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  • Whar parts of functionality should be refactored into a directive? [AngularJS]

    - by Sprottenwels
    I am creating an application from legacy code using AngularJS. I wonder what parts of my code should be moved into a directive. For example, i had thought of moving a table which is used multiple times across the application into a directive. The tables alter from headings and size. Is it worth the effort or even a good practice to turn such things into their own directives or should i create each table in a unique way?

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  • Silverlight 4 Training Kit

    - by ScottGu
    We recently released a new free Silverlight 4 Training Kit that walks you through building business applications with Silverlight 4.  You can browse the training kit online or alternatively download an entire offline version of the training kit.  The training material is structured on teaching how to use the new Silverlight 4 features to build an end to end business application. The training kit includes 8 modules, 25 videos, and several hands on labs. Below is a breakdown and links to all of the content. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Module 1: Introduction Click here to watch this module. In this video John Papa and Ian Griffiths discuss the key areas that the Building Business Applications with Silverlight 4 course focuses on. This module is the overview of the course and covers many key scenarios that are faced when building business applications, and how Silverlight can help address them. Module 2: WCF RIA Services Click here to explore this module. In this lab, you will create a web site for managing conferences that will be the basis for the other labs in this course. Don’t worry if you don’t complete a particular lab in the series – all lab manual instructions are accompanied by completed solutions, so you can either build your own solution from start to finish, or dive straight in at any point using the solutions provided as a starting point. In this lab you will learn how to set up WCF RIA Services, create bindings to the domain context, filter using the domain data source, and create domain service queries. Online Link Download Source Download Lab Document Videos Module 2.1 - WCF RIA Services Ian Griffiths sets up the Entity Framework and WCF RIA Services for the sample Event Manager application for the course. He covers how to set up the services, how the Domain Services work and the role that the DomainContext plays in the sample application. He also reviews the metadata classes and integrating the navigation framework. Module 2.2 – Using WCF RIA Services to Edit Entities Ian Griffiths discusses how he adds the ability to edit and create individual entities with the features built into WCF RIA Services into the sample Event Manager application. He covers data binding fundamentals, IQueryable, LINQ, the DomainDataSource, navigation to a single entity using the navigation framework, and how to use the Visual Studio designer to do much of the work . Module 2.3 – Showing Master/Details Records Using WCF RIA Services Ian Griffiths reviews how to display master/detail records for the sample Event Manager application using WCF RIA Services. He covers how to use the Include attribute to indicate which elements to serialize back to the client. Ian also demonstrates how to use the Data Sources window in the designer to add and bind controls to specific data elements. He wraps up by showing how to create custom services to the Domain Services. Module 3 – Authentication, Validation, MVVM, Commands, Implicit Styles and RichTextBox Click here to visit this module. This lab demonstrates how to build a login screen, integrate ASP.NET authentication, and perform validation on data elements. Model-View-ViewModel (MVVM) is introduced and used in this lab as a pattern to help separate the UI and business logic. You will also learn how to use implicit styling and the new RichTextBox control. Online Link Download Source Download Lab Document Videos Module 3.1 – Authentication Ian Griffiths covers how to integrate a login screen and authentication into the sample Event Manager application. Ian shows how to use the ASP.NET authentication and integrate it into WCF RIA Services and the Silverlight presentation layer. Module 3.2 – MVVM Ian Griffiths covers how to Model-View-ViewModel (MVVM) patterns into the sample Event Manager application. He discusses why MVVM exists, what separated presentation means, and why it is important. He shows how to connect the View to the ViewModel, why data binding is important in this symbiosis, and how everything fits together in the overall application. Module 3.3 –Validation Ian Griffiths discusses how validation of user input can be integrated into the sample Event Manager application. He demonstrates how to use the DataAnnotations, the INotifyDataErrorInfo interface, binding markup extensions, and WCF RIA Services in concert to achieve great validation in the sample application. He discusses how this technique allows for property level validation, entity level validation, and asynchronous server side validation. Module 3.4 – Implicit Styles Ian Griffiths discusses how why implicit styles are important and how they can be integrated into the sample Event Manager application. He shows how implicit styles defined in a resource dictionary can be applied to all elements of a particular kind throughout the application. Module 3.5 – RichTextBox Ian Griffiths discusses how the new RichTextBox control and it can be integrated into the sample Event Manager application. He demonstrates how the RichTextBox can provide editing for the event information and how it can display the rich text for selection and copying. Module 4 – User Profiles, Drop Targets, Webcam and Clipboard Click here to visit this module. This lab builds new features into the sample application to take the user's photo. It teaches you how to use the webcam to capture an image, use Silverlight as a drop target, and take advantage of programmatic access to the clipboard. Link Download Source Download Lab Document Videos Module 4.1 – Webcam Ian Griffiths demonstrates how the webcam adds value to the sample Event Manager application by capturing an image of the attendee. He discusses the VideoCaptureDevice, the CaptureDviceConfiguration, and the CaptureSource classes and how they allow audio and video to be captured so you can grab an image from the capture device and save it. Module 4.2 - Drag and Drop in Silverlight Ian Griffiths demonstrates how to capture and handle the Drop in the sample Event Manager application so the user can drag a photo from a file and drop it into the application. Ian reviews