rules engines - Page 180

Dependency injection: At what point am I allowed to create a new object?

- by Gaz_Edge

I am refactoring a PHP application, and I am trying to do has much dependency injection (DI) as possible. I feel like I've got a good grasp of how it works, and I can certainly see my classes becoming a lot leaner and more robust. I'm refactoring so that I can inject a dependency rather than create a new object within the class, but at some point I am going to have to create some objects, that is, use the dreaded new keyword. The problem I have now run into is at what point can I actually create new objects? It's looking like I'll end up at a top level class, creating loads of new objects as there is no where else to go. This feels wrong. I've read some blogs that use factory classes to create all the objects, and then you inject the factory into other classes. You can then call the factory methods, and the factory creates the new object for you. My concern with doing this is now my factory classes are going to be a new free-for-all! I guess this may be OK as they are factory classes, but are there some rules to stick to when using a factory pattern and DI, or am I going way off the mark here?

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Using mod_rewrite for a Virtual Filesystem vs. Real Filesystem

- by philtune

I started working in a department that uses a CMS in which the entire "filesystem" is like this: create a named file or folder - this file is given a unique node (ex. 2345) as well as a default "filename" (ex. /WelcomeToOurProductsPage) and apply a template assign one or more aliases to the file for a URL redirect (ex. /home-page-products - can also be accessed by /home-page-products.aspx) A new Rewrite command is written on the .htaccess file for each and every alias Server accesses either /WelcomeToOurProductsPage or /home-page-products and redirects to something like /template.aspx?tmp=2&node=2345 (here I'm guessing what it does - I only have front-end access for now - but I have enough clues to strongly assume) Node 2345 grabs content stored in a SQL Db and applies it to the template. Note: There are no actual files being created on the filesystem. It's entirely virtual. This is probably a very common thing, but since I have never run across this kind of system before two months ago, I wanted to explain it in case it isn't common. I'm not a fan at all of ASP or closed-sourced systems, so it may be that this is common practice for ASP developers. My question, that has taken far too long to ask, is: what are the benefits of this kind of system, as opposed to creating an actual file hierarchy? Are there any drawbacks to having every single file server call redirected? To having the .htaccess file hold rewrite rules for every single alias?

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SQL 2008/2005 Hosting :: Error - “Named Pipes Provider, error: 40 – Could not open a connection to SQL Server”

- by mbridge

When setting up a Microsoft Windows Server 2008 system, I went through the motions to set up IIS, MS SQL Server 2008, and Visual Studio 2010 to use as a test-bed. One of the immediate benefits of setting up such a system is that most development can be done remotely: MS SQL Server Management Studio, Visual Studio’s Web development suite, as well as file shares, remote desktop, etc, make for a great way to remotely develop in ‘pristine’ conditions. But there are drawbacks, too, such as needing to deal with firewall issues, not being able to penetrate past a router or the requirement of setting up a VPN. One of the problems I encountered when trying to remote into the MS SQL Server 2008 that I’d set up was the following error: Named Pipes Provider, error: 40 – Could not open a connection to SQL Server I followed the below steps, and was able to connect to the server after just a few moments of tinkering: 1. From the server in question, surf to this Microsoft article, and download and install the Firewall rules modification program. Never drop your firewall, even on a development machine, unless you have a really good reason to. 2. Launch SQL Server Configuration Manager. Navigate to SQL Server Network Configuration, then Protocols for your server name. Enable TCP/IP and Named Pipes by right-clicking and choosing Enable for each given Protocol Name. 3. Restart the SQL Server service from Services (or from command line, subsequently run “net stop mssqlserver” then “net start mssqlserver”. 4. Try your remote connection once more, and you should be able to connect. It’s not a terribly difficult concept, but one of the more challenging tasks developers face is dealing with environment setup. And while there is a certain blurred-line overlap between software development and server administration, sometimes the latter is daunting, especially given that you might set up only a handful of servers during your career.

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Iptables working strangely

- by user109985

I have Ubuntu 12.04 x64 installed in my laptop. I'm quite new to linux, and I wanted to specify certain rules for the iptables firewall. This is the saved config of my iptables: *mangle :PREROUTING ACCEPT [0:0] :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] COMMIT *nat :PREROUTING ACCEPT [0:0] :INPUT ACCEPT [0:0] :OUTPUT ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] -A PREROUTING -p tcp -m tcp --dport 3306 -j DNAT --to-destination 192.168.1.100:3306 -A PREROUTING -p tcp -m tcp --dport 11002 -j DNAT --to-destination 192.168.1.100:11002 -A PREROUTING -p tcp -m tcp --dport 13000 -j DNAT --to-destination 192.168.1.100:13000 -A PREROUTING -p tcp -m tcp --dport 13001 -j DNAT --to-destination 192.168.1.100:13001 -A PREROUTING -p tcp -m tcp --dport 13002 -j DNAT --to-destination 192.168.1.100:13002 -A PREROUTING -p tcp -m tcp --dport 13003 -j DNAT --to-destination 192.168.1.100:13003 -A PREROUTING -p tcp -m tcp --dport 13004 -j DNAT --to-destination 192.168.1.100:13004 -A PREROUTING -p tcp -m tcp --dport 13061 -j DNAT --to-destination 192.168.1.100:13061 -A PREROUTING -p tcp -m tcp --dport 13099 -j DNAT --to-destination 192.168.1.100:13099 -A POSTROUTING -j MASQUERADE COMMIT *filter :INPUT DROP [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A INPUT -i eth0 -p tcp -m tcp --dport 3306 -j ACCEPT -A INPUT -i eth0 -p tcp -m tcp --dport 80 -j ACCEPT COMMIT In theory, what it does is to drop all connections in all ports except for http, mysql and few other ports. Moreover, it redirects all mysql and 13000-13004..etc port connections to a specific local ip in the same port, which is 192.168.1.100. But what I find strange is that when my firewall is active, it blocks absolutely all the input connections, even those which must not block (http, mysql). In fact, I'm literally blocked and I can't establish any external connection. What am I doing wrong? PS: I tested the firewall without those redirections, and it still block all inputs, so I suppose it's not the problem.

