications are not specific for a certain O/R mapper framework. Too often, the developer looks at the wrong part of the application, trying to fix what isn't a problem in that part, and getting frustrated that 'things are so slow with <insert your favorite framework X here>'. I'm in the O/R mapper business for a long time now (almost 10 years, full time) and as it's a small world, we O/R mapper developers know almost all tricks to pull off by now: we all know what to do to make task ABC faster and what compromises (because there are almost always compromises) to deal with if we decide to make ABC faster that way. Some O/R mapper frameworks are faster in X, others in Y, but you can be sure the difference is mainly a result of a compromise some developers are willing to deal with and others aren't. That's why the O/R mapper frameworks on the market today are different in many ways, even though they all fetch and save entities from and to a database. I'm not suggesting there's no room for improvement in today's O/R mapper frameworks, there always is, but it's not a matter of 'the slowness of the application is caused by the O/R mapper' anymore. Perhaps query generation can be optimized a bit here, row materialization can be optimized a bit there, but it's mainly coming down to milliseconds. Still worth it if you're a framework developer, but it's not much compared to the time spend inside databases and in user code: if a complete fetch takes 40ms or 50ms (from call to entity object collection), it won't make a difference for your application as that 10ms difference won't be noticed. That's why it's very important to find the real locations of the problems so developers can fix them properly and don't get frustrated because their quest to get a fast, performing application failed. Performance tuning basics and rules Finding and fixing performance problems in any application is a strict procedure with four prescribed steps: isolate, analyze, interpret and fix, in that order. It's key that you don't skip a step nor make assumptions: these steps help you find the reason of a problem which seems to be there, and how to fix it or leave it as-is. Skipping a step, or when you assume things will be bad/slow without doing analysis will lead to the path of premature optimization and won't actually solve your problems, only create new ones. The most important rule of finding and fixing performance problems in software is that you have to understand what 'performance problem' actually means. Most developers will say "when a piece of software / code is slow, you have a performance problem". But is that actually the case? If I write a Linq query which will aggregate, group and sort 5 million rows from several tables to produce a resultset of 10 rows, it might take more than a couple of milliseconds before that resultset is ready to be consumed by other logic. If I solely look at the Linq query, the code consuming the resultset of the 10 rows and then look at the time it takes to complete the whole procedure, it will appear to me to be slow: all that time taken to produce and consume 10 rows? But if you look closer, if you analyze and interpret the situation, you'll see it does a tremendous amount of work, and in that light it might even be extremely fast. With every performance problem you encounter, always do realize that what you're trying to solve is perhaps not a technical problem at all, but a perception problem. The second most important rule you have to understand is based on the old saying "Penny wise, Pound Foolish": the part which takes e.g. 5% of the total time T for a given task isn't worth optimizing if you have another part which takes a much larger part of the total time T for that same given task. Optimizing parts which are relatively insignificant for the total time taken is not going to bring you better results overall, even if you totally optimize that part away. This is the core reason why analysis of the complete set of application parts which participate in a given task is key to being successful in solving performance problems: No analysis -> no problem -> no solution. One warning up front: hunting for performance will always include making compromises. Fast software can be made maintainable, but if you want to squeeze as much performance out of your software, you will inevitably be faced with the dilemma of compromising one or more from the group {readability, maintainability, features} for the extra performance you think you'll gain. It's then up to you to decide whether it's worth it. In almost all cases it's not. The reason for this is simple: the vast majority of performance problems can be solved by implementing the proper algorithms, the ones with proven Big O-characteristics so you know the performance you'll get plus you know the algorithm will work. The time taken by the algorithm implementing code is inevitable: you already implemented the best algorithm. You might find some optimizations on the technical level but in general these are minor. Let's look at the four steps to see how they guide us through the quest to find and fix performance problems. Isolate The first thing you need to do is to isolate the areas in your application which are assumed to be slow. For example, if your application is a web application and a given page is taking several seconds or even minutes to load, it's a good candidate to check out. It's important to start with the isolate step because it allows you to focus on a single code path per area with a clear begin and end and ignore the rest. The rest of the steps are taken per identified problematic area. Keep in mind that isolation focuses on tasks in an application, not code snippets. A task is something that's started in your application by either another task or the user, or another program, and has a beginning and an end. You can see a task as a piece of functionality offered by your application.  Analyze Once you've determined the problem areas, you have to perform analysis on the code paths of each area, to see where the performance problems occur and which areas are not the problem. This is a multi-layered effort: an application which uses an O/R mapper typically consists of multiple parts: there's likely some kind of interface (web, webservice, windows etc.), a part which controls the interface and business logic, the O/R mapper part and the RDBMS, all connected with either a network or inter-process connections provided by the OS or other means. Each of these parts, including the connectivity plumbing, eat up a part of the total time it takes to complete a task, e.g. load a webpage with all orders of a given customer X. To understand which parts participate in the task / area we're investigating and how much they contribute to the total time taken to complete the task, analysis of each participating task is essential. Start with the code you wrote which starts the task, analyze the code and track the path it follows through your application. What does the code do along the way, verify whether it's correct or not. Analyze whether you have implemented the right algorithms in your code for this particular area. Remember we're looking at one area at a time, which means we're ignoring all other code paths, just the code path of the current problematic area, from begin to end and back. Don't dig in and start optimizing at the code level just yet. We're just analyzing. If your analysis reveals big architectural stupidity, it's perhaps a good idea to rethink the architecture at this point. For the rest, we're analyzing which means we collect data about what could be wrong, for each participating part of the complete application. Reviewing the code you wrote is a good tool to get deeper understanding of what is going on for a given task but ultimately it lacks precision and overview what really happens: humans aren't good code interpreters, computers are. We therefore need to utilize tools to get deeper understanding about which parts contribute how much time to the total task, triggered by which other parts and for example how many times are they called. There are two different kind of tools which are necessary: .NET profilers and O/R mapper / RDBMS profilers. .NET profiling .NET profilers (e.g. dotTrace by JetBrains or Ants by Red Gate software) show exactly which pieces of code are called, how many times they're called, and the time it took to run that piece of code, at the method level and sometimes even at the line level. The .NET profilers are essential tools for understanding whether the time taken to complete a given task / area in your application is consumed by .NET code, where exactly in your code, the path to that code, how many times that code was called by other code and thus reveals where hotspots are located: the areas where a solution can be found. Importantly, they also reveal which areas can be left alone: remember our penny wise pound foolish saying: if a profiler reveals that a group of methods are fast, or don't contribute much to the total time taken for a given task, ignore them. Even if the code in them is perhaps complex and looks like a candidate for optimization: you can work all day on that, it won't matter.  As we're focusing on a single area of the application, it's best to start profiling right before you actually activate the task/area. Most .NET profilers support this by starting the application without starting the profiling procedure just yet. You navigate to the particular part which is slow, start profiling in the profiler, in your application you perform the actions which are considered slow, and afterwards you get a snapshot in the profiler. The snapshot contains the data collected by the profiler during the slow action, so most data is produced by code in the area to investigate. This is important, because it allows you to stay focused on a single area. O/R mapper and RDBMS profiling .NET profilers give you a good insight in the .NET side of things, but not in the RDBMS side of the application. As this article is about O/R mapper powered applications, we're also looking at databases, and the software making it possible to consume the database in your application: the O/R mapper. To understand which parts of the O/R mapper and database participate how much to the total time taken for task T, we need different tools. There are two kind of tools focusing on O/R mappers and database performance profiling: O/R mapper profilers and RDBMS profilers. For O/R mapper profilers, you can look at LLBLGen Prof by hibernating rhinos or the Linq to Sql/LLBLGen Pro profiler by Huagati. Hibernating rhinos also have profilers for other O/R mappers like NHibernate (NHProf) and Entity Framework (EFProf) and work the same as LLBLGen Prof. For RDBMS profilers, you have to look whether the RDBMS vendor has a profiler. For example for SQL Server, the profiler is shipped with SQL Server, for Oracle it's build into the RDBMS, however there are also 3rd party tools. Which tool you're using isn't really important, what's important is that you get insight in which queries are executed during the task / area we're currently focused on and how long they took. Here, the O/R mapper profilers have an advantage as they collect the time it took to execute the query from the application's perspective so they also collect the time it took to transport data across the network. This is important because a query which returns a massive resultset or a resultset with large blob/clob/ntext/image fields takes more time to get transported across the network than a small resultset and a database profiler doesn't take this into account most of the time. Another tool to use in this case, which is more low level and not all O/R mappers support it (though LLBLGen Pro and NHibernate as well do) is tracing: most O/R mappers offer some form of tracing or logging system which you can use to collect the SQL generated and executed and often also other activity behind the scenes. While tracing can produce a tremendous amount of data in some cases, it also gives insight in what's going on. Interpret After we've completed the analysis step it's time to look at the data we've collected. We've done code reviews to see whether we've done anything stupid and which parts actually take place and if the proper algorithms have been implemented. We've done .NET profiling to see which parts are choke points and how much time they contribute to the total time taken to complete the task we're investigating. We've performed O/R mapper profiling and RDBMS profiling to see which queries were executed during the task, how many queries were generated and executed and how long they took to complete, including network transportation. All this data reveals two things: which parts are big contributors to the total time taken and which parts are irrelevant. Both aspects are very important. The parts which are irrelevant (i.e. don't contribute significantly to the total time taken) can be ignored from now on, we won't look at them. The parts which contribute a lot to the total time taken are important to look at. We now have to first look at the .NET profiler results, to see whether the time taken is consumed in our own code, in .NET framework code, in the O/R mapper itself or somewhere else. For example if most of the time is consumed by DbCommand.ExecuteReader, the time it took to complete the task is depending on the time the data is fetched from the database. If there was just 1 query executed, according to tracing or O/R mapper profilers / RDBMS profilers, check whether that query is optimal, uses indexes or has to deal with a lot of data. Interpret means that you follow the path from begin to end through the data collected and determine where, along the path, the most time is contributed. It also means that you have to check whether this was expected or is totally unexpected. My previous example of the 10 row resultset of a query which groups millions of rows will likely reveal that a long time is spend inside the database and almost no time is spend in the .NET code, meaning the RDBMS part contributes the most to the total time taken, the rest is compared to that time, irrelevant. Considering the vastness of the source data set, it's expected this will take some time. However, does it need tweaking? Perhaps all possible tweaks are already in place. In the interpret step you then have to decide that further action in this area is necessary or not, based on what the analysis results show: if the analysis results were unexpected and in the area where the most time is contributed to the total time taken is room for improvement, action should be taken. If not, you can only accept the situation and move on. In all cases, document your decision together with the analysis you've done. If you decide that the perceived performance problem is actually expected due to the nature of the task performed, it's essential that in the future when someone else looks at the application and starts asking questions you can answer them properly and new analysis is only necessary if situations changed. Fix After interpreting the analysis results you've concluded that some areas need adjustment. This is the fix step: you're actively correcting the performance problem with proper action targeted at the real cause. In many cases related to O/R mapper powered applications it means you'll use different features of the O/R mapper to achieve the same goal, or apply optimizations at the RDBMS level. It could also mean you apply caching inside your application (compromise memory consumption over performance) to avoid unnecessary re-querying data and re-consuming the results. After applying a change, it's key you re-do the analysis and interpretation steps: compare the results and expectations with what you had before, to see whether your actions had any effect or whether it moved the problem to a different part of the application. Don't fall into the trap to do partly analysis: do the full analysis again: .NET profiling and O/R mapper / RDBMS profiling. It might very well be that the changes you've made make one part faster but another part significantly slower, in such a way that the overall problem hasn't changed at all. Performance tuning is dealing with compromises and making choices: to use one feature over the other, to accept a higher memory footprint, to go away from the strict-OO path and execute queries directly onto the RDBMS, these are choices and compromises which will cross your path if you want to fix performance problems with respect to O/R mappers or data-access and databases in general. In most cases it's not a big issue: alternatives are often good choices too and the compromises aren't that hard to deal with. What is important is that you document why you made a choice, a compromise: which analysis data, which interpretation led you to the choice made. This is key for good maintainability in the years to come. Most common performance problems with O/R mappers Below is an incomplete list of common performance problems related to data-access / O/R mappers / RDBMS code. It will help you with fixing the hotspots you found in the interpretation step. SELECT N+1: (Lazy-loading specific). Lazy loading triggered performance bottlenecks. Consider a list of Orders bound to a grid. You have a Field mapped onto a related field in Order, Customer.CompanyName. Showing this column in the grid will make the grid fetch (indirectly) for each row the Customer row. This means you'll get for the single list not 1 query (for the orders) but 1+(the number of orders shown) queries. To solve this: use eager loading using a prefetch path to fetch the customers with the orders. SELECT N+1 is easy to spot with an O/R mapper profiler or RDBMS profiler: if you see a lot of identical queries executed at once, you have this problem. Prefetch paths using many path nodes or sorting, or limiting. Eager loading problem. Prefetch paths can help with performance, but as 1 query is fetched per node, it can be the number of data fetched in a child node is bigger than you think. Also consider that data in every node is merged on the client within the parent. This is fast, but it also can take some time if you fetch massive amounts of entities. If you keep fetches small, you can use tuning parameters like the ParameterizedPrefetchPathThreshold setting to get more optimal queries. Deep inheritance hierarchies of type Target Per Entity/Type. If you use inheritance of type Target per Entity / Type (each type in the inheritance hierarchy is mapped onto its own table/view), fetches will join subtype- and supertype tables in many cases, which can lead to a lot of performance problems if the hierarchy has many types. With this problem, keep inheritance to a minimum if possible, or switch to a hierarchy of type Target Per Hierarchy, which means all entities in the inheritance hierarchy are mapped onto the same table/view. Of course this has its own set of drawbacks, but it's a compromise you might want to take. Fetching massive amounts of data by fetching large lists of entities. LLBLGen Pro supports paging (and limiting the # of rows returned), which is often key to process through large sets of data. Use paging on the RDBMS if possible (so a query is executed which returns only the rows in the page requested). When using paging in a web application, be sure that you switch server-side paging on on the datasourcecontrol used. In this case, paging on the grid alone is not enough: this can lead to fetching a lot of data which is then loaded into the grid and paged there. Keep note that analyzing queries for paging could lead to the false assumption that paging doesn't occur, e.g. when the query contains a field of type ntext/image/clob/blob and DISTINCT can't be applied while it should have (e.g. due to a join): the datareader will do DISTINCT filtering on the client. this is a little slower but it does perform paging functionality on the data-reader so it won't fetch all rows even if the query suggests it does. Fetch massive amounts of data because blob/clob/ntext/image fields aren't excluded. LLBLGen Pro supports field exclusion for queries. You can exclude fields (also in prefetch paths) per query to avoid fetching all fields of an entity, e.g. when you don't need them for the logic consuming the resultset. Excluding fields can greatly reduce the amount of time spend on data-transport across the network. Use this optimization if you see that there's a big difference between query execution time on the RDBMS and the time reported by the .NET profiler for the ExecuteReader method call. Doing client-side aggregates/scalar calculations by consuming a lot of data. If possible, try to formulate a scalar query or group by query using the projection system or GetScalar functionality of LLBLGen Pro to do data consumption on the RDBMS server. It's far more efficient to process data on the RDBMS server than to first load it all in memory, then traverse the data in-memory to calculate a value. Using .ToList() constructs inside linq queries. It might be you use .ToList() somewhere in a Linq query which makes the query be run partially in-memory. Example: var q = from c in metaData.Customers.ToList() where c.Country=="Norway" select c; This will actually fetch all customers in-memory and do an in-memory filtering, as the linq query is defined on an IEnumerable<T>, and not on the IQueryable<T>. Linq is nice, but it can often be a bit unclear where some parts of a Linq query might run. Fetching all entities to delete into memory first. To delete a set of entities it's rather inefficient to first fetch them all into memory and then delete them one by one. It's more efficient to execute a DELETE FROM ... WHERE query on the database directly to delete the entities in one go. LLBLGen Pro supports this feature, and so do some other O/R mappers. It's not always possible to do this operation in the context of an O/R mapper however: if an O/R mapper relies on a cache, these kind of operations are likely not supported because they make it impossible to track whether an entity is actually removed from the DB and thus can be removed from the cache. Fetching all entities to update with an expression into memory first. Similar to the previous point: it is more efficient to update a set of entities directly with a single UPDATE query using an expression instead of fetching the entities into memory first and then updating the entities in a loop, and afterwards saving them. It might however be a compromise you don't want to take as it is working around the idea of having an object graph in memory which is manipulated and instead makes the code fully aware there's a RDBMS somewhere. Conclusion Performance tuning is almost always about compromises and making choices. It's also about knowing where to look and how the systems in play behave and should behave. The four steps I provided should help you stay focused on the real problem and lead you towards the solution. Knowing how to optimally use the systems participating in your own code (.NET framework, O/R mapper, RDBMS, network/services) is key for success as well as knowing what's going on inside the application you built. I hope you'll find this guide useful in tracking down performance problems and dealing with them in a useful way.  

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  • Ancillary Objects: Separate Debug ELF Files For Solaris

    - by Ali Bahrami
    We introduced a new object ELF object type in Solaris 11 Update 1 called the Ancillary Object. This posting describes them, using material originally written during their development, the PSARC arc case, and the Solaris Linker and Libraries Manual. ELF objects contain allocable sections, which are mapped into memory at runtime, and non-allocable sections, which are present in the file for use by debuggers and observability tools, but which are not mapped or used at runtime. Typically, all of these sections exist within a single object file. Ancillary objects allow them to instead go into a separate file. There are different reasons given for wanting such a feature. One can debate whether the added complexity is worth the benefit, and in most cases it is not. However, one important case stands out — customers with very large 32-bit objects who are not ready or able to make the transition to 64-bits. We have customers who build extremely large 32-bit objects. Historically, the debug sections in these objects have used the stabs format, which is limited, but relatively compact. In recent years, the industry has transitioned to the powerful but verbose DWARF standard. In some cases, the size of these debug sections is large enough to push the total object file size past the fundamental 4GB limit for 32-bit ELF object files. The best, and ultimately only, solution to overly large objects is to transition to 64-bits. However, consider environments where: Hundreds of users may be executing the code on large shared systems. (32-bits use less memory and bus bandwidth, and on sparc runs just as fast as 64-bit code otherwise). Complex finely tuned code, where the original authors may no longer be available. Critical production code, that was expensive to qualify and bring online, and which is otherwise serving its intended purpose without issue. Users in these risk adverse and/or high scale categories have good reasons to push 32-bits objects to the limit before moving on. Ancillary objects offer these users a longer runway. Design The design of ancillary objects is intended to be simple, both to help human understanding when examining elfdump output, and to lower the bar for debuggers such as dbx to support them. The primary and ancillary objects have the same set of section headers, with the same names, in the same order (i.e. each section has the same index in both files). A single added section of type SHT_SUNW_ANCILLARY is added to both objects, containing information that allows a debugger to identify and validate both files relative to each other. Given one of these files, the ancillary section allows you to identify the other. Allocable sections go in the primary object, and non-allocable ones go into the ancillary object. A small set of non-allocable objects, notably the symbol table, are copied into both objects. As noted above, most sections are only written to one of the two objects, but both objects have the same section header array. The section header in the file that does not contain the section data is tagged with the SHF_SUNW_ABSENT section header flag to indicate its placeholder status. Compiler writers and others who produce objects can set the SUNW_SHF_PRIMARY section header flag to mark non-allocable sections that should go to the primary object rather than the ancillary. If you don't request an ancillary object, the Solaris ELF format is unchanged. Users who don't use ancillary objects do not pay for the feature. This is important, because they exist to serve a small subset of our users, and must not complicate the common case. If you do request an ancillary object, the runtime behavior of the primary object will be the same as that of a normal object. There is no added runtime cost. The primary and ancillary object together represent a logical single object. This is facilitated by the use of a single set of section headers. One can easily imagine a tool that can merge a primary and ancillary object into a single file, or the reverse. (Note that although this is an interesting intellectual exercise, we don't actually supply such a tool because there's little practical benefit above and beyond using ld to create the files). Among the benefits of this approach are: There is no need for per-file symbol tables to reflect the contents of each file. The same symbol table that would be produced for a standard object can be used. The section contents are identical in either case — there is no need to alter data to accommodate multiple files. It is very easy for a debugger to adapt to these new files, and the processing involved can be encapsulated in input/output routines. Most of the existing debugger implementation applies without modification. The limit of a 4GB 32-bit output object is now raised to 4GB of code, and 4GB of debug data. There is also the future possibility (not currently supported) to support multiple ancillary objects, each of which could contain up to 4GB of additional debug data. It must be noted however that the 32-bit DWARF debug format is itself inherently 32-bit limited, as it uses 32-bit offsets between debug sections, so the ability to employ multiple ancillary object files may not turn out to be useful. Using Ancillary Objects (From the Solaris Linker and Libraries Guide) By default, objects contain both allocable and non-allocable sections. Allocable sections are the sections that contain executable code and the data needed by that code at runtime. Non-allocable sections contain supplemental information that is not required to execute an object at runtime. These sections support the operation of debuggers and other observability tools. The non-allocable sections in an object are not loaded into memory at runtime by the operating system, and so, they have no impact on memory use or other aspects of runtime performance no matter their size. For convenience, both allocable and non-allocable sections are normally maintained in the same file. However, there are situations in which it can be useful to separate these sections. To reduce the size of objects in order to improve the speed at which they can be copied across wide area networks. To support fine grained debugging of highly optimized code requires considerable debug data. In modern systems, the debugging data can easily be larger than the code it describes. The size of a 32-bit object is limited to 4 Gbytes. In very large 32-bit objects, the debug data can cause this limit to be exceeded and prevent the creation of the object. To limit the exposure of internal implementation details. Traditionally, objects have been stripped of non-allocable sections in order to address these issues. Stripping is effective, but destroys data that might be needed later. The Solaris link-editor can instead write non-allocable sections to an ancillary object. This feature is enabled with the -z ancillary command line option. $ ld ... -z ancillary[=outfile] ...By default, the ancillary file is given the same name as the primary output object, with a .anc file extension. However, a different name can be provided by providing an outfile value to the -z ancillary option. When -z ancillary is specified, the link-editor performs the following actions. All allocable sections are written to the primary object. In addition, all non-allocable sections containing one or more input sections that have the SHF_SUNW_PRIMARY section header flag set are written to the primary object. All remaining non-allocable sections are written to the ancillary object. The following non-allocable sections are written to both the primary object and ancillary object. .shstrtab The section name string table. .symtab The full non-dynamic symbol table. .symtab_shndx The symbol table extended index section associated with .symtab. .strtab The non-dynamic string table associated with .symtab. .SUNW_ancillary Contains the information required to identify the primary and ancillary objects, and to identify the object being examined. The primary object and all ancillary objects contain the same array of sections headers. Each section has the same section index in every file. Although the primary and ancillary objects all define the same section headers, the data for most sections will be written to a single file as described above. If the data for a section is not present in a given file, the SHF_SUNW_ABSENT section header flag is set, and the sh_size field is 0. This organization makes it possible to acquire a full list of section headers, a complete symbol table, and a complete list of the primary and ancillary objects from either of the primary or ancillary objects. The following example illustrates the underlying implementation of ancillary objects. An ancillary object is created by adding the -z ancillary command line option to an otherwise normal compilation. The file utility shows that the result is an executable named a.out, and an associated ancillary object named a.out.anc. $ cat hello.c #include <stdio.h> int main(int argc, char **argv) { (void) printf("hello, world\n"); return (0); } $ cc -g -zancillary hello.c $ file a.out a.out.anc a.out: ELF 32-bit LSB executable 80386 Version 1 [FPU], dynamically linked, not stripped, ancillary object a.out.anc a.out.anc: ELF 32-bit LSB ancillary 80386 Version 1, primary object a.out $ ./a.out hello worldThe resulting primary object is an ordinary executable that can be executed in the usual manner. It is no different at runtime than an executable built without the use of ancillary objects, and then stripped of non-allocable content using the strip or mcs commands. As previously described, the primary object and ancillary objects contain the same section headers. To see how this works, it is helpful to use the elfdump utility to display these section headers and compare them. The following table shows the section header information for a selection of headers from the previous link-edit example. Index Section Name Type Primary Flags Ancillary Flags Primary Size Ancillary Size 13 .text PROGBITS ALLOC EXECINSTR ALLOC EXECINSTR SUNW_ABSENT 0x131 0 20 .data PROGBITS WRITE ALLOC WRITE ALLOC SUNW_ABSENT 0x4c 0 21 .symtab SYMTAB 0 0 0x450 0x450 22 .strtab STRTAB STRINGS STRINGS 0x1ad 0x1ad 24 .debug_info PROGBITS SUNW_ABSENT 0 0 0x1a7 28 .shstrtab STRTAB STRINGS STRINGS 0x118 0x118 29 .SUNW_ancillary SUNW_ancillary 0 0 0x30 0x30 The data for most sections is only present in one of the two files, and absent from the other file. The SHF_SUNW_ABSENT section header flag is set when the data is absent. The data for allocable sections needed at runtime are found in the primary object. The data for non-allocable sections used for debugging but not needed at runtime are placed in the ancillary file. A small set of non-allocable sections are fully present in both files. These are the .SUNW_ancillary section used to relate the primary and ancillary objects together, the section name string table .shstrtab, as well as the symbol table.symtab, and its associated string table .strtab. It is possible to strip the symbol table from the primary object. A debugger that encounters an object without a symbol table can use the .SUNW_ancillary section to locate the ancillary object, and access the symbol contained within. The primary object, and all associated ancillary objects, contain a .SUNW_ancillary section that allows all the objects to be identified and related together. $ elfdump -T SUNW_ancillary a.out a.out.anc a.out: Ancillary Section: .SUNW_ancillary index tag value [0] ANC_SUNW_CHECKSUM 0x8724 [1] ANC_SUNW_MEMBER 0x1 a.out [2] ANC_SUNW_CHECKSUM 0x8724 [3] ANC_SUNW_MEMBER 0x1a3 a.out.anc [4] ANC_SUNW_CHECKSUM 0xfbe2 [5] ANC_SUNW_NULL 0 a.out.anc: Ancillary Section: .SUNW_ancillary index tag value [0] ANC_SUNW_CHECKSUM 0xfbe2 [1] ANC_SUNW_MEMBER 0x1 a.out [2] ANC_SUNW_CHECKSUM 0x8724 [3] ANC_SUNW_MEMBER 0x1a3 a.out.anc [4] ANC_SUNW_CHECKSUM 0xfbe2 [5] ANC_SUNW_NULL 0 The ancillary sections for both objects contain the same number of elements, and are identical except for the first element. Each object, starting with the primary object, is introduced with a MEMBER element that gives the file name, followed by a CHECKSUM that identifies the object. In this example, the primary object is a.out, and has a checksum of 0x8724. The ancillary object is a.out.anc, and has a checksum of 0xfbe2. The first element in a .SUNW_ancillary section, preceding the MEMBER element for the primary object, is always a CHECKSUM element, containing the checksum for the file being examined. The presence of a .SUNW_ancillary section in an object indicates that the object has associated ancillary objects. The names of the primary and all associated ancillary objects can be obtained from the ancillary section from any one of the files. It is possible to determine which file is being examined from the larger set of files by comparing the first checksum value to the checksum of each member that follows. Debugger Access and Use of Ancillary Objects Debuggers and other observability tools must merge the information found in the primary and ancillary object files in order to build a complete view of the object. This is equivalent to processing the information from a single file. This merging is simplified by the primary object and ancillary objects containing the same section headers, and a single symbol table. The following steps can be used by a debugger to assemble the information contained in these files. Starting with the primary object, or any of the ancillary objects, locate the .SUNW_ancillary section. The presence of this section identifies the object as part of an ancillary group, contains information that can be used to obtain a complete list of the files and determine which of those files is the one currently being examined. Create a section header array in memory, using the section header array from the object being examined as an initial template. Open and read each file identified by the .SUNW_ancillary section in turn. For each file, fill in the in-memory section header array with the information for each section that does not have the SHF_SUNW_ABSENT flag set. The result will be a complete in-memory copy of the section headers with pointers to the data for all sections. Once this information has been acquired, the debugger can proceed as it would in the single file case, to access and control the running program. Note - The ELF definition of ancillary objects provides for a single primary object, and an arbitrary number of ancillary objects. At this time, the Oracle Solaris link-editor only produces a single ancillary object containing all non-allocable sections. This may change in the future. Debuggers and other observability tools should be written to handle the general case of multiple ancillary objects. ELF Implementation Details (From the Solaris Linker and Libraries Guide) To implement ancillary objects, it was necessary to extend the ELF format to add a new object type (ET_SUNW_ANCILLARY), a new section type (SHT_SUNW_ANCILLARY), and 2 new section header flags (SHF_SUNW_ABSENT, SHF_SUNW_PRIMARY). In this section, I will detail these changes, in the form of diffs to the Solaris Linker and Libraries manual. Part IV ELF Application Binary Interface Chapter 13: Object File Format Object File Format Edit Note: This existing section at the beginning of the chapter describes the ELF header. There's a table of object file types, which now includes the new ET_SUNW_ANCILLARY type. e_type Identifies the object file type, as listed in the following table. NameValueMeaning ET_NONE0No file type ET_REL1Relocatable file ET_EXEC2Executable file ET_DYN3Shared object file ET_CORE4Core file ET_LOSUNW0xfefeStart operating system specific range ET_SUNW_ANCILLARY0xfefeAncillary object file ET_HISUNW0xfefdEnd operating system specific range ET_LOPROC0xff00Start processor-specific range ET_HIPROC0xffffEnd processor-specific range Sections Edit Note: This overview section defines the section header structure, and provides a high level description of known sections. It was updated to define the new SHF_SUNW_ABSENT and SHF_SUNW_PRIMARY flags and the new SHT_SUNW_ANCILLARY section. ... sh_type Categorizes the section's contents and semantics. Section types and their descriptions are listed in Table 13-5. sh_flags Sections support 1-bit flags that describe miscellaneous attributes. Flag definitions are listed in Table 13-8. ... Table 13-5 ELF Section Types, sh_type NameValue . . . SHT_LOSUNW0x6fffffee SHT_SUNW_ancillary0x6fffffee . . . ... SHT_LOSUNW - SHT_HISUNW Values in this inclusive range are reserved for Oracle Solaris OS semantics. SHT_SUNW_ANCILLARY Present when a given object is part of a group of ancillary objects. Contains information required to identify all the files that make up the group. See Ancillary Section. ... Table 13-8 ELF Section Attribute Flags NameValue . . . SHF_MASKOS0x0ff00000 SHF_SUNW_NODISCARD0x00100000 SHF_SUNW_ABSENT0x00200000 SHF_SUNW_PRIMARY0x00400000 SHF_MASKPROC0xf0000000 . . . ... SHF_SUNW_ABSENT Indicates that the data for this section is not present in this file. When ancillary objects are created, the primary object and any ancillary objects, will all have the same section header array, to facilitate merging them to form a complete view of the object, and to allow them to use the same symbol tables. Each file contains a subset of the section data. The data for allocable sections is written to the primary object while the data for non-allocable sections is written to an ancillary file. The SHF_SUNW_ABSENT flag is used to indicate that the data for the section is not present in the object being examined. When the SHF_SUNW_ABSENT flag is set, the sh_size field of the section header must be 0. An application encountering an SHF_SUNW_ABSENT section can choose to ignore the section, or to search for the section data within one of the related ancillary files. SHF_SUNW_PRIMARY The default behavior when ancillary objects are created is to write all allocable sections to the primary object and all non-allocable sections to the ancillary objects. The SHF_SUNW_PRIMARY flag overrides this behavior. Any output section containing one more input section with the SHF_SUNW_PRIMARY flag set is written to the primary object without regard for its allocable status. ... Two members in the section header, sh_link, and sh_info, hold special information, depending on section type. Table 13-9 ELF sh_link and sh_info Interpretation sh_typesh_linksh_info . . . SHT_SUNW_ANCILLARY The section header index of the associated string table. 0 . . . Special Sections Edit Note: This section describes the sections used in Solaris ELF objects, using the types defined in the previous description of section types. It was updated to define the new .SUNW_ancillary (SHT_SUNW_ANCILLARY) section. Various sections hold program and control information. Sections in the following table are used by the system and have the indicated types and attributes. Table 13-10 ELF Special Sections NameTypeAttribute . . . .SUNW_ancillarySHT_SUNW_ancillaryNone . . . ... .SUNW_ancillary Present when a given object is part of a group of ancillary objects. Contains information required to identify all the files that make up the group. See Ancillary Section for details. ... Ancillary Section Edit Note: This new section provides the format reference describing the layout of a .SUNW_ancillary section and the meaning of the various tags. Note that these sections use the same tag/value concept used for dynamic and capabilities sections, and will be familiar to anyone used to working with ELF. In addition to the primary output object, the Solaris link-editor can produce one or more ancillary objects. Ancillary objects contain non-allocable sections that would normally be written to the primary object. When ancillary objects are produced, the primary object and all of the associated ancillary objects contain a SHT_SUNW_ancillary section, containing information that identifies these related objects. Given any one object from such a group, the ancillary section provides the information needed to identify and interpret the others. This section contains an array of the following structures. See sys/elf.h. typedef struct { Elf32_Word a_tag; union { Elf32_Word a_val; Elf32_Addr a_ptr; } a_un; } Elf32_Ancillary; typedef struct { Elf64_Xword a_tag; union { Elf64_Xword a_val; Elf64_Addr a_ptr; } a_un; } Elf64_Ancillary; For each object with this type, a_tag controls the interpretation of a_un. a_val These objects represent integer values with various interpretations. a_ptr These objects represent file offsets or addresses. The following ancillary tags exist. Table 13-NEW1 ELF Ancillary Array Tags NameValuea_un ANC_SUNW_NULL0Ignored ANC_SUNW_CHECKSUM1a_val ANC_SUNW_MEMBER2a_ptr ANC_SUNW_NULL Marks the end of the ancillary section. ANC_SUNW_CHECKSUM Provides the checksum for a file in the c_val element. When ANC_SUNW_CHECKSUM precedes the first instance of ANC_SUNW_MEMBER, it provides the checksum for the object from which the ancillary section is being read. When it follows an ANC_SUNW_MEMBER tag, it provides the checksum for that member. ANC_SUNW_MEMBER Specifies an object name. The a_ptr element contains the string table offset of a null-terminated string, that provides the file name. An ancillary section must always contain an ANC_SUNW_CHECKSUM before the first instance of ANC_SUNW_MEMBER, identifying the current object. Following that, there should be an ANC_SUNW_MEMBER for each object that makes up the complete set of objects. Each ANC_SUNW_MEMBER should be followed by an ANC_SUNW_CHECKSUM for that object. A typical ancillary section will therefore be structured as: TagMeaning ANC_SUNW_CHECKSUMChecksum of this object ANC_SUNW_MEMBERName of object #1 ANC_SUNW_CHECKSUMChecksum for object #1 . . . ANC_SUNW_MEMBERName of object N ANC_SUNW_CHECKSUMChecksum for object N ANC_SUNW_NULL An object can therefore identify itself by comparing the initial ANC_SUNW_CHECKSUM to each of the ones that follow, until it finds a match. Related Other Work The GNU developers have also encountered the need/desire to support separate debug information files, and use the solution detailed at http://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html. At the current time, the separate debug file is constructed by building the standard object first, and then copying the debug data out of it in a separate post processing step, Hence, it is limited to a total of 4GB of code and debug data, just as a single object file would be. They are aware of this, and I have seen online comments indicating that they may add direct support for generating these separate files to their link-editor. It is worth noting that the GNU objcopy utility is available on Solaris, and that the Studio dbx debugger is able to use these GNU style separate debug files even on Solaris. Although this is interesting in terms giving Linux users a familiar environment on Solaris, the 4GB limit means it is not an answer to the problem of very large 32-bit objects. We have also encountered issues with objcopy not understanding Solaris-specific ELF sections, when using this approach. The GNU community also has a current effort to adapt their DWARF debug sections in order to move them to separate files before passing the relocatable objects to the linker. The details of Project Fission can be found at http://gcc.gnu.org/wiki/DebugFission. The goal of this project appears to be to reduce the amount of data seen by the link-editor. The primary effort revolves around moving DWARF data to separate .dwo files so that the link-editor never encounters them. The details of modifying the DWARF data to be usable in this form are involved — please see the above URL for details.