the AllowDrop property, the Drop event, how to access the file that can be dropped, and the other drag related events. He also reviews how to make this work across browsers and the challenges for this. Module 5 – Schedule Planner and Right Mouse Click Click here to visit this module. This lab builds on the application to allow grouping in the DataGrid and implement right mouse click features to add context menu support. Link Download Source Download Lab Document Videos Module 5.1 – Grouping and Binding Ian Griffiths demonstrates how to use the grouping features for data binding in the DataGrid and how it applies to the sample Event Manager application. He reviews the role of the CollectionViewSource in grouping, customizing the templates for headers, and how to work with grouping with ItemsControls. Module 5.2 – Layout Visual States Ian Griffiths demonstrates how to use the Fluid UI animation support for visual states in the ListBox control DataGrid and how it applies to the sample Event Manager application. He reviews the 3 visual states of BeforeLoaded, AfterLoaded, and BeforeUnloaded. Module 5.3 – Right Mouse Click Ian Griffiths demonstrates how to add support for handling the right mouse button click event to display a context menu for the Event Manager application. He demonstrates how to handle the event, show a custom context menu control, and integrate it into the scheduling portion of the application. Module 6 – Printing the Schedule Click here to visit this module. This lab teaches how to use the new printing features in Silverlight 4. The lab walks through the PrintDocument class and the ViewBox control, while showing how to print multiple pages of content using them. Link Download Source Download Lab Document Videos Module 6.1 – Printing and the Viewbox Ian Griffiths demonstrates how to add the ability to print the schedule to the sample Event Manager application. He walks through the importance of the PrintDocument class and its members. He also shows how to handle printing the visual tree and how the ViewBox control can help. Module 6.2 – Multi Page Printing Ian Griffiths expands on his printing discussion by showing how to handle printing multiple pages of content for the sample Event Manager application. He shows how to paginate the content and points out various tips to keep in mind when determining the printable area. Module 7 – Running the Event Dashboard Out of Browser Click here to visit this module. This lab builds a dashboard for the sample application while explaining the fundamentals of the out of browser features, how to handle authentication, displaying notifications (toasts), and how to use native integration to use COM Interop with Silverlight. Link Download Source Download Lab Document Videos Module 7.1 – Out of Browser Ian Griffiths discusses the role of an Out of Browser application for administrators to manage the events and users in the sample Event Manager application. He discusses several reasons why out of browser applications may better suit your needs including custom chrome, toasts, window placement, cross domain access, and file access. He demonstrates the basic technique to take your application and make it work out of browser using the tools. Module 7.2 – NotificationWindow (Toasts) for Elevated Trust Out of Browser Applications Ian Griffiths discusses the how toasts can be used in the sample Event Manager application to show information that may require the user's attention. Ian covers how to create a toast using the NotificationWindow, security implications, and how to make the toast appear as needed. Module 7.3 – Out of Browser Window Placement Ian Griffiths discusses the how to manage the window positioning when building an out of browser application, handling the windows state, and controlling and handling activation of the window. Module 7.4 – Out of Browser Elevated Trust Application Overview Ian Griffiths discusses the implications of creating trusted out of browser application for the Event Manager sample application. He reviews why you might want to use elevated trust, what features is opens to you, and how to take advantage of them. Topics Ian covers include the dynamic keyword in C# 4, the AutomationFactory class, the API to check if you are in a trusted application, and communicating with Excel. Module 8 – Advanced Out of Browser and MEF Click here to visit this module. This hands-on lab walks through the creation of a trusted out of browser application and the new functionality that comes with that. You will learn to use COM Automation, handle the window closing event, set custom window chrome, digitally sign your Silverlight out of browser trusted application, create a silent install option, and take advantage of MEF. Link Download Source Download Lab Document Videos Module 8.1 – Custom Window Chrome for Elevated Trust Out of Browser Applications Ian Griffiths discusses how to replace the standard operating system window chrome with customized chrome for an elevated trusted out of browser application. He covers how it is important to handle close, resize, minimize, and maximize events. Ian mentions that the tooling was not ready when he shot this video, but the good news is that the tooling now supports setting the custom chrome directly from the property page for the Silverlight application. Module 8.2 – Window Closing Event for Out of Browser Applications Ian Griffiths discusses the WindowClosing event and how to handle and optionally cancel the event. Module 8.3 – Silent Install of Out of Browser Applications Ian Griffiths discusses how to use the SLLauncher executable to install an out of browser application. He discusses the optional command line switches that can be set including how the emulate switch can help you emulate the install process. Ian also shows how to setup a shortcut for the application and tell the application where it should look for future updates online. Module 8.4 – Digitally Signing Out of Browser Application Ian Griffiths discusses how and why to digitally sign an out of browser application using the signtool program. He covers what trusted certificates are, the implications of signing (or not signing), and the effect on the user experience. Module 8.5 – The Value of MEF with Silverlight Ian Griffiths discusses what MEF is, how your application can benefit from it, and the fundamental features it puts at your disposal. He covers the 3 step import, export and compose process as well as how to dynamically import XAP files using MEF. Summary As you can probably tell from the long list above – this series contains a ton of great content, and hopefully provides a nice end-to-end walkthrough that helps explain how to take advantage of Silverlight 4 (and all its new features).  Hope this helps, Scott