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Dependency Injection: What point am I allowed to create a new object?

- by Gaz_Edge

I am refactoring a php application and I am trying to do has much dependency injection as possible. I feel like I've got a good grasp of how it works, and I can certainly see my classes becoming a lot leaner and more robust. Im refactoring so that I can inject a dependency rather than create a new object within the class, but at some point I am going to have to create some objects i.e. use the dreaded new keyword. The problem I have now run into is at what point can I actually create new objects? Its looking like I'll end up at a top level class, creating loads of new objects as there is no where else to go. This feels wrong. I've read some blogs that use factory classes to create all the objects, and then you inject the factory into other classes. You can then call the factory methods, and the factory creates the new object for you. My concern with doing this is now my factory classes are going to be a new free-for-all! I guess this may be ok as they are factory classes, but are there some rules to stick to when using factory pattern and DI, or am I going way off the mark here.

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SQL Server Editions and Integration Services

The SQL Server 2005 and SQL Server 2008 product family has quite a few editions now, so what does this mean for SQL Server Integration Services? Starting from the bottom we have the free edition known as Express, and the entry level Workgroup edition, as well as the new Web edition. None of these three include the full SSIS product, but they do all include the SQL Server Import and Export Wizard, with access to basic data sources but nothing more, so for simple loading and extraction of data this should suffice. You will not be able to build packages though, this is just a one shot deal aimed at using the wizard on an ad-hoc basis. To get the full power of Integration Services you need to start with Standard edition. This includes the BI Development Studio, for building your own packages, and fully functional IDE integrated into Visual Studio. (You get the full VS 2005/2008 IDE with the product). All core functions will be available but with a restricted set of transformations and tasks. The SQL Server 2005 Features Comparison or Features Supported by the Editions of SQL Server 2008 describes standard edition as having basic transforms, compared to Enterprise which includes the advanced transforms. I think basic is a little harsh considering the power you get with Standard, but the advanced covers the truly ground-breaking capabilities of data mining, text mining and cleansing or fuzzy transforms. The power of performing these operations within your ETL pipeline should not be underestimated, but not all processes will require these capabilities, so it seems like a reasonable delineation. Thankfully there are no feature limitations or artificial governors within Standard compared to Enterprise. The same control flow and data flow engines underpin both editions, with the same configuration and deployment options allowing you to work seamlessly between environments and editions if using the common components. In fact there are no govenors at all in SSIS, so whilst the SQL Database engine is limited to 4 CPUs in Standard edition, SSIS is only limited by the base operating system. The advanced transforms only available with Enterprise edition: Data Mining Training Destination Data Mining Query Component Fuzzy Grouping Fuzzy Lookup Term Extraction Term Lookup Dimension Processing Destination Partition Processing Destination The advanced tasks only available with Enterprise edition: Data Mining Query Task So in summary, if you want SQL Server Integration Services, you need SQL Server Standard edition, and for the more advanced tasks and transforms you need SQL Server Enterprise edition. To recap, the answer to the often asked question is no, SQL Server Integration Services is not available in SQL Server Express or Workgroup editions.

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Rendering ASP.NET MVC Views to String