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  • XNA Screen Manager problem with transitions

    - by NexAddo
    I'm having issues using the game statemanagement example in the game I am developing. I have no issues with my first three screens transitioning between one another. I have a main menu screen, a splash screen and a high score screen that cycle: mainMenuScreen->splashScreen->highScoreScreen->mainMenuScreen The screens change every 15 seconds. Transition times public MainMenuScreen() { TransitionOnTime = TimeSpan.FromSeconds(0.5); TransitionOffTime = TimeSpan.FromSeconds(0.0); currentCreditAmount = Global.CurrentCredits; } public SplashScreen() { TransitionOnTime = TimeSpan.FromSeconds(0.5); TransitionOffTime = TimeSpan.FromSeconds(0.5); } public HighScoreScreen() { TransitionOnTime = TimeSpan.FromSeconds(0.5); TransitionOffTime = TimeSpan.FromSeconds(0.5); } public GamePlayScreen() { TransitionOnTime = TimeSpan.FromSeconds(0.5); TransitionOffTime = TimeSpan.FromSeconds(0.5); } When a user inserts credits they can play the game after pressing start mainMenuScreen->splashScreen->highScoreScreen->(loops forever) || || || ===========Credits In============= || Start || \/ LoadingScreen || Start || \/ GamePlayScreen During each of these transitions, between screens, the same code is used, which exits(removes) all current active screens and respects transitions, then adds the new screen to the screen manager: foreach (GameScreen screen in ScreenManager.GetScreens()) screen.ExitScreen(); //AddScreen takes a new screen to manage and the controlling player ScreenManager.AddScreen(new NameOfScreenHere(), null); Each screen is removed from the ScreenManager with ExitScreen() and using this function, each screen transition is respected. The problem I am having is with my gamePlayScreen. When the current game is finished and the transition is complete for the gamePlayScreen, it should be removed and the next screens should be added to the ScreenManager. GamePlayScreen Code Snippet private void FinishCurrentGame() { AudioManager.StopSounds(); this.UnloadContent(); if (Global.SaveDevice.IsReady) Stats.Save(); if (HighScoreScreen.IsInHighscores(timeLimit)) { foreach (GameScreen screen in ScreenManager.GetScreens()) screen.ExitScreen(); Global.TimeRemaining = timeLimit; ScreenManager.AddScreen(new BackgroundScreen(), null); ScreenManager.AddScreen(new MessageBoxScreen("Enter your Initials", true), null); } else { foreach (GameScreen screen in ScreenManager.GetScreens()) screen.ExitScreen(); ScreenManager.AddScreen(new BackgroundScreen(), null); ScreenManager.AddScreen(new MainMenuScreen(), null); } } The problem is that when isExiting is set to true by screen.ExitScreen() for the gamePlayScreen, the transition never completes the transition and removes the screen from the ScreenManager. Every other screen that I use the same technique to add and remove each screen fully transitions On/Off and is removed at the appropriate time from the ScreenManager, but noy my GamePlayScreen. Has anyone that has used the GameStateManagement example experienced this issue or can someone see the mistake I am making? EDIT This is what I tracked down. When the game is done, I call foreach (GameScreen screen in ScreenManager.GetScreens()) screen.ExitScreen(); to start the transition off process for the gameplay screen. At this point there is only 1 screen on the ScreenManager stack. The gamePlay screen gets isExiting set to true and starts to transition off. Right after the above call to ExitScreen() I add a background screen and menu screen to the screenManager: ScreenManager.AddScreen(new background(), null); ScreenManager.AddScreen(new Menu(), null); The count of the ScreenManager is now 3. What I noticed while stepping through the updates for GameScreen and ScreenManager, the gameplay screen never gets to the point where the transistion process finishes so the ScreenManager can remove it from the stack. This anomaly does not happen to any of my other screens when I switch between them. Screen Manager Code #region File Description //----------------------------------------------------------------------------- // ScreenManager.cs // // Microsoft XNA Community Game Platform // Copyright (C) Microsoft Corporation. All rights reserved. //----------------------------------------------------------------------------- #endregion #define DEMO #region Using Statements using System; using System.Diagnostics; using System.Collections.Generic; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.Graphics; using PerformanceUtility.GameDebugTools; #endregion namespace GameStateManagement { /// <summary> /// The screen manager is a component which manages one or more GameScreen /// instances. It maintains a stack of screens, calls their Update and Draw /// methods at the appropriate times, and automatically routes input to the /// topmost active screen. /// </summary> public class ScreenManager : DrawableGameComponent { #region Fields List<GameScreen> screens = new List<GameScreen>(); List<GameScreen> screensToUpdate = new List<GameScreen>(); InputState input = new InputState(); SpriteBatch spriteBatch; SpriteFont font; Texture2D blankTexture; bool isInitialized; bool getOut; bool traceEnabled; #if DEBUG DebugSystem debugSystem; Stopwatch stopwatch = new Stopwatch(); bool debugTextEnabled; #endif #endregion #region Properties /// <summary> /// A default SpriteBatch shared by all the screens. This saves /// each screen having to bother creating their own local instance. /// </summary> public SpriteBatch SpriteBatch { get { return spriteBatch; } } /// <summary> /// A default font shared by all the screens. This saves /// each screen having to bother loading their own local copy. /// </summary> public SpriteFont Font { get { return font; } } public Rectangle ScreenRectangle { get { return new Rectangle(0, 0, GraphicsDevice.Viewport.Width, GraphicsDevice.Viewport.Height); } } /// <summary> /// If true, the manager prints out a list of all the screens /// each time it is updated. This can be useful for making sure /// everything is being added and removed at the right times. /// </summary> public bool TraceEnabled { get { return traceEnabled; } set { traceEnabled = value; } } #if DEBUG public bool DebugTextEnabled { get { return debugTextEnabled; } set { debugTextEnabled = value; } } public DebugSystem DebugSystem { get { return debugSystem; } } #endif #endregion #region Initialization /// <summary> /// Constructs a new screen manager component. /// </summary> public ScreenManager(Game game) : base(game) { // we must set EnabledGestures before we can query for them, but // we don't assume the game wants to read them. //TouchPanel.EnabledGestures = GestureType.None; } /// <summary> /// Initializes the screen manager component. /// </summary> public override void Initialize() { base.Initialize(); #if DEBUG debugSystem = DebugSystem.Initialize(Game, "Fonts/MenuFont"); #endif isInitialized = true; } /// <summary> /// Load your graphics content. /// </summary> protected override void LoadContent() { // Load content belonging to the screen manager. ContentManager content = Game.Content; spriteBatch = new SpriteBatch(GraphicsDevice); font = content.Load<SpriteFont>(@"Fonts\menufont"); blankTexture = content.Load<Texture2D>(@"Textures\Backgrounds\blank"); // Tell each of the screens to load their content. foreach (GameScreen screen in screens) { screen.LoadContent(); } } /// <summary> /// Unload your graphics content. /// </summary> protected override void UnloadContent() { // Tell each of the screens to unload their content. foreach (GameScreen screen in screens) { screen.UnloadContent(); } } #endregion #region Update and Draw /// <summary> /// Allows each screen to run logic. /// </summary> public override void Update(GameTime gameTime) { #if DEBUG debugSystem.TimeRuler.StartFrame(); debugSystem.TimeRuler.BeginMark("Update", Color.Blue); if (debugTextEnabled && getOut == false) { debugSystem.FpsCounter.Visible = true; debugSystem.TimeRuler.Visible = true; debugSystem.TimeRuler.ShowLog = true; getOut = true; } else if (debugTextEnabled == false) { getOut = false; debugSystem.FpsCounter.Visible = false; debugSystem.TimeRuler.Visible = false; debugSystem.TimeRuler.ShowLog = false; } #endif // Read the keyboard and gamepad. input.Update(); // Make a copy of the master screen list, to avoid confusion if // the process of updating one screen adds or removes others. screensToUpdate.Clear(); foreach (GameScreen screen in screens) screensToUpdate.Add(screen); bool otherScreenHasFocus = !Game.IsActive; bool coveredByOtherScreen = false; // Loop as long as there are screens waiting to be updated. while (screensToUpdate.Count > 0) { // Pop the topmost screen off the waiting list. GameScreen screen = screensToUpdate[screensToUpdate.Count - 1]; screensToUpdate.RemoveAt(screensToUpdate.Count - 1); // Update the screen. screen.Update(gameTime, otherScreenHasFocus, coveredByOtherScreen); if (screen.ScreenState == ScreenState.TransitionOn || screen.ScreenState == ScreenState.Active) { // If this is the first active screen we came across, // give it a chance to handle input. if (!otherScreenHasFocus) { screen.HandleInput(input); otherScreenHasFocus = true; } // If this is an active non-popup, inform any subsequent // screens that they are covered by it. if (!screen.IsPopup) coveredByOtherScreen = true; } } // Print debug trace? if (traceEnabled) TraceScreens(); #if DEBUG debugSystem.TimeRuler.EndMark("Update"); #endif } /// <summary> /// Prints a list of all the screens, for debugging. /// </summary> void TraceScreens() { List<string> screenNames = new List<string>(); foreach (GameScreen screen in screens) screenNames.Add(screen.GetType().Name); Debug.WriteLine(string.Join(", ", screenNames.ToArray())); } /// <summary> /// Tells each screen to draw itself. /// </summary> public override void Draw(GameTime gameTime) { #if DEBUG debugSystem.TimeRuler.StartFrame(); debugSystem.TimeRuler.BeginMark("Draw", Color.Yellow); #endif foreach (GameScreen screen in screens) { if (screen.ScreenState == ScreenState.Hidden) continue; screen.Draw(gameTime); } #if DEBUG debugSystem.TimeRuler.EndMark("Draw"); #endif #if DEMO SpriteBatch.Begin(); SpriteBatch.DrawString(font, "DEMO - NOT FOR RESALE", new Vector2(20, 80), Color.White); SpriteBatch.End(); #endif } #endregion #region Public Methods /// <summary> /// Adds a new screen to the screen manager. /// </summary> public void AddScreen(GameScreen screen, PlayerIndex? controllingPlayer) { screen.ControllingPlayer = controllingPlayer; screen.ScreenManager = this; screen.IsExiting = false; // If we have a graphics device, tell the screen to load content. if (isInitialized) { screen.LoadContent(); } screens.Add(screen); } /// <summary> /// Removes a screen from the screen manager. You should normally /// use GameScreen.ExitScreen instead of calling this directly, so /// the screen can gradually transition off rather than just being /// instantly removed. /// </summary> public void RemoveScreen(GameScreen screen) { // If we have a graphics device, tell the screen to unload content. if (isInitialized) { screen.UnloadContent(); } screens.Remove(screen); screensToUpdate.Remove(screen); } /// <summary> /// Expose an array holding all the screens. We return a copy rather /// than the real master list, because screens should only ever be added /// or removed using the AddScreen and RemoveScreen methods. /// </summary> public GameScreen[] GetScreens() { return screens.ToArray(); } /// <summary> /// Helper draws a translucent black fullscreen sprite, used for fading /// screens in and out, and for darkening the background behind popups. /// </summary> public void FadeBackBufferToBlack(float alpha) { Viewport viewport = GraphicsDevice.Viewport; spriteBatch.Begin(); spriteBatch.Draw(blankTexture, new Rectangle(0, 0, viewport.Width, viewport.Height), Color.Black * alpha); spriteBatch.End(); } #endregion } } Game Screen Parent of GamePlayScreen #region File Description //----------------------------------------------------------------------------- // GameScreen.cs // // Microsoft XNA Community Game Platform // Copyright (C) Microsoft Corporation. All rights reserved. //----------------------------------------------------------------------------- #endregion #region Using Statements using System; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Input; //using Microsoft.Xna.Framework.Input.Touch; using System.IO; #endregion namespace GameStateManagement { /// <summary> /// Enum describes the screen transition state. /// </summary> public enum ScreenState { TransitionOn, Active, TransitionOff, Hidden, } /// <summary> /// A screen is a single layer that has update and draw logic, and which /// can be combined with other layers to build up a complex menu system. /// For instance the main menu, the options menu, the "are you sure you /// want to quit" message box, and the main game itself are all implemented /// as screens. /// </summary> public abstract class GameScreen { #region Properties /// <summary> /// Normally when one screen is brought up over the top of another, /// the first screen will transition off to make room for the new /// one. This property indicates whether the screen is only a small /// popup, in which case screens underneath it do not need to bother /// transitioning off. /// </summary> public bool IsPopup { get { return isPopup; } protected set { isPopup = value; } } bool isPopup = false; /// <summary> /// Indicates how long the screen takes to /// transition on when it is activated. /// </summary> public TimeSpan TransitionOnTime { get { return transitionOnTime; } protected set { transitionOnTime = value; } } TimeSpan transitionOnTime = TimeSpan.Zero; /// <summary> /// Indicates how long the screen takes to /// transition off when it is deactivated. /// </summary> public TimeSpan TransitionOffTime { get { return transitionOffTime; } protected set { transitionOffTime = value; } } TimeSpan transitionOffTime = TimeSpan.Zero; /// <summary> /// Gets the current position of the screen transition, ranging /// from zero (fully active, no transition) to one (transitioned /// fully off to nothing). /// </summary> public float TransitionPosition { get { return transitionPosition; } protected set { transitionPosition = value; } } float transitionPosition = 1; /// <summary> /// Gets the current alpha of the screen transition, ranging /// from 1 (fully active, no transition) to 0 (transitioned /// fully off to nothing). /// </summary> public float TransitionAlpha { get { return 1f - TransitionPosition; } } /// <summary> /// Gets the current screen transition state. /// </summary> public ScreenState ScreenState { get { return screenState; } protected set { screenState = value; } } ScreenState screenState = ScreenState.TransitionOn; /// <summary> /// There are two possible reasons why a screen might be transitioning /// off. It could be temporarily going away to make room for another /// screen that is on top of it, or it could be going away for good. /// This property indicates whether the screen is exiting for real: /// if set, the screen will automatically remove itself as soon as the /// transition finishes. /// </summary> public bool IsExiting { get { return isExiting; } protected internal set { isExiting = value; } } bool isExiting = false; /// <summary> /// Checks whether this screen is active and can respond to user input. /// </summary> public bool IsActive { get { return !otherScreenHasFocus && (screenState == ScreenState.TransitionOn || screenState == ScreenState.Active); } } bool otherScreenHasFocus; /// <summary> /// Gets the manager that this screen belongs to. /// </summary> public ScreenManager ScreenManager { get { return screenManager; } internal set { screenManager = value; } } ScreenManager screenManager; public KeyboardState KeyboardState { get {return Keyboard.GetState();} } /// <summary> /// Gets the index of the player who is currently controlling this screen, /// or null if it is accepting input from any player. This is used to lock /// the game to a specific player profile. The main menu responds to input /// from any connected gamepad, but whichever player makes a selection from /// this menu is given control over all subsequent screens, so other gamepads /// are inactive until the controlling player returns to the main menu. /// </summary> public PlayerIndex? ControllingPlayer { get { return controllingPlayer; } internal set { controllingPlayer = value; } } PlayerIndex? controllingPlayer; /// <summary> /// Gets whether or not this screen is serializable. If this is true, /// the screen will be recorded into the screen manager's state and /// its Serialize and Deserialize methods will be called as appropriate. /// If this is false, the screen will be ignored during serialization. /// By default, all screens are assumed to be serializable. /// </summary> public bool IsSerializable { get { return isSerializable; } protected set { isSerializable = value; } } bool isSerializable = true; #endregion #region Initialization /// <summary> /// Load graphics content for the screen. /// </summary> public virtual void LoadContent() { } /// <summary> /// Unload content for the screen. /// </summary> public virtual void UnloadContent() { } #endregion #region Update and Draw /// <summary> /// Allows the screen to run logic, such as updating the transition position. /// Unlike HandleInput, this method is called regardless of whether the screen /// is active, hidden, or in the middle of a transition. /// </summary> public virtual void Update(GameTime gameTime, bool otherScreenHasFocus, bool coveredByOtherScreen) { this.otherScreenHasFocus = otherScreenHasFocus; if (isExiting) { // If the screen is going away to die, it should transition off. screenState = ScreenState.TransitionOff; if (!UpdateTransition(gameTime, transitionOffTime, 1)) { // When the transition finishes, remove the screen. ScreenManager.RemoveScreen(this); } } else if (coveredByOtherScreen) { // If the screen is covered by another, it should transition off. if (UpdateTransition(gameTime, transitionOffTime, 1)) { // Still busy transitioning. screenState = ScreenState.TransitionOff; } else { // Transition finished! screenState = ScreenState.Hidden; } } else { // Otherwise the screen should transition on and become active. if (UpdateTransition(gameTime, transitionOnTime, -1)) { // Still busy transitioning. screenState = ScreenState.TransitionOn; } else { // Transition finished! screenState = ScreenState.Active; } } } /// <summary> /// Helper for updating the screen transition position. /// </summary> bool UpdateTransition(GameTime gameTime, TimeSpan time, int direction) { // How much should we move by? float transitionDelta; if (time == TimeSpan.Zero) transitionDelta = 1; else transitionDelta = (float)(gameTime.ElapsedGameTime.TotalMilliseconds / time.TotalMilliseconds); // Update the transition position. transitionPosition += transitionDelta * direction; // Did we reach the end of the transition? if (((direction < 0) && (transitionPosition <= 0)) || ((direction > 0) && (transitionPosition >= 1))) { transitionPosition = MathHelper.Clamp(transitionPosition, 0, 1); return false; } // Otherwise we are still busy transitioning. return true; } /// <summary> /// Allows the screen to handle user input. Unlike Update, this method /// is only called when the screen is active, and not when some other /// screen has taken the focus. /// </summary> public virtual void HandleInput(InputState input) { } public KeyboardState currentKeyState; public KeyboardState lastKeyState; public bool IsKeyHit(Keys key) { if (currentKeyState.IsKeyDown(key) && lastKeyState.IsKeyUp(key)) return true; return false; } /// <summary> /// This is called when the screen should draw itself. /// </summary> public virtual void Draw(GameTime gameTime) { } #endregion #region Public Methods /// <summary> /// Tells the screen to serialize its state into the given stream. /// </summary> public virtual void Serialize(Stream stream) { } /// <summary> /// Tells the screen to deserialize its state from the given stream. /// </summary> public virtual void Deserialize(Stream stream) { } /// <summary> /// Tells the screen to go away. Unlike ScreenManager.RemoveScreen, which /// instantly kills the screen, this method respects the transition timings /// and will give the screen a chance to gradually transition off. /// </summary> public void ExitScreen() { if (TransitionOffTime == TimeSpan.Zero) { // If the screen has a zero transition time, remove it immediately. ScreenManager.RemoveScreen(this); } else { // Otherwise flag that it should transition off and then exit. isExiting = true; } } #endregion #region Helper Methods /// <summary> /// A helper method which loads assets using the screen manager's /// associated game content loader. /// </summary> /// <typeparam name="T">Type of asset.</typeparam> /// <param name="assetName">Asset name, relative to the loader root /// directory, and not including the .xnb extension.</param> /// <returns></returns> public T Load<T>(string assetName) { return ScreenManager.Game.Content.Load<T>(assetName); } #endregion } }

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  • Scaling-out Your Services by Message Bus based WCF Transport Extension &ndash; Part 1 &ndash; Background