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  • In-Application Support Made Easier

    - by matt.hicks
    With the availability of Oracle UPK 3.6.1 and Enablement Service Pack 1 for Oracle UPK 3.6.1 (Oracle Support login required for both), there are quite a few changes for content admins to absorb. In addition to the support added for dozens of application releases, patches and new target applications, we've also added features to make implementing and using In-Application Support even easier. First, the old Help Menu Integration Guides have been updated and combined into a single In-Application Support Guide. If you integrate UPK content for user assistance, or if you're interested in doing so, read the new guide! It covers all the integration steps, including a section on the new In-Application Support Configuration Utility. If you've integrated content in multiple languages, or if you've ever had to make configuration changes for UPK Help Integration, then you know how cumbersome it was to manually edit javascript files. No longer! The Player now includes a configuration utility that provides a web browser interface for setting all In-Application Support options. From the main screen, you see a list of applications covered by the published content. Clicking on an application name takes you to the edit configuration screen where you can set all Player options for that application. No more digging through the Player folders to find the right javascript file to edit. No complicated javascript syntax to make changes. And with Enablement Service Pack 1 we've added a new feature we're calling the Tabbed Gateway. The Tabbed Gateway is a top-level navigation bar for Help Integration. And all tabs, links, and text are controlled with the Configuration Utility... I think the Tabbed Gateway is a really cool and exciting feature for content launch. I can't wait to hear how your ideas for how to use it for your content. Let me know in comments or email!

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  • How to Change the Default Application for Android Tasks

    - by Jason Fitzpatrick
    When it comes time to switch from using one application to another on your Android device it isn’t immediately clear how to do so. Follow along as we walk you through swapping the default application for any Android task. Initially changing the default application in Android is a snap. After you install the new application (new web browser, new messaging tool, new whatever) Android prompts you to pick which application (the new or the old) you wish to use for that task the first time you attempt to open a web page, check your text message, or otherwise trigger the event. Easy! What about when it comes time to uninstall the app or just change back to your old app? There’s no helpful pop-up dialog box for that. Read on as we show you how to swap out any default application for any other with a minimum of fuss. Latest Features How-To Geek ETC How to Change the Default Application for Android Tasks Stop Believing TV’s Lies: The Real Truth About "Enhancing" Images The How-To Geek Valentine’s Day Gift Guide Inspire Geek Love with These Hilarious Geek Valentines RGB? CMYK? Alpha? What Are Image Channels and What Do They Mean? How to Recover that Photo, Picture or File You Deleted Accidentally Now Together and Complete – McBain: The Movie [Simpsons Video] Be Creative by Using Hex and RGB Codes for Crayola Crayon Colors on Your Next Web or Art Project [Geek Fun] Flash Updates; Finally Supports Full Screen Video on Multiple Monitors 22 Ways to Recycle an Altoids Mint Tin Make Your Desktop Go Native with the Tribal Arts Theme for Windows 7 A History of Vintage Transformers: Decepticons Edition [Infographic]