- by Rick Strahl

It's not uncommon in my applications that I require longish text output that does not have to be rendered into the HTTP output stream. The most common scenario I have for 'template driven' non-Web text is for emails of all sorts. Logon confirmations and verifications, email confirmations for things like orders, status updates or scheduler notifications - all of which require merged text output both within and sometimes outside of Web applications. On other occasions I also need to capture the output from certain views for logging purposes. Rather than creating text output in code, it's much nicer to use the rendering mechanism that ASP.NET MVC already provides by way of it's ViewEngines - using Razor or WebForms views - to render output to a string. This is nice because it uses the same familiar rendering mechanism that I already use for my HTTP output and it also solves the problem of where to store the templates for rendering this content in nothing more than perhaps a separate view folder. The good news is that ASP.NET MVC's rendering engine is much more modular than the full ASP.NET runtime engine which was a real pain in the butt to coerce into rendering output to string. With MVC the rendering engine has been separated out from core ASP.NET runtime, so it's actually a lot easier to get View output into a string. Getting View Output from within an MVC Application If you need to generate string output from an MVC and pass some model data to it, the process to capture this output is fairly straight forward and involves only a handful of lines of code. The catch is that this particular approach requires that you have an active ControllerContext that can be passed to the view. This means that the following approach is limited to access from within Controller methods. Here's a class that wraps the process and provides both instance and static methods to handle the rendering:/// <summary> /// Class that renders MVC views to a string using the /// standard MVC View Engine to render the view. /// /// Note: This class can only be used within MVC /// applications that have an active ControllerContext. /// </summary> public class ViewRenderer { /// <summary> /// Required Controller Context /// </summary> protected ControllerContext Context { get; set; } public ViewRenderer(ControllerContext controllerContext) { Context = controllerContext; } /// <summary> /// Renders a full MVC view to a string. Will render with the full MVC /// View engine including running _ViewStart and merging into _Layout /// </summary> /// <param name="viewPath"> /// The path to the view to render. Either in same controller, shared by /// name or as fully qualified ~/ path including extension /// </param> /// <param name="model">The model to render the view with</param> /// <returns>String of the rendered view or null on error</returns> public string RenderView(string viewPath, object model) { return RenderViewToStringInternal(viewPath, model, false); } /// <summary> /// Renders a partial MVC view to string. Use this method to render /// a partial view that doesn't merge with _Layout and doesn't fire /// _ViewStart. /// </summary> /// <param name="viewPath"> /// The path to the view to render. Either in same controller, shared by /// name or as fully qualified ~/ path including extension /// </param> /// <param name="model">The model to pass to the viewRenderer</param> /// <returns>String of the rendered view or null on error</returns> public string RenderPartialView(string viewPath, object model) { return RenderViewToStringInternal(viewPath, model, true); } public static string RenderView(string viewPath, object model, ControllerContext controllerContext) { ViewRenderer renderer = new ViewRenderer(controllerContext); return renderer.RenderView(viewPath, model); } public static string RenderPartialView(string viewPath, object model, ControllerContext controllerContext) { ViewRenderer renderer = new ViewRenderer(controllerContext); return renderer.RenderPartialView(viewPath, model); } protected string RenderViewToStringInternal(string viewPath, object model, bool partial = false) { // first find the ViewEngine for this view ViewEngineResult viewEngineResult = null; if (partial) viewEngineResult = ViewEngines.Engines.FindPartialView(Context, viewPath); else viewEngineResult = ViewEngines.Engines.FindView(Context, viewPath, null); if (viewEngineResult == null) throw new FileNotFoundException(Properties.Resources.ViewCouldNotBeFound); // get the view and attach the model to view data var view = viewEngineResult.View; Context.Controller.ViewData.Model = model; string result = null; using (var sw = new StringWriter()) { var ctx = new ViewContext(Context, view, Context.Controller.ViewData, Context.Controller.TempData, sw); view.Render(ctx, sw); result = sw.ToString(); } return result; } } The key is the RenderViewToStringInternal method. The method first tries to find the view to render based on its path which can either be in the current controller's view path or the shared view path using its simple name (PasswordRecovery) or alternately by its full virtual path (~/Views/Templates/PasswordRecovery.cshtml). This code should work both for Razor and WebForms views although I've only tried it with Razor Views. Note that WebForms Views might actually be better for plain text as Razor adds all sorts of white space into its output when there are code blocks in the template. The Web Forms engine provides more accurate rendering for raw text scenarios. Once a view engine is found the view to render can be retrieved. Views in MVC render based on data that comes off the controller like the ViewData which contains the model along with the actual ViewData and ViewBag. From the View and some of the Context data a ViewContext is created which is then used to render the view with. The View picks up the Model and other data from the ViewContext internally and processes the View the same it would be processed if it were to send its output into the HTTP output stream. The difference is that we can override the ViewContext's output stream which we provide and capture into a StringWriter(). After rendering completes the result holds the output string. If an error occurs the error behavior is similar what you see with regular MVC errors - you get a full yellow screen of death including the view error information with the line of error highlighted. It's your responsibility to handle the error - or let it bubble up to your regular Controller Error filter if you have one. To use the simple class you only need a single line of code if you call the static methods. Here's an example of some Controller code that is used to send a user notification to a customer via email in one of my applications:[HttpPost] public ActionResult ContactSeller(ContactSellerViewModel model) { InitializeViewModel(model); var entryBus = new busEntry(); var entry = entryBus.LoadByDisplayId(model.EntryId); if ( string.IsNullOrEmpty(model.Email) ) entryBus.ValidationErrors.Add("Email address can't be empty.","Email"); if ( string.IsNullOrEmpty(model.Message)) entryBus.ValidationErrors.Add("Message can't be empty.","Message"); model.EntryId = entry.DisplayId; model.EntryTitle = entry.Title; if (entryBus.ValidationErrors.Count > 0) { ErrorDisplay.AddMessages(entryBus.ValidationErrors); ErrorDisplay.ShowError("Please correct the following:"); } else { string message = ViewRenderer.RenderView("~/views/template/ContactSellerEmail.cshtml",model, ControllerContext); string title = entry.Title + " (" + entry.DisplayId + ") - " + App.Configuration.ApplicationName; AppUtils.SendEmail(title, message, model.Email, entry.User.Email, false, false)) } return View(model); } Simple! The view in this case is just a plain MVC view and in this case it's a very simple plain text email message (edited for brevity here) that is created and sent off:@model ContactSellerViewModel @{ Layout = null; }re: @Model.EntryTitle @Model.ListingUrl @Model.Message ** SECURITY ADVISORY - AVOID SCAMS ** Avoid: wiring money, cross-border deals, work-at-home ** Beware: cashier checks, money orders, escrow, shipping ** More Info: @(App.Configuration.ApplicationBaseUrl)scams.html Obviously this is a very simple view (I edited out more from this page to keep it brief) - but other template views are much more complex HTML documents or long messages that are occasionally updated and they are a perfect fit for Razor rendering. It even works with nested partial views and _layout pages. Partial Rendering Notice that I'm rendering a full View here. In the view I explicitly set the