    - by Shaun
    Cloud computing gives us more flexibility on the computing resource, we can provision and deploy an application or service with multiple instances over multiple machines. With the increment of the service instances, how to balance the incoming message and workload would become a new challenge. Currently there are two approaches we can use to pass the incoming messages to the service instances, I would like call them dispatcher mode and pulling mode.   Dispatcher Mode The dispatcher mode introduces a role which takes the responsible to find the best service instance to process the request. The image below describes the sharp of this mode. There are four clients communicate with the service through the underlying transportation. For example, if we are using HTTP the clients might be connecting to the same service URL. On the server side there’s a dispatcher listening on this URL and try to retrieve all messages. When a message came in, the dispatcher will find a proper service instance to process it. There are three mechanism to find the instance: Round-robin: Dispatcher will always send the message to the next instance. For example, if the dispatcher sent the message to instance 2, then the next message will be sent to instance 3, regardless if instance 3 is busy or not at that moment. Random: Dispatcher will find a service instance randomly, and same as the round-robin mode it regardless if the instance is busy or not. Sticky: Dispatcher will send all related messages to the same service instance. This approach always being used if the service methods are state-ful or session-ful. But as you can see, all of these approaches are not really load balanced. The clients will send messages at any time, and each message might take different process duration on the server side. This means in some cases, some of the service instances are very busy while others are almost idle. For example, if we were using round-robin mode, it could be happened that most of the simple task messages were passed to instance 1 while the complex ones were sent to instance 3, even though instance 1 should be idle. This brings some problem in our architecture. The first one is that, the response to the clients might be longer than it should be. As it’s shown in the figure above, message 6 and 9 can be processed by instance 1 or instance 2, but in reality they were dispatched to the busy instance 3 since the dispatcher and round-robin mode. Secondly, if there are many requests came from the clients in a very short period, service instances might be filled by tons of pending tasks and some instances might be crashed. Third, if we are using some cloud platform to host our service instances, for example the Windows Azure, the computing resource is billed by service deployment period instead of the actual CPU usage. This means if any service instance is idle it is wasting our money! Last one, the dispatcher would be the bottleneck of our system since all incoming messages must be routed by the dispatcher. If we are using HTTP or TCP as the transport, the dispatcher would be a network load balance. If we wants more capacity, we have to scale-up, or buy a hardware load balance which is very expensive, as well as scaling-out the service instances. Pulling Mode Pulling mode doesn’t need a dispatcher to route the messages. All service instances are listening to the same transport and try to retrieve the next proper message to process if they are idle. Since there is no dispatcher in pulling mode, it requires some features on the transportation. The transportation must support multiple client connection and server listening. HTTP and TCP doesn’t allow multiple clients are listening on the same address and port, so it cannot be used in pulling mode directly. All messages in the transportation must be FIFO, which means the old message must be received before the new one. Message selection would be a plus on the transportation. This means both service and client can specify some selection criteria and just receive some specified kinds of messages. This feature is not mandatory but would be very useful when implementing the request reply and duplex WCF channel modes. Otherwise we must have a memory dictionary to store the reply messages. I will explain more about this in the following articles. Message bus, or the message queue would be best candidate as the transportation when using the pulling mode. First, it allows multiple application to listen on the same queue, and it’s FIFO. Some of the message bus also support the message selection, such as TIBCO EMS, RabbitMQ. Some others provide in memory dictionary which can store the reply messages, for example the Redis. The principle of pulling mode is to let the service instances self-managed. This means each instance will try to retrieve the next pending incoming message if they finished the current task. This gives us more benefit and can solve the problems we met with in the dispatcher mode. The incoming message will be received to the best instance to process, which means this will be very balanced. And it will not happen that some instances are busy while other are idle, since the idle one will retrieve more tasks to make them busy. Since all instances are try their best to be busy we can use less instances than dispatcher mode, which more cost effective. Since there’s no dispatcher in the system, there is no bottleneck. When we introduced more service instances, in dispatcher mode we have to change something to let the dispatcher know the new instances. But in pulling mode since all service instance are self-managed, there no extra change at all. If there are many incoming messages, since the message bus can queue them in the transportation, service instances would not be crashed. All above are the benefits using the pulling mode, but it will introduce some problem as well. The process tracking and debugging become more difficult. Since the service instances are self-managed, we cannot know which instance will process the message. So we need more information to support debug and track. Real-time response may not be supported. All service instances will process the next message after the current one has done, if we have some real-time request this may not be a good solution. Compare with the Pros and Cons above, the pulling mode would a better solution for the distributed system architecture. Because what we need more is the scalability, cost-effect and the self-management.   WCF and WCF Transport Extensibility Windows Communication Foundation (WCF) is a framework for building service-oriented applications. In the .NET world WCF is the best way to implement the service. In this series I’m going to demonstrate how to implement the pulling mode on top of a message bus by extending the WCF. I don’t want to deep into every related field in WCF but will highlight its transport extensibility. When we implemented an RPC foundation there are many aspects we need to deal with, for example the message encoding, encryption, authentication and message sending and receiving. In WCF, each aspect is represented by a channel. A message will be passed through all necessary channels and finally send to the underlying transportation. And on the other side the message will be received from the transport and though the same channels until the business logic. This mode is called “Channel Stack” in WCF, and the last channel in the channel stack must always be a transport channel, which takes the responsible for sending and receiving the messages. As we are going to implement the WCF over message bus and implement the pulling mode scaling-out solution, we need to create our own transport channel so that the client and service can exchange messages over our bus. Before we deep into the transport channel, let’s have a look on the message exchange patterns that WCF defines. Message exchange pattern (MEP) defines how client and service exchange the messages over the transportation. WCF defines 3 basic MEPs which are datagram, Request-Reply and Duplex. Datagram: Also known as one-way, or fire-forgot mode. The message sent from the client to the service, and no need any reply from the service. The client doesn’t care about the message result at all. Request-Reply: Very common used pattern. The client send the request message to the service and wait until the reply message comes from the service. Duplex: The client sent message to the service, when the service processing the message it can callback to the client. When callback the service would be like a client while the client would be like a service. In WCF, each MEP represent some channels associated. MEP Channels Datagram IInputChannel, IOutputChannel Request-Reply IRequestChannel, IReplyChannel Duplex IDuplexChannel And the channels are created by ChannelListener on the server side, and ChannelFactory on the client side. The ChannelListener and ChannelFactory are created by the TransportBindingElement. The TransportBindingElement is created by the Binding, which can be defined as a new binding or from a custom binding. For more information about the transport channel mode, please refer to the MSDN document. The figure below shows the transport channel objects when using the request-reply MEP. And this is the datagram MEP. And this is the duplex MEP. After investigated the WCF transport architecture, channel mode and MEP, we finally identified what we should do to extend our message bus based transport layer. They are: Binding: (Optional) Defines the channel elements in the channel stack and added our transport binding element at the bottom of the stack. But we can use the build-in CustomBinding as well. TransportBindingElement: Defines which MEP is supported in our transport and create the related ChannelListener and ChannelFactory. This also defines the scheme of the endpoint if using this transport. ChannelListener: Create the server side channel based on the MEP it’s. We can have one ChannelListener to create channels for all supported MEPs, or we can have ChannelListener for each MEP. In this series I will use the second approach. ChannelFactory: Create the client side channel based on the MEP it’s. We can have one ChannelFactory to create channels for all supported MEPs, or we can have ChannelFactory for each MEP. In this series I will use the second approach. Channels: Based on the MEPs we want to support, we need to implement the channels accordingly. For example, if we want our transport support Request-Reply mode we should implement IRequestChannel and IReplyChannel. In this series I will implement all 3 MEPs listed above one by one. Scaffold: In order to make our transport extension works we also need to implement some scaffold stuff. For example we need some classes to send and receive message though out message bus. We also need some codes to read and write the WCF message, etc.. These are not necessary but would be very useful in our example.   Message Bus There is only one thing remained before we can begin to implement our scaling-out support WCF transport, which is the message bus. As I mentioned above, the message bus must have some features to fulfill all the WCF MEPs. In my company we will be using TIBCO EMS, which is an enterprise message bus product. And I have said before we can use any message bus production if it’s satisfied with our requests. Here I would like to introduce an interface to separate the message bus from the WCF. This allows us to implement the bus operations by any kinds bus we are going to use. The interface would be like this. 1: public interface IBus : IDisposable 2: { 3: string SendRequest(string message, bool fromClient, string from, string to = null); 4:  5: void SendReply(string message, bool fromClient, string replyTo); 6:  7: BusMessage Receive(bool fromClient, string replyTo); 8: } There are only three methods for the bus interface. Let me explain one by one. The SendRequest method takes the responsible for sending the request message into the bus. The parameters description are: message: The WCF message content. fromClient: Indicates if this message was came from the client. from: The channel ID that this message was sent from. The channel ID will be generated when any kinds of channel was created, which will be explained in the following articles. to: The channel ID that this message should be received. In Request-Reply and Duplex MEP this is necessary since the reply message must be received by the channel which sent the related request message. The SendReply method takes the responsible for sending the reply message. It’s very similar as the previous one but no “from” parameter. This is because it’s no need to reply a reply message again in any MEPs. The Receive method takes the responsible for waiting for a incoming message, includes the request message and specified reply message. It returned a BusMessage object, which contains some information about the channel information. The code of the BusMessage class is 1: public class BusMessage 2: { 3: public string MessageID { get; private set; } 4: public string From { get; private set; } 5: public string ReplyTo { get; private set; } 6: public string Content { get; private set; } 7:  8: public BusMessage(string messageId, string fromChannelId, string replyToChannelId, string content) 9: { 10: MessageID = messageId; 11: From = fromChannelId; 12: ReplyTo = replyToChannelId; 13: Content = content; 14: } 15: } Now let’s implement a message bus based on the IBus interface. Since I don’t want you to buy and install the TIBCO EMS or any other message bus products, I will implement an in process memory bus. This bus is only for test and sample purpose. It can only be used if the service and client are in the same process. Very straightforward. 1: public class InProcMessageBus : IBus 2: { 3: private readonly ConcurrentDictionary<Guid, InProcMessageEntity> _queue; 4: private readonly object _lock; 5:  6: public InProcMessageBus() 7: { 8: _queue = new ConcurrentDictionary<Guid, InProcMessageEntity>(); 9: _lock = new object(); 10: } 11:  12: public string SendRequest(string message, bool fromClient, string from, string to = null) 13: { 14: var entity = new InProcMessageEntity(message, fromClient, from, to); 15: _queue.TryAdd(entity.ID, entity); 16: return entity.ID.ToString(); 17: } 18:  19: public void SendReply(string message, bool fromClient, string replyTo) 20: { 21: var entity = new InProcMessageEntity(message, fromClient, null, replyTo); 22: _queue.TryAdd(entity.ID, entity); 23: } 24:  25: public BusMessage Receive(bool fromClient, string replyTo) 26: { 27: InProcMessageEntity e = null; 28: while (true) 29: { 30: lock (_lock) 31: { 32: var entity = _queue 33: .Where(kvp => kvp.Value.FromClient == fromClient && (kvp.Value.To == replyTo || string.IsNullOrWhiteSpace(kvp.Value.To))) 34: .FirstOrDefault(); 35: if (entity.Key != Guid.Empty && entity.Value != null) 36: { 37: _queue.TryRemove(entity.Key, out e); 38: } 39: } 40: if (e == null) 41: { 42: Thread.Sleep(100); 43: } 44: else 45: { 46: return new BusMessage(e.ID.ToString(), e.From, e.To, e.Content); 47: } 48: } 49: } 50:  51: public void Dispose() 52: { 53: } 54: } The InProcMessageBus stores the messages in the objects of InProcMessageEntity, which can take some extra information beside the WCF message itself. 1: public class InProcMessageEntity 2: { 3: public Guid ID { get; set; } 4: public string Content { get; set; } 5: public bool FromClient { get; set; } 6: public string From { get; set; } 7: public string To { get; set; } 8:  9: public InProcMessageEntity() 10: : this(string.Empty, false, string.Empty, string.Empty) 11: { 12: } 13:  14: public InProcMessageEntity(string content, bool fromClient, string from, string to) 15: { 16: ID = Guid.NewGuid(); 17: Content = content; 18: FromClient = fromClient; 19: From = from; 20: To = to; 21: } 22: }   Summary OK, now I have all necessary stuff ready. The next step would be implementing our WCF message bus transport extension. In this post I described two scaling-out approaches on the service side especially if we are using the cloud platform: dispatcher mode and pulling mode. And I compared the Pros and Cons of them. Then I introduced the WCF channel stack, channel mode and the transport extension part, and identified what we should do to create our own WCF transport extension, to let our WCF services using pulling mode based on a message bus. And finally I provided some classes that need to be used in the future posts that working against an in process memory message bus, for the demonstration purpose only. In the next post I will begin to implement the transport extension step by step.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • Security Issues with Single Page Apps

    - by Stephen.Walther
    Last week, I was asked to do a code review of a Single Page App built using the ASP.NET Web API, Durandal, and Knockout (good stuff!). In particular, I was asked to investigate whether there any special security issues associated with building a Single Page App which are not present in the case of a traditional server-side ASP.NET application. In this blog entry, I discuss two areas in which you need to exercise extra caution when building a Single Page App. I discuss how Single Page Apps are extra vulnerable to both Cross-Site Scripting (XSS) attacks and Cross-Site Request Forgery (CSRF) attacks. This goal of this blog post is NOT to persuade you to avoid writing Single Page Apps. I’m a big fan of Single Page Apps. Instead, the goal is to ensure that you are fully aware of some of the security issues related to Single Page Apps and ensure that you know how to guard against them. Cross-Site Scripting (XSS) Attacks According to WhiteHat Security, over 65% of public websites are open to XSS attacks. That’s bad. By taking advantage of XSS holes in a website, a hacker can steal your credit cards, passwords, or bank account information. Any website that redisplays untrusted information is open to XSS attacks. Let me give you a simple example. Imagine that you want to display the name of the current user on a page. To do this, you create the following server-side ASP.NET page located at http://MajorBank.com/SomePage.aspx: <%@Page Language="C#" %> <html> <head> <title>Some Page</title> </head> <body> Welcome <%= Request["username"] %> </body> </html> Nothing fancy here. Notice that the page displays the current username by using Request[“username”]. Using Request[“username”] displays the username regardless of whether the username is present in a cookie, a form field, or a query string variable. Unfortunately, by using Request[“username”] to redisplay untrusted information, you have now opened your website to XSS attacks. Here’s how. Imagine that an evil hacker creates the following link on another website (hackers.com): <a href="/SomePage.aspx?username=<script src=Evil.js></script>">Visit MajorBank</a> Notice that the link includes a query string variable named username and the value of the username variable is an HTML <SCRIPT> tag which points to a JavaScript file named Evil.js. When anyone clicks on the link, the <SCRIPT> tag will be injected into SomePage.aspx and the Evil.js script will be loaded and executed. What can a hacker do in the Evil.js script? Anything the hacker wants. For example, the hacker could display a popup dialog on the MajorBank.com site which asks the user to enter their password. The script could then post the password back to hackers.com and now the evil hacker has your secret password. ASP.NET Web Forms and ASP.NET MVC have two automatic safeguards against this type of attack: Request Validation and Automatic HTML Encoding. Protecting Coming In (Request Validation) In a server-side ASP.NET app, you are protected against the XSS attack described above by a feature named Request Validation. If you attempt to submit “potentially dangerous” content — such as a JavaScript <SCRIPT> tag — in a form field or query string variable then you get an exception. Unfortunately, Request Validation only applies to server-side apps. Request Validation does not help in the case of a Single Page App. In particular, the ASP.NET Web API does not pay attention to Request Validation. You can post any content you want – including <SCRIPT> tags – to an ASP.NET Web API action. For example, the following HTML page contains a form. When you submit the form, the form data is submitted to an ASP.NET Web API controller on the server using an Ajax request: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> </head> <body> <form data-bind="submit:submit"> <div> <label> User Name: <input data-bind="value:user.userName" /> </label> </div> <div> <label> Email: <input data-bind="value:user.email" /> </label> </div> <div> <input type="submit" value="Submit" /> </div> </form> <script src="Scripts/jquery-1.7.1.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { user: { userName: ko.observable(), email: ko.observable() }, submit: function () { $.post("/api/users", ko.toJS(this.user)); } }; ko.applyBindings(viewModel); </script> </body> </html> The form above is using Knockout to bind the form fields to a view model. When you submit the form, the view model is submitted to an ASP.NET Web API action on the server. Here’s the server-side ASP.NET Web API controller and model class: public class UsersController : ApiController { public HttpResponseMessage Post(UserViewModel user) { var userName = user.UserName; return Request.CreateResponse(HttpStatusCode.OK); } } public class UserViewModel { public string UserName { get; set; } public string Email { get; set; } } If you submit the HTML form, you don’t get an error. The “potentially dangerous” content is passed to the server without any exception being thrown. In the screenshot below, you can see that I was able to post a username form field with the value “<script>alert(‘boo’)</script”. So what this means is that you do not get automatic Request Validation in the case of a Single Page App. You need to be extra careful in a Single Page App about ensuring that you do not display untrusted content because you don’t have the Request Validation safety net which you have in a traditional server-side ASP.NET app. Protecting Going Out (Automatic HTML Encoding) Server-side ASP.NET also protects you from XSS attacks when you render content. By default, all content rendered by the razor view engine is HTML encoded. For example, the following razor view displays the text “<b>Hello!</b>” instead of the text “Hello!” in bold: @{ var message = "<b>Hello!</b>"; } @message   If you don’t want to render content as HTML encoded in razor then you need to take the extra step of using the @Html.Raw() helper. In a Web Form page, if you use <%: %> instead of <%= %> then you get automatic HTML Encoding: <%@ Page Language="C#" %> <% var message = "<b>Hello!</b>"; %> <%: message %> This automatic HTML Encoding will prevent many types of XSS attacks. It prevents <script> tags from being rendered and only allows &lt;script&gt; tags to be rendered which are useless for executing JavaScript. (This automatic HTML encoding does not protect you from all forms of XSS attacks. For example, you can assign the value “javascript:alert(‘evil’)” to the Hyperlink control’s NavigateUrl property and execute the JavaScript). The situation with Knockout is more complicated. If you use the Knockout TEXT binding then you get HTML encoded content. On the other hand, if you use the HTML binding then you do not: <!-- This JavaScript DOES NOT execute --> <div data-bind="text:someProp"></div> <!-- This Javacript DOES execute --> <div data-bind="html:someProp"></div> <script src="Scripts/jquery-1.7.1.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { someProp : "<script>alert('Evil!')<" + "/script>" }; ko.applyBindings(viewModel); </script>   So, in the page above, the DIV element which uses the TEXT binding is safe from XSS attacks. According to the Knockout documentation: “Since this binding sets your text value using a text node, it’s safe to set any string value without risking HTML or script injection.” Just like server-side HTML encoding, Knockout does not protect you from all types of XSS attacks. For example, there is nothing in Knockout which prevents you from binding JavaScript to a hyperlink like this: <a data-bind="attr:{href:homePageUrl}">Go</a> <script src="Scripts/jquery-1.7.1.min.js"></script> <script src="Scripts/knockout-2.1.0.js"></script> <script> var viewModel = { homePageUrl: "javascript:alert('evil!')" }; ko.applyBindings(viewModel); </script> In the page above, the value “javascript:alert(‘evil’)” is bound to the HREF attribute using Knockout. When you click the link, the JavaScript executes. Cross-Site Request Forgery (CSRF) Attacks Cross-Site Request Forgery (CSRF) attacks rely on the fact that a session cookie does not expire until you close your browser. In particular, if you visit and login to MajorBank.com and then you navigate to Hackers.com then you will still be authenticated against MajorBank.com even after you navigate to Hackers.com. Because MajorBank.com cannot tell whether a request is coming from MajorBank.com or Hackers.com, Hackers.com can submit requests to MajorBank.com pretending to be you. For example, Hackers.com can post an HTML form from Hackers.com to MajorBank.com and change your email address at MajorBank.com. Hackers.com can post a form to MajorBank.com using your authentication cookie. After your email address has been changed, by using a password reset page at MajorBank.com, a hacker can access your bank account. To prevent CSRF attacks, you need some mechanism for detecting whether a request is coming from a page loaded from your website or whether the request is coming from some other website. The recommended way of preventing Cross-Site Request Forgery attacks is to use the “Synchronizer Token Pattern” as described here: https://www.owasp.org/index.php/Cross-Site_Request_Forgery_%28CSRF%29_Prevention_Cheat_Sheet When using the Synchronizer Token Pattern, you include a hidden input field which contains a random token whenever you display an HTML form. When the user opens the form, you add a cookie to the user’s browser with the same random token. When the user posts the form, you verify that the hidden form token and the cookie token match. Preventing Cross-Site Request Forgery Attacks with ASP.NET MVC ASP.NET gives you a helper and an action filter which you can use to thwart Cross-Site Request Forgery attacks. For example, the following razor form for creating a product shows how you use the @Html.AntiForgeryToken() helper: @model MvcApplication2.Models.Product <h2>Create Product</h2> @using (Html.BeginForm()) { @Html.AntiForgeryToken(); <div> @Html.LabelFor( p => p.Name, "Product Name:") @Html.TextBoxFor( p => p.Name) </div> <div> @Html.LabelFor( p => p.Price, "Product Price:") @Html.TextBoxFor( p => p.Price) </div> <input type="submit" /> } The @Html.AntiForgeryToken() helper generates a random token and assigns a serialized version of the same random token to both a cookie and a hidden form field. (Actually, if you dive into the source code, the AntiForgeryToken() does something a little more complex because it takes advantage of a user’s identity when generating the token). Here’s what the hidden form field looks like: <input name=”__RequestVerificationToken” type=”hidden” value=”NqqZGAmlDHh6fPTNR_mti3nYGUDgpIkCiJHnEEL59S7FNToyyeSo7v4AfzF2i67Cv0qTB1TgmZcqiVtgdkW2NnXgEcBc-iBts0x6WAIShtM1″ /> And here’s what the cookie looks like using the Google Chrome developer toolbar: You use the [ValidateAntiForgeryToken] action filter on the controller action which is the recipient of the form post to validate that the token in the hidden form field matches the token in the cookie. If the tokens don’t match then validation fails and you can’t post the form: public ActionResult Create() { return View(); } [ValidateAntiForgeryToken] [HttpPost] public ActionResult Create(Product productToCreate) { if (ModelState.IsValid) { // save product to db return RedirectToAction("Index"); } return View(); } How does this all work? Let’s imagine that a hacker has copied the Create Product page from MajorBank.com to Hackers.com – the hacker grabs the HTML source and places it at Hackers.com. Now, imagine that the hacker trick you into submitting the Create Product form from Hackers.com to MajorBank.com. You’ll get the following exception: The Cross-Site Request Forgery attack is blocked because the anti-forgery token included in the Create Product form at Hackers.com won’t match the anti-forgery token stored in the cookie in your browser. The tokens were generated at different times for different users so the attack fails. Preventing Cross-Site Request Forgery Attacks with a Single Page App In a Single Page App, you can’t prevent Cross-Site Request Forgery attacks using the same method as a server-side ASP.NET MVC app. In a Single Page App, HTML forms are not generated on the server. Instead, in a Single Page App, forms are loaded dynamically in the browser. Phil Haack has a blog post on this topic where he discusses passing the anti-forgery token in an Ajax header instead of a hidden form field. He also describes how you can create a custom anti-forgery token attribute to compare the token in the Ajax header and the token in the cookie. See: http://haacked.com/archive/2011/10/10/preventing-csrf-with-ajax.aspx Also, take a look at Johan’s update to Phil Haack’s original post: http://johan.driessen.se/posts/Updated-Anti-XSRF-Validation-for-ASP.NET-MVC-4-RC (Other server frameworks such as Rails and Django do something similar. For example, Rails uses an X-CSRF-Token to prevent CSRF attacks which you generate on the server – see http://excid3.com/blog/rails-tip-2-include-csrf-token-with-every-ajax-request/#.UTFtgDDkvL8 ). For example, if you are creating a Durandal app, then you can use the following razor view for your one and only server-side page: @{ Layout = null; } <!DOCTYPE html> <html> <head> <title>Index</title> </head> <body> @Html.AntiForgeryToken() <div id="applicationHost"> Loading app.... </div> @Scripts.Render("~/scripts/vendor") <script type="text/javascript" src="~/App/durandal/amd/require.js" data-main="/App/main"></script> </body> </html> Notice that this page includes a call to @Html.AntiForgeryToken() to generate the anti-forgery token. Then, whenever you make an Ajax request in the Durandal app, you can retrieve the anti-forgery token from the razor view and pass the token as a header: var csrfToken = $("input[name='__RequestVerificationToken']").val(); $.ajax({ headers: { __RequestVerificationToken: csrfToken }, type: "POST", dataType: "json", contentType: 'application/json; charset=utf-8', url: "/api/products", data: JSON.stringify({ name: "Milk", price: 2.33 }), statusCode: { 200: function () { alert("Success!"); } } }); Use the following code to create an action filter which you can use to match the header and cookie tokens: using System.Linq; using System.Net.Http; using System.Web.Helpers; using System.Web.Http.Controllers; namespace MvcApplication2.Infrastructure { public class ValidateAjaxAntiForgeryToken : System.Web.Http.AuthorizeAttribute { protected override bool IsAuthorized(HttpActionContext actionContext) { var headerToken = actionContext .Request .Headers .GetValues("__RequestVerificationToken") .FirstOrDefault(); ; var cookieToken = actionContext .Request .Headers .GetCookies() .Select(c => c[AntiForgeryConfig.CookieName]) .FirstOrDefault(); // check for missing cookie or header if (cookieToken == null || headerToken == null) { return false; } // ensure that the cookie matches the header try { AntiForgery.Validate(cookieToken.Value, headerToken); } catch { return false; } return base.IsAuthorized(actionContext); } } } Notice that the action filter derives from the base AuthorizeAttribute. The ValidateAjaxAntiForgeryToken only works when the user is authenticated and it will not work for anonymous requests. Add the action filter to your ASP.NET Web API controller actions like this: [ValidateAjaxAntiForgeryToken] public HttpResponseMessage PostProduct(Product productToCreate) { // add product to db return Request.CreateResponse(HttpStatusCode.OK); } After you complete these steps, it won’t be possible for a hacker to pretend to be you at Hackers.com and submit a form to MajorBank.com. The header token used in the Ajax request won’t travel to Hackers.com. This approach works, but I am not entirely happy with it. The one thing that I don’t like about this approach is that it creates a hard dependency on using razor. Your single page in your Single Page App must be generated from a server-side razor view. A better solution would be to generate the anti-forgery token in JavaScript. Unfortunately, until all browsers support a way to generate cryptographically strong random numbers – for example, by supporting the window.crypto.getRandomValues() method — there is no good way to generate anti-forgery tokens in JavaScript. So, at least right now, the best solution for generating the tokens is the server-side solution with the (regrettable) dependency on razor. Conclusion The goal of this blog entry was to explore some ways in which you need to handle security differently in the case of a Single Page App than in the case of a traditional server app. In particular, I focused on how to prevent Cross-Site Scripting and Cross-Site Request Forgery attacks in the case of a Single Page App. I want to emphasize that I am not suggesting that Single Page Apps are inherently less secure than server-side apps. Whatever type of web application you build – regardless of whether it is a Single Page App, an ASP.NET MVC app, an ASP.NET Web Forms app, or a Rails app – you must constantly guard against security vulnerabilities.

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  • CodePlex Daily Summary for Wednesday, November 23, 2011