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  • How to structure an application that combines WCF and WPF

    - by CiaranG
    I'm in the process of learning how to use WCF (Windows Communication Foundation) to allow a client/server desktop application to communicate. The application's UI will be implemented using WPF, and we will probably use SQL Server for our database. What I'm struggling with, is understanding how to structure such an application. From what I've read, there are three components of a WCF application (which in the examples I've seen have existed as separate projects): A WCF service A WCF service host A WCF service client My question then, is - should these projects solely implement the functionality of sending/receiving data from the client/server? Would it make better sense this way? Would it make sense to create a separate WPF (Windows Presentation Foundation) project to implement the UI for the application? And so, when I need to send/receive data from the client/server, I could simply invoke the operations provided in the WCF projects that I have created? For anyone who has built similar applications previously, perhaps you could explain what worked best for you in terms of structuring your application? For example, if I create a user registration page. When the user clicks the 'Register' button, the client application will need to send the data to the server. In this case, could I just invoke the methods provided in the WCF projects to send the data? Also, what data structures worked best for you when sending/receiving data? My initial thought is sending/receiving XML containing the data. Is this an option that is easy to implement? I realise that answers to this question may well be a matter of opinion - unless there are specific best practices that I'm not aware of. Thank you

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  • Using PreApplicationStartMethod for ASP.NET 4.0 Application to Initialize assemblies

    - by ChrisD
    Sometimes your ASP.NET application needs to hook up some code before even the Application is started. Assemblies supports a custom attribute called PreApplicationStartMethod which can be applied to any assembly that should be loaded to your ASP.NET application, and the ASP.NET engine will call the method you specify within it before actually running any of code defined in the application. Lets discuss how to use it using Steps : 1. Add an assembly to an application and add this custom attribute to the AssemblyInfo.cs. Remember, the method you speicify for initialize should be public static void method without any argument. Lets define a method Initialize. You need to write : [assembly:PreApplicationStartMethod(typeof(MyInitializer.InitializeType), "InitializeApp")] 2. After you define this to an assembly you need to add some code inside InitializeType.InitializeApp method within the assembly. public static class InitializeType {     public static void InitializeApp()     {           // Initialize application     } } 3. You must reference this class library so that when the application starts and ASP.NET starts loading the dependent assemblies, it will call the method InitializeApp automatically. Warning Even though you can use this attribute easily, you should be aware that you can define these kind of method in all of your assemblies that you reference, but there is no guarantee in what order each of the method to be called. Hence it is recommended to define this method to be isolated and without side effect of other dependent assemblies. The method InitializeApp will be called way before the Application_start event or even before the App_code is compiled. This attribute is mainly used to write code for registering assemblies or build providers. Read Documentation I hope this post would come helpful.

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  • Suggestion for setting web application parameters

    - by user40730
    I'm creating a web application on GWT. I'm using MVP pattern with activities and places. I have a xml config file containing some parameters to be used by the application. Content of this xml file is sent to the client using HttpRequest; I'm using a singleton class to hold the information from the xml file. Right now, the application is getting the data when the user starts the application in the home page, that is working well. Now, since I'm using activities and places, a user can bookmark a page and starts the application in any other page (Place). And here comes the problem: Since I'm using some of the information from the xml file to set some ui widgets, I have to check if the xml config file was read and the application already has the parameters (I do this by checking the singleton class). But the xml file is read by using an HttpRequest, so I got errors 'cause the application needs some parameters to initialize some ui widgets, but these parameters aren't ready on time. I was thinking on using an synchronous request to fix the problem, but it seems complicated and not recommendable to do that. So, I'd like to hear some other suggestions. Thanks.

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  • Saving a list of items in Application State ASP.NET MVC ?