Layout=null to avoid pulling in _layout.cshtml for this view. This can also be controlled externally by calling the RenderPartial method instead: string message = ViewRenderer.RenderPartialView("~/views/template/ContactSellerEmail.cshtml",model, ControllerContext); with this line of code no layout page (or _viewstart) will be loaded, so the output generated is just what's in the view. I find myself using Partials most of the time when rendering templates, since the target of templates usually tend to be emails or other HTML fragment like output, so the RenderPartialView() method is definitely useful to me. Rendering without a ControllerContext The preceding class is great when you're need template rendering from within MVC controller actions or anywhere where you have access to the request Controller. But if you don't have a controller context handy - maybe inside a utility function that is static, a non-Web application, or an operation that runs asynchronously in ASP.NET - which makes using the above code impossible. I haven't found a way to manually create a Controller context to provide the ViewContext() what it needs from outside of the MVC infrastructure. However, there are ways to accomplish this, but they are a bit more complex. It's possible to host the RazorEngine on your own, which side steps all of the MVC framework and HTTP and just deals with the raw rendering engine. I wrote about this process in Hosting the Razor Engine in Non-Web Applications a long while back. It's quite a process to create a custom Razor engine and runtime, but it allows for all sorts of flexibility. There's also a RazorEngine CodePlex project that does something similar. I've been meaning to check out the latter but haven't gotten around to it since I have my own code to do this. The trick to hosting the RazorEngine to have it behave properly inside of an ASP.NET application and properly cache content so templates aren't constantly rebuild and reparsed. Anyway, in the same app as above I have one scenario where no ControllerContext is available: I have a background scheduler running inside of the app that fires on timed intervals. This process could be external but because it's lightweight we decided to fire it right inside of the ASP.NET app on a separate thread. In my app the code that renders these templates does something like this:var model = new SearchNotificationViewModel() { Entries = entries, Notification = notification, User = user }; // TODO: Need logging for errors sending string razorError = null; var result = AppUtils.RenderRazorTemplate("~/views/template/SearchNotificationTemplate.cshtml", model, razorError); which references a couple of helper functions that set up my RazorFolderHostContainer class:public static string RenderRazorTemplate(string virtualPath, object model,string errorMessage = null) { var razor = AppUtils.CreateRazorHost(); var path = virtualPath.Replace("~/", "").Replace("~", "").Replace("/", "\\"); var merged = razor.RenderTemplateToString(path, model); if (merged == null) errorMessage = razor.ErrorMessage; return merged; } /// <summary> /// Creates a RazorStringHostContainer and starts it /// Call .Stop() when you're done with it. /// /// This is a static instance /// </summary> /// <param name="virtualPath"></param> /// <param name="binBasePath"></param> /// <param name="forceLoad"></param> /// <returns></returns> public static RazorFolderHostContainer CreateRazorHost(string binBasePath = null, bool forceLoad = false) { if (binBasePath == null) { if (HttpContext.Current != null) binBasePath = HttpContext.Current.Server.MapPath("~/"); else binBasePath = AppDomain.CurrentDomain.BaseDirectory; } if (_RazorHost == null || forceLoad) { if (!binBasePath.EndsWith("\\")) binBasePath += "\\"; //var razor = new RazorStringHostContainer(); var razor = new RazorFolderHostContainer(); razor.TemplatePath = binBasePath; binBasePath += "bin\\"; razor.BaseBinaryFolder = binBasePath; razor.UseAppDomain = false; razor.ReferencedAssemblies.Add(binBasePath + "ClassifiedsBusiness.dll"); razor.ReferencedAssemblies.Add(binBasePath + "ClassifiedsWeb.dll"); razor.ReferencedAssemblies.Add(binBasePath + "Westwind.Utilities.dll"); razor.ReferencedAssemblies.Add(binBasePath + "Westwind.Web.dll"); razor.ReferencedAssemblies.Add(binBasePath + "Westwind.Web.Mvc.dll"); razor.ReferencedAssemblies.Add("System.Web.dll"); razor.ReferencedNamespaces.Add("System.Web"); razor.ReferencedNamespaces.Add("ClassifiedsBusiness"); razor.ReferencedNamespaces.Add("ClassifiedsWeb"); razor.ReferencedNamespaces.Add("Westwind.Web"); razor.ReferencedNamespaces.Add("Westwind.Utilities"); _RazorHost = razor; _RazorHost.Start(); //_RazorHost.Engine.Configuration.CompileToMemory = false; } return _RazorHost; } The RazorFolderHostContainer essentially is a full runtime that mimics a folder structure like a typical Web app does including caching semantics and compiling code only if code changes on disk. It maps a folder hierarchy to views using the ~/ path syntax. The host is then configured to add assemblies and namespaces. Unfortunately the engine is not exactly like MVC's Razor - the expression expansion and code execution are the same, but some of the support methods like sections, helpers etc. are not all there so templates have to be a bit simpler. There are other folder hosts provided as well to directly execute templates from strings (using RazorStringHostContainer). The following is an example of an HTML email template @inherits RazorHosting.RazorTemplateFolderHost <ClassifiedsWeb.SearchNotificationViewModel> <html> <head> <title>Search Notifications</title> <style> body { margin: 5px;font-family: Verdana, Arial; font-size: 10pt;} h3 { color: SteelBlue; } .entry-item { border-bottom: 1px solid grey; padding: 8px; margin-bottom: 5px; } </style> </head> <body> Hello @Model.User.Name,<br /> <p>Below are your Search Results for the search phrase:</p> <h3>@Model.Notification.SearchPhrase</h3> <small>since @TimeUtils.ShortDateString(Model.Notification.LastSearch)</small> <hr /> You can see that the syntax is a little different. Instead of the familiar @model header the raw Razor @inherits tag is used to specify the template base class (which you can extend). I took a quick look through the feature set of RazorEngine on CodePlex (now Github I guess) and the template implementation they use is closer to MVC's razor but there are other differences. In the end don't expect exact behavior like MVC templates if you use an external Razor rendering engine. This is not what I would consider an ideal solution, but it works well enough for this project. My biggest concern is the overhead of hosting a second razor engine in a Web app and the fact that here the differences in template rendering between 'real' MVC Razor views and another RazorEngine really are noticeable. You win some, you lose some It's extremely nice to see that if you have a ControllerContext handy (which probably addresses 99% of Web app scenarios) rendering a view to string using the native MVC Razor engine is pretty simple. Kudos on making that happen - as it solves a problem I see in just about every Web application I work on. But it is a bummer that a ControllerContext is required to make this simple code work. It'd be really sweet if there was a way to render views without being so closely coupled to the ASP.NET or MVC infrastructure that requires a ControllerContext. Alternately it'd be nice to have a way for an MVC based application to create a minimal ControllerContext from scratch - maybe somebody's been down that path. I tried for a few hours to come up with a way to make that work but gave up in the soup of nested contexts (MVC/Controller/View/Http). I suspect going down this path would be similar to hosting the ASP.NET runtime requiring a WorkerRequest. Brrr…. The sad part is that it seems to me that a View should really not require much 'context' of any kind to render output to string. Yes there are a few things that clearly are required like paths to the virtual and possibly the disk paths to the root of the app, but beyond that view rendering should not require much. But, no such luck. For now custom RazorHosting seems to be the only way to make Razor rendering go outside of the MVC context… Resources Full ViewRenderer.cs source code from Westwind.Web.Mvc library Hosting the Razor Engine for Non-Web Applications RazorEngine on GitHub© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET ASP.NET MVC 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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Running an intern program