    CodePlex Daily Summary for Wednesday, November 23, 2011Popular ReleasesVisual Leak Detector for Visual C++ 2008/2010: v2.2.1: Enhancements: * strdup and _wcsdup functions support added. * Preliminary support for VS 11 added. Bugs Fixed: * Low performance after upgrading from VLD v2.1. * Memory leaks with static linking fixed (disabled calloc support). * Runtime error R6002 fixed because of wrong memory dump format. * version.h fixed in installer. * Some PVS studio warning fixed.NetSqlAzMan - .NET SQL Authorization Manager: 3.6.0.10: 3.6.0.10 22-Nov-2011 Update: Removed PreEmptive Platform integration (PreEmptive analytics) Removed all PreEmptive attributes Removed PreEmptive.dll assembly references from all projects Added first support to ADAM/AD LDS Thanks to PatBea. Work Item 9775: http://netsqlazman.codeplex.com/workitem/9775Developer Team Article System Management: DTASM v1.3: ?? ??? ???? 3 ????? ???? ???? ????? ??? : - ????? ?????? ????? ???? ?? ??? ???? ????? ?? ??? ? ?? ???? ?????? ???? ?? ???? ????? ?? . - ??? ?? ???? ????? ???? ????? ???? ???? ?? ????? , ?????? ????? ????? ?? ??? . - ??? ??????? ??? ??? ???? ?? ????? ????? ????? .SharePoint 2010 FBA Pack: SharePoint 2010 FBA Pack 1.2.0: Web parts are now fully customizable via html templates (Issue #323) FBA Pack is now completely localizable using resource files. Thank you David Chen for submitting the code as well as Chinese translations of the FBA Pack! The membership request web part now gives the option of having the user enter the password and removing the captcha (Issue # 447) The FBA Pack will now work in a zone that does not have FBA enabled (Another zone must have FBA enabled, and the zone must contain the me...SharePoint 2010 Education Demo Project: Release SharePoint SP1 for Education Solutions: This release includes updates to the Content Packs for SharePoint SP1. All Content Packs have been updated to install successfully under SharePoint SP1SQL Monitor - tracking sql server activities: SQLMon 4.1 alpha 6: 1. improved support for schema 2. added find reference when right click on object list 3. added object rename supportBugNET Issue Tracker: BugNET 0.9.126: First stable release of version 0.9. Upgrades from 0.8 are fully supported and upgrades to future releases will also be supported. This release is now compiled against the .NET 4.0 framework and is a requirement. Because of this the web.config has significantly changed. After upgrading, you will need to configure the authentication settings for user registration and anonymous access again. Please see our installation / upgrade instructions for more details: http://wiki.bugnetproject.c...Anno 2070 Assistant: v0.1.0 (STABLE): Version 0.1.0 Features Production Chains Eco Production Chains (Complete) Tycoon Production Chains (Disabled - Incomplete) Tech Production Chains (Disabled - Incomplete) Supply (Disabled - Incomplete) Calculator (Disabled - Incomplete) Building Layouts Eco Building Layouts (Complete) Tycoon Building Layouts (Disabled - Incomplete) Tech Building Layouts (Disabled - Incomplete) Credits (Complete)Free SharePoint 2010 Sites Templates: SharePoint Server 2010 Sites Templates: here is the list of sites templates to be downloadedVsTortoise - a TortoiseSVN add-in for Microsoft Visual Studio: VsTortoise Build 30 Beta: Note: This release does not work with custom VsTortoise toolbars. These get removed every time when you shutdown Visual Studio. (#7940) Build 30 (beta)New: Support for TortoiseSVN 1.7 added. (the download contains both setups, for TortoiseSVN 1.6 and 1.7) New: OpenModifiedDocumentDialog displays conflicted files now. New: OpenModifiedDocument allows to group items by changelist now. Fix: OpenModifiedDocumentDialog caused Visual Studio 2010 to freeze sometimes. Fix: The installer didn...nopCommerce. Open source shopping cart (ASP.NET MVC): nopcommerce 2.30: Highlight features & improvements: • Performance optimization. • Back in stock notifications. • Product special price support. • Catalog mode (based on customer role) To see the full list of fixes and changes please visit the release notes page (http://www.nopCommerce.com/releasenotes.aspx).WPF Converters: WPF Converters V1.2.0.0: support for enumerations, value types, and reference types in the expression converter's equality operators the expression converter now handles DependencyProperty.UnsetValue as argument values correctly (#4062) StyleCop conformance (more or less)Json.NET: Json.NET 4.0 Release 4: Change - JsonTextReader.Culture is now CultureInfo.InvariantCulture by default Change - KeyValurPairConverter no longer cares about the order of the key and value properties Change - Time zone conversions now use new TimeZoneInfo instead of TimeZone Fix - Fixed boolean values sometimes being capitalized when converting to XML Fix - Fixed error when deserializing ConcurrentDictionary Fix - Fixed serializing some Uris returning the incorrect value Fix - Fixed occasional error when...Media Companion: MC 3.423b Weekly: Ensure .NET 4.0 Full Framework is installed. (Available from http://www.microsoft.com/download/en/details.aspx?id=17718) Ensure the NFO ID fix is applied when transitioning from versions prior to 3.416b. (Details here) Replaced 'Rebuild' with 'Refresh' throughout entire code. Rebuild will now be known as Refresh. mc_com.exe has been fully updated TV Show Resolutions... Resolved issue #206 - having to hit save twice when updating runtime manually Shrunk cache size and lowered loading times f...Delta Engine: Delta Engine Beta Preview v0.9.1: v0.9.1 beta release with lots of refactoring, fixes, new samples and support for iOS, Android and WP7 (you need a Marketplace account however). If you want a binary release for the games (like v0.9.0), just say so in the Forum or here and we will quickly prepare one. It is just not much different from v0.9.0, so I left it out this time. See http://DeltaEngine.net/Wiki.Roadmap for details.ASP.net Awesome Samples (Web-Forms): 1.0 samples: Demos and Tutorials for ASP.net Awesome VS2008 are in .NET 3.5 VS2010 are in .NET 4.0 (demos for the ASP.net Awesome jQuery Ajax Controls)SharpMap - Geospatial Application Framework for the CLR: SharpMap-0.9-AnyCPU-Trunk-2011.11.17: This is a build of SharpMap from the 0.9 development trunk as per 2011-11-17 For most applications the AnyCPU release is the recommended, but in case you need an x86 build that is included to. For some dataproviders (GDAL/OGR, SqLite, PostGis) you need to also referense the SharpMap.Extensions assembly For SqlServer Spatial you need to reference the SharpMap.SqlServerSpatial assemblyAJAX Control Toolkit: November 2011 Release: AJAX Control Toolkit Release Notes - November 2011 Release Version 51116November 2011 release of the AJAX Control Toolkit. AJAX Control Toolkit .NET 4 - Binary – AJAX Control Toolkit for .NET 4 and sample site (Recommended). AJAX Control Toolkit .NET 3.5 - Binary – AJAX Control Toolkit for .NET 3.5 and sample site (Recommended). Notes: - The current version of the AJAX Control Toolkit is not compatible with ASP.NET 2.0. The latest version that is compatible with ASP.NET 2.0 can be found h...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.36: Fix for issue #16908: string literals containing ASP.NET replacement syntax fail if the ASP.NET code contains the same character as the string literal delimiter. Also, we shouldn't be changing the delimiter for those literals or combining them with other literals; the developer may have specifically chosen the delimiter used because of possible content inserted by ASP.NET code. This logic is normally off; turn it on via the -aspnet command-line flag (or the Code.Settings.AllowEmbeddedAspNetBl...MVC Controls Toolkit: Mvc Controls Toolkit 1.5.5: Added: Now the DateRanteAttribute accepts complex expressions containing "Now" and "Today" as static minimum and maximum. Menu, MenuFor helpers capable of handling a "currently selected element". The developer can choose between using a standard nested menu based on a standard SimpleMenuItem class or specifying an item template based on a custom class. Added also helpers to build the tree structure containing all data items the menu takes infos from. Improved the pager. Now the developer ...New ProjectsActiveWorlds World Server Admin PowerShell SnapIn: The purpose of this PowerShell SnapIn is to provide a set of tools to administer the world server from PowerShell. It leverages the ActiveWorlds SDK .NET Wrapper to provide this functionality.Aigu: Enter special characters like you would on your mobile phone. For instance, if you want to type 'é', you just hold down 'e' and a menu will appear. Selected the desired character using the arrow keys and press 'enter'. Simple but powerful.Are you workaholic?: Are you a workaholic? Did your Doctor advice you not to stare at the computer monitor for a long time? Then this app is perfectly made for you. It runs in the background, and alerts you to take periodic rests for your eyes and body. What's more, It's open source (MS-PL).ATDIS PoC: privateAuto Version Web Assets: The AVWA project is an HTTP Module written in C# that is designed to allow for versioning of various web assets such as .CSS and .JS files. This allows you to publish new versions of these files without having to force the server or the client browsers to expire cache.Bachelor Thesis Algorithm Test Bed: Algorithm Test Bed for my Bachelor ThesisBase64: Simple application helps converting strings and files from or to Base64 string. You can use any encoding to convert while a sidebar previews decoded string for all other encodings.BoracayExpress: BoracayExpressC++ Framework for Test Driven Development: A testing framework for C++ written in C++.Class2Table: Class2Table aka Entity2Table. Easy tool that allows creation of SQL tables from .Net types.Code for Demos & Experiments: This is where I will post code from demos and presentationsCodeMaker: CodeMaker?????????: 1、?????????? 2、???? 3、????? 4、??Python????????? ConsoleCommand: ConsoleCommand provides certain .Net commands for access from javascript console engines. Included are commands to set the text and background colors, as well as list and extract resources compiled in a .Net dll. Converter: Character code conversion tools ???????? CryptoInator - self contained, self-encrypting, self-decrypting image viewer: Original developed to encrypt and store NemID images in Denmark. DAiBears: Something, something, botDelicious Notify Plugin: Lets you push a blog post straight to Delicious from Live WriterDeveloperFile: Compresses Javascripts using the YUI .NET project. Loops through the root folder and subfolders for files matching the debug extension and creates new files using the release extension. (File extensions must match exactly).DotNetNuke SharePoint File Explorer: A DotNetNuke SharePoint File ExplorerDouban FM: WP7 Douban FM appGame Lib: Game Library is a open-source game library to allow focusing on the fun part of a game. It is developed in C#, but will be ported to C++ and VB.net.Google reader notes to Delicious Export tool (WPF): Google reader discontinued note in reader features. Current google reader allows to export users old notes in JSON format, This App will parse the JSON file & upload it to it delicious , delicious is a good alternative for note in readerHtml Source Transmitter Control: This web control allows getting a source of a web page, that will displayed before submit. So, developer can store a view of the html page, that was before server exception. It helps to reproduce bugs and can be used with other logging systems.Ideopuzzle: A puzzle gameImageShack-Uploader: This project demonstrates how to upload files automated to imageshack.us and other image hosters with C#.Insert Acronym Tags: Lets you insert <acronym> and <abbr> tags into your blog entry more easily.Insert Quick Link: Allows you to paste a link into the Writer window and have the a window similar to the one in Writer where you can change what text is to appear, open in new window, etc.Insert Video Plugin: Allows you to insert a video into a blog entry from a multitude of different sitesIoCWrap: Provides a wrapper to the various IoC container implementations so that it is possible to switch to a different provider without changing any application code.kaveepoj: sharepoint projectKinect Quiz Engine: Fun quiz game for the Kinect.Klaverjas: Test application for testing different new technologies in .NET (WCF, DataServices, C# stuff, Entity...etc.)Man In The Middle: A cyberpunk themed action with puzzle and strategy elements. Made with XNA as part of a game development course at the IT University of Copenhagen by Bo Bendtsen, Jonas Flensbak, Daniel Kromand, Jess Rahbek & Darryl Woodford.MediaSelektor: Simple tool to select mediasMicajah Mindtouch Deki Wiki Copier: Small C# application to move data between 2 Deki Wiki installs or, more importantly, from a wik.is account to a locally installed systemMineFlagger: MineFlagger is a mine clearing game modeled after Microsoft’s Minesweeper. In addition to standard play, MineFlagger incorporates an AI for fun and training.myXbyqwrhjadsfasfhgf: myXbyqwrhjadsfasfhgfnatoop: natoopNauplius.KeyStore: Provides secure application key storage backed by SQL 2008 and Active Directory.ObjectDB: An object database written using C# 4 and Mono.Cecil.PaceR: PaceR is an attempt to encapsulate a lot of the common code functionality I use on different projects. Instead of recreating functionality from memory or worse, copying from older projects, I'd like to have a central location to maintain this common code. Parseq: Parseq is a Parser Combinator library written in C# (version 2.0).PowerShell Network Adapter Configuration module: PowerShell Network Adapter Configuration module is a PowerShell module which provides functions for managing network adapters using WMI.public traffic tracker: This is a university project for a .net course. We develop a public traffic tracker applications for Windows Phone 7 devices, that can give information about the actual positions of the nearest vehicle on a given line. The speciality is that we use only the GPS information of the users' WP7 devices, so this is a completely software solution without any hardware investment. The disatvantage is that for the real operation we would need a lot of active WP7 user.puyo: puyoRadioTroll: Projeto web Radio TrollRead Feed Community: Read Feed CommunityReviewer: Reviewer.dk - Dansk spil og anmeldelsessite.Rollout Sharepoint Solutions - ROSS: ROSS performs the following actions: - Delete sitecollection and restart services - 'Get Latest Version' from SourceSafe - Rebuild Solution - Install all wsp solutions - Create SiteCollections - Check for build en provisioning errors - Send email to developers if errors occurredSchool Management: school managementSQL File Executer: This project is a class library written in c# which is used for executing *.sql files in remote server. Simply one dll file. You include it in your web project, add using statement at the top of your page, pass the parameters inside. Rest, it will do.Startup Manager: Startup Manager launches all startup programs at a managed rate therefore meaning that your computer doesn't crash everytime it starts up and you can use it immediately.stetic: ...Test Infrastructure Guidance: The purpose of this project is to provide guidance to testers in using TFS effectively as an ALM solution. TFS is much more than a simple code repository. Used with Visual Studio it can form a powerful testing solution and remove a lot of pain in dealing with test infrastructure overhead.Tête-à-tête: Tete-a-tete is an address book with a built-in function to send electronic mail over the Internet.Tipeysh! - Add-in that helps you creating C/C++ header files on a single click: Are you also feel miserable when you need to create a new header file in your Visual Studio C/C++ project? Repeatedly choosing "new header file", then writing the annoying (but needed) "#ifndef" section, then writing the class name with it's "private", "protected" and "public" access modifiers... too much clicks and typewriting! Well, there is a solution: Tipeysh! is a simple, easy to use, very handy and configurable Visual Studio Add-In, compatible for both the 2005 and 2008 versions. Once ...UMN Dashboard Project: academic projUsersMOSS: UsersMOSS est une petite application permettant de consulter sur un serveur MOSS les sites web (SPWeb) les users (SPUser), et les groupes (SPGroup). Cette application utilise le modèle objet de MOSS pour inspecter le contenu des objets d'un serveur MOSS. Cette application est loin d'être professionnelle, ou même terminée, mais elle me rend très souvent service. Surtout ne l'utilisez pas sur un serveur de production car le gestion du GC n'est pas faite, ce qui peut provoquer des plantages de v...UtilityLibrary.Win32: UtilityLibrary.Win32UW iLearn: The iLearn activity inference platform is a suite of desktop and mobile tools for logging, modeling, and classifying sensor data for mobile devices. It was created at the University of Washington.VsDocGen: Dynamic javascript documentation generation directly from xml comment documented source code.Windows Live Spaces Photo Album plugin: This is going to be a plugin for Windows Live Writer that will allow you to browse a Windows Live Space Photo Album.Windows Live Writer Plugin for Amazon Books using CueCat: This Windows Live Writer Plugin is for users who use WLW and wish to use their CueCat to scan books. ItemLookups are run against Amazon via its AWS and book image, title, author, and publisher is returned. This project was first created by Scott Hanselman on MSDN's Coding4Fun! X7: X7 makes it easier for win7user to clean the system. You'll no longer have to delete useless stuff in your win7. It's developed in bat.xDT - Commander: Using this application, the user can assign shortcuts (short texts) for various links/URLs. These short texts will be typed into a Textbox to then launch/go to the target (similar to the "Run" program in Windows).

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  • C#/.NET Little Wonders: The ConcurrentDictionary

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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  • Using Stub Objects

    - by user9154181
    Having told the long and winding tale of where stub objects came from and how we use them to build Solaris, I'd like to focus now on the the nuts and bolts of building and using them. The following new features were added to the Solaris link-editor (ld) to support the production and use of stub objects: -z stub This new command line option informs ld that it is to build a stub object rather than a normal object. In this mode, it accepts the same command line arguments as usual, but will quietly ignore any objects and sharable object dependencies. STUB_OBJECT Mapfile Directive In order to build a stub version of an object, its mapfile must specify the STUB_OBJECT directive. When producing a non-stub object, the presence of STUB_OBJECT causes the link-editor to perform extra validation to ensure that the stub and non-stub objects will be compatible. ASSERT Mapfile Directive All data symbols exported from the object must have an ASSERT symbol directive in the mapfile that declares them as data and supplies the size, binding, bss attributes, and symbol aliasing details. When building the stub objects, the information in these ASSERT directives is used to create the data symbols. When building the real object, these ASSERT directives will ensure that the real object matches the linking interface presented by the stub. Although ASSERT was added to the link-editor in order to support stub objects, they are a general purpose feature that can be used independently of stub objects. For instance you might choose to use an ASSERT directive if you have a symbol that must have a specific address in order for the object to operate properly and you want to automatically ensure that this will always be the case. The material presented here is derived from a document I originally wrote during the development effort, which had the dual goals of providing supplemental materials for the stub object PSARC case, and as a set of edits that were eventually applied to the Oracle Solaris Linker and Libraries Manual (LLM). The Solaris 11 LLM contains this information in a more polished form. Stub Objects A stub object is a shared object, built entirely from mapfiles, that supplies the same linking interface as the real object, while containing no code or data. Stub objects cannot be used at runtime. However, an application can be built against a stub object, where the stub object provides the real object name to be used at runtime, and then use the real object at runtime. When building a stub object, the link-editor ignores any object or library files specified on the command line, and these files need not exist in order to build a stub. Since the compilation step can be omitted, and because the link-editor has relatively little work to do, stub objects can be built very quickly. Stub objects can be used to solve a variety of build problems: Speed Modern machines, using a version of make with the ability to parallelize operations, are capable of compiling and linking many objects simultaneously, and doing so offers significant speedups. However, it is typical that a given object will depend on other objects, and that there will be a core set of objects that nearly everything else depends on. It is necessary to impose an ordering that builds each object before any other object that requires it. This ordering creates bottlenecks that reduce the amount of parallelization that is possible and limits the overall speed at which the code can be built. Complexity/Correctness In a large body of code, there can be a large number of dependencies between the various objects. The makefiles or other build descriptions for these objects can become very complex and difficult to understand or maintain. The dependencies can change as the system evolves. This can cause a given set of makefiles to become slightly incorrect over time, leading to race conditions and mysterious rare build failures. Dependency Cycles It might be desirable to organize code as cooperating shared objects, each of which draw on the resources provided by the other. Such cycles cannot be supported in an environment where objects must be built before the objects that use them, even though the runtime linker is fully capable of loading and using such objects if they could be built. Stub shared objects offer an alternative method for building code that sidesteps the above issues. Stub objects can be quickly built for all the shared objects produced by the build. Then, all the real shared objects and executables can be built in parallel, in any order, using the stub objects to stand in for the real objects at link-time. Afterwards, the executables and real shared objects are kept, and the stub shared objects are discarded. Stub objects are built from a mapfile, which must satisfy the following requirements. The mapfile must specify the STUB_OBJECT directive. This directive informs the link-editor that the object can be built as a stub object, and as such causes the link-editor to perform validation and sanity checking intended to guarantee that an object and its stub will always provide identical linking interfaces. All function and data symbols that make up the external interface to the object must be explicitly listed in the mapfile. The mapfile must use symbol scope reduction ('*'), to remove any symbols not explicitly listed from the external interface. All global data exported from the object must have an ASSERT symbol attribute in the mapfile to specify the symbol type, size, and bss attributes. In the case where there are multiple symbols that reference the same data, the ASSERT for one of these symbols must specify the TYPE and SIZE attributes, while the others must use the ALIAS attribute to reference this primary symbol. Given such a mapfile, the stub and real versions of the shared object can be built using the same command line for each, adding the '-z stub' option to the link for the stub object, and omiting the option from the link for the real object. To demonstrate these ideas, the following code implements a shared object named idx5, which exports data from a 5 element array of integers, with each element initialized to contain its zero-based array index. This data is available as a global array, via an alternative alias data symbol with weak binding, and via a functional interface. % cat idx5.c int _idx5[5] = { 0, 1, 2, 3, 4 }; #pragma weak idx5 = _idx5 int idx5_func(int index) { if ((index 4)) return (-1); return (_idx5[index]); } A mapfile is required to describe the interface provided by this shared object. % cat mapfile $mapfile_version 2 STUB_OBJECT; SYMBOL_SCOPE { _idx5 { ASSERT { TYPE=data; SIZE=4[5] }; }; idx5 { ASSERT { BINDING=weak; ALIAS=_idx5 }; }; idx5_func; local: *; }; The following main program is used to print all the index values available from the idx5 shared object. % cat main.c #include <stdio.h> extern int _idx5[5], idx5[5], idx5_func(int); int main(int argc, char **argv) { int i; for (i = 0; i The following commands create a stub version of this shared object in a subdirectory named stublib. elfdump is used to verify that the resulting object is a stub. The command used to build the stub differs from that of the real object only in the addition of the -z stub option, and the use of a different output file name. This demonstrates the ease with which stub generation can be added to an existing makefile. % cc -Kpic -G -M mapfile -h libidx5.so.1 idx5.c -o stublib/libidx5.so.1 -zstub % ln -s libidx5.so.1 stublib/libidx5.so % elfdump -d stublib/libidx5.so | grep STUB [11] FLAGS_1 0x4000000 [ STUB ] The main program can now be built, using the stub object to stand in for the real shared object, and setting a runpath that will find the real object at runtime. However, as we have not yet built the real object, this program cannot yet be run. Attempts to cause the system to load the stub object are rejected, as the runtime linker knows that stub objects lack the actual code and data found in the real object, and cannot execute. % cc main.c -L stublib -R '$ORIGIN/lib' -lidx5 -lc % ./a.out ld.so.1: a.out: fatal: libidx5.so.1: open failed: No such file or directory Killed % LD_PRELOAD=stublib/libidx5.so.1 ./a.out ld.so.1: a.out: fatal: stublib/libidx5.so.1: stub shared object cannot be used at runtime Killed We build the real object using the same command as we used to build the stub, omitting the -z stub option, and writing the results to a different file. % cc -Kpic -G -M mapfile -h libidx5.so.1 idx5.c -o lib/libidx5.so.1 Once the real object has been built in the lib subdirectory, the program can be run. % ./a.out [0] 0 0 0 [1] 1 1 1 [2] 2 2 2 [3] 3 3 3 [4] 4 4 4 Mapfile Changes The version 2 mapfile syntax was extended in a number of places to accommodate stub objects. Conditional Input The version 2 mapfile syntax has the ability conditionalize mapfile input using the $if control directive. As you might imagine, these directives are used frequently with ASSERT directives for data, because a given data symbol will frequently have a different size in 32 or 64-bit code, or on differing hardware such as x86 versus sparc. The link-editor maintains an internal table of names that can be used in the logical expressions evaluated by $if and $elif. At startup, this table is initialized with items that describe the class of object (_ELF32 or _ELF64) and the type of the target machine (_sparc or _x86). We found that there were a small number of cases in the Solaris code base in which we needed to know what kind of object we were producing, so we added the following new predefined items in order to address that need: NameMeaning ...... _ET_DYNshared object _ET_EXECexecutable object _ET_RELrelocatable object ...... STUB_OBJECT Directive The new STUB_OBJECT directive informs the link-editor that the object described by the mapfile can be built as a stub object. STUB_OBJECT; A stub shared object is built entirely from the information in the mapfiles supplied on the command line. When the -z stub option is specified to build a stub object, the presence of the STUB_OBJECT directive in a mapfile is required, and the link-editor uses the information in symbol ASSERT attributes to create global symbols that match those of the real object. When the real object is built, the presence of STUB_OBJECT causes the link-editor to verify that the mapfiles accurately describe the real object interface, and that a stub object built from them will provide the same linking interface as the real object it represents. All function and data symbols that make up the external interface to the object must be explicitly listed in the mapfile. The mapfile must use symbol scope reduction ('*'), to remove any symbols not explicitly listed from the external interface. All global data in the object is required to have an ASSERT attribute that specifies the symbol type and size. If the ASSERT BIND attribute is not present, the link-editor provides a default assertion that the symbol must be GLOBAL. If the ASSERT SH_ATTR attribute is not present, or does not specify that the section is one of BITS or NOBITS, the link-editor provides a default assertion that the associated section is BITS. All data symbols that describe the same address and size are required to have ASSERT ALIAS attributes specified in the mapfile. If aliased symbols are discovered that do not have an ASSERT ALIAS specified, the link fails and no object is produced. These rules ensure that the mapfiles contain a description of the real shared object's linking interface that is sufficient to produce a stub object with a completely compatible linking interface. SYMBOL_SCOPE/SYMBOL_VERSION ASSERT Attribute The SYMBOL_SCOPE and SYMBOL_VERSION mapfile directives were extended with a symbol attribute named ASSERT. The syntax for the ASSERT attribute is as follows: ASSERT { ALIAS = symbol_name; BINDING = symbol_binding; TYPE = symbol_type; SH_ATTR = section_attributes; SIZE = size_value; SIZE = size_value[count]; }; The ASSERT attribute is used to specify the expected characteristics of the symbol. The link-editor compares the symbol characteristics that result from the link to those given by ASSERT attributes. If the real and asserted attributes do not agree, a fatal error is issued and the output object is not created. In normal use, the link editor evaluates the ASSERT attribute when present, but does not require them, or provide default values for them. The presence of the STUB_OBJECT directive in a mapfile alters the interpretation of ASSERT to require them under some circumstances, and to supply default assertions if explicit ones are not present. See the definition of the STUB_OBJECT Directive for the details. When the -z stub command line option is specified to build a stub object, the information provided by ASSERT attributes is used to define the attributes of the global symbols provided by the object. ASSERT accepts the following: ALIAS Name of a previously defined symbol that this symbol is an alias for. An alias symbol has the same type, value, and size as the main symbol. The ALIAS attribute is mutually exclusive to the TYPE, SIZE, and SH_ATTR attributes, and cannot be used with them. When ALIAS is specified, the type, size, and section attributes are obtained from the alias symbol. BIND Specifies an ELF symbol binding, which can be any of the STB_ constants defined in <sys/elf.h>, with the STB_ prefix removed (e.g. GLOBAL, WEAK). TYPE Specifies an ELF symbol type, which can be any of the STT_ constants defined in <sys/elf.h>, with the STT_ prefix removed (e.g. OBJECT, COMMON, FUNC). In addition, for compatibility with other mapfile usage, FUNCTION and DATA can be specified, for STT_FUNC and STT_OBJECT, respectively. TYPE is mutually exclusive to ALIAS, and cannot be used in conjunction with it. SH_ATTR Specifies attributes of the section associated with the symbol. The section_attributes that can be specified are given in the following table: Section AttributeMeaning BITSSection is not of type SHT_NOBITS NOBITSSection is of type SHT_NOBITS SH_ATTR is mutually exclusive to ALIAS, and cannot be used in conjunction with it. SIZE Specifies the expected symbol size. SIZE is mutually exclusive to ALIAS, and cannot be used in conjunction with it. The syntax for the size_value argument is as described in the discussion of the SIZE attribute below. SIZE The SIZE symbol attribute existed before support for stub objects was introduced. It is used to set the size attribute of a given symbol. This attribute results in the creation of a symbol definition. Prior to the introduction of the ASSERT SIZE attribute, the value of a SIZE attribute was always numeric. While attempting to apply ASSERT SIZE to the objects in the Solaris ON consolidation, I found that many data symbols have a size based on the natural machine wordsize for the class of object being produced. Variables declared as long, or as a pointer, will be 4 bytes in size in a 32-bit object, and 8 bytes in a 64-bit object. Initially, I employed the conditional $if directive to handle these cases as follows: $if _ELF32 foo { ASSERT { TYPE=data; SIZE=4 } }; bar { ASSERT { TYPE=data; SIZE=20 } }; $elif _ELF64 foo { ASSERT { TYPE=data; SIZE=8 } }; bar { ASSERT { TYPE=data; SIZE=40 } }; $else $error UNKNOWN ELFCLASS $endif I found that the situation occurs frequently enough that this is cumbersome. To simplify this case, I introduced the idea of the addrsize symbolic name, and of a repeat count, which together make it simple to specify machine word scalar or array symbols. Both the SIZE, and ASSERT SIZE attributes support this syntax: The size_value argument can be a numeric value, or it can be the symbolic name addrsize. addrsize represents the size of a machine word capable of holding a memory address. The link-editor substitutes the value 4 for addrsize when building 32-bit objects, and the value 8 when building 64-bit objects. addrsize is useful for representing the size of pointer variables and C variables of type long, as it automatically adjusts for 32 and 64-bit objects without requiring the use of conditional input. The size_value argument can be optionally suffixed with a count value, enclosed in square brackets. If count is present, size_value and count are multiplied together to obtain the final size value. Using this feature, the example above can be written more naturally as: foo { ASSERT { TYPE=data; SIZE=addrsize } }; bar { ASSERT { TYPE=data; SIZE=addrsize[5] } }; Exported Global Data Is Still A Bad Idea As you can see, the additional plumbing added to the Solaris link-editor to support stub objects is minimal. Furthermore, about 90% of that plumbing is dedicated to handling global data. We have long advised against global data exported from shared objects. There are many ways in which global data does not fit well with dynamic linking. Stub objects simply provide one more reason to avoid this practice. It is always better to export all data via a functional interface. You should always hide your data, and make it available to your users via a function that they can call to acquire the address of the data item. However, If you do have to support global data for a stub, perhaps because you are working with an already existing object, it is still easilily done, as shown above. Oracle does not like us to discuss hypothetical new features that don't exist in shipping product, so I'll end this section with a speculation. It might be possible to do more in this area to ease the difficulty of dealing with objects that have global data that the users of the library don't need. Perhaps someday... Conclusions It is easy to create stub objects for most objects. If your library only exports function symbols, all you have to do to build a faithful stub object is to add STUB_OBJECT; and then to use the same link command you're currently using, with the addition of the -z stub option. Happy Stubbing!

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  • Towards Database Continuous Delivery – What Next after Continuous Integration? A Checklist