    - by Calibre2010
    Hi Guys, I'm having a bit of trouble with knowing how I can save items from a list I have in Application state in the global.asax as- Application[""]. My controller basically takes in some user input, I then pass this to another classes Method as parameters it gets added to a list all the time. This data thats getting added to the list I want to store it, but without using a db. By using Application State. . I have been instantiating this class and calling its method to return the list of items but I dont think Application State is saving it. Here is what I have so far. . protected void Application_Start() { RegisterRoutes(RouteTable.Routes); TimeLineInformation t = new TimeLineInformation(); IList<SWTimeEnvInfoDTO> g = t.getInfo(); Application["AppID"] = g; } ^ Global.asax IList<SWTimeEnvInfoDTO> result = new List<SWTimeEnvInfoDTO>(); public void returnTimeLineInfo(string SWrelease, string EnvName, DateTime SDate, DateTime EDate) { SWTimeEnvInfoDTO myDTO = new SWTimeEnvInfoDTO(); myDTO.softwareReleaseName = SWrelease; myDTO.environmentName = EnvName; myDTO.StartDate = SDate; myDTO.EndDate = EDate; result.Add(myDTO); getInfo(); } public IList<SWTimeEnvInfoDTO> getInfo() { return result; } ^ class im calling The SWTimeEnvInfoDTO type has get and set methods for the data. I am calling the application from a View as well. It works with a string Application["AppID"] = "fgt"; and shows this once i read it from my view.

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  • A Visual Studio tool eliminating the need to rewrite for web and mobile

    - by Visual WebGui
    We have already covered the BYOD requirements that an application developer is faced with, in an earlier blog entry ( How to Bring Your Own Device (BYOD) to a .NET application ). In that entry we emphasized the fact that application developers will need to prepare their applications for serving multiple types of devices on multiple platforms, ranging from the smallest mobile devices up to and beyond the largest desktop devices. The experts prediction is that in the near future we will see that the...(read more)

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  • Creating extendible applications with MEF

    - by Visual WebGui
    Ever wanted to create an application that is easy to maintain and even more easy to extend? Then the following piece by Michael Hensen about Microsoft Extension Framework (MEF) could be a solution for your needs! With MEF, which is part of VS2010 own extensions platform, you can write parts of an application is an enclosed dll. This way you can build up your application the normal way and based on the requirements of a client you can add or remove functions as easy as removing a dll from the base...(read more)

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  • Why should I use Zend_Application?

    - by Billy ONeal
    I've been working on a Zend Framework application which currently does a bunch of things through Zend Application and a few resource plugins written for it. However, looking at this codebase now, it seems to me that using Zend_Application just makes things more complicated; and a plain, more "traditional" bootstrap file would do a better job of being transparent. This is even more the case because the individual components of Zend -- Zend_Controller, Zend_Navigation, etc. -- don't reference Zend_Application at all. Therefore they do things like "Well just call setRoute and be on your way," and the user is left scratching their head as to how to implement that in terms of the application.ini configuration file. This is not to say that one can't figure out what's going on by doing spelunking through the ZF source code. My problem with that approach is that it's to easy to depend on something that's an implementation detail, rather than a contract, and that all it seems to do is add an extra layer of indirection that one must wade through to understand an application. I look at pre ZF 1.8 example code, before Zend_Application existed, and everywhere I see plain bootstrap files that setup the MVC framework and get on their way. The code is clear and easy to understand, even if it is a bit repetitive. I like the DRY concept that Application gets you, but particularly when I'm assuming first people looking at the app's code aren't really familiar with Zend at all, I'm considering blowing away any dependence I have on Zend_Application and returning to a traditional bootstrap file. Now, my concern here is that I don't have much experience doing this, and I don't want to get rid of Zend_Application if it does something particularly important of which I am unaware, or something of that nature. Is there a really good reason I should keep it around?

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  • Is shipping a Clojure desktop app realistic?

    - by Cedric Martin
    I'm currently shipping a desktop Java application. It is a plain old Java 5 Java / Swing app and so far everything worked nicely. Java 5 was targetted because some users were on OS X version / computers that shall never have Java 6 (we may lift this limitation soon and switch to a newer Java and simply abandoning my users stuck with Java 5). I'm quickly getting up to speed with Clojure but I haven't really done lots of Clojure-to-Java and Java-to-Clojure yet and I was wondering if it was realistic to ship a Clojure desktop application instead of a Java application? The application I'm shipping is currently about 12 MB with all the .jar so adding Clojure doesn't seen to be too much of an issue. My plan would be to have Clojure call Java APIs: my application is already divided in several independent jars. If I understand correctly calling Clojure from Java is harder than calling Java code from Clojure which is why I'd basically rewrite all the UI (part of the UI, mixing Swing components and self-made BufferedImages needs to be rewritten anyway due to the rise of retina display), and do all the 'wiring' from Clojure. So that's the problem I'm facing: is it realistic to ship a Clojure desktop app? (it certainly doesn't seem to be very widespread but then shipping plain Java desktop apps ain't that common either and I'm doing it anyway) Technically, what would need to be done? (compared to shipping a Java app)

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  • How to map different UI views in a RESTful web application?