- by dotneteer

This year I am running an unpaid internship program for high school students. I work for a small company. We have ideas for a few side projects but never have time to do them. So we experiment by making them intern projects. In return, we give these interns guidance to learn, personal attentions, and opportunities with real-world projects. A few years ago, I blogged about the idea of teaching kids to write application with no more than 6 hours of training. This time, I was able to reduce the instruction time to 4 hours and immediately put them into real work projects. When they encounter problems, I combine directions, pointer to various materials on w3school, Udacity, Codecademy and UTube, as well as encouraging them to search for solutions with search engines. Now entering the third week, I am more than encouraged and feeling accomplished. Our the most senior intern, Christopher Chen, is a recent high school graduate and is heading to UC Berkeley to study computer science after the summer. He previously only had one year of Java experience through the AP computer science course but had no web development experience. Only 12 days into his internship, he has already gain advanced css skills with deeper understanding than more than half of the “senior” developers that I have ever worked with. I put him on a project to migrate an existing website to the Orchard content management system (CMS) with which I am new as well. We were able to teach each other and quickly gain advanced Orchard skills such as creating custom theme and modules. I felt very much a relationship similar to the those between professors and graduate students. On the other hand, I quite expect that I will lose him the next summer to companies like Google, Facebook or Microsoft. As a side note, Christopher and I will do a two part Orchard presentations together at the next SoCal code camp at UC San Diego July 27-28. The first part, “creating an Orchard website on Azure in 60 minutes”, is an introductory lecture and we will discuss how to create a website using Orchard without writing code. The 2nd part, “customizing Orchard websites without limit”, is an advanced lecture and we will discuss custom theme and module development with WebMatrix and Visual Studio.

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Web.Config is Cached

- by SGWellens

There was a question from a student over on the Asp.Net forums about improving site performance. The concern was that every time an app setting was read from the Web.Config file, the disk would be accessed. With many app settings and many users, it was believed performance would suffer. Their intent was to create a class to hold all the settings, instantiate it and fill it from the Web.Config file on startup. Then, all the settings would be in RAM. I knew this was not correct and didn't want to just say so without any corroboration, so I did some searching. Surprisingly, this is a common misconception. I found other code postings that cached the app settings from Web.Config. Many people even thanked the posters for the code. In a later post, the student said their text book recommended caching the Web.Config file. OK, here's the deal. The Web.Config file is already cached. You do not need to re-cache it. From this article http://msdn.microsoft.com/en-us/library/aa478432.aspx It is important to realize that the entire <appSettings> section is read, parsed, and cached the first time we retrieve a setting value. From that point forward, all requests for setting values come from an in-memory cache, so access is quite fast and doesn't incur any subsequent overhead for accessing the file or parsing the XML. The reason the misconception is prevalent may be because it's hard to search for Web.Config and cache without getting a lot of hits on how to setup caching in the Web.Config file. So here's a string for search engines to index on: "Is the Web.Config file Cached?" A follow up question was, are the connection strings cached? Yes. http://msdn.microsoft.com/en-us/library/ms178683.aspx At run time, ASP.NET uses the Web.Config files to hierarchically compute a unique collection of configuration settings for each incoming URL request. These settings are calculated only once and then cached on the server. And, as everyone should know, if you modify the Web.Config file, the web application will restart. I hope this helps people to NOT write code! Steve WellensCodeProject

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Web.Config is Cached

- by SGWellens

There was a question from a student over on the Asp.Net forums about improving site performance. The concern was that every time an app setting was read from the Web.Config file, the disk would be accessed. With many app settings and many users, it was believed performance would suffer. Their intent was to create a class to hold all the settings, instantiate it and fill it from the Web.Config file on startup. Then, all the settings would be in RAM. I knew this was not correct and didn't want to just say so without any corroboration, so I did some searching. Surprisingly, this is a common misconception. I found other code postings that cached the app settings from Web.Config. Many people even thanked the posters for the code. In a later post, the student said their text book recommended caching the Web.Config file. OK, here's the deal. The Web.Config file is already cached. You do not need to re-cache it. From this article http://msdn.microsoft.com/en-us/library/aa478432.aspx It is important to realize that the entire <appSettings> section is read, parsed, and cached the first time we retrieve a setting value. From that point forward, all requests for setting values come from an in-memory cache, so access is quite fast and doesn't incur any subsequent overhead for accessing the file or parsing the XML. The reason the misconception is prevalent may be because it's hard to search for Web.Config and cache without getting a lot of hits on how to setup caching in the Web.Config file. So here's a string for search engines to index on: "Is the Web.Config file Cached?" A follow up question was, are the connection strings cached? Yes. http://msdn.microsoft.com/en-us/library/ms178683.aspx At run time, ASP.NET uses the Web.Config files to hierarchically compute a unique collection of configuration settings for each incoming URL request. These settings are calculated only once and then cached on the server. And, as everyone should know, if you modify the Web.Config file, the web application will restart. I hope this helps people to NOT write code! Steve WellensCodeProject