    - by Ben Rees
    .dbd-banner p{ font-size:0.75em; padding:0 0 10px; margin:0 } .dbd-banner p span{ color:#675C6D; } .dbd-banner p:last-child{ padding:0; } @media ALL and (max-width:640px){ .dbd-banner{ background:#f0f0f0; padding:5px; color:#333; margin-top: 5px; } } -- Database delivery patterns & practices STAGE 4 AUTOMATED DEPLOYMENT If you’ve been fortunate enough to get to the stage where you’ve implemented some sort of continuous integration process for your database updates, then hopefully you’re seeing the benefits of that investment – constant feedback on changes your devs are making, advanced warning of data loss (prior to the production release on Saturday night!), a nice suite of automated tests to check business logic, so you know it’s going to work when it goes live, and so on. But what next? What can you do to improve your delivery process further, moving towards a full continuous delivery process for your database? In this article I describe some of the issues you might need to tackle on the next stage of this journey, and how to plan to overcome those obstacles before they appear. Our Database Delivery Learning Program consists of four stages, really three – source controlling a database, running continuous integration processes, then how to set up automated deployment (the middle stage is split in two – basic and advanced continuous integration, making four stages in total). If you’ve managed to work through the first three of these stages – source control, basic, then advanced CI, then you should have a solid change management process set up where, every time one of your team checks in a change to your database (whether schema or static reference data), this change gets fully tested automatically by your CI server. But this is only part of the story. Great, we know that our updates work, that the upgrade process works, that the upgrade isn’t going to wipe our 4Tb of production data with a single DROP TABLE. But – how do you get this (fully tested) release live? Continuous delivery means being always ready to release your software at any point in time. There’s a significant gap between your latest version being tested, and it being easily releasable. Just a quick note on terminology – there’s a nice piece here from Atlassian on the difference between continuous integration, continuous delivery and continuous deployment. This piece also gives a nice description of the benefits of continuous delivery. These benefits have been summed up by Jez Humble at Thoughtworks as: “Continuous delivery is a set of principles and practices to reduce the cost, time, and risk of delivering incremental changes to users” There’s another really useful piece here on Simple-Talk about the need for continuous delivery and how it applies to the database written by Phil Factor – specifically the extra needs and complexities of implementing a full CD solution for the database (compared to just implementing CD for, say, a web app). So, hopefully you’re convinced of moving on the the next stage! The next step after CI is to get some sort of automated deployment (or “release management”) process set up. But what should I do next? What do I need to plan and think about for getting my automated database deployment process set up? Can’t I just install one of the many release management tools available and hey presto, I’m ready! If only it were that simple. Below I list some of the areas that it’s worth spending a little time on, where a little planning and prep could go a long way. It’s also worth pointing out, that this should really be an evolving process. Depending on your starting point of course, it can be a long journey from your current setup to a full continuous delivery pipeline. If you’ve got a CI mechanism in place, you’re certainly a long way down that path. Nevertheless, we’d recommend evolving your process incrementally. Pages 157 and 129-141 of the book on Continuous Delivery (by Jez Humble and Dave Farley) have some great guidance on building up a pipeline incrementally: http://www.amazon.com/Continuous-Delivery-Deployment-Automation-Addison-Wesley/dp/0321601912 For now, in this post, we’ll look at the following areas for your checklist: You and Your Team Environments The Deployment Process Rollback and Recovery Development Practices You and Your Team It’s a cliché in the DevOps community that “It’s not all about processes and tools, really it’s all about a culture”. As stated in this DevOps report from Puppet Labs: “DevOps processes and tooling contribute to high performance, but these practices alone aren’t enough to achieve organizational success. The most common barriers to DevOps adoption are cultural: lack of manager or team buy-in, or the value of DevOps isn’t understood outside of a specific group”. Like most clichés, there’s truth in there – if you want to set up a database continuous delivery process, you need to get your boss, your department, your company (if relevant) onside. Why? Because it’s an investment with the benefits coming way down the line. But the benefits are huge – for HP, in the book A Practical Approach to Large-Scale Agile Development: How HP Transformed LaserJet FutureSmart Firmware, these are summarized as: -2008 to present: overall development costs reduced by 40% -Number of programs under development increased by 140% -Development costs per program down 78% -Firmware resources now driving innovation increased by a factor of 8 (from 5% working on new features to 40% But what does this mean? It means that, when moving to the next stage, to make that extra investment in automating your deployment process, it helps a lot if everyone is convinced that this is a good thing. That they understand the benefits of automated deployment and are willing to make the effort to transform to a new way of working. Incidentally, if you’re ever struggling to convince someone of the value I’d strongly recommend just buying them a copy of this book – a great read, and a very practical guide to how it can really work at a large org. I’ve spoken to many customers who have implemented database CI who describe their deployment process as “The point where automation breaks down. Up to that point, the CI process runs, untouched by human hand, but as soon as that’s finished we revert to manual.” This deployment process can involve, for example, a DBA manually comparing an environment (say, QA) to production, creating the upgrade scripts, reading through them, checking them against an Excel document emailed to him/her the night before, turning to page 29 in his/her notebook to double-check how replication is switched off and on for deployments, and so on and so on. Painful, error-prone and lengthy. But the point is, if this is something like your deployment process, telling your DBA “We’re changing everything you do and your toolset next week, to automate most of your role – that’s okay isn’t it?” isn’t likely to go down well. There’s some work here to bring him/her onside – to explain what you’re doing, why there will still be control of the deployment process and so on. Or of course, if you’re the DBA looking after this process, you have to do a similar job in reverse. You may have researched and worked out how you’d like to change your methodology to start automating your painful release process, but do the dev team know this? What if they have to start producing different artifacts for you? Will they be happy with this? Worth talking to them, to find out. As well as talking to your DBA/dev team, the other group to get involved before implementation is your manager. And possibly your manager’s manager too. As mentioned, unless there’s buy-in “from the top”, you’re going to hit problems when the implementation starts to get rocky (and what tool/process implementations don’t get rocky?!). You need to have support from someone senior in your organisation – someone you can turn to when you need help with a delayed implementation, lack of resources or lack of progress. Actions: Get your DBA involved (or whoever looks after live deployments) and discuss what you’re planning to do or, if you’re the DBA yourself, get the dev team up-to-speed with your plans, Get your boss involved too and make sure he/she is bought in to the investment. Environments Where are you going to deploy to? And really this question is – what environments do you want set up for your deployment pipeline? Assume everyone has “Production”, but do you have a QA environment? Dedicated development environments for each dev? Proper pre-production? I’ve seen every setup under the sun, and there is often a big difference between “What we want, to do continuous delivery properly” and “What we’re currently stuck with”. Some of these differences are: What we want What we’ve got Each developer with their own dedicated database environment A single shared “development” environment, used by everyone at once An Integration box used to test the integration of all check-ins via the CI process, along with a full suite of unit-tests running on that machine In fact if you have a CI process running, you’re likely to have some sort of integration server running (even if you don’t call it that!). Whether you have a full suite of unit tests running is a different question… Separate QA environment used explicitly for manual testing prior to release “We just test on the dev environments, or maybe pre-production” A proper pre-production (or “staging”) box that matches production as closely as possible Hopefully a pre-production box of some sort. But does it match production closely!? A production environment reproducible from source control A production box which has drifted significantly from anything in source control The big question is – how much time and effort are you going to invest in fixing these issues? In reality this just involves figuring out which new databases you’re going to create and where they’ll be hosted – VMs? Cloud-based? What about size/data issues – what data are you going to include on dev environments? Does it need to be masked to protect access to production data? And often the amount of work here really depends on whether you’re working on a new, greenfield project, or trying to update an existing, brownfield application. There’s a world if difference between starting from scratch with 4 or 5 clean environments (reproducible from source control of course!), and trying to re-purpose and tweak a set of existing databases, with all of their surrounding processes and quirks. But for a proper release management process, ideally you have: Dedicated development databases, An Integration server used for testing continuous integration and running unit tests. [NB: This is the point at which deployments are automatic, without human intervention. Each deployment after this point is a one-click (but human) action], QA – QA engineers use a one-click deployment process to automatically* deploy chosen releases to QA for testing, Pre-production. The environment you use to test the production release process, Production. * A note on the use of the word “automatic” – when carrying out automated deployments this does not mean that the deployment is happening without human intervention (i.e. that something is just deploying over and over again). It means that the process of carrying out the deployment is automatic in that it’s not a person manually running through a checklist or set of actions. The deployment still requires a single-click from a user. Actions: Get your environments set up and ready, Set access permissions appropriately, Make sure everyone understands what the environments will be used for (it’s not a “free-for-all” with all environments to be accessed, played with and changed by development). The Deployment Process As described earlier, most existing database deployment processes are pretty manual. The following is a description of a process we hear very often when we ask customers “How do your database changes get live? How does your manual process work?” Check pre-production matches production (use a schema compare tool, like SQL Compare). Sometimes done by taking a backup from production and restoring in to pre-prod, Again, use a schema compare tool to find the differences between the latest version of the database ready to go live (i.e. what the team have been developing). This generates a script, User (generally, the DBA), reviews the script. This often involves manually checking updates against a spreadsheet or similar, Run the script on pre-production, and check there are no errors (i.e. it upgrades pre-production to what you hoped), If all working, run the script on production.* * this assumes there’s no problem with production drifting away from pre-production in the interim time period (i.e. someone has hacked something in to the production box without going through the proper change management process). This difference could undermine the validity of your pre-production deployment test. Red Gate is currently working on a free tool to detect this problem – sign up here at www.sqllighthouse.com, if you’re interested in testing early versions. There are several variations on this process – some better, some much worse! How do you automate this? In particular, step 3 – surely you can’t automate a DBA checking through a script, that everything is in order!? The key point here is to plan what you want in your new deployment process. There are so many options. At one extreme, pure continuous deployment – whenever a dev checks something in to source control, the CI process runs (including extensive and thorough testing!), before the deployment process keys in and automatically deploys that change to the live box. Not for the faint hearted – and really not something we recommend. At the other extreme, you might be more comfortable with a semi-automated process – the pre-production/production matching process is automated (with an error thrown if these environments don’t match), followed by a manual intervention, allowing for script approval by the DBA. One he/she clicks “Okay, I’m happy for that to go live”, the latter stages automatically take the script through to live. And anything in between of course – and other variations. But we’d strongly recommended sitting down with a whiteboard and your team, and spending a couple of hours mapping out “What do we do now?”, “What do we actually want?”, “What will satisfy our needs for continuous delivery, but still maintaining some sort of continuous control over the process?” NB: Most of what we’re discussing here is about production deployments. It’s important to note that you will also need to map out a deployment process for earlier environments (for example QA). However, these are likely to be less onerous, and many customers opt for a much more automated process for these boxes. Actions: Sit down with your team and a whiteboard, and draw out the answers to the questions above for your production deployments – “What do we do now?”, “What do we actually want?”, “What will satisfy our needs for continuous delivery, but still maintaining some sort of continuous control over the process?” Repeat for earlier environments (QA and so on). Rollback and Recovery If only every deployment went according to plan! Unfortunately they don’t – and when things go wrong, you need a rollback or recovery plan for what you’re going to do in that situation. Once you move in to a more automated database deployment process, you’re far more likely to be deploying more frequently than before. No longer once every 6 months, maybe now once per week, or even daily. Hence the need for a quick rollback or recovery process becomes paramount, and should be planned for. NB: These are mainly scenarios for handling rollbacks after the transaction has been committed. If a failure is detected during the transaction, the whole transaction can just be rolled back, no problem. There are various options, which we’ll explore in subsequent articles, things like: Immediately restore from backup, Have a pre-tested rollback script (remembering that really this is a “roll-forward” script – there’s not really such a thing as a rollback script for a database!) Have fallback environments – for example, using a blue-green deployment pattern. Different options have pros and cons – some are easier to set up, some require more investment in infrastructure; and of course some work better than others (the key issue with using backups, is loss of the interim transaction data that has been added between the failed deployment and the restore). The best mechanism will be primarily dependent on how your application works and how much you need a cast-iron failsafe mechanism. Actions: Work out an appropriate rollback strategy based on how your application and business works, your appetite for investment and requirements for a completely failsafe process. Development Practices This is perhaps the more difficult area for people to tackle. The process by which you can deploy database updates is actually intrinsically linked with the patterns and practices used to develop that database and linked application. So you need to decide whether you want to implement some changes to the way your developers actually develop the database (particularly schema changes) to make the deployment process easier. A good example is the pattern “Branch by abstraction”. Explained nicely here, by Martin Fowler, this is a process that can be used to make significant database changes (e.g. splitting a table) in a step-wise manner so that you can always roll back, without data loss – by making incremental updates to the database backward compatible. Slides 103-108 of the following slidedeck, from Niek Bartholomeus explain the process: https://speakerdeck.com/niekbartho/orchestration-in-meatspace As these slides show, by making a significant schema change in multiple steps – where each step can be rolled back without any loss of new data – this affords the release team the opportunity to have zero-downtime deployments with considerably less stress (because if an increment goes wrong, they can roll back easily). There are plenty more great patterns that can be implemented – the book Refactoring Databases, by Scott Ambler and Pramod Sadalage is a great read, if this is a direction you want to go in: http://www.amazon.com/Refactoring-Databases-Evolutionary-paperback-Addison-Wesley/dp/0321774515 But the question is – how much of this investment are you willing to make? How often are you making significant schema changes that would require these best practices? Again, there’s a difference here between migrating old projects and starting afresh – with the latter it’s much easier to instigate best practice from the start. Actions: For your business, work out how far down the path you want to go, amending your database development patterns to “best practice”. It’s a trade-off between implementing quality processes, and the necessity to do so (depending on how often you make complex changes). Socialise these changes with your development group. No-one likes having “best practice” changes imposed on them, so good to introduce these ideas and the rationale behind them early.   Summary The next stages of implementing a continuous delivery pipeline for your database changes (once you have CI up and running) require a little pre-planning, if you want to get the most out of the work, and for the implementation to go smoothly. We’ve covered some of the checklist of areas to consider – mainly in the areas of “Getting the team ready for the changes that are coming” and “Planning our your pipeline, environments, patterns and practices for development”, though there will be more detail, depending on where you’re coming from – and where you want to get to. This article is part of our database delivery patterns & practices series on Simple Talk. Find more articles for version control, automated testing, continuous integration & deployment.

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  • Microsoft Introduces WebMatrix

    - by Rick Strahl
    originally published in CoDe Magazine Editorial Microsoft recently released the first CTP of a new development environment called WebMatrix, which along with some of its supporting technologies are squarely aimed at making the Microsoft Web Platform more approachable for first-time developers and hobbyists. But in the process, it also provides some updated technologies that can make life easier for existing .NET developers. Let’s face it: ASP.NET development isn’t exactly trivial unless you already have a fair bit of familiarity with sophisticated development practices. Stick a non-developer in front of Visual Studio .NET or even the Visual Web Developer Express edition and it’s not likely that the person in front of the screen will be very productive or feel inspired. Yet other technologies like PHP and even classic ASP did provide the ability for non-developers and hobbyists to become reasonably proficient in creating basic web content quickly and efficiently. WebMatrix appears to be Microsoft’s attempt to bring back some of that simplicity with a number of technologies and tools. The key is to provide a friendly and fully self-contained development environment that provides all the tools needed to build an application in one place, as well as tools that allow publishing of content and databases easily to the web server. WebMatrix is made up of several components and technologies: IIS Developer Express IIS Developer Express is a new, self-contained development web server that is fully compatible with IIS 7.5 and based on the same codebase that IIS 7.5 uses. This new development server replaces the much less compatible Cassini web server that’s been used in Visual Studio and the Express editions. IIS Express addresses a few shortcomings of the Cassini server such as the inability to serve custom ISAPI extensions (i.e., things like PHP or ASP classic for example), as well as not supporting advanced authentication. IIS Developer Express provides most of the IIS 7.5 feature set providing much better compatibility between development and live deployment scenarios. SQL Server Compact 4.0 Database access is a key component for most web-driven applications, but on the Microsoft stack this has mostly meant you have to use SQL Server or SQL Server Express. SQL Server Compact is not new-it’s been around for a few years, but it’s been severely hobbled in the past by terrible tool support and the inability to support more than a single connection in Microsoft’s attempt to avoid losing SQL Server licensing. The new release of SQL Server Compact 4.0 supports multiple connections and you can run it in ASP.NET web applications simply by installing an assembly into the bin folder of the web application. In effect, you don’t have to install a special system configuration to run SQL Compact as it is a drop-in database engine: Copy the small assembly into your BIN folder (or from the GAC if installed fully), create a connection string against a local file-based database file, and then start firing SQL requests. Additionally WebMatrix includes nice tools to edit the database tables and files, along with tools to easily upsize (and hopefully downsize in the future) to full SQL Server. This is a big win, pending compatibility and performance limits. In my simple testing the data engine performed well enough for small data sets. This is not only useful for web applications, but also for desktop applications for which a fully installed SQL engine like SQL Server would be overkill. Having a local data store in those applications that can potentially be accessed by multiple users is a welcome feature. ASP.NET Razor View Engine What? Yet another native ASP.NET view engine? We already have Web Forms and various different flavors of using that view engine with Web Forms and MVC. Do we really need another? Microsoft thinks so, and Razor is an implementation of a lightweight, script-only view engine. Unlike the Web Forms view engine, Razor works only with inline code, snippets, and markup; therefore, it is more in line with current thinking of what a view engine should represent. There’s no support for a “page model” or any of the other Web Forms features of the full-page framework, but just a lightweight scripting engine that works with plain markup plus embedded expressions and code. The markup syntax for Razor is geared for minimal typing, plus some progressive detection of where a script block/expression starts and ends. This results in a much leaner syntax than the typical ASP.NET Web Forms alligator (<% %>) tags. Razor uses the @ sign plus standard C# (or Visual Basic) block syntax to delineate code snippets and expressions. Here’s a very simple example of what Razor markup looks like along with some comment annotations: <!DOCTYPE html> <html>     <head>         <title></title>     </head>     <body>     <h1>Razor Test</h1>          <!-- simple expressions -->     @DateTime.Now     <hr />     <!-- method expressions -->     @DateTime.Now.ToString("T")          <!-- code blocks -->     @{         List<string> names = new List<string>();         names.Add("Rick");         names.Add("Markus");         names.Add("Claudio");         names.Add("Kevin");     }          <!-- structured block statements -->     <ul>     @foreach(string name in names){             <li>@name</li>     }     </ul>           <!-- Conditional code -->        @if(true) {                        <!-- Literal Text embedding in code -->        <text>         true        </text>;    }    else    {        <!-- Literal Text embedding in code -->       <text>       false       </text>;    }    </body> </html> Like the Web Forms view engine, Razor parses pages into code, and then executes that run-time compiled code. Effectively a “page” becomes a code file with markup becoming literal text written into the Response stream, code snippets becoming raw code, and expressions being written out with Response.Write(). The code generated from Razor doesn’t look much different from similar Web Forms code that only uses script tags; so although the syntax may look different, the operational model is fairly similar to the Web Forms engine minus the overhead of the large Page object model. However, there are differences: -Razor pages are based on a new base class, Microsoft.WebPages.WebPage, which is hosted in the Microsoft.WebPages assembly that houses all the Razor engine parsing and processing logic. Browsing through the assembly (in the generated ASP.NET Temporary Files folder or GAC) will give you a good idea of the functionality that Razor provides. If you look closely, a lot of the feature set matches ASP.NET MVC’s view implementation as well as many of the helper classes found in MVC. It’s not hard to guess the motivation for this sort of view engine: For beginning developers the simple markup syntax is easier to work with, although you obviously still need to have some understanding of the .NET Framework in order to create dynamic content. The syntax is easier to read and grok and much shorter to type than ASP.NET alligator tags (<% %>) and also easier to understand aesthetically what’s happening in the markup code. Razor also is a better fit for Microsoft’s vision of ASP.NET MVC: It’s a new view engine without the baggage of Web Forms attached to it. The engine is more lightweight since it doesn’t carry all the features and object model of Web Forms with it and it can be instantiated directly outside of the HTTP environment, which has been rather tricky to do for the Web Forms view engine. Having a standalone script parser is a huge win for other applications as well – it makes it much easier to create script or meta driven output generators for many types of applications from code/screen generators, to simple form letters to data merging applications with user customizability. For me personally this is very useful side effect and who knows maybe Microsoft will actually standardize they’re scripting engines (die T4 die!) on this engine. Razor also better fits the “view-based” approach where the view is supposed to be mostly a visual representation that doesn’t hold much, if any, code. While you can still use code, the code you do write has to be self-contained. Overall I wouldn’t be surprised if Razor will become the new standard view engine for MVC in the future – and in fact there have been announcements recently that Razor will become the default script engine in ASP.NET MVC 3.0. Razor can also be used in existing Web Forms and MVC applications, although that’s not working currently unless you manually configure the script mappings and add the appropriate assemblies. It’s possible to do it, but it’s probably better to wait until Microsoft releases official support for Razor scripts in Visual Studio. Once that happens, you can simply drop .cshtml and .vbhtml pages into an existing ASP.NET project and they will work side by side with classic ASP.NET pages. WebMatrix Development Environment To tie all of these three technologies together, Microsoft is shipping WebMatrix with an integrated development environment. An integrated gallery manager makes it easy to download and load existing projects, and then extend them with custom functionality. It seems to be a prominent goal to provide community-oriented content that can act as a starting point, be it via a custom templates or a complete standard application. The IDE includes a project manager that works with a single project and provides an integrated IDE/editor for editing the .cshtml and .vbhtml pages. A run button allows you to quickly run pages in the project manager in a variety of browsers. There’s no debugging support for code at this time. Note that Razor pages don’t require explicit compilation, so making a change, saving, and then refreshing your page in the browser is all that’s needed to see changes while testing an application locally. It’s essentially using the auto-compiling Web Project that was introduced with .NET 2.0. All code is compiled during run time into dynamically created assemblies in the ASP.NET temp folder. WebMatrix also has PHP Editing support with syntax highlighting. You can load various PHP-based applications from the WebMatrix Web Gallery directly into the IDE. Most of the Web Gallery applications are ready to install and run without further configuration, with Wizards taking you through installation of tools, dependencies, and configuration of the database as needed. WebMatrix leverages the Web Platform installer to pull the pieces down from websites in a tight integration of tools that worked nicely for the four or five applications I tried this out on. Click a couple of check boxes and fill in a few simple configuration options and you end up with a running application that’s ready to be customized. Nice! You can easily deploy completed applications via WebDeploy (to an IIS server) or FTP directly from within the development environment. The deploy tool also can handle automatically uploading and installing the database and all related assemblies required, making deployment a simple one-click install step. Simplified Database Access The IDE contains a database editor that can edit SQL Compact and SQL Server databases. There is also a Database helper class that facilitates database access by providing easy-to-use, high-level query execution and iteration methods: @{       var db = Database.OpenFile("FirstApp.sdf");     string sql = "select * from customers where Id > @0"; } <ul> @foreach(var row in db.Query(sql,1)){         <li>@row.FirstName @row.LastName</li> } </ul> The query function takes a SQL statement plus any number of positional (@0,@1 etc.) SQL parameters by simple values. The result is returned as a collection of rows which in turn have a row object with dynamic properties for each of the columns giving easy (though untyped) access to each of the fields. Likewise Execute and ExecuteNonQuery allow execution of more complex queries using similar parameter passing schemes. Note these queries use string-based queries rather than LINQ or Entity Framework’s strongly typed LINQ queries. While this may seem like a step back, it’s also in line with the expectations of non .NET script developers who are quite used to writing and using SQL strings in code rather than using OR/M frameworks. The only question is why was something not included from the beginning in .NET and Microsoft made developers build custom implementations of these basic building blocks. The implementation looks a lot like a DataTable-style data access mechanism, but to be fair, this is a common approach in scripting languages. This type of syntax that uses simple, static, data object methods to perform simple data tasks with one line of code are common in scripting languages and are a good match for folks working in PHP/Python, etc. Seems like Microsoft has taken great advantage of .NET 4.0’s dynamic typing to provide this sort of interface for row iteration where each row has properties for each field. FWIW, all the examples demonstrate using local SQL Compact files - I was unable to get a SQL Server connection string to work with the Database class (the connection string wasn’t accepted). However, since the code in the page is still plain old .NET, you can easily use standard ADO.NET code or even LINQ or Entity Framework models that are created outside of WebMatrix in separate assemblies as required. The good the bad the obnoxious - It’s still .NET The beauty (or curse depending on how you look at it :)) of Razor and the compilation model is that, behind it all, it’s still .NET. Although the syntax may look foreign, it’s still all .NET behind the scenes. You can easily access existing tools, helpers, and utilities simply by adding them to the project as references or to the bin folder. Razor automatically recognizes any assembly reference from assemblies in the bin folder. In the default configuration, Microsoft provides a host of helper functions in a Microsoft.WebPages assembly (check it out in the ASP.NET temp folder for your application), which includes a host of HTML Helpers. If you’ve used ASP.NET MVC before, a lot of the helpers should look familiar. Documentation at the moment is sketchy-there’s a very rough API reference you can check out here: http://www.asp.net/webmatrix/tutorials/asp-net-web-pages-api-reference Who needs WebMatrix? Uhm… good Question Clearly Microsoft is trying hard to create an environment with WebMatrix that is easy to use for newbie developers. The goal seems to be simplicity in providing a minimal development environment and an easy-to-use script engine/language that makes it easy to get started with. There’s also some focus on community features that can be used as starting points, such as Web Gallery applications and templates. The community features in particular are very nice and something that would be nice to eventually see in Visual Studio as well. The question is whether this is too little too late. Developers who have been clamoring for a simpler development environment on the .NET stack have mostly left for other simpler platforms like PHP or Python which are catering to the down and dirty developer. Microsoft will be hard pressed to win those folks-and other hardcore PHP developers-back. Regardless of how much you dress up a script engine fronted by the .NET Framework, it’s still the .NET Framework and all the complexity that drives it. While .NET is a fine solution in its breadth and features once you get a basic handle on the core features, the bar of entry to being productive with the .NET Framework is still pretty high. The MVC style helpers Microsoft provides are a good step in the right direction, but I suspect it’s not enough to shield new developers from having to delve much deeper into the Framework to get even basic applications built. Razor and its helpers is trying to make .NET more accessible but the reality is that in order to do useful stuff that goes beyond the handful of simple helpers you still are going to have to write some C# or VB or other .NET code. If the target is a hobby/amateur/non-programmer the learning curve isn’t made any easier by WebMatrix it’s just been shifted a tad bit further along in your development endeavor when you run out of canned components that are supplied either by Microsoft or the community. The database helpers are interesting and actually I’ve heard a lot of discussion from various developers who’ve been resisting .NET for a really long time perking up at the prospect of easier data access in .NET than the ridiculous amount of code it takes to do even simple data access with raw ADO.NET. It seems sad that such a simple concept and implementation should trigger this sort of response (especially since it’s practically trivial to create helpers like these or pick them up from countless libraries available), but there it is. It also shows that there are plenty of developers out there who are more interested in ‘getting stuff done’ easily than necessarily following the latest and greatest practices which are overkill for many development scenarios. Sometimes it seems that all of .NET is focused on the big life changing issues of development, rather than the bread and butter scenarios that many developers are interested in to get their work accomplished. And that in the end may be WebMatrix’s main raison d'être: To bring some focus back at Microsoft that simpler and more high level solutions are actually needed to appeal to the non-high end developers as well as providing the necessary tools for the high end developers who want to follow the latest and greatest trends. The current version of WebMatrix hits many sweet spots, but it also feels like it has a long way to go before it really can be a tool that a beginning developer or an accomplished developer can feel comfortable with. Although there are some really good ideas in the environment (like the gallery for downloading apps and components) which would be a great addition for Visual Studio as well, the rest of the development environment just feels like crippleware with required functionality missing especially debugging and Intellisense, but also general editor support. It’s not clear whether these are because the product is still in an early alpha release or whether it’s simply designed that way to be a really limited development environment. While simple can be good, nobody wants to feel left out when it comes to necessary tool support and WebMatrix just has that left out feeling to it. If anything WebMatrix’s technology pieces (which are really independent of the WebMatrix product) are what are interesting to developers in general. The compact IIS implementation is a nice improvement for development scenarios and SQL Compact 4.0 seems to address a lot of concerns that people have had and have complained about for some time with previous SQL Compact implementations. By far the most interesting and useful technology though seems to be the Razor view engine for its light weight implementation and it’s decoupling from the ASP.NET/HTTP pipeline to provide a standalone scripting/view engine that is pluggable. The first winner of this is going to be ASP.NET MVC which can now have a cleaner view model that isn’t inconsistent due to the baggage of non-implemented WebForms features that don’t work in MVC. But I expect that Razor will end up in many other applications as a scripting and code generation engine eventually. Visual Studio integration for Razor is currently missing, but is promised for a later release. The ASP.NET MVC team has already mentioned that Razor will eventually become the default MVC view engine, which will guarantee continued growth and development of this tool along those lines. And the Razor engine and support tools actually inherit many of the features that MVC pioneered, so there’s some synergy flowing both ways between Razor and MVC. As an existing ASP.NET developer who’s already familiar with Visual Studio and ASP.NET development, the WebMatrix IDE doesn’t give you anything that you want. The tools provided are minimal and provide nothing that you can’t get in Visual Studio today, except the minimal Razor syntax highlighting, so there’s little need to take a step back. With Visual Studio integration coming later there’s little reason to look at WebMatrix for tooling. It’s good to see that Microsoft is giving some thought about the ease of use of .NET as a platform For so many years, we’ve been piling on more and more new features without trying to take a step back and see how complicated the development/configuration/deployment process has become. Sometimes it’s good to take a step - or several steps - back and take another look and realize just how far we’ve come. WebMatrix is one of those reminders and one that likely will result in some positive changes on the platform as a whole. © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET   IIS7  

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  • iPhone SDK vs. Windows Phone 7 Series SDK Challenge, Part 2: MoveMe