    - by MicE
    Hello, I'm designing a web application, which will support both standard UIs (accessed via browsers) and a RESTful API (an XML/JSON-based web service). User agents will be able to differentiate between these by using different values in the Accept HTTP header. The RESTful API will use the following URI structure (example for an "article" resource): GET /article/ - gets a list of articles POST /article/ - adds a new article PUT /article/{id} - updates an existing article based on {id} DELETE /article/{id} - deletes an existing article based on {id} The UI part of the application will however need to support multiple views, for example: a standard resource view a view for submitting a new resource a view for editing an existing resource a view for deleting an existing resource (i.e. display delete confirmation) Note that the latter three views are still accessed via GET, even though they are processed via overloaded POST. Possible solution: Introduce additional parameters (keywords) into URIs which would identify individual views - i.e. on top of the above, the application would support the following URIs (but only for Content-Type: text/html): GET /article/add - displays a form for adding a new article (fetched via GET, processed via POST) GET /article/123 - displays article 123 in "view" mode (fetched via GET) GET /article/123/edit - displays article 123 in "edit" mode (fetched via GET, processed via PUT overloaded as POST) GET /article/123/delete - displays "delete" confirmation for article 123 (fetched via GET, processed via DELETE overloaded as POST) A better implementation of the above might be to put the add/edit/delete keywords into a GET parameter - since they do not change the resource we're working with, it might be better to keep the base URI same for all of them. My question is: How would you map the above URI structure to UIs served to the regular user, considering that there can be several views per each resource, please? Do you agree with the possible solution detailed above, or would you recommend a different approach based on your experience? NB: we've already implemented an application which consists of a standalone RESTful API and a standalone web application. I'm currently looking into options for future projects where these two would be merged together (i.e. in order to reduce overhead). Thank you, M.

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  • What is common architecture of notification system on the web-forum, PMB and etc.?

    - by glaz666
    What I need is - list of new stuff from last visit - when user has already checked out some new entity since his last visit (ex. post on forum), mark this entity as read in the list - count different types of entities - private messages, posts, comments and etc. There are lot of websites using this technique for private messaging, listing new stuff and etc (ex. phpBB, this one and etc). Are there any common pattern, description of the system core which will events, making lists?

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  • Looking for design/architecture suggestions for a simple HTML game.

    - by z-boss
    Imagine that HTML page is a game surface (see picture). User can have n number of boards (blue divs) on his page. Each board can be moved, re-sized, relabeled, created new and removed. Inside each board there are m number of figures (purple divs). Each of these user can move inside the board or to another board, re-size, change color and label, delete, add new. The goal of the game is not important, but let's say it is to rearrange figures in a certain way so that they disappear. But the goal of the programmer is to save the whole game surface in the database for every user of the site, and to load it later when he returns. So, how do I go about data exchange between client and the database? I'll give my idea in one of the answers.

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  • High Availability for IaaS, PaaS and SaaS in the Cloud