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The Sitemap Paradox

- by Jeff Atwood

We use a sitemap on Stack Overflow, but I have mixed feelings about it. Web crawlers usually discover pages from links within the site and from other sites. Sitemaps supplement this data to allow crawlers that support Sitemaps to pick up all URLs in the Sitemap and learn about those URLs using the associated metadata. Using the Sitemap protocol does not guarantee that web pages are included in search engines, but provides hints for web crawlers to do a better job of crawling your site. Based on our two years' experience with sitemaps, there's something fundamentally paradoxical about the sitemap: Sitemaps are intended for sites that are hard to crawl properly. If Google can't successfully crawl your site to find a link, but is able to find it in the sitemap it gives the sitemap link no weight and will not index it! That's the sitemap paradox -- if your site isn't being properly crawled (for whatever reason), using a sitemap will not help you! Google goes out of their way to make no sitemap guarantees: "We cannot make any predictions or guarantees about when or if your URLs will be crawled or added to our index" citation "We don't guarantee that we'll crawl or index all of your URLs. For example, we won't crawl or index image URLs contained in your Sitemap." citation "submitting a Sitemap doesn't guarantee that all pages of your site will be crawled or included in our search results" citation Given that links found in sitemaps are merely recommendations, whereas links found on your own website proper are considered canonical ... it seems the only logical thing to do is avoid having a sitemap and make damn sure that Google and any other search engine can properly spider your site using the plain old standard web pages everyone else sees. By the time you have done that, and are getting spidered nice and thoroughly so Google can see that your own site links to these pages, and would be willing to crawl the links -- uh, why do we need a sitemap, again? The sitemap can be actively harmful, because it distracts you from ensuring that search engine spiders are able to successfully crawl your whole site. "Oh, it doesn't matter if the crawler can see it, we'll just slap those links in the sitemap!" Reality is quite the opposite in our experience. That seems more than a little ironic considering sitemaps were intended for sites that have a very deep collection of links or complex UI that may be hard to spider. In our experience, the sitemap does not help, because if Google can't find the link on your site proper, it won't index it from the sitemap anyway. We've seen this proven time and time again with Stack Overflow questions. Am I wrong? Do sitemaps make sense, and we're somehow just using them incorrectly?

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The right way to start out in game development/design [closed]

- by Marco Sacristão

Greetings everyone I'm a 19 year old student looking for some help in the field of game development. This question may or may not seem a bit overused, but the fact is that game development has been my life long dream, and after several hours of search I've realized that I've been going in circles for the past three or four months whilst doing such research on how to really get down and dirty with game development, therefor I decided to ask you guys if you could help me out at all. Let me start off with some information about me and things i've already learned about GameDev which might help you out on helping me out (wordplay!): I'm not an expert programmer, but I do have knowledge on how to program in several languages including C and Java (Currently learning Java in my degree in Computer Engineering), but my methodology might not be most correct in terms of syntax (hence my difficulty in starting out, i'm afraid that the starting point might not be the most correct, and it would deploy a wrongful development methodology that would be to corrected later on, in terms of game development or other projects). I have yet to work in a project as large as a game, never in my learning curve of programming I've done a project to the scale of a video game, only very small software (PHP Front-ends and Back-ends, with some basic JQuery and CSS knowledge). I'm not the biggest mathematician or physicist, but I already know that is not a problem, because there are several game engines already available for use and integration with home-made projects (Box2D, etc). I've also learned about some libraries that could be included in said projects, to ease out some process in game development, like SDL for example. I do not know how sprites, states, particles or any specific game-related techniques work. With that being said, you can see that I have some ideas on game development, but I have absolutely no clue on how to design and produce a game, or even how game-like mechanics work. It does not have to be a complex game just to start out, I'd rather learn the basic of game design (Like 2D drawing, tiling, object collision) and test that out in a language that I feel comfortable in which could be later on migrated to other platforms, as long that what I've learned is the correct way to do things, and not just something that I've learned from some guy on Youtube by replicating that code on the video. I'm sorry if my question is not in the best format possible, but I've got so many questions on my mind that are still un-answered that I don't know were to start! Thank you for reading.

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Illegal characters for SharePoint 2010 Content Type name

- by Kelly Jones

Quick tip: you can’t include a backslash in the name of the SharePoint 2010 Content Type. In fact, there are several illegal characters: \ / : * ? " # % < > { } | ~ & , two consecutive periods (..), or special characters such as a tab. What, you didn’t know that after entering one of these characters in the name? Is it because you saw this screen: Oh, that’s right….you need to turn off custom errors in the layouts folder…See this blog post for details and you’ll also need to turn off for the web application. Once you do that, you’ll see this: I wonder why the SharePoint team just doesn’t let the user know that the content type name contains illegal characters before the user hits the create button. Here’s a copy of the complete error (for the search engines): Server Error in '/' Application. -------------------------------------------------------------------------------- The content type name 'asdfadsf\asdfasf' cannot contain: \ / : * ? " # % < > { } | ~ & , two consecutive periods (..), or special characters such as a tab. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: Microsoft.SharePoint.SPInvalidContentTypeNameException: The content type name 'asdfadsf\asdfasf' cannot contain: \ / : * ? " # % < > { } | ~ & , two consecutive periods (..), or special characters such as a tab. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [SPInvalidContentTypeNameException: The content type name 'asdfadsf\asdfasf' cannot contain: \ / : * ? " # % < > { } | ~ & , two consecutive periods (..), or special characters such as a tab.] Microsoft.SharePoint.SPContentType.ValidateName(String name) +27419522 Microsoft.SharePoint.SPContentType.ValidateNameWithResource(String strVal, String& strLocalized) +423 Microsoft.SharePoint.SPContentType.set_Name(String value) +151 Microsoft.SharePoint.SPContentType.Initialize(SPContentType parentContentType, SPContentTypeCollection collection, String name) +112 Microsoft.SharePoint.SPContentType..ctor(SPContentType parentContentType, SPContentTypeCollection collection, String name) +132 Microsoft.SharePoint.ApplicationPages.ContentTypeCreatePage.BtnOK_Click(Object sender, EventArgs e) +497 System.Web.UI.WebControls.Button.OnClick(EventArgs e) +115 System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +140 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +29 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2981 -------------------------------------------------------------------------------- Version Information: Microsoft .NET Framework Version:2.0.50727.4927; ASP.NET Version:2.0.50727.4927

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Sharing data between graphics and physics engine in the game?