    In this series, I will be taking sample applications from the iPhone SDK and implementing them on Windows Phone 7 Series.  My goal is to do as much of an apples-to-apples comparison as I can.  This series will be written to not only compare and contrast how easy or difficult it is to complete tasks on either platform, how many lines of code, etc., but Id also like it to be a way for iPhone developers to either get started on Windows Phone 7 Series development, or for developers in general to learn the platform. Heres my methodology: Run the iPhone SDK app in the iPhone Simulator to get a feel for what it does and how it works, without looking at the implementation Implement the equivalent functionality on Windows Phone 7 Series using Silverlight. Compare the two implementations based on complexity, functionality, lines of code, number of files, etc. Add some functionality to the Windows Phone 7 Series app that shows off a way to make the scenario more interesting or leverages an aspect of the platform, or uses a better design pattern to implement the functionality. You can download Microsoft Visual Studio 2010 Express for Windows Phone CTP here, and the Expression Blend 4 Beta here. If youre seeing this series for the first time, check out Part 1: Hello World. A note on methodologyin the prior post there was some feedback about lines of code not being a very good metric for this exercise.  I dont really disagree, theres a lot more to this than lines of code but I believe that is a relevant metric, even if its not the ultimate one.  And theres no perfect answer here.  So I am going to continue to report the number of lines of code that I, as a developer would need to write in these apps as a data point, and Ill leave it up to the reader to determine how that fits in with overall complexity, etc.  The first example was so basic that I think it was difficult to talk about in real terms.  I think that as these apps get more complex, the subjective differences in concept count and will be more important.  MoveMe The MoveMe app is the main end-to-end app writing example in the iPhone SDK, called Creating an iPhone Application.  This application demonstrates a few concepts, including handling touch input, how to do animations, and how to do some basic transforms. The behavior of the application is pretty simple.  User touches the button: The button does a throb type animation where it scales up and then back down briefly. User drags the button: After a touch begins, moving the touch point will drag the button around with the touch. User lets go of the button: The button animates back to its original position, but does a few small bounces as it reaches its original point, which makes the app fun and gives it an extra bit of interactivity. Now, how would I write an app that meets this spec for Windows Phone 7 Series, and how hard would it be?  Lets find out!     Implementing the UI Okay, lets build the UI for this application.  In the HelloWorld example, we did all the UI design in Visual Studio and/or by hand in XAML.  In this example, were going to use the Expression Blend 4 Beta. You might be wondering when to use Visual Studio, when to use Blend, and when to do XAML by hand.  Different people will have different takes on this, but heres mine: XAML by hand simple UI that doesnt contain animations, gradients, etc., and or UI that I want to really optimize and craft when I know exactly what I want to do. Visual Studio Basic UI layout, property setting, data binding, etc. Blend Any serious design work needs to be done in Blend, including animations, handling states and transitions, styling and templating, editing resources. As in Part 1, go ahead and fire up Visual Studio 2010 Express for Windows Phone (yes, soon it will take longer to say the name of our products than to start them up!), and create a new Windows Phone Application.  As in Part 1, clear out the XAML from the designer.  An easy way to do this is to just: Click on the design surface Hit Control+A Hit Delete Theres a little bit left over (the Grid.RowDefinitions element), just go ahead and delete that element so were starting with a clean state of only one outer Grid element. To use Blend, we need to save this project.  See, when you create a project with Visual Studio Express, it doesnt commit it to the disk (well, in a place where you can find it, at least) until you actually save the project.  This is handy if youre doing some fooling around, because it doesnt clutter your disk with WindowsPhoneApplication23-like directories.  But its also kind of dangerous, since when you close VS, if you dont save the projectits all gone.  Yes, this has bitten me since I was saving files and didnt remember that, so be careful to save the project/solution via Save All, at least once. So, save and note the location on disk.  Start Expression Blend 4 Beta, and chose File > Open Project/Solution, and load your project.  You should see just about the same thing you saw over in VS: a blank, black designer surface. Now, thinking about this application, we dont really need a button, even though it looks like one.  We never click it.  So were just going to create a visual and use that.  This is also true in the iPhone example above, where the visual is actually not a button either but a jpg image with a nice gradient and round edges.  Well do something simple here that looks pretty good. In Blend, look in the tool pane on the left for the icon that looks like the below (the highlighted one on the left), and hold it down to get the popout menu, and choose Border:    Okay, now draw out a box in the middle of the design surface of about 300x100.  The Properties Pane to the left should show the properties for this item. First, lets make it more visible by giving it a border brush.  Set the BorderBrush to white by clicking BorderBrush and dragging the color selector all the way to the upper right in the palette.  Then, down a bit farther, make the BorderThickness 4 all the way around, and the CornerRadius set to 6. In the Layout section, do the following to Width, Height, Horizontal and Vertical Alignment, and Margin (all 4 margin values): Youll see the outline now is in the middle of the design surface.  Now lets give it a background color.  Above BorderBrush select Background, and click the third tab over: Gradient Brush.  Youll see a gradient slider at the bottom, and if you click the markers, you can edit the gradient stops individually (or add more).  In this case, you can select something you like, but wheres what I chose: Left stop: #BFACCFE2 (I just picked a spot on the palette and set opacity to 75%, no magic here, feel free to fiddle these or just enter these numbers into the hex area and be done with it) Right stop: #FF3E738F Okay, looks pretty good.  Finally set the name of the element in the Name field at the top of the Properties pane to welcome. Now lets add some text.  Just hit T and itll select the TextBlock tool automatically: Now draw out some are inside our welcome visual and type Welcome!, then click on the design surface (to exit text entry mode) and hit V to go back into selection mode (or the top item in the tool pane that looks like a mouse pointer).  Click on the text again to select it in the tool pane.  Just like the border, we want to center this.  So set HorizontalAlignment and VerticalAlignment to Center, and clear the Margins: Thats it for the UI.  Heres how it looks, on the design surface: Not bad!  Okay, now the fun part Adding Animations Using Blend to build animations is a lot of fun, and its easy.  In XAML, I can not only declare elements and visuals, but also I can declare animations that will affect those visuals.  These are called Storyboards. To recap, well be doing two animations: The throb animation when the element is touched The center animation when the element is released after being dragged. The throb animation is just a scale transform, so well do that first.  In the Objects and Timeline Pane (left side, bottom half), click the little + icon to add a new Storyboard called touchStoryboard: The timeline view will appear.  In there, click a bit to the right of 0 to create a keyframe at .2 seconds: Now, click on our welcome element (the Border, not the TextBlock in it), and scroll to the bottom of the Properties Pane.  Open up Transform, click the third tab ("Scale), and set X and Y to 1.2: This all of this says that, at .2 seconds, I want the X and Y size of this element to scale to 1.2. In fact you can see this happen.  Push the Play arrow in the timeline view, and youll see the animation run! Lets make two tweaks.  First, we want the animation to automatically reverse so it scales up then back down nicely. Click in the dropdown that says touchStoryboard in Objects and Timeline, then in the Properties pane check Auto Reverse: Now run it again, and youll see it go both ways. Lets even make it nicer by adding an easing function. First, click on the Render Transform item in the Objects tree, then, in the Property Pane, youll see a bunch of easing functions to choose from.  Feel free to play with this, then seeing how each runs.  I chose Circle In, but some other ones are fun.  Try them out!  Elastic In is kind of fun, but well stick with Circle In.  Thats it for that animation. Now, we also want an animation to move the Border back to its original position when the user ends the touch gesture.  This is exactly the same process as above, but just targeting a different transform property. Create a new animation called releaseStoryboard Select a timeline point at 1.2 seconds. Click on the welcome Border element again Scroll to the Transforms panel at the bottom of the Properties Pane Choose the first tab (Translate), which may already be selected Set both X and Y values to 0.0 (we do this just to make the values stick, because the value is already 0 and we need Blend to know we want to save that value) Click on RenderTransform in the Objects tree In the properties pane, choose Bounce Out Set Bounces to 6, and Bounciness to 4 (feel free to play with these as well) Okay, were done. Note, if you want to test this Storyboard, you have to do something a little tricky because the final value is the same as the initial value, so playing it does nothing.  If you want to play with it, do the following: Next to the selection dropdown, hit the little "x (Close Storyboard) Go to the Translate Transform value for welcome Set X,Y to 50, 200, respectively (or whatever) Select releaseStoryboard again from the dropdown Hit play, see it run Go into the object tree and select RenderTransform to change the easing function. When youre done, hit the Close Storyboard x again and set the values in Transform/Translate back to 0 Wiring Up the Animations Okay, now go back to Visual Studio.  Youll get a prompt due to the modification of MainPage.xaml.  Hit Yes. In the designer, click on the welcome Border element.  In the Property Browser, hit the Events button, then double click each of ManipulationStarted, ManipulationDelta, ManipulationCompleted.  Youll need to flip back to the designer from code, after each double click. Its code time.  Here we go. Here, three event handlers have been created for us: welcome_ManipulationStarted: This will execute when a manipulation begins.  Think of it as MouseDown. welcome_ManipulationDelta: This executes each time a manipulation changes.  Think MouseMove. welcome_ManipulationCompleted: This will  execute when the manipulation ends. Think MouseUp. Now, in ManipuliationStarted, we want to kick off the throb animation that we called touchAnimation.  Thats easy: 1: private void welcome_ManipulationStarted(object sender, ManipulationStartedEventArgs e) 2: { 3: touchStoryboard.Begin(); 4: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Likewise, when the manipulation completes, we want to re-center the welcome visual with our bounce animation: 1: private void welcome_ManipulationCompleted(object sender, ManipulationCompletedEventArgs e) 2: { 3: releaseStoryboard.Begin(); 4: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Note there is actually a way to kick off these animations from Blend directly via something called Triggers, but I think its clearer to show whats going on like this.  A Trigger basically allows you to say When this event fires, trigger this Storyboard, so its the exact same logical process as above, but without the code. But how do we get the object to move?  Well, for that we really dont want an animation because we want it to respond immediately to user input. We do this by directly modifying the transform to match the offset for the manipulation, and then well let the animation bring it back to zero when the manipulation completes.  The manipulation events do a great job of keeping track of all the stuff that you usually had to do yourself when doing drags: where you started from, how far youve moved, etc. So we can easily modify the position as below: 1: private void welcome_ManipulationDelta(object sender, ManipulationDeltaEventArgs e) 2: { 3: CompositeTransform transform = (CompositeTransform)welcome.RenderTransform; 4:   5: transform.TranslateX = e.CumulativeManipulation.Translation.X; 6: transform.TranslateY = e.CumulativeManipulation.Translation.Y; 7: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Thats it! Go ahead and run the app in the emulator.  I suggest running without the debugger, its a little faster (CTRL+F5).  If youve got a machine that supports DirectX 10, youll see nice smooth GPU accelerated graphics, which also what it looks like on the phone, running at about 60 frames per second.  If your machine does not support DX10 (like the laptop Im writing this on!), it wont be quite a smooth so youll have to take my word for it! Comparing Against the iPhone This is an example where the flexibility and power of XAML meets the tooling of Visual Studio and Blend, and the whole experience really shines.  So, for several things that are declarative and 100% toolable with the Windows Phone 7 Series, this example does them with code on the iPhone.  In parens is the lines of code that I count to do these operations. PlacardView.m: 19 total LOC Creating the view that hosts the button-like image and the text Drawing the image that is the background of the button Drawing the Welcome text over the image (I think you could technically do this step and/or the prior one using Interface Builder) MoveMeView.m:  63 total LOC Constructing and running the scale (throb) animation (25) Constructing the path describing the animation back to center plus bounce effect (38) Beyond the code count, yy experience with doing this kind of thing in code is that its VERY time intensive.  When I was a developer back on Windows Forms, doing GDI+ drawing, we did this stuff a lot, and it took forever!  You write some code and even once you get it basically working, you see its not quite right, you go back, tweak the interval, or the math a bit, run it again, etc.  You can take a look at the iPhone code here to judge for yourself.  Scroll down to animatePlacardViewToCenter toward the bottom.  I dont think this code is terribly complicated, but its not what Id call simple and its not at all simple to get right. And then theres a few other lines of code running around for setting up the ViewController and the Views, about 15 lines between MoveMeAppDelegate, PlacardView, and MoveMeView, plus the assorted decls in the h files. Adding those up, I conservatively get something like 100 lines of code (19+63+15+decls) on iPhone that I have to write, by hand, to make this project work. The lines of code that I wrote in the examples above is 5 lines of code on Windows Phone 7 Series. In terms of incremental concept counts beyond the HelloWorld app, heres a shot at that: iPhone: Drawing Images Drawing Text Handling touch events Creating animations Scaling animations Building a path and animating along that Windows Phone 7 Series: Laying out UI in Blend Creating & testing basic animations in Blend Handling touch events Invoking animations from code This was actually the first example I tried converting, even before I did the HelloWorld, and I was pretty surprised.  Some of this is luck that this app happens to match up with the Windows Phone 7 Series platform just perfectly.  In terms of time, I wrote the above application, from scratch, in about 10 minutes.  I dont know how long it would take a very skilled iPhone developer to write MoveMe on that iPhone from scratch, but if I was to write it on Silverlight in the same way (e.g. all via code), I think it would likely take me at least an hour or two to get it all working right, maybe more if I ended up picking the wrong strategy or couldnt get the math right, etc. Making Some Tweaks Silverlight contains a feature called Projections to do a variety of 3D-like effects with a 2D surface. So lets play with that a bit. Go back to Blend and select the welcome Border in the object tree.  In its properties, scroll down to the bottom, open Transform, and see Projection at the bottom.  Set X,Y,Z to 90.  Youll see the element kind of disappear, replaced by a thin blue line. Now Create a new animation called startupStoryboard. Set its key time to .5 seconds in the timeline view Set the projection values above to 0 for X, Y, and Z. Save Go back to Visual Studio, and in the constructor, add the following bold code (lines 7-9 to the constructor: 1: public MainPage() 2: { 3: InitializeComponent(); 4:   5: SupportedOrientations = SupportedPageOrientation.Portrait; 6:   7: this.Loaded += (s, e) => 8: { 9: startupStoryboard.Begin(); 10: }; 11: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If the code above looks funny, its using something called a lambda in C#, which is an inline anonymous method.  Its just a handy shorthand for creating a handler like the manipulation ones above. So with this youll get a nice 3D looking fly in effect when the app starts up.  Here it is, in flight: Pretty cool!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Apache + Codeigniter + New Server + Unexpected Errors

    - by ngl5000
    Alright here is the situation: I use to have my codeigniter site at bluehost were I did not have root access, I have since moved that site to rackspace. I have not changed any of the PHP code yet there has been some unexpected behavior. Unexpected Behavior: http://mysite.com/robots.txt Both old and new resolve to the robots file http://mysite.com/robots.txt/ The old bluehost setup resolves to my codeigniter 404 error page. The rackspace config resolves to: Not Found The requested URL /robots.txt/ was not found on this server. **This instance leads me to believe that there could be a problem with my mod rewrites or lack there of. The first one produces the error correctly through php while it seems the second senario lets the server handle this error. The next instance of this problem is even more troubling: 'http://mysite.com/search/term/9 x 1-1%2F2 white/' New site results in: Bad Request Your browser sent a request that this server could not understand. Old site results in: The actual page being loaded and the search term being unencoded. I have to assume that this has something to do with the fact that when I went to the new server I went from root level htaccess file to httpd.conf file and virtual server default and default-ssl. Here they are: Default file: <VirtualHost *:80> ServerAdmin webmaster@localhost ServerName mysite.com DocumentRoot /var/www <Directory /> Options +FollowSymLinks AllowOverride None </Directory> <Directory /var/www> Options -Indexes +FollowSymLinks -MultiViews AllowOverride None Order allow,deny allow from all RewriteEngine On RewriteBase / # force no www. (also does the IP thing) RewriteCond %{HTTPS} !=on RewriteCond %{HTTP_HOST} !^mysite\.com [NC] RewriteRule ^(.*)$ http://mysite.com/$1 [R=301,L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.+)\.(\d+)\.(js|css|png|jpg|gif)$ $1.$3 [L] # index.php remove any index.php parts RewriteCond %{THE_REQUEST} /index\.(php|html) RewriteRule (.*)index\.(php|html)(.*)$ /$1$3 [r=301,L] # codeigniter direct RewriteCond $0 !^(index\.php|assets|robots\.txt|sitemap\.xml|favicon\.ico) RewriteRule ^.*$ index.php [L] </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog ${APACHE_LOG_DIR}/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog ${APACHE_LOG_DIR}/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> </VirtualHost> Default-ssl File <IfModule mod_ssl.c> <VirtualHost _default_:443> ServerAdmin webmaster@localhost ServerName mysite.com DocumentRoot /var/www <Directory /> Options +FollowSymLinks AllowOverride None </Directory> <Directory /var/www> Options -Indexes +FollowSymLinks -MultiViews AllowOverride None Order allow,deny allow from all RewriteEngine On RewriteBase / RewriteCond %{SERVER_PORT} !^443 RewriteRule ^ https://mysite.com%{REQUEST_URI} [R=301,L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^(.+)\.(\d+)\.(js|css|png|jpg|gif)$ $1.$3 [L] # index.php remove any index.php parts RewriteCond %{THE_REQUEST} /index\.(php|html) RewriteRule (.*)index\.(php|html)(.*)$ /$1$3 [r=301,L] # codeigniter direct RewriteCond $0 !^(index\.php|assets|robots\.txt|sitemap\.xml|favicon\.ico) RewriteRule ^.*$ index.php [L] </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog ${APACHE_LOG_DIR}/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog ${APACHE_LOG_DIR}/ssl_access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> # SSL Engine Switch: # Enable/Disable SSL for this virtual host. SSLEngine on # Use our self-signed certificate by default SSLCertificateFile /etc/apache2/ssl/certs/www.mysite.com.crt SSLCertificateKeyFile /etc/apache2/ssl/private/www.mysite.com.key # A self-signed (snakeoil) certificate can be created by installing # the ssl-cert package. See # /usr/share/doc/apache2.2-common/README.Debian.gz for more info. # If both key and certificate are stored in the same file, only the # SSLCertificateFile directive is needed. # SSLCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem # SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key # Server Certificate Chain: # Point SSLCertificateChainFile at a file containing the # concatenation of PEM encoded CA certificates which form the # certificate chain for the server certificate. Alternatively # the referenced file can be the same as SSLCertificateFile # when the CA certificates are directly appended to the server # certificate for convinience. #SSLCertificateChainFile /etc/apache2/ssl.crt/server-ca.crt # Certificate Authority (CA): # Set the CA certificate verification path where to find CA # certificates for client authentication or alternatively one # huge file containing all of them (file must be PEM encoded) # Note: Inside SSLCACertificatePath you need hash symlinks # to point to the certificate files. Use the provided # Makefile to update the hash symlinks after changes. #SSLCACertificatePath /etc/ssl/certs/ #SSLCACertificateFile /etc/apache2/ssl.crt/ca-bundle.crt # Certificate Revocation Lists (CRL): # Set the CA revocation path where to find CA CRLs for client # authentication or alternatively one huge file containing all # of them (file must be PEM encoded) # Note: Inside SSLCARevocationPath you need hash symlinks # to point to the certificate files. Use the provided # Makefile to update the hash symlinks after changes. #SSLCARevocationPath /etc/apache2/ssl.crl/ #SSLCARevocationFile /etc/apache2/ssl.crl/ca-bundle.crl # Client Authentication (Type): # Client certificate verification type and depth. Types are # none, optional, require and optional_no_ca. Depth is a # number which specifies how deeply to verify the certificate # issuer chain before deciding the certificate is not valid. #SSLVerifyClient require #SSLVerifyDepth 10 # Access Control: # With SSLRequire you can do per-directory access control based # on arbitrary complex boolean expressions containing server # variable checks and other lookup directives. The syntax is a # mixture between C and Perl. See the mod_ssl documentation # for more details. #<Location /> #SSLRequire ( %{SSL_CIPHER} !~ m/^(EXP|NULL)/ \ # and %{SSL_CLIENT_S_DN_O} eq "Snake Oil, Ltd." \ # and %{SSL_CLIENT_S_DN_OU} in {"Staff", "CA", "Dev"} \ # and %{TIME_WDAY} >= 1 and %{TIME_WDAY} <= 5 \ # and %{TIME_HOUR} >= 8 and %{TIME_HOUR} <= 20 ) \ # or %{REMOTE_ADDR} =~ m/^192\.76\.162\.[0-9]+$/ #</Location> # SSL Engine Options: # Set various options for the SSL engine. # o FakeBasicAuth: # Translate the client X.509 into a Basic Authorisation. This means that # the standard Auth/DBMAuth methods can be used for access control. The # user name is the `one line' version of the client's X.509 certificate. # Note that no password is obtained from the user. Every entry in the user # file needs this password: `xxj31ZMTZzkVA'. # o ExportCertData: # This exports two additional environment variables: SSL_CLIENT_CERT and # SSL_SERVER_CERT. These contain the PEM-encoded certificates of the # server (always existing) and the client (only existing when client # authentication is used). This can be used to import the certificates # into CGI scripts. # o StdEnvVars: # This exports the standard SSL/TLS related `SSL_*' environment variables. # Per default this exportation is switched off for performance reasons, # because the extraction step is an expensive operation and is usually # useless for serving static content. So one usually enables the # exportation for CGI and SSI requests only. # o StrictRequire: # This denies access when "SSLRequireSSL" or "SSLRequire" applied even # under a "Satisfy any" situation, i.e. when it applies access is denied # and no other module can change it. # o OptRenegotiate: # This enables optimized SSL connection renegotiation handling when SSL # directives are used in per-directory context. #SSLOptions +FakeBasicAuth +ExportCertData +StrictRequire <FilesMatch "\.(cgi|shtml|phtml|php)$"> SSLOptions +StdEnvVars </FilesMatch> <Directory /usr/lib/cgi-bin> SSLOptions +StdEnvVars </Directory> # SSL Protocol Adjustments: # The safe and default but still SSL/TLS standard compliant shutdown # approach is that mod_ssl sends the close notify alert but doesn't wait for # the close notify alert from client. When you need a different shutdown # approach you can use one of the following variables: # o ssl-unclean-shutdown: # This forces an unclean shutdown when the connection is closed, i.e. no # SSL close notify alert is send or allowed to received. This violates # the SSL/TLS standard but is needed for some brain-dead browsers. Use # this when you receive I/O errors because of the standard approach where # mod_ssl sends the close notify alert. # o ssl-accurate-shutdown: # This forces an accurate shutdown when the connection is closed, i.e. a # SSL close notify alert is send and mod_ssl waits for the close notify # alert of the client. This is 100% SSL/TLS standard compliant, but in # practice often causes hanging connections with brain-dead browsers. Use # this only for browsers where you know that their SSL implementation # works correctly. # Notice: Most problems of broken clients are also related to the HTTP # keep-alive facility, so you usually additionally want to disable # keep-alive for those clients, too. Use variable "nokeepalive" for this. # Similarly, one has to force some clients to use HTTP/1.0 to workaround # their broken HTTP/1.1 implementation. Use variables "downgrade-1.0" and # "force-response-1.0" for this. BrowserMatch "MSIE [2-6]" \ nokeepalive ssl-unclean-shutdown \ downgrade-1.0 force-response-1.0 # MSIE 7 and newer should be able to use keepalive BrowserMatch "MSIE [17-9]" ssl-unclean-shutdown httpd.conf File Just a lot of stuff from html5 boiler plate, I will post it if need be Old htaccess file <IfModule mod_rewrite.c> # index.php remove any index.php parts RewriteCond %{THE_REQUEST} /index\.(php|html) RewriteRule (.*)index\.(php|html)(.*)$ /$1$3 [r=301,L] RewriteCond $1 !^(index\.php|assets|robots\.txt|sitemap\.xml|favicon\.ico) RewriteRule ^(.*)/$ /$1 [r=301,L] # codeigniter direct RewriteCond $1 !^(index\.php|assets|robots\.txt|sitemap\.xml|favicon\.ico) RewriteRule ^(.*)$ /index.php/$1 [L] </IfModule> Any Help would be hugely appreciated!!

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  • AutoMapper is not working for a Container class

    - by rboarman
    Hello, I have an AutoMapper issue that has been driving me crazy for way too long now. A similar question was also posted on the AutoMapper user site but has not gotten much love. The summary is that I have a container class that holds a Dictionary of components. The components are a derived object of a common base class. I also have a parallel structure that I am using as DTO objects to which I want to map. The error that gets generated seems to say that the mapper cannot map between two of the classes that I have included in the CreateMap calls. I think the error has to do with the fact that I have a Dictionary of objects that are not part of the container‘s hierarchy. I apologize in advance for the length of the code below. My simple test cases work. Needless to say, it’s only the more complex case that is failing. Here are the classes: #region Dto objects public class ComponentContainerDTO { public Dictionary<string, ComponentDTO> Components { get; set; } public ComponentContainerDTO() { this.Components = new Dictionary<string, ComponentDTO>(); } } public class EntityDTO : ComponentContainerDTO { public int Id { get; set; } } public class ComponentDTO { public EntityDTO Owner { get; set; } public int Id { get; set; } public string Name { get; set; } public string ComponentType { get; set; } } public class HealthDTO : ComponentDTO { public decimal CurrentHealth { get; set; } } public class PhysicalLocationDTO : ComponentDTO { public Point2D Location { get; set; } } #endregion #region Domain objects public class ComponentContainer { public Dictionary<string, Component> Components { get; set; } public ComponentContainer() { this.Components = new Dictionary<string, Component>(); } } public class Entity : ComponentContainer { public int Id { get; set; } } public class Component { public Entity Owner { get; set; } public int Id { get; set; } public string Name { get; set; } public string ComponentType { get; set; } } public class Health : Component { public decimal CurrentHealth { get; set; } } public struct Point2D { public decimal X; public decimal Y; public Point2D(decimal x, decimal y) { X = x; Y = y; } } public class PhysicalLocation : Component { public Point2D Location { get; set; } } #endregion The code: var entity = new Entity() { Id = 1 }; var healthComponent = new Health() { CurrentHealth = 100, Owner = entity, Name = "Health", Id = 2 }; entity.Components.Add("1", healthComponent); var locationComponent = new PhysicalLocation() { Location = new Point2D() { X = 1, Y = 2 }, Owner = entity, Name = "PhysicalLocation", Id = 3 }; entity.Components.Add("2", locationComponent); Mapper.CreateMap<ComponentContainer, ComponentContainerDTO>() .Include<Entity, EntityDTO>(); Mapper.CreateMap<Entity, EntityDTO>(); Mapper.CreateMap<Component, ComponentDTO>() .Include<Health, HealthDTO>() .Include<PhysicalLocation, PhysicalLocationDTO>(); Mapper.CreateMap<Component, ComponentDTO>(); Mapper.CreateMap<Health, HealthDTO>(); Mapper.CreateMap<PhysicalLocation, PhysicalLocationDTO>(); Mapper.AssertConfigurationIsValid(); var targetEntity = Mapper.Map<Entity, EntityDTO>(entity); The error when I call Map() (abbreviated stack crawls): AutoMapper.AutoMapperMappingException was unhandled Message=Trying to map MapperTest1.Entity to MapperTest1.EntityDTO. Using mapping configuration for MapperTest1.Entity to MapperTest1.EntityDTO Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) . . . InnerException: AutoMapper.AutoMapperMappingException Message=Trying to map System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[MapperTest1.Component, ElasticTest1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]] to System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[MapperTest1.ComponentDTO, ElasticTest1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]. Using mapping configuration for MapperTest1.Entity to MapperTest1.EntityDTO Destination property: Components Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.Mappers.TypeMapObjectMapperRegistry.PropertyMapMappingStrategy.MapPropertyValue(ResolutionContext context, IMappingEngineRunner mapper, Object mappedObject, PropertyMap propertyMap) . . InnerException: AutoMapper.AutoMapperMappingException Message=Trying to map System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[MapperTest1.Component, ElasticTest1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]] to System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[MapperTest1.ComponentDTO, ElasticTest1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]. Using mapping configuration for MapperTest1.Entity to MapperTest1.EntityDTO Destination property: Components Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) . InnerException: AutoMapper.AutoMapperMappingException Message=Trying to map MapperTest1.Component to MapperTest1.ComponentDTO. Using mapping configuration for MapperTest1.Health to MapperTest1.HealthDTO Destination property: Components Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) . . InnerException: AutoMapper.AutoMapperMappingException Message=Trying to map System.Decimal to System.Decimal. Using mapping configuration for MapperTest1.Health to MapperTest1.HealthDTO Destination property: CurrentHealth Exception of type 'AutoMapper.AutoMapperMappingException' was thrown. Source=AutoMapper StackTrace: at AutoMapper.Mappers.TypeMapObjectMapperRegistry.PropertyMapMappingStrategy.MapPropertyValue(ResolutionContext context, IMappingEngineRunner mapper, Object mappedObject, PropertyMap propertyMap) . . InnerException: System.InvalidCastException Message=Unable to cast object of type 'MapperTest1.ComponentDTO' to type 'MapperTest1.HealthDTO'. Source=Anonymously Hosted DynamicMethods Assembly StackTrace: at SetCurrentHealth(Object , Object ) . . Thank you in advance. Rick

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  • ASP.Net MVC2 CustomModelBinder not working... Changed from MVC1

    - by Ian
    (My apologies if this seems verbose - trying to provide all relevant code) I've just upgraded to VS2010, and am now having trouble trying to get a new CustomModelBinder working. In MVC1 I would have written something like public class AwardModelBinder: DefaultModelBinder { : public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) { // do the base binding to bind all simple types Award award = base.BindModel(controllerContext, bindingContext) as Award; // Get complex values from ValueProvider dictionary award.EffectiveFrom = Convert.ToDateTime(bindingContext.ValueProvider["Model.EffectiveFrom"].AttemptedValue.ToString()); string sEffectiveTo = bindingContext.ValueProvider["Model.EffectiveTo"].AttemptedValue.ToString(); if (sEffectiveTo.Length > 0) award.EffectiveTo = Convert.ToDateTime(bindingContext.ValueProvider["Model.EffectiveTo"].AttemptedValue.ToString()); // etc return award; } } Of course I'd register the custom binder in Global.asax.cs: protected void Application_Start() { RegisterRoutes(RouteTable.Routes); // register custom model binders ModelBinders.Binders.Add(typeof(Voucher), new VoucherModelBinder(DaoFactory.UserInstance("EH1303"))); ModelBinders.Binders.Add(typeof(AwardCriterion), new AwardCriterionModelBinder(DaoFactory.UserInstance("EH1303"), new VOPSDaoFactory())); ModelBinders.Binders.Add(typeof(SelectedVoucher), new SelectedVoucherModelBinder(DaoFactory.UserInstance("IT0706B"))); ModelBinders.Binders.Add(typeof(Award), new AwardModelBinder(DaoFactory.UserInstance("IT0706B"))); } Now, in MVC2, I'm finding that my call to base.BindModel returns an object where everything is null, and I simply don't want to have to iterate all the form fields surfaced by the new ValueProvider.GetValue() function. Google finds no matches for this error, so I assume I'm doing something wrong. Here's my actual code: My domain object (infer what you like about the encapsulated child objects - I know I'll need custom binders for those too, but the three "simple" fields (ie. base types) Id, TradingName and BusinessIncorporated are also coming back null): public class Customer { /// <summary> /// Initializes a new instance of the Customer class. /// </summary> public Customer() { Applicant = new Person(); Contact = new Person(); BusinessContact = new ContactDetails(); BankAccount = new BankAccount(); } /// <summary> /// Gets or sets the unique customer identifier. /// </summary> public int Id { get; set; } /// <summary> /// Gets or sets the applicant details. /// </summary> public Person Applicant { get; set; } /// <summary> /// Gets or sets the customer's secondary contact. /// </summary> public Person Contact { get; set; } /// <summary> /// Gets or sets the trading name of the business. /// </summary> [Required(ErrorMessage = "Please enter your Business or Trading Name")] [StringLength(50, ErrorMessage = "A maximum of 50 characters is permitted")] public string TradingName { get; set; } /// <summary> /// Gets or sets the date the customer's business began trading. /// </summary> [Required(ErrorMessage = "You must supply the date your business started trading")] [DateRange("01/01/1900", "01/01/2020", ErrorMessage = "This date must be between {0} and {1}")] public DateTime BusinessIncorporated { get; set; } /// <summary> /// Gets or sets the contact details for the customer's business. /// </summary> public ContactDetails BusinessContact { get; set; } /// <summary> /// Gets or sets the customer's bank account details. /// </summary> public BankAccount BankAccount { get; set; } } My controller method: /// <summary> /// Saves a Customer object from the submitted application form. /// </summary> /// <param name="customer">A populate instance of the Customer class.</param> /// <returns>A partial view indicating success or failure.</returns> /// <httpmethod>POST</httpmethod> /// <url>/Customer/RegisterCustomerAccount</url> [HttpPost] [ValidateAntiForgeryToken] public ActionResult RegisterCustomerAccount(Customer customer) { if (ModelState.IsValid) { // save the Customer // return indication of success, or otherwise return PartialView(); } else { ViewData.Model = customer; // load necessary reference data into ViewData ViewData["PersonTitles"] = new SelectList(ReferenceDataCache.Get("PersonTitle"), "Id", "Name"); return PartialView("CustomerAccountRegistration", customer); } } My custom binder: public class CustomerModelBinder : DefaultModelBinder { public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) { ValueProviderResult vpResult = bindingContext .ValueProvider.GetValue(bindingContext.ModelName); // vpResult is null // MVC2 - ValueProvider is now an IValueProvider, not dictionary based anymore if (bindingContext.ValueProvider.GetValue("Model.Applicant.Title") != null) { // works } Customer customer = base.BindModel(controllerContext, bindingContext) as Customer; // customer instanitated with null (etc) throughout return customer; } } My binder registration: /// <summary> /// Application_Start is called once when the web application is first accessed. /// </summary> protected void Application_Start() { RegisterRoutes(RouteTable.Routes); // register custom model binders ModelBinders.Binders.Add(typeof(Customer), new CustomerModelBinder()); ReferenceDataCache.Populate(); } ... and a snippet from my view (could this be a prefix problem?) <div class="inputContainer"> <label class="above" for="Model_Applicant_Title" accesskey="t"><span class="accesskey">T</span>itle<span class="mandatoryfield">*</span></label> <%= Html.DropDownList("Model.Applicant.Title", ViewData["PersonTitles"] as SelectList, "Select ...", new { @class = "validate[required]" })%> <% Html.ValidationMessageFor(model => model.Applicant.Title); %> </div> <div class="inputContainer"> <label class="above" for="Model_Applicant_Forename" accesskey="f"><span class="accesskey">F</span>orename / First name<span class="mandatoryfield">*</span></label> <%= Html.TextBox("Model.Applicant.Forename", Html.Encode(Model.Applicant.Forename), new { @class = "validate[required,custom[onlyLetter],length[2,20]]", title="Enter your forename", maxlength = 20, size = 20, autocomplete = "off", onkeypress = "return maskInput(event,re_mask_alpha);" })%> </div> <div class="inputContainer"> <label class="above" for="Model_Applicant_MiddleInitials" accesskey="i">Middle <span class="accesskey">I</span>nitial(s)</label> <%= Html.TextBox("Model.Applicant.MiddleInitials", Html.Encode(Model.Applicant.MiddleInitials), new { @class = "validate[optional,custom[onlyLetter],length[0,8]]", title = "Please enter your middle initial(s)", maxlength = 8, size = 8, autocomplete = "off", onkeypress = "return maskInput(event,re_mask_alpha);" })%> </div>