    - by BuckWoody
    Outages, natural disasters and unforeseen events have proved that even in a distributed architecture, you need to plan for High Availability (HA). In this entry I'll explain a few considerations for HA within Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). In a separate post I'll talk more about Disaster Recovery (DR), since each paradigm has a different way to handle that. Planning for HA in IaaS IaaS involves Virtual Machines - so in effect, an HA strategy here takes on many of the same characteristics as it would on-premises. The primary difference is that the vendor controls the hardware, so you need to verify what they do for things like local redundancy and so on from the hardware perspective. As far as what you can control and plan for, the primary factors fall into three areas: multiple instances, geographical dispersion and task-switching. In almost every cloud vendor I've studied, to ensure your application will be protected by any level of HA, you need to have at least two of the Instances (VM's) running. This makes sense, but you might assume that the vendor just takes care of that for you - they don't. If a single VM goes down (for whatever reason) then the access to it is lost. Depending on multiple factors, you might be able to recover the data, but you should assume that you can't. You should keep a sync to another location (perhaps the vendor's storage system in another geographic datacenter or to a local location) to ensure you can continue to serve your clients. You'll also need to host the same VM's in another geographical location. Everything from a vendor outage to a network path problem could prevent your users from reaching the system, so you need to have multiple locations to handle this. This means that you'll have to figure out how to manage state between the geo's. If the system goes down in the middle of a transaction, you need to figure out what part of the process the system was in, and then re-create or transfer that state to the second set of systems. If you didn't write the software yourself, this is non-trivial. You'll also need a manual or automatic process to detect the failure and re-route the traffic to your secondary location. You could flip a DNS entry (if your application can tolerate that) or invoke another process to alias the first system to the second, such as load-balancing and so on. There are many options, but all of them involve coding the state into the application layer. If you've simply moved a state-ful application to VM's, you may not be able to easily implement an HA solution. Planning for HA in PaaS Implementing HA in PaaS is a bit simpler, since it's built on the concept of stateless applications deployment. Once again, you need at least two copies of each element in the solution (web roles, worker roles, etc.) to remain available in a single datacenter. Also, you need to deploy the application again in a separate geo, but the advantage here is that you could work out a "shared storage" model such that state is auto-balanced across the world. In fact, you don't have to maintain a "DR" site, the alternate location can be live and serving clients, and only take on extra load if the other site is not available. In Windows Azure, you can use the Traffic Manager service top route the requests as a type of auto balancer. Even with these benefits, I recommend a second backup of storage in another geographic location. Storage is inexpensive; and that second copy can be used for not only HA but DR. Planning for HA in SaaS In Software-as-a-Service (such as Office 365, or Hadoop in Windows Azure) You have far less control over the HA solution, although you still maintain the responsibility to ensure you have it. Since each SaaS is different, check with the vendor on the solution for HA - and make sure you understand what they do and what you are responsible for. They may have no HA for that solution, or pin it to a particular geo, or perhaps they have a massive HA built in with automatic load balancing (which is often the case).   All of these options (with the exception of SaaS) involve higher costs for the design. Do not sacrifice reliability for cost - that will always cost you more in the end. Build in the redundancy and HA at the very outset of the project - if you try to tack it on later in the process the business will push back and potentially not implement HA. References: http://www.bing.com/search?q=windows+azure+High+Availability  (each type of implementation is different, so I'm routing you to a search on the topic - look for the "Patterns and Practices" results for the area in Azure you're interested in)

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  • View controller/NIB architecture for non-navigation application with transitions?

    - by Ben
    I'm tinkering with an app that doesn't use the UINavigation root view control system, so I don't have natural ownership for each app "view". I essentially have two basic views, a document list view, and a document edit view. I'm playing with UIView animation for getting from a selected document to the edit view. I also have a toolbar that exists in both "views". Because I don't have UINavigation running the show for me, I have a tendency to just throw more and more stuff into one NIB and one view controller that owns the whole container. But now I'm trying to figure out how to segue from the document list view to the edit view if the edit view lives inside a different NIB, preserving the toolbar too. Anyone have thoughts or experience on app structures like this? I find the docs lacking on best practices around code/UI structure for anything except trivial one-screen apps or full-on navigation apps. Thanks!

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  • External modules security

    - by Jlouro
    I am developing some external modules for an application. These modules are BPL files and if present in the application folder the application loads them and uses whatever is available inside. How can I prevent the sharing of these modules by my clients? I need them to be authorized to use the modules (module by module). To have some sort of license, registration of the module, what is the best method? Thanks

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  • Using pkexec policy to run out of /opt/

    - by liberavia
    I still try to make it possible to run my app with root priveleges. Therefore I created two policies to run the application via pkexec (one for /usr/bin and one for /opt/extras... ) and added them to the setup.py: data_files=[('/usr/share/polkit-1/actions', ['data/com.ubuntu.pkexec.armorforge.policy']), ('/usr/share/polkit-1/actions', ['data/com.ubuntu.extras.pkexec.armorforge.policy']), ('/usr/bin/', ['data/armorforge-pkexec'])] ) additionally I added a startscript which uses pkexec for starting the application. It distinguishes between the two places and is used in the Exec-Statement of the desktopfile: #!/bin/sh if [ -f /opt/extras.ubuntu.com/armorforge/bin/armorforge ]; then pkexec "/opt/extras.ubuntu.com/armorforge/bin/armorforge" "$@" else pkexec `which armorforge` "$@" fi If I simply do a quickly package everything will work right. But if I package with extras option: quickly package --extras the Exec-statement will be exchanged. Even if I try to simulate the pkexec call via armorforge-pkexec It will aks for a password and then returns this: andre@andre-desktop:~/Entwicklung/Ubuntu/armorforge$ armorforge-pkexec (armorforge:10108): GLib-GIO-ERROR **: Settings schema 'org.gnome.desktop.interface' is not installed Trace/breakpoint trap (core dumped) So ok, I could not trick the opt-thing. How can I make sure, that my Application will run with root priveleges out of opt. I copied the way of using pkexec from synaptic. My application is for communicating with apparmor which currently has no dbus interface. Else I need to write into /etc/apparmor.d-folder. How should I deal with the opt-build which, as far as I understand, is required to submit my application to the ubuntu software center. Thanks for any hints and/or links :-)

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  • DB Architecture : Linking to intersection or to main tables?