- by PolGraphic

I'm writing the game engine that consists of few modules. Two of them are the graphics engine and the physics engine. I wonder if it's a good solution to share data between them? Two ways (sharing or not) looks like that: Without sharing data GraphicsModel{ //some common for graphics and physics data like position //some only graphic data //like textures and detailed model's verticles that physics doesn't need }; PhysicsModel{ //some common for graphics and physics data like position //some only physics data //usually my physics data contains A LOT more informations than graphics data } engine3D->createModel3D(...); physicsEngine->createModel3D(...); //connect graphics and physics data //e.g. update graphics model's position when physics model's position will change I see two main problems: A lot of redundant data (like two positions for both physics and graphics data) Problem with updating data (I have to manually update graphics data when physics data changes) With sharing data Model{ //some common for graphics and physics data like position }; GraphicModel : public Model{ //some only graphics data //like textures and detailed model's verticles that physics doesn't need }; PhysicsModel : public Model{ //some only physics data //usually my physics data contains A LOT more informations than graphics data } model = engine3D->createModel3D(...); physicsEngine->assingModel3D(&model); //will cast to //PhysicsModel for it's purposes?? //when physics changes anything (like position) in model //(which it treats like PhysicsModel), the position for graphics data //will change as well (because it's the same model) Problems here: physicsEngine cannot create new objects, just "assing" existing ones from engine3D (somehow it looks more anti-independent for me) Casting data in assingModel3D function physicsEngine and graphicsEngine must be careful - they cannot delete data when they don't need them (because second one may need it). But it's rare situation. Moreover, they can just delete the pointer, not the object. Or we can assume that graphicsEngine will delete objects, physicsEngine just pointers to them. Which way is better? Which will produce more problems in the future? I like the second solution more, but I wonder why most graphics and physics engines prefer the first one (maybe because they normally make only graphics or only physics engine and somebody else connect them in the game?). Have they any more hidden pros & contras?

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ASP.NET Frameworks and Raw Throughput Performance