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  • Javascript For-Each Loop Syntax Help

    - by radrew
    Hey guys, I've got a complex block of PHP/Javascript that isn't functioning. I'm trying to manipulate a form that contains 4 dropdown select lists. Each dropdown is dependent upon what was selected in the one above it. I apologize for the huge amount of code, but I was hoping someone might be able to spot a syntax error or something else simple that I'm missing. The form in question is located in the right sidebar of the following site: http://www.buyautocovers.com $Manufacturer_array[] = array('id' => 'all', 'text' => $this->__('Choose Make')); $Model_array[] = array('id' = 'all', 'text' = $this-('Choose Model')); $Number_array[] = array('id' = 'all', 'text' = $this-('Choose Year')); $Body_array[] = array('id' = 'all', 'text' = $this-__('Choose Body Type')); $javascript = ' // var a = new Array(); var b = new Array(); var c = new Array(); var d = new Array();'; $M_a = array(); foreach ($rows as $r) { if (!isset($M_a [$r['manufacturer']])) $Manufacturer_array[] = array('id' = $r['manufacturer'], 'text' = $r['manufacturer']); $M_a [$r['manufacturer']][$r['model']][$r['number']][$r['body']] = 1; } $i = 0; foreach ($M_a as $k =$v){ $javascript .= 'a['.$i.']="'.$k.'";b['.$i.'];c['.$i.'];=new Array('; $ii = 0; $s = ''; foreach ($M_a[$k] as $kk =$vv){ $javascript .= ($ii != 0 ? ',' : '').'"'.$kk.'"'; $ss = ''; $iii = 0; foreach ($M_a[$k][$kk] as $kkk = $vvv){ $javascript .= ($iii != 0 ? ',' : '').'"'.$kkk.'"'; $sss = ''; $iiii = 0; foreach ($M_a[$k][$kk][$kkk] as $kkkk = $vvvv){ $sss .= ($iiii != 0 ? ',' : '').'"'.$kkkk.'"'; $iiii++; } $ss .= 'd['.$i.']['.$ii.']['.$iii.']=new Array('.$sss.');'; $iii++; } $s .= 'd['.$i.']['.$ii.']=new Array('.$ss.');'; $ii++; } $javascript .= ');d['.$i.']=new Array();'.$s; $i++; } $javascript .= ' function pop_model(){ var o ="' . $this-('Choose Model') . '"; var sv = $(\'mmn_manufacturer\').value; if(sv != "all"){ var v = a.length; while(v--) if(sv == a[v]) break; for(var i = 0; i < b[v].length; i++) o+=""+b[v][i]+""; } o+=""; $(\'model_select\').innerHTML= o; $(\'number_select\').innerHTML= "' . $this-('Choose Year') . '"; } function pop_number(){ var o ="' . $this-('Choose Year') . '"; var sv = $(\'mmn_manufacturer\').value; if(sv != "all"){ var v = a.length; while(v--) if(sv == a[v]) break; var sv2 = $(\'mmn_model\').value; if(sv2 != "all"){ var v2 = b[v].length; while(v2--) if(sv2 == b[v][v2]) break; for(var i = 0; i < c[v][v2].length; i++) o+=""+c[v][v2][i]+""; } } o+=""; $(\'number_select\').innerHTML= o; $(\'body_select\').innerHTML= "' . $this-('Choose Body Type') . '"; } function pop_body(){ var o ="' . $this-__('Choose Body Type') . '"; var sv = $(\'mmn_manufacturer\').value; if(sv != "all"){ var v = a.length; while(v--) if(sv == a[v]) break; var sv2 = $(\'mmn_model\').value; if(sv2 != "all"){ var v2 = b[v].length; while(v2--) if(sv2 == b[v][v2]) break; var sv3 = $(\'mmn_number\').value; if(sv3 != "all"){ var v3 = c[v].length; while(v3--) if(sv3 == b[v]c[v2][v3]) break; for(var i = 0; i < d[v]c[v2][v3].length; i++) o+=""+d[v]c[v2][v3][i]+""; } } } o+=""; $(\'number_select\').innerHTML= o; } //]] '; $expire = time()+60*60*24*90; if (isset($_GET['Manufacturer'])){ setcookie("Manufacturer_selected", $_GET['Manufacturer'], $expire,'/'); if ($_GET['Manufacturer'] != 'all') $Manufacturer_selected_var = $_GET['Manufacturer']; } elseif (isset($_COOKIE['Manufacturer_selected']) && $_COOKIE['Manufacturer_selected'] != 'all') $Manufacturer_selected_var = $_COOKIE['Manufacturer_selected']; if (isset($_GET['Model'])){ setcookie("Model_selected", $_GET['Model'], $expire,'/'); if ($_GET['Model'] != 'all') $Model_selected_var = $_GET['Model']; } elseif (isset($_COOKIE['Model_selected']) && $_COOKIE['Model_selected'] != 'all') $Model_selected_var = $_COOKIE['Model_selected']; if (isset($_GET['Number'])){ setcookie("Number_selected", $_GET['Number'], $expire,'/'); if ($_GET['Number'] != 'all') $Number_selected_var = $_GET['Number']; } elseif (isset($_COOKIE['Number_selected']) && $_COOKIE['Number_selected'] != 'all') $Number_selected_var = $_COOKIE['Number_selected']; if (isset($_GET['Body'])){ setcookie("Body_selected", $_GET['Body'], $expire,'/'); if ($_GET['Body'] != 'all') $Body_selected_var = $_GET['Body']; } elseif (isset($_COOKIE['Body_selected']) && $_COOKIE['Body_selected'] != 'all') $Body_selected_var = $_COOKIE['Body_selected']; if (isset($Manufacturer_selected_var) && isset($M_a[$Manufacturer_selected_var])) foreach ($M_a[$Manufacturer_selected_var] as $k => $v) $Model_array[] = array('id' = $k, 'text' = $k); if (isset($Manufacturer_selected_var) && isset($Model_selected_var) && isset($M_a[$Manufacturer_selected_var][$Model_selected_var])) foreach ($M_a[$Manufacturer_selected_var][$Model_selected_var] as $k = $v) $Number_array[] = array('id' = $k, 'text' = $k); if (isset($Manufacturer_selected_var) && isset($Model_selected_var) && isset($Number_selected_var) && isset($M_a[$Manufacturer_selected_var][$Model_selected_var][$Number_selected_var])) foreach ($M_a[$Manufacturer_selected_var][$Model_selected_var][$Number_selected_var] as $k = $v) $Body_array[] = array('id' = $k, 'text' = $k); echo $javascript;

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  • Benchmark Linq2SQL, Subsonic2, Subsonic3 - Any other ideas to make them faster ?

    - by Aristos
    I am working with Subsonic 2 more than 3 years now... After Linq appears and then Subsonic 3, I start thinking about moving to the new Linq futures that are connected to sql. I must say that I start move and port my subsonic 2 with SubSonic 3, and very soon I discover that the speed was so slow thats I didn't believe it - and starts all that tests. Then I test Linq2Sql and see also a delay - compare it with Subsonic 2. My question here is, especial for the linq2sql, and the up-coming dotnet version 4, what else can I do to speed it up ? What else on linq2sql settings, or classes, not on this code that I have used for my messures I place here the project that I make the tests, also the screen shots of the results. How I make the tests - and the accurate of my measures. I use only for my question Google chrome, because its difficult for me to show here a lot of other measures that I have done with more complex programs. This is the most simple one, I just measure the Data Read. How can I prove that. I make a simple Thread.Sleep(10 seconds) and see if I see that 10 seconds on Google Chrome Measure, and yes I see it. here are more test with this Sleep thead to see whats actually Chrome gives. 10 seconds delay 100 ms delay Zero delay There is only a small 15ms thats get on messure, is so small compare it with the rest of my tests that I do not care about. So what I measure I measure just the data read via each method - did not count the data or database delay, or any disk read or anything like that. Later on the image with the result I show that no disk activity exist on the measures See this image to see what really I measure and if this is correct Why I chose this kind of test Its simple, it's real, and it's near my real problem that I found the delay of subsonic 3 in real program with real data. Now lets tests the dals Start by see this image I have 4-5 calls on every method, the one after the other. The results are. For a loop of 100 times, ask for 5 Rows, one not exist, approximatively.. Simple adonet:81ms SubSonic 2 :210ms linq2sql :1.70sec linq2sql using CompiledQuery.Compile :239ms Subsonic 3 :15.00sec (wow - extreme slow) The project http://www.planethost.gr/DalSpeedTests.rar Can any one confirm this benchmark, or make any optimizations to help me out ? Other tests Some one publish here this link http://ormbattle.net/ (and then remove it - don not know why) In this page you can find a really useful advanced tests for all, except subsonic 2 and subsonic 3 that I have here ! Optimizing What I really ask here is if some one can now any trick how to optimize the DALs, not by changing the test code, but by changing the code and the settings on each dal. For example... Optimizing Linq2SQL I start search how to optimize Linq2sql and found this article, and maybe more exist. Finally I make the tricks from that page to run, and optimize the code using them all. The speed was near 1.50sec from 1.70.... big improvement, but still slow. Then I found a different way - same idea article, and wow ! the speed is blow up. Using this trick with CompiledQuery.Compile, the time from 1.5sec is now 239ms. Here is the code for the precompiled... Func<DataClassesDataContext, int, IQueryable<Product>> compiledQuery = CompiledQuery.Compile((DataClassesDataContext meta, int IdToFind) => (from myData in meta.Products where myData.ProductID.Equals(IdToFind) select myData)); StringBuilder Test = new StringBuilder(); int[] MiaSeira = { 5, 6, 10, 100, 7 }; using (DataClassesDataContext context = new DataClassesDataContext()) { context.ObjectTrackingEnabled = false; for (int i = 0; i < 100; i++) { foreach (int EnaID in MiaSeira) { var oFindThat2P = compiledQuery(context, EnaID); foreach (Product One in oFindThat2P) { Test.Append("<br />"); Test.Append(One.ProductName); } } } } Optimizing SubSonic 3 and problems I make many performance profiling, and start change the one after the other and the speed is better but still too slow. I post them on subsonic group but they ignore the problem, they say that everything is fast... Here is some capture of my profiling and delay points inside subsonic source code I have end up that subsonic3 make more call on the structure of the database rather than on data itself. Needs to reconsider the hole way of asking for data, and follow the subsonic2 idea if this is possible. Try to make precompile to subsonic 3 like I did in linq2Sql but fail for the moment... Optimizing SubSonic 2 After I discover that subsonic 3 is extreme slow, I start my checks on subsonic 2 - that I have never done before believing that is fast. (and it is) So its come up with some points that can be faster. For example there are many loops like this ones that actually is slow because of string manipulation and compares inside the loop. I must say to you that this code called million of times ! on a period of few minutes ! of data asking from the program. On small amount of tables and small fields maybe this is not a big think for some people, but on large amount of tables, the delay is even more. So I decide and optimize the subsonic 2 by my self, by replacing the string compares, with number compares! Simple. I do that almost on every point that profiler say that is slow. I change also all small points that can be even a little faster, and disable some not so used thinks. The results, 5% faster on NorthWind database, near 20% faster on my database with 250 tables. That is count with 500ms less in 10 seconds process on northwind, 100ms faster on my database on 500ms process time. I do not have captures to show you for that because I have made them with different code, different time, and track them down on paper. Anyway this is my story and my question on all that, what else do you know to make them even faster... For this measures I have use Subsonic 2.2 optimized by me, Subsonic 3.0.0.3 a little optimized by me, and Dot.Net 3.5

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  • strings and textfields, AS3

    - by VideoDnd
    How do I get my text fields to populate correctly and show single digits? Description Each textfield receives a substring. This doesn't limit it's input, because the text fields shows extra numbers. See illustration. Ex A //Tweening method 'could substitute code with Tweener' import fl.transitions.Tween; import fl.transitions.easing.*; //Timer that will run a sec and repeat var timer:Timer = new Timer(1000); //Integer values var count:int = +220000000; var fcount:int = 0; //Events and starting timer timer.addEventListener(TimerEvent.TIMER, incrementCounter); addEventListener(Event.ENTER_FRAME, checkOdometerPosition); timer.start(); //Tween Variables var smoothLoop:int = 0; var originalYPosition:Number = 0; var upwardYPosition:Number = -99; //Formatting String function formatCount(i:int):String { var fraction:int = i % 100; var whole:int = i / 100; return ("0000000" + whole).substr(-7, 7) + "." + (fraction < 10 ? "0" + fraction : fraction); } //First Digit 'trigger set by using var upwardPosition as a constant' function checkOdometerPosition(event:Event):void{ if (seconds9.y <= upwardYPosition){ var toText:String = formatCount(fcount); //seconds9.firstDigit.text = formatCount(fcount); seconds9.firstDigit.text = toText.substr(9, 9); seconds9.y = originalYPosition; seconds8.firstDigit.text = toText.substr(8, 8); seconds8.y = originalYPosition; seconds7dec.firstDigit.text = toText.substr(7, 7); seconds7dec.y = originalYPosition; seconds6.firstDigit.text = toText.substr(6, 6); seconds6.y = originalYPosition; seconds5.firstDigit.text = toText.substr(5, 5); seconds5.y = originalYPosition; seconds5.firstDigit.text = toText.substr(4, 4); seconds5.y = originalYPosition; seconds3.firstDigit.text = toText.substr(3, 3); seconds3.y = originalYPosition; seconds2.firstDigit.text = toText.substr(2, 2); seconds2.y = originalYPosition; seconds1.firstDigit.text = toText.substr(1, 1); seconds1.y = originalYPosition; seconds1.firstDigit.text = toText.substr(1, 1); seconds1.y = originalYPosition; seconds0.firstDigit.text = toText.substr(0, 1); seconds0.y = originalYPosition; } } //Second Digit function incrementCounter(event:TimerEvent):void{ count++; fcount=int(count) if (smoothLoop < 9){ smoothLoop++; } else { smoothLoop = 0; } var lolly:String = formatCount(fcount-1); //seconds9.secondDigit.text = formatCount(fcount); seconds9.secondDigit.text = lolly.substr(9, 9); var addTween9:Tween = new Tween(seconds9, "y", Strong.easeOut,0,-222, .7, true); seconds8.secondDigit.text = lolly.substr(8, 8); var addTween8:Tween = new Tween(seconds8, "y", Strong.easeOut,0,-222, .7, true); seconds7dec.secondDigit.text = lolly.substr(7, 7); var addTween7dec:Tween = new Tween(seconds7dec, "y", Strong.easeOut,0,-222, .7, true); seconds6.secondDigit.text = lolly.substr(6, 6); var addTween6:Tween = new Tween(seconds6, "y", Strong.easeOut,0,-222, .7, true); seconds5.secondDigit.text = lolly.substr(5, 5); var addTween5:Tween = new Tween(seconds5, "y", Strong.easeOut,0,-222, .7, true); seconds4.secondDigit.text = lolly.substr(4, 4); var addTween4:Tween = new Tween(seconds4, "y", Strong.easeOut,0,-222, .7, true); seconds3.secondDigit.text = lolly.substr(3, 3); var addTween3:Tween = new Tween(seconds3, "y", Strong.easeOut,0,-222, .7, true); seconds2.secondDigit.text = lolly.substr(2, 2); var addTween2:Tween = new Tween(seconds2, "y", Strong.easeOut,0,-222, .7, true); seconds1.secondDigit.text = lolly.substr(1, 1); var addTween1:Tween = new Tween(seconds1, "y", Strong.easeOut,0,-222, .7, true); seconds0.secondDigit.text = lolly.substr(0, 1); var addTween0:Tween = new Tween(seconds0, "y", Strong.easeOut,0,-222, .7, true); } Ex A has 10 text objects, each with a pair of text fields. It’s move complex than Ex B, because it has a Y animation and pairs of numbers. The text objects are animated to create a scrolling effect. It moves vertically, and has a lead number and a catch up number contained in each symbol. See illustration for more description. The counters are set to 2,200,000.00, just to see if the numbers are populating. Ex B work fine! for example only //STRING SPLITTER COUNTER with nine individual text fields //Timer settings var delay:uint = 1000/100; var repeat:uint = 0; var timer:Timer; timer = new Timer(delay,repeat); timer.addEventListener(TimerEvent.TIMER, incrementCounter); timer.start(); //Integer values var count:int = 0; var fcount:int = 0; //Format Count function formatCount(i:int):String { var fraction:int = i % 100; var whole:int = i / 100; return ("0000000" + whole).substr(-7, 7) + "." + (fraction < 10 ? "0" + fraction : fraction); } //Split strings off to individual text fields function incrementCounter(event:TimerEvent) { count++; fcount=int(count+220000000) var toText:String = formatCount(fcount); mytext9.text = toText.substr(9, 9); mytext8.text = toText.substr(8, 8); mytext7dec.text = toText.substr(7, 7); mytext6.text = toText.substr(6, 6); mytext5.text = toText.substr(5, 5); mytext4.text = toText.substr(4, 4); mytext3.text = toText.substr(3, 3); mytext2.text = toText.substr(2, 2); mytext1.text = toText.substr(1, 1); mytext0.text = toText.substr(0, 1); } Here's a link to the files

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  • Need guidance on a Google Map application that has to show 250 000 polylines.

    - by lucian.jp
    I am looking for advice for an application I am developing that uses Google Map. Summary: A user has a list of criteria for searching a street segment that fulfills the criteria. The street segments will be colored with 3 colors for showing those below average, average and over average. Then the user clicks on the street segment to see an information window showing the properties of that specific segment hiding those not selected until he/she closes the window and other polyline becomes visible again. This looks quite like the Monopoly City Streets game Hasbro made some month ago the difference being I do not use Flash, I can’t use Open Street Map because it doesn’t list street segment (if it does the IDs won’t be the same anyway) and I do not have to show Google sketch building over. Information: I have a database of street segments with IDs, polyline points and centroid. The database has 6,000,000 street segment records in it. To narrow the generated data a bit we focus on city. The largest city we must show has 250,000 street segments. This means 250,000 line segment polyline to show. Our longest polyline uses 9600 characters which is stored in two 8000 varchar columns in SQL Server 2008. We need to use the API v3 because it is faster than the API v2 and the application will be ported to iPhone. For now it's an ASP.NET 3.5 with SQl Server 2008 application. Performance is a priority. Problems: Most of the demo projects that do this are made with API v2. So besides tutorial on the Google API v3 reference page I have nothing to compare performance or technology use to achieve my goal. There is no available .NET wrapper for the API v3 yet. Generating a 250,000 line segment polyline creates a heavy file which takes time to transfer and parse. (I have found a demo of one polyline of 390,000 points. I think the encoder would be far less efficient with more polylines with less points since there will be less rounding.) Since streets segments are shown based on criteria, polylines must be dynamically created and cache can't be used. Some thoughts: KML/KMZ: Pros: Since it is a standard we can easily load Bing maps, Yahoo! maps, Google maps, Google Earth, with the same KML file. The data generation would be the same. Cons: LineString in KML cannot be encoded polyline like the Google map API can handle. So it would probably be bigger and slower to display. Zipping the file at the size it will take more processing time and require the client side to uncompress the data and I am not quite sure with 250,000 data how an iPhone would handle this and how a server would handle 40 users browsing at the same time. JavaScript file: Pros: JavaScript file can have encoded polyline and would significantly reduce the file to transfer. Cons: Have to create my own stripped version of API v3 to add overlays, create polyline, etc. It is more complex than just create a KML file and point to the source. GeoRSS: This option isn't adapted for my needs I think, but I could be wrong. MapServer: I saw some post suggesting using MapServer to generate overlays. Not quite sure for the connection with our database and the performance it would give. Plus it requires a plugin for generating KML. It seems to me that it wouldn't allow me to do better than creating my own KML or JavaScript file. Maintenance would be simpler without. Monopoly City Streets: The game is now over, but for those who know what I am talking about Monopoly City Streets was showing at max zoom level only the streets that the centroid was inside the Bounds of the window. Moving the map was sending request to the server for the new streets to show. While I think this was ingenious, I have no idea how to implement something similar. The only thing I thought about was to compare if the long was inside the bound of map area X and same with Y. While this could improve performance significantly at high zoom level, this would give nothing when showing a whole city. Clustering: While cluster is awesome for marker, it seems we cannot cluster polylines. I would have liked something like MarkerClusterer for polylines and be able to cluster by my 3 polyline colors. This will probably stay as a “would have been freaking awesome but forget it”. Arrow: I will have in a future version to show a direction for the polyline and will have to show an arrow at the centroid. Loading an image or marker will only double my data so creating a custom overlay will probably be my only option. I have found that demo for something similar I would like to achieve. Unfortunately, the demo is very slow, but I only wish to show 1 arrow per polyline and not multiple like the demo. This functionality will depend on the format of data since I don't think KML support custom overlays. Criteria: While the application is done with ASP.NET 3.5, the port to the iPhone won't use the web to show the application and be limited in screen size for selecting the criteria. This is why I was more orienting on a service or page generating the file based on criteria passed in parameters. The service would than generate the file I need to display the polylines on the map. I could also create an aspx page that does this. The aspx page is more documented than the service way. There should be a reason. Questions: Should I create a web service to returns the street segments file or create an aspx page that return the file? Should I create a JavaScript file with encoded polyline or a KML with longitude/latitude based on the fact that maximum longitude/latitude polyline have 9600 characters and I have to render maximum 250,000 line segment polyline. Or should I go with a MapServer that generate the overlay? Will I be able to display simple arrow on the polyline on the next version. In case of KML generation is it faster to create the file with XDocument, XmlDocument, XmlWriter and this manually or just serialize the street segment in the stream? This is more a brainstorming Stack Overflow question than an actual code problem. Any answer helping narrow the possibilities is as good as someone having all the knowledge to point me out a better choice.

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  • error in coding a lexer in c

    - by mekasperasky
    #include<stdio.h> #include<ctype.h> #include<string.h> /* this is a lexer which recognizes constants , variables ,symbols, identifiers , functions , comments and also header files . It stores the lexemes in 3 different files . One file contains all the headers and the comments . Another file will contain all the variables , another will contain all the symbols. */ int main() { int i=0,j,k,count=0; char a,b[100],c[10000],d[100]; memset ( d, 0, 100 ); j=30; FILE *fp1,*fp2; fp1=fopen("source.txt","r"); //the source file is opened in read only mode which will passed through the lexer fp2=fopen("lext.txt","w"); //now lets remove all the white spaces and store the rest of the words in a file if(fp1==NULL) { perror("failed to open source.txt"); //return EXIT_FAILURE; } i=0; k=0; while(!feof(fp1)) { a=fgetc(fp1); if(a!=' '&&a!='\n') { if (!isalpha(a)) { switch(a) { case '+':{fprintf(fp2,"+ ----> PLUS \n"); i=0;break;} case '-':{fprintf(fp2,"- ---> MINUS \n"); i=0;break;} case '*':{fprintf(fp2, "* --->MULT \n"); i=0;break;} case '/':{fprintf(fp2, "/ --->DIV \n"); i=0;break;} //case '+=':fprintf(fp2, "%.20s\n", "ADD_ASSIGN"); //case '-=':fprintf(fp2, "%.20s\n", "SUB_ASSIGN"); case '=':{fprintf(fp2, "= ---> ASSIGN \n"); i=0;break;} case '%':{fprintf(fp2, "% ---> MOD \n"); i=0;break;} case '<':{fprintf(fp2, "< ---> LESSER_THAN \n"); i=0;break;} case '>':{fprintf(fp2, "> --> GREATER_THAN \n"); i=0;break;} //case '++':fprintf(fp2, "%.20s\n", "INCREMENT"); //case '--':fprintf(fp2, "%.20s\n", "DECREMENT"); //case '==':fprintf(fp2, "%.20s\n", "ASSIGNMENT"); case ';':{fprintf(fp2, "; --->SEMI_COLUMN \n"); i=0;break;} case ':':{fprintf(fp2, ": --->COLUMN \n"); i=0;break;} case '(':{fprintf(fp2, "( --->LPAR \n"); i=0;break;} case ')':{fprintf(fp2, ") --->RPAR \n"); i=0;break;} case '{':{fprintf(fp2, "{ --->LBRACE \n"); i=0;break;} case '}':{fprintf(fp2, "} ---> RBRACE \n"); i=0;break;} } } else { d[i]=a; //printf("%c\n",d[i]); i=i+1; } //} /* we can make the lexer more complex by including even more depths of checks for the symbols*/ } else { d[i+1]='\0'; printf("\n"); if((strcmp(d,"if ")==0)){fprintf(fp2,"if ----> IDENTIFIER \n"); //printf("%s \n",d); memset ( d, 0, 100 ); //printf("%s \n",d); count=count+1;} else if(strcmp(d,"then")==0){fprintf(fp2,"then ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"else")==0){fprintf(fp2,"else ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"switch")==0){fprintf(fp2,"switch ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"printf")==0){fprintf(fp2,"prtintf ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"scanf")==0){fprintf(fp2,"scanf ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"NULL")==0){fprintf(fp2,"NULL ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"int")==0){fprintf(fp2,"INT ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"char")==0){fprintf(fp2,"char ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"float")==0){fprintf(fp2,"float ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"long")==0){fprintf(fp2,"long ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"double")==0){fprintf(fp2,"double ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"const")==0){fprintf(fp2,"const ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"continue")==0)fprintf(fp2,"continue ----> IDENTIFIER \n"); else if(strcmp(d,"size of")==0){fprintf(fp2,"size of ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"register")==0){fprintf(fp2,"register ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"short")==0){fprintf(fp2,"short ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"auto")==0){fprintf(fp2,"auto ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"while")==0){fprintf(fp2,"while ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"do")==0){fprintf(fp2,"do ----> IDENTIFIER \n"); count=count+1;} else if(strcmp(d,"case")==0){fprintf(fp2,"case ----> IDENTIFIER \n"); count=count+1;} else if (isdigit(d[i])) { fprintf(fp2,"%s ---->NUMBER",d); } else if (isalpha(a)) { fprintf(fp2,"%s ----> Variable",d); //printf("%s",d); // memset ( d, 0, 100 );} //fprintf(fp2, "s\n", b); i=0; k=k+1; continue; } i=i+1; k=k+1; } fclose(fp1); fclose(fp2); printf("%d",count); return 0; } In this code , my source.txt has if (a+b) stored . But only ( , + and ) is getting written into lext.txt and not the identifier if or the variable a and b . Any particular reason why?