    - by Jean-Nicolas
    Hi, I'm creating fantasy football system on my website but i'm very confuse about how I should link some of my table. Tables The main table is Pool which have all the info about the ruling of the fantasy draft. A standard table User, which contains the usual stuff. Intersection table called pools_users which contains id,pool_id,user_id because a user could be in more than one pool, and a pool contains more than 1 user. The problem Table Selections = that's the table that is causing problem. That's the selection that the user choose for his pool. This is related to the Player table but thats not relevant for this problem. Should I link this table to the table Pools_users or should I link it with both main table Pool and User. This table contains id,pool_id,user_id,player_id,... What is the best way link my tables? When I want to retrieve my data, I normally want the information to be divided BY users. "This user have those selections, this one those selections, etc).

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  • GTK app: How do I create a working indicator with Qt/C++?

    - by hakermania
    I've tried in 2 forums, but I had no luck so far. So, I am using Qt IDE in order to build my application so as to participate to the Ubuntu Showdown contest. In my application, I've done the following: void show_app(MainWindow *data) { //this works fine: app_indicator_set_status(appindicator, APP_INDICATOR_STATUS_PASSIVE); //this crashes the application: data->show(); } void MainWindow::make_indicator() { if(appindicator){ //appindicator has already been created return; } appindicator = app_indicator_new("Format Junkie Indicator", "formatjunkie", APP_INDICATOR_CATEGORY_APPLICATION_STATUS); GtkWidget* showapp_option; GtkWidget* indicatormenu = gtk_menu_new(); GtkWidget* item = gtk_menu_item_new_with_label("Format Junkie main menu"); gtk_menu_item_set_submenu(GTK_MENU_ITEM(item), indicatormenu); showapp_option = gtk_menu_item_new_with_label("Show App!"); g_signal_connect(showapp_option, "activate", G_CALLBACK(show_app), this); gtk_menu_shell_append(GTK_MENU_SHELL(indicatormenu), showapp_option); gtk_widget_show_all(indicatormenu); app_indicator_set_status(appindicator, APP_INDICATOR_STATUS_ACTIVE); app_indicator_set_attention_icon(appindicator, "dialog-warning"); app_indicator_set_menu(appindicator, GTK_MENU (indicatormenu)); } So, basically I am trying to make a simple indicator entry, which, on click, it will hide the indicator and display the application. The indicator can be successfully hidden using the PASSIVE thingy over there, but, during the call data-show();, the application crashes. Any help on what I am doing wrong would be appreciated! Also, please help me to correct this problem I'm facing (alternatively, I will migrate to the old and good tray icon (it works fine in 12.04, anyway) which I can handle very easily and efficiently)

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  • Booking logic and architecture, database sync: Hotels, tennis courts reservation system ...

    - by coulix
    Hello Stackers, Imagine that you want to design a tennis booking system. You have 5 tennis clubs as partenrs with no online api allowing you to check on their side if a court is booked or not: You have to build this part as well. Every time a booking is done on their side you want it to be know by our system. Probably using a POST request form tennis partner to our server. Every time a booking is done on our website, we want to push the booking to their system. The difficulty is that their system need to be online and accessible from outside. Ip may change, we have to use a dns updater. In case their system is not available we still accept the booking and fallback to an async email with 'i confirm booking/reject booking' link sent to the club. I find the whole process quite complex and was wondering about the way online hotel booking system and hotel were working. Do they all have their data open and online ? The good thing is that the data will grow large and fits nicely to some no SQL ;) like couch db

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  • CMS (Web Application OR Windows Application)

    - by Raha
    I am a little bit puzzled about something. I am creating a ASP.NET MVC eCommerce application and currently I have written all the back end in ASP.NET MVC. I was thinking if its better to write all the management in WPF instead of HTML, as its probably even less prone to be exploited by hackers. I am a Windows user so I am not really bothered about using Linux/Mac at the moment so I am quite aware that having all the back-end written in HTML will allow users to have access to the admin area using other OS. I would like to see what are the advantages and disadvantages of having WPF to manage the content of the website as its probably much easier to develop and manage (think about Live Writer).

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