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  • Mysql - help me optimize this query

    - by sandeepan-nath
    About the system: -The system has a total of 8 tables - Users - Tutor_Details (Tutors are a type of User,Tutor_Details table is linked to Users) - learning_packs, (stores packs created by tutors) - learning_packs_tag_relations, (holds tag relations meant for search) - tutors_tag_relations and tags and orders (containing purchase details of tutor's packs), order_details linked to orders and tutor_details. For a more clear idea about the tables involved please check the The tables section in the end. -A tags based search approach is being followed.Tag relations are created when new tutors register and when tutors create packs (this makes tutors and packs searcheable). For details please check the section How tags work in this system? below. Following is a simpler representation (not the actual) of the more complex query which I am trying to optimize:- I have used statements like explanation of parts in the query select SUM(DISTINCT( t.tag LIKE "%Dictatorship%" )) as key_1_total_matches, SUM(DISTINCT( t.tag LIKE "%democracy%" )) as key_2_total_matches, td., u., count(distinct(od.id_od)), if (lp.id_lp > 0) then some conditional logic on lp fields else 0 as tutor_popularity from Tutor_Details AS td JOIN Users as u on u.id_user = td.id_user LEFT JOIN Learning_Packs_Tag_Relations AS lptagrels ON td.id_tutor = lptagrels.id_tutor LEFT JOIN Learning_Packs AS lp ON lptagrels.id_lp = lp.id_lp LEFT JOIN `some other tables on lp.id_lp - let's call learning pack tables set (including Learning_Packs table)` LEFT JOIN Order_Details as od on td.id_tutor = od.id_author LEFT JOIN Orders as o on od.id_order = o.id_order LEFT JOIN Tutors_Tag_Relations as ttagrels ON td.id_tutor = ttagrels.id_tutor JOIN Tags as t on (t.id_tag = ttagrels.id_tag) OR (t.id_tag = lptagrels.id_tag) where some condition on Users table's fields AND CASE WHEN ((t.id_tag = lptagrels.id_tag) AND (lp.id_lp 0)) THEN `some conditions on learning pack tables set` ELSE 1 END AND CASE WHEN ((t.id_tag = wtagrels.id_tag) AND (wc.id_wc 0)) THEN `some conditions on webclasses tables set` ELSE 1 END AND CASE WHEN (od.id_od0) THEN od.id_author = td.id_tutor and some conditions on Orders table's fields ELSE 1 END AND ( t.tag LIKE "%Dictatorship%" OR t.tag LIKE "%democracy%") group by td.id_tutor HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 order by tutor_popularity desc, u.surname asc, u.name asc limit 0,20 ===================================================================== What does the above query do? Does AND logic search on the search keywords (2 in this example - "Democracy" and "Dictatorship"). Returns only those tutors for which both the keywords are present in the union of the two sets - tutors details and details of all the packs created by a tutor. To make things clear - Suppose a Tutor name "Sandeepan Nath" has created a pack "My first pack", then:- Searching "Sandeepan Nath" returns Sandeepan Nath. Searching "Sandeepan first" returns Sandeepan Nath. Searching "Sandeepan second" does not return Sandeepan Nath. ====================================================================================== The problem The results returned by the above query are correct (AND logic working as per expectation), but the time taken by the query on heavily loaded databases is like 25 seconds as against normal query timings of the order of 0.005 - 0.0002 seconds, which makes it totally unusable. It is possible that some of the delay is being caused because all the possible fields have not yet been indexed, but I would appreciate a better query as a solution, optimized as much as possible, displaying the same results ========================================================================================== How tags work in this system? When a tutor registers, tags are entered and tag relations are created with respect to tutor's details like name, surname etc. When a Tutors create packs, again tags are entered and tag relations are created with respect to pack's details like pack name, description etc. tag relations for tutors stored in tutors_tag_relations and those for packs stored in learning_packs_tag_relations. All individual tags are stored in tags table. ==================================================================== The tables Most of the following tables contain many other fields which I have omitted here. CREATE TABLE IF NOT EXISTS users ( id_user int(10) unsigned NOT NULL AUTO_INCREMENT, name varchar(100) NOT NULL DEFAULT '', surname varchar(155) NOT NULL DEFAULT '', PRIMARY KEY (id_user) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=636 ; CREATE TABLE IF NOT EXISTS tutor_details ( id_tutor int(10) NOT NULL AUTO_INCREMENT, id_user int(10) NOT NULL DEFAULT '0', PRIMARY KEY (id_tutor), KEY Users_FKIndex1 (id_user) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=51 ; CREATE TABLE IF NOT EXISTS orders ( id_order int(10) unsigned NOT NULL AUTO_INCREMENT, PRIMARY KEY (id_order), KEY Orders_FKIndex1 (id_user), ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=275 ; ALTER TABLE orders ADD CONSTRAINT Orders_ibfk_1 FOREIGN KEY (id_user) REFERENCES users (id_user) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS order_details ( id_od int(10) unsigned NOT NULL AUTO_INCREMENT, id_order int(10) unsigned NOT NULL DEFAULT '0', id_author int(10) NOT NULL DEFAULT '0', PRIMARY KEY (id_od), KEY Order_Details_FKIndex1 (id_order) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=284 ; ALTER TABLE order_details ADD CONSTRAINT Order_Details_ibfk_1 FOREIGN KEY (id_order) REFERENCES orders (id_order) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS learning_packs ( id_lp int(10) unsigned NOT NULL AUTO_INCREMENT, id_author int(10) unsigned NOT NULL DEFAULT '0', PRIMARY KEY (id_lp), KEY Learning_Packs_FKIndex2 (id_author), KEY id_lp (id_lp) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=23 ; CREATE TABLE IF NOT EXISTS tags ( id_tag int(10) unsigned NOT NULL AUTO_INCREMENT, tag varchar(255) DEFAULT NULL, PRIMARY KEY (id_tag), UNIQUE KEY tag (tag), KEY id_tag (id_tag), KEY tag_2 (tag), KEY tag_3 (tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3419 ; CREATE TABLE IF NOT EXISTS tutors_tag_relations ( id_tag int(10) unsigned NOT NULL DEFAULT '0', id_tutor int(10) DEFAULT NULL, KEY Tutors_Tag_Relations (id_tag), KEY id_tutor (id_tutor), KEY id_tag (id_tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; ALTER TABLE tutors_tag_relations ADD CONSTRAINT Tutors_Tag_Relations_ibfk_1 FOREIGN KEY (id_tag) REFERENCES tags (id_tag) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS learning_packs_tag_relations ( id_tag int(10) unsigned NOT NULL DEFAULT '0', id_tutor int(10) DEFAULT NULL, id_lp int(10) unsigned DEFAULT NULL, KEY Learning_Packs_Tag_Relations_FKIndex1 (id_tag), KEY id_lp (id_lp), KEY id_tag (id_tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; ALTER TABLE learning_packs_tag_relations ADD CONSTRAINT Learning_Packs_Tag_Relations_ibfk_1 FOREIGN KEY (id_tag) REFERENCES tags (id_tag) ON DELETE NO ACTION ON UPDATE NO ACTION; =================================================================================== Following is the exact query (this includes classes also - tutors can create classes and search terms are matched with classes created by tutors):- select count(distinct(od.id_od)) as tutor_popularity, CASE WHEN (IF((wc.id_wc 0), ( wc.wc_api_status = 1 AND wc.wc_type = 0 AND wc.class_date '2010-06-01 22:00:56' AND wccp.status = 1 AND (wccp.country_code='IE' or wccp.country_code IN ('INT'))), 0)) THEN 1 ELSE 0 END as 'classes_published', CASE WHEN (IF((lp.id_lp 0), (lp.id_status = 1 AND lp.published = 1 AND lpcp.status = 1 AND (lpcp.country_code='IE' or lpcp.country_code IN ('INT'))),0)) THEN 1 ELSE 0 END as 'packs_published', td . * , u . * from Tutor_Details AS td JOIN Users as u on u.id_user = td.id_user LEFT JOIN Learning_Packs_Tag_Relations AS lptagrels ON td.id_tutor = lptagrels.id_tutor LEFT JOIN Learning_Packs AS lp ON lptagrels.id_lp = lp.id_lp LEFT JOIN Learning_Packs_Categories AS lpc ON lpc.id_lp_cat = lp.id_lp_cat LEFT JOIN Learning_Packs_Categories AS lpcp ON lpcp.id_lp_cat = lpc.id_parent LEFT JOIN Learning_Pack_Content as lpct on (lp.id_lp = lpct.id_lp) LEFT JOIN Webclasses_Tag_Relations AS wtagrels ON td.id_tutor = wtagrels.id_tutor LEFT JOIN WebClasses AS wc ON wtagrels.id_wc = wc.id_wc LEFT JOIN Learning_Packs_Categories AS wcc ON wcc.id_lp_cat = wc.id_wp_cat LEFT JOIN Learning_Packs_Categories AS wccp ON wccp.id_lp_cat = wcc.id_parent LEFT JOIN Order_Details as od on td.id_tutor = od.id_author LEFT JOIN Orders as o on od.id_order = o.id_order LEFT JOIN Tutors_Tag_Relations as ttagrels ON td.id_tutor = ttagrels.id_tutor JOIN Tags as t on (t.id_tag = ttagrels.id_tag) OR (t.id_tag = lptagrels.id_tag) OR (t.id_tag = wtagrels.id_tag) where (u.country='IE' or u.country IN ('INT')) AND CASE WHEN ((t.id_tag = lptagrels.id_tag) AND (lp.id_lp 0)) THEN lp.id_status = 1 AND lp.published = 1 AND lpcp.status = 1 AND (lpcp.country_code='IE' or lpcp.country_code IN ('INT')) ELSE 1 END AND CASE WHEN ((t.id_tag = wtagrels.id_tag) AND (wc.id_wc 0)) THEN wc.wc_api_status = 1 AND wc.wc_type = 0 AND wc.class_date '2010-06-01 22:00:56' AND wccp.status = 1 AND (wccp.country_code='IE' or wccp.country_code IN ('INT')) ELSE 1 END AND CASE WHEN (od.id_od0) THEN od.id_author = td.id_tutor and o.order_status = 'paid' and CASE WHEN (od.id_wc 0) THEN od.can_attend_class=1 ELSE 1 END ELSE 1 END AND 1 group by td.id_tutor order by tutor_popularity desc, u.surname asc, u.name asc limit 0,20 Please note - The provided database structure does not show all the fields and tables as in this query

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  • http server implentation, the page does not show properly

    - by none
    well, as i am doing a small project of coding an http server. the code is at http://code.google.com/p/reactor/ the current puzzle is when asked to parse a page with java script and css. As an http server it just sends a page (copied from another website) and it parsed inproperly. when a simple html page is been parse , by my firefox, it shows ok, however when parsing a more complex page(css+javascript) the page is all wired like this : ???? ????? if(getCookie('pais999')==null){varisToplayerDouble="True";isToplayerDouble=(isToplayerDouble=="True")?true:falsevarToplayerCookieName='pais999';varTopLayerCookieExpiredDays=1;varToplayerLink='http://xads.zedo.com/ads2/c?a=239671;g=0;c=455000000;i=0;x=7168;n=455;s=0;k=http://www.pais.co.il/Pais/Games/Lotto/';varToplayerImpression='http://l4.zedo.com/log/p.gif?a=239671;c=455000000;x=7168;n=455;e=i;i=0;s=0;z='+Math.random();varToplayerBigPath='pais/January2007/98one_toplayer.swf';varToplayerSmallPath='pais/January2007/98one_reminder.swf';varToplayerBigWidth=1005;varToplayerBigHeight=500;varToplayerSmallWidth=100;varToplayerSmallHeight=100;varToplayerBigLeft=(0==0)?resWidth/2-ToplayerBigWidth/2:resWidth/2-ToplayerBigWidth/2+0varToplayerBigTop=0;varToplayerSmallLeft=resWidth-ToplayerSmallWidth-0;varToplayerSmallTop=0;varSecondsToChangeBigToSmall=15;}elseif(getCookie('NF999')==null){varisToplayerDouble="True";isToplayerDouble=(isToplayerDouble=="True")?true:falsevarToplayerCookieName='NF999';varTopLayerCookieExpiredDays=1;varToplayerLink='http://xads.zedo.com/ads2/c?a=238663;g=0;c=455000000;i=0;x=7168;n=455;s=0;k=http://www.new-pharm.co.il/SkiGame/?ToolID=OLJD8O';varToplayerImpression='http://l4.zedo.com/log/p.gif?a=238663;c=455000000;x=7168;n=455;e=i;i=0;s=0;z='+Math.random();varToplayerBigPath='NewFarm/Ski/995ONE_TopLayer_550x360.swf';varToplayerSmallPath='NewFarm/Ski/995ONE_Reminder_100x100.swf';varToplayerBigWidth=550;varToplayerBigHeight=360;varToplayerSmallWidth=100;varToplayerSmallHeight=100;varToplayerBigLeft=(0==0)?resWidth/2-ToplayerBigWidth/2:resWidth/2-ToplayerBigWidth/2+0varToplayerBigTop=0;varToplayerSmallLeft=resWidth-ToplayerSmallWidth-0;varToplayerSmallTop=0;varSecondsToChangeBigToSmall=15;}elseif(1==0){}$("divToplayerBig").style.width=ToplayerBigWidth;$("divToplayerBig").style.height=ToplayerBigHeight;$("divToplayerBig").style.left=resWidth/2-ToplayerBigWidth/2;$("divToplayerSmall").style.width=ToplayerSmallWidth;$("divToplayerSmall").style.height=ToplayerSmallHeight;$("divToplayerSmall").style.right=ToplayerSmallWidthvartopOff=0;if(ToplayerBigTop0)topOff=resHeight-ToplayerBigHeight+ToplayerBigTop;varisMain=false;#divToplayerBig{position:absolute;right:20px;bottom:1px;}bodydiv#divToplayerBig{position:fixed;}#divToplayerSmall{position:absolute;right:20px;bottom:10px;}bodydiv#divToplayerSmall{position:fixed;}????|??????LIVE|???????????|ONE???????|ONETV |????'??|BigONE|?????????| CrazyONE | where the source code of the html is : ONE:???:??????????????????????????? ????  ????? if(getCookie('pais999')==null){varisToplayerDouble="True";isToplayerDouble=(isToplayerDouble=="True")?true:falsevarToplayerCookieName='pais999';varTopLayerCookieExpiredDays=1;varToplayerLink='http://xads.zedo.com/ads2/c?a=239671;g=0;c=455000000;i=0;x=7168;n=455;s=0;k=http://www.pais.co.il/Pais/Games/Lotto/';varToplayerImpression='http://l4.zedo.com/log/p.gif?a=239671;c=455000000;x=7168;n=455;e=i;i=0;s=0;z='+Math.random();varToplayerBigPath='pais/January2007/98one_toplayer.swf';varToplayerSmallPath='pais/January2007/98one_reminder.swf';varToplayerBigWidth=1005;varToplayerBigHeight=500;varToplayerSmallWidth=100;varToplayerSmallHeight=100;varToplayerBigLeft=(0==0)?resWidth/2-ToplayerBigWidth/2:resWidth/2-ToplayerBigWidth/2+0varToplayerBigTop=0;varToplayerSmallLeft=resWidth-ToplayerSmallWidth-0;varToplayerSmallTop=0;varSecondsToChangeBigToSmall=15;}elseif(getCookie('NF999')==null){varisToplayerDouble="True";isToplayerDouble=(isToplayerDouble=="True")?true:falsevarToplayerCookieName='NF999';varTopLayerCookieExpiredDays=1;varToplayerLink='http://xads.zedo.com/ads2/c?a=238663;g=0;c=455000000;i=0;x=7168;n=455;s=0;k=http://www.new-pharm.co.il/SkiGame/?ToolID=OLJD8O';varToplayerImpression='http://l4.zedo.com/log/p.gif?a=238663;c=455000000;x=7168;n=455;e=i;i=0;s=0;z='+Math.random();varToplayerBigPath='NewFarm/Ski/995ONE_TopLayer_550x360.swf';varToplayerSmallPath='NewFarm/Ski/995ONE_Reminder_100x100.swf';varToplayerBigWidth=550;varToplayerBigHeight=360;varToplayerSmallWidth=100;varToplayerSmallHeight=100;varToplayerBigLeft=(0==0)?resWidth/2-ToplayerBigWidth/2:resWidth/2-ToplayerBigWidth/2+0varToplayerBigTop=0;varToplayerSmallLeft=resWidth-ToplayerSmallWidth-0;varToplayerSmallTop=0;varSecondsToChangeBigToSmall=15;}elseif(1==0){}$("divToplayerBig").style.width=ToplayerBigWidth;$("divToplayerBig").style.height=ToplayerBigHeight;$("divToplayerBig").style.left=resWidth/2-ToplayerBigWidth/2;$("divToplayerSmall").style.width=ToplayerSmallWidth;$("divToplayerSmall").style.height=ToplayerSmallHeight;$("divToplayerSmall").style.right=ToplayerSmallWidthvartopOff=0;if(ToplayerBigTop0)topOff=resHeight-ToplayerBigHeight+ToplayerBigTop;varisMain=false;#divToplayerBig{position:absolute;right:20px;bottom:1px;}bodydiv#divToplayerBig{position:fixed;}div#divToplayerBig{right:auto;bottom:auto;left:expression((-20-divToplayerBig.offsetWidth+(document.documentElement.clientWidth?document.documentElement.clientWidth:document.body.clientWidth)+(ignoreMe2=document.documentElement.scrollLeft?document.documentElement.scrollLeft:document.body.scrollLeft))+'px');top:expression((0-divToplayerBig.offsetHeight-topOff+(document.documentElement.clientHeight?document.documentElement.clientHeight:document.body.clientHeight)+(ignoreMe=document.documentElement.scrollTop?document.documentElement.scrollTop:document.body.scrollTop))+'px');}#divToplayerSmall{position:absolute;right:20px;bottom:10px;}bodydiv#divToplayerSmall{position:fixed;}div#divToplayerSmall{right:auto;bottom:auto;left:expression((-20-divToplayerSmall.offsetWidth+(document.documentElement.clientWidth?document.documentElement.clientWidth:document.body.clientWidth)+(ignoreMe2=document.documentElement.scrollLeft?document.documentElement.scrollLeft:document.body.scrollLeft))+'px');top:expression((0-divToplayerSmall.offsetHeight+(document.documentElement.clientHeight?document.documentElement.clientHeight:document.body.clientHeight)+(ignoreMe=document.documentElement.scrollTop?document.documentElement.scrollTop:document.body.scrollTop))+'px');}varisTopTrans=(ToplayerBigPath.indexOf("transparent")-1)?false:true;varisRemTrans=(ToplayerSmallPath.indexOf("transparent")-1)?false:true;vartop1session=3;vartop2session=5;InitToplayer(isTopTrans,isRemTrans);window.onload=StartToplayer;????|??????LIVE|???????????|ONE???????|ONETV |????'??|BigONE|?????????|  CrazyONE |????????????????????????????????????????????????????????19/01/07  19:30?????????????????????-?????:?????????????????????????19/01/07  18:43??????????????:??????????????????????19/01/07  17:41???:??????????????????????????????????19/01/07  16:49?????:??????"?????????????/?????1:2,??????"??????19/01/07  16:45????????????????????????????,?????2.5???????????????19/01/07  16:37???????:???"?????????????????-19:30?????????????19/01/07  14:32?????"?????????-18:30?????????"????????,????'??????19/01/07  14:45????????????????????????????????"?:??????????????19/01/07  14:37??????????:??????????????????????????????0:019/01/07  13:46varswfPeleSmall=newSWFObject("http://images.one.co.il/images/PeleEmulator/emulator_pelephone_01a.swf","peleSmall",160,470,"6","#FFFFFF");swfPeleSmall.addParam("quality","high");swfPeleSmall.addParam("wmode","transparent");swfPeleSmall.write("divPeleSmall");varswfPeleBig=newSWFObject("http://images.one.co.il/images/PeleEmulator/emulator_pelephone_02d.swf","peleBig",400,470,"6","#FFFFFF");swfPeleBig.addParam("quality","high");swfPeleBig.addParam("wmode","transparent");swfPeleBig.write("divWithBig");???:???????????????????????????????????????-ONE????????????????????????????????????????????.????????,???????????1:2,?????????????:"???????????"DisplayFlash("W_S_round_border_pic.swf","156","201","1","style=position:absolute");?????????????????????????(??????)?????????                          19/01/20077:26???????????????(????)????????????????????????????6:3,5:7?-5:7???????????????????????,???????23?????.?????,????????????????????????????????,???????????????????????????????????????????,????????????????????.??????????????????????????,??????????????????????????.????????????????????????????-1:1?????????.?????????????????????????????'?????????????????????????????.?????????????.???????????????????????????????(16???????),???????????????????????????????????????3???????,???????????????????????.????????- (only part of of the page presentation in firefox and page source html) why is it happening? what is midding in the http response? StringBuffer tResponse = new StringBuffer(); tResponse.append("HTTP/1.1 200 OK\n"); tResponse.append("Date: "+new Date().toString() +'\n'); tResponse.append("server: http-reactor/0.1-dev\n"); tResponse.append("last-Modified:"+ d.toString() +'\n'); tResponse.append("Content-Type: text/html; charset=windows-1255\n"); tResponse.append("Accept-Language: he; q=1.0, en; q=0.5:); tResponse.append("Content-Length: "+tFileContent.length()+'\n'); tResponse.append('\n'); tResponse.append(tFileContent); public StringBuffer FetchData(String FileName) throws FileNotFoundException{ StringBuffer tFileContent = new StringBuffer(); if (FileName.contains("../")) throw new SecurityException(); if (FileName.equals("/")) FileName = "\\index.html"; FileName.replace('/', '\\'); File f = new File(_root + FileName); Scanner scanner = new Scanner(f); while(scanner.hasNext()) tFileContent.append(scanner.next()); return generateResponse(tFileContent,f.lastModified()); } private StringBuffer generateResponse(StringBuffer tFileContent, long l) { StringBuffer tResponse = new StringBuffer(); Date d = new Date(l); tResponse.append("HTTP/1.1 200 OK\n"); tResponse.append("Date: "+new Date().toString() +'\n'); tResponse.append("server: http-reactor/0.1-dev\n"); tResponse.append("last-Modified:"+ d.toString() +'\n'); tResponse.append("Content-Type: text/html; charset=windows-1255\n"); tResponse.append("Accept-Language: he; q=1.0, en; q=0.5:); tResponse.append("Content-Length: "+tFileContent.length()+'\n'); tResponse.append('\n'); tResponse.append(tFileContent); return tResponse; }

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  • PHP - My array returns NULL values when placed in a function, but works fine outside of the function

    - by orbit82
    Okay, let me see if I can explain this. I am making a newspaper WordPress theme. The theme pulls posts from categories. The front page shows multiple categories, organized as "newsboxes". Each post should show up only ONCE on the front page, even if said post is in two or more categories. To prevent posts from duplicating on the front page, I've created an array that keeps track of the individual post IDs. When a post FIRST shows up on the front page, its ID gets added to the array. Before looping through the posts for each category, the code first checks the array to see which posts have ALREADY been displayed. OK, so now remember how I said earlier that the front page shows multiple categories organized as "newsboxes"? Well, these newsboxes are called onto the front page using PHP includes. I have 6 newsboxes appearing on the front page, and the code to call them is EXACTLY the same. I didn't want to repeat the same code 6 times, so I put all of the inclusion code into a function. The function works, but the only problem is that it screws up the duplicate posts code I mentioned earlier. The posts all repeat. Running a var_dump on the $do_not_duplicate variable returns an array with null indices. Everything works PERFECTLY if I don't put the code inside a function, but once I do put them in a function it's like the arrays aren't even connecting with the posts. Here is the code with the arrays. The key variables in question here include $do_not_duplicate[] = $post-ID, $do_not_duplicate and 'post__not_in' = $do_not_duplicate <?php query_posts('cat='.$settings['cpress_top_story_category'].'&posts_per_page='.$settings['cpress_number_of_top_stories'].'');?> <?php if (have_posts()) : ?> <!--TOP STORY--> <div id="topStory"> <?php while ( have_posts() ) : the_post(); $do_not_duplicate[] = $post->ID; ?> <a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_post_thumbnail('top-story-thumbnail'); ?></a> <h2 class="extraLargeHeadline"><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2> <div class="topStory_author"><?php cpress_show_post_author_byline(); ?></div> <div <?php post_class('topStory_entry') ?> id="post-<?php the_ID(); ?>"> <?php if($settings['cpress_excerpt_or_content_top_story_newsbox'] == "content") { the_content(); ?><a href="<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>"><span class="read_more"><?php echo $settings['cpress_more_text']; ?></span></a> <?php } else { the_excerpt(); ?><a href="<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>"><span class="read_more"><?php echo $settings['cpress_more_text']; ?></span></a> <?php }?> </div><!--/topStoryentry--> <div class="topStory_meta"><?php cpress_show_post_meta(); ?></div> <?php endwhile; wp_reset_query(); ?> <?php if(!$settings['cpress_hide_top_story_more_stories']) { ?> <!--More Top Stories--><div id="moreTopStories"> <?php $category_link = get_category_link(''.$settings['cpress_top_story_category'].''); ?> <?php if (have_posts()) : ?> <?php query_posts( array( 'cat' => ''.$settings['cpress_top_story_category'].'', 'posts_per_page' => ''.$settings['cpress_number_of_more_top_stories'].'', 'post__not_in' => $do_not_duplicate ) ); ?> <h4 class="moreStories"> <?php if($settings['cpress_make_top_story_more_stories_link']) { ?> <a href="<?php echo $category_link; ?>" title="<?php echo strip_tags($settings['cpress_top_story_more_stories_text']);?>"><?php echo strip_tags($settings['cpress_top_story_more_stories_text']);?></a><?php } else { echo strip_tags($settings['cpress_top_story_more_stories_text']); } ?> </h4> <ul> <?php while( have_posts() ) : the_post(); $do_not_duplicate[] = $post->ID; ?> <li><h2 class="mediumHeadline"><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2> <?php if(!$settings['cpress_hide_more_top_stories_excerpt']) { ?> <div <?php post_class('moreTopStory_postExcerpt') ?> id="post-<?php the_ID(); ?>"><?php if($settings['cpress_excerpt_or_content_top_story_newsbox'] == "content") { the_content(); ?><a href="<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>"><span class="read_more"><?php echo $settings['cpress_more_text']; ?></span></a> <?php } else { the_excerpt(); ?> <a href="<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>"><span class="read_more"><?php echo $settings['cpress_more_text']; ?></span></a> <?php }?> </div><?php } ?> <div class="moreTopStory_postMeta"><?php cpress_show_post_meta(); ?></div> </li> <?php endwhile; wp_reset_query(); ?> </ul> <?php endif;?> </div><!--/moreTopStories--> <?php } ?> <?php echo(var_dump($do_not_duplicate)); ?> </div><!--/TOP STORY--> <?php endif; ?> And here is the code that includes the newsboxes onto the front page. This is the code I'm trying to put into a function to avoid duplicating it 6 times on one page. function cpress_show_templatebitsf($tbit_num, $tbit_option) { global $tbit_path; global $shortname; $settings = get_option($shortname.'_options'); //display the templatebits (usually these will be sidebars) for ($i=1; $i<=$tbit_num; $i++) { $tbit = strip_tags($settings[$tbit_option .$i]); if($tbit !="") { include_once(TEMPLATEPATH . $tbit_path. $tbit.'.php'); } //if }//for loop unset($tbit_option); } I hope this makes sense. It's kind of a complex thing to explain but I've tried many things to fix it and have had no luck. I'm stumped. I'm hoping it's just some little thing I'm overlooking because it seems like it shouldn't be such a problem.

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  • Null-free "maps": Is a callback solution slower than tryGet()?

    - by David Moles
    In comments to "How to implement List, Set, and Map in null free design?", Steven Sudit and I got into a discussion about using a callback, with handlers for "found" and "not found" situations, vs. a tryGet() method, taking an out parameter and returning a boolean indicating whether the out parameter had been populated. Steven maintained that the callback approach was more complex and almost certain to be slower; I maintained that the complexity was no greater and the performance at worst the same. But code speaks louder than words, so I thought I'd implement both and see what I got. The original question was fairly theoretical with regard to language ("And for argument sake, let's say this language don't even have null") -- I've used Java here because that's what I've got handy. Java doesn't have out parameters, but it doesn't have first-class functions either, so style-wise, it should suck equally for both approaches. (Digression: As far as complexity goes: I like the callback design because it inherently forces the user of the API to handle both cases, whereas the tryGet() design requires callers to perform their own boilerplate conditional check, which they could forget or get wrong. But having now implemented both, I can see why the tryGet() design looks simpler, at least in the short term.) First, the callback example: class CallbackMap<K, V> { private final Map<K, V> backingMap; public CallbackMap(Map<K, V> backingMap) { this.backingMap = backingMap; } void lookup(K key, Callback<K, V> handler) { V val = backingMap.get(key); if (val == null) { handler.handleMissing(key); } else { handler.handleFound(key, val); } } } interface Callback<K, V> { void handleFound(K key, V value); void handleMissing(K key); } class CallbackExample { private final Map<String, String> map; private final List<String> found; private final List<String> missing; private Callback<String, String> handler; public CallbackExample(Map<String, String> map) { this.map = map; found = new ArrayList<String>(map.size()); missing = new ArrayList<String>(map.size()); handler = new Callback<String, String>() { public void handleFound(String key, String value) { found.add(key + ": " + value); } public void handleMissing(String key) { missing.add(key); } }; } void test() { CallbackMap<String, String> cbMap = new CallbackMap<String, String>(map); for (int i = 0, count = map.size(); i < count; i++) { String key = "key" + i; cbMap.lookup(key, handler); } System.out.println(found.size() + " found"); System.out.println(missing.size() + " missing"); } } Now, the tryGet() example -- as best I understand the pattern (and I might well be wrong): class TryGetMap<K, V> { private final Map<K, V> backingMap; public TryGetMap(Map<K, V> backingMap) { this.backingMap = backingMap; } boolean tryGet(K key, OutParameter<V> valueParam) { V val = backingMap.get(key); if (val == null) { return false; } valueParam.value = val; return true; } } class OutParameter<V> { V value; } class TryGetExample { private final Map<String, String> map; private final List<String> found; private final List<String> missing; public TryGetExample(Map<String, String> map) { this.map = map; found = new ArrayList<String>(map.size()); missing = new ArrayList<String>(map.size()); } void test() { TryGetMap<String, String> tgMap = new TryGetMap<String, String>(map); for (int i = 0, count = map.size(); i < count; i++) { String key = "key" + i; OutParameter<String> out = new OutParameter<String>(); if (tgMap.tryGet(key, out)) { found.add(key + ": " + out.value); } else { missing.add(key); } } System.out.println(found.size() + " found"); System.out.println(missing.size() + " missing"); } } And finally, the performance test code: public static void main(String[] args) { int size = 200000; Map<String, String> map = new HashMap<String, String>(); for (int i = 0; i < size; i++) { String val = (i % 5 == 0) ? null : "value" + i; map.put("key" + i, val); } long totalCallback = 0; long totalTryGet = 0; int iterations = 20; for (int i = 0; i < iterations; i++) { { TryGetExample tryGet = new TryGetExample(map); long tryGetStart = System.currentTimeMillis(); tryGet.test(); totalTryGet += (System.currentTimeMillis() - tryGetStart); } System.gc(); { CallbackExample callback = new CallbackExample(map); long callbackStart = System.currentTimeMillis(); callback.test(); totalCallback += (System.currentTimeMillis() - callbackStart); } System.gc(); } System.out.println("Avg. callback: " + (totalCallback / iterations)); System.out.println("Avg. tryGet(): " + (totalTryGet / iterations)); } On my first attempt, I got 50% worse performance for callback than for tryGet(), which really surprised me. But, on a hunch, I added some garbage collection, and the performance penalty vanished. This fits with my instinct, which is that we're basically talking about taking the same number of method calls, conditional checks, etc. and rearranging them. But then, I wrote the code, so I might well have written a suboptimal or subconsicously penalized tryGet() implementation. Thoughts?

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