- by Rick Strahl

A few days ago I had a curious thought: With all these different technologies that the ASP.NET stack has to offer, what's the most efficient technology overall to return data for a server request? When I started this it was mere curiosity rather than a real practical need or result. Different tools are used for different problems and so performance differences are to be expected. But still I was curious to see how the various technologies performed relative to each just for raw throughput of the request getting to the endpoint and back out to the client with as little processing in the actual endpoint logic as possible (aka Hello World!). I want to clarify that this is merely an informal test for my own curiosity and I'm sharing the results and process here because I thought it was interesting. It's been a long while since I've done any sort of perf testing on ASP.NET, mainly because I've not had extremely heavy load requirements and because overall ASP.NET performs very well even for fairly high loads so that often it's not that critical to test load performance. This post is not meant to make a point or even come to a conclusion which tech is better, but just to act as a reference to help understand some of the differences in perf and give a starting point to play around with this yourself. I've included the code for this simple project, so you can play with it and maybe add a few additional tests for different things if you like. Source Code on GitHub I looked at this data for these technologies: ASP.NET Web API ASP.NET MVC WebForms ASP.NET WebPages ASMX AJAX Services (couldn't get AJAX/JSON to run on IIS8 ) WCF Rest Raw ASP.NET HttpHandlers It's quite a mixed bag, of course and the technologies target different types of development. What started out as mere curiosity turned into a bit of a head scratcher as the results were sometimes surprising. What I describe here is more to satisfy my curiosity more than anything and I thought it interesting enough to discuss on the blog :-) First test: Raw Throughput The first thing I did is test raw throughput for the various technologies. This is the least practical test of course since you're unlikely to ever create the equivalent of a 'Hello World' request in a real life application. The idea here is to measure how much time a 'NOP' request takes to return data to the client. So for this request I create the simplest Hello World request that I could come up for each tech. Http Handler The first is the lowest level approach which is an HTTP handler. public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public bool IsReusable { get { return true; } } } WebForms Next I added a couple of ASPX pages - one using CodeBehind and one using only a markup page. The CodeBehind page simple does this in CodeBehind without any markup in the ASPX page: public partial class HelloWorld_CodeBehind : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Response.Write("Hello World. Time is: " + DateTime.Now.ToString() ); Response.End(); } } while the Markup page only contains some static output via an expression:<%@ Page Language="C#" AutoEventWireup="false" CodeBehind="HelloWorld_Markup.aspx.cs" Inherits="AspNetFrameworksPerformance.HelloWorld_Markup" %> Hello World. Time is <%= DateTime.Now %> ASP.NET WebPages WebPages is the freestanding Razor implementation of ASP.NET. Here's the simple HelloWorld.cshtml page:Hello World @DateTime.Now WCF REST WCF REST was the token REST implementation for ASP.NET before WebAPI and the inbetween step from ASP.NET AJAX. I'd like to forget that this technology was ever considered for production use, but I'll include it here. Here's an OperationContract class: [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World" + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } } WCF REST can return arbitrary results by returning a Stream object and a content type. The code above turns the string result into a stream and returns that back to the client. ASP.NET AJAX (ASMX Services) I also wanted to test ASP.NET AJAX services because prior to WebAPI this is probably still the most widely used AJAX technology for the ASP.NET stack today. Unfortunately I was completely unable to get this running on my Windows 8 machine. Visual Studio 2012 removed adding of ASP.NET AJAX services, and when I tried to manually add the service and configure the script handler references it simply did not work - I always got a SOAP response for GET and POST operations. No matter what I tried I always ended up getting XML results even when explicitly adding the ScriptHandler. So, I didn't test this (but the code is there - you might be able to test this on a Windows 7 box). ASP.NET MVC Next up is probably the most popular ASP.NET technology at the moment: MVC. Here's the small controller: public class MvcPerformanceController : Controller { public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } } ASP.NET WebAPI Next up is WebAPI which looks kind of similar to MVC. Except here I have to use a StringContent result to return the response: public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } } Testing Take a minute to think about each of the technologies… and take a guess which you think is most efficient in raw throughput. The fastest should be pretty obvious, but the others - maybe not so much. The testing I did is pretty informal since it was mainly to satisfy my curiosity - here's how I did this: I used Apache Bench (ab.exe) from a full Apache HTTP installation to run and log the test results of hitting the server. ab.exe is a small executable that lets you hit a URL repeatedly and provides counter information about the number of requests, requests per second etc. ab.exe and the batch file are located in the \LoadTests folder of the project. An ab.exe command line looks like this: ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld which hits the specified URL 100,000 times with a load factor of 20 concurrent requests. This results in output like this: It's a great way to get a quick and dirty performance summary. Run it a few times to make sure there's not a large amount of varience. You might also want to do an IISRESET to clear the Web Server. Just make sure you do a short test run to warm up the server first - otherwise your first run is likely to be skewed downwards. ab.exe also allows you to specify headers and provide POST data and many other things if you want to get a little more fancy. Here all tests are GET requests to keep it simple. I ran each test: 100,000 iterations Load factor of 20 concurrent connections IISReset before starting A short warm up run for API and MVC to make sure startup cost is mitigated Here is the batch file I used for the test: IISRESET REM make sure you add REM C:\Program Files (x86)\Apache Software Foundation\Apache2.2\bin REM to your path so ab.exe can be found REM Warm up ab.exe -n100 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJsonab.exe -n100 -c20 http://localhost/aspnetperf/api/HelloWorldJson ab.exe -n100 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld ab.exe -n100000 -c20 http://localhost/aspnetperf/handler.ashx > handler.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_CodeBehind.aspx > AspxCodeBehind.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/HelloWorld_Markup.aspx > AspxMarkup.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorld > Wcf.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldCode > Mvc.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorld > WebApi.txt I ran each of these tests 3 times and took the average score for Requests/second, with the machine otherwise idle. I did see a bit of variance when running many tests but the values used here are the medians. Part of this has to do with the fact I ran the tests on my local machine - result would probably more consistent running the load test on a separate machine hitting across the network. I ran these tests locally on my laptop which is a Dell XPS with quad core Sandibridge I7-2720QM @ 2.20ghz and a fast SSD drive on Windows 8. CPU load during tests ran to about 70% max across all 4 cores (IOW, it wasn't overloading the machine). Ideally you can try running these tests on a separate machine hitting the local machine. If I remember correctly IIS 7 and 8 on client OSs don't throttle so the performance here should be Results Ok, let's cut straight to the chase. Below are the results from the tests… It's not surprising that the handler was fastest. But it was a bit surprising to me that the next fastest was WebForms and especially Web Forms with markup over a CodeBehind page. WebPages also fared fairly well. MVC and WebAPI are a little slower and the slowest by far is WCF REST (which again I find surprising). As mentioned at the start the raw throughput tests are not overly practical as they don't test scripting performance for the HTML generation engines or serialization performances of the data engines. All it really does is give you an idea of the raw throughput for the technology from time of request to reaching the endpoint and returning minimal text data back to the client which indicates full round trip performance. But it's still interesting to see that Web Forms performs better in throughput than either MVC, WebAPI or WebPages. It'd be interesting to try this with a few pages that actually have some parsing logic on it, but that's beyond the scope of this throughput test. But what's also amazing about this test is the sheer amount of traffic that a laptop computer is handling. Even the slowest tech managed 5700 requests a second, which is one hell of a lot of requests if you extrapolate that out over a 24 hour period. Remember these are not static pages, but dynamic requests that are being served. Another test - JSON Data Service Results The second test I used a JSON result from several of the technologies. I didn't bother running WebForms and WebPages through this test since that doesn't make a ton of sense to return data from the them (OTOH, returning text from the APIs didn't make a ton of sense either :-) In these tests I have a small Person class that gets serialized and then returned to the client. The Person class looks like this: public class Person { public Person() { Id = 10; Name = "Rick"; Entered = DateTime.Now; } public int Id { get; set; } public string Name { get; set; } public DateTime Entered { get; set; } } Here are the updated handler classes that use Person: Handler public class Handler : IHttpHandler { public void ProcessRequest(HttpContext context) { var action = context.Request.QueryString["action"]; if (action == "json") JsonRequest(context); else TextRequest(context); } public void TextRequest(HttpContext context) { context.Response.ContentType = "text/plain"; context.Response.Write("Hello World. Time is: " + DateTime.Now.ToString()); } public void JsonRequest(HttpContext context) { var json = JsonConvert.SerializeObject(new Person(), Formatting.None); context.Response.ContentType = "application/json"; context.Response.Write(json); } public bool IsReusable { get { return true; } } } This code adds a little logic to check for a action query string and route the request to an optional JSON result method. To generate JSON, I'm using the same JSON.NET serializer (JsonConvert.SerializeObject) used in Web API to create the JSON response. WCF REST [ServiceContract(Namespace = "")] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] public class WcfService { [OperationContract] [WebGet] public Stream HelloWorld() { var data = Encoding.Unicode.GetBytes("Hello World " + DateTime.Now.ToString()); var ms = new MemoryStream(data); // Add your operation implementation here return ms; } [OperationContract] [WebGet(ResponseFormat=WebMessageFormat.Json,BodyStyle=WebMessageBodyStyle.WrappedRequest)] public Person HelloWorldJson() { // Add your operation implementation here return new Person(); } } For WCF REST all I have to do is add a method with the Person result type. ASP.NET MVC public class MvcPerformanceController : Controller { // // GET: /MvcPerformance/ public ActionResult Index() { return View(); } public ActionResult HelloWorldCode() { return new ContentResult() { Content = "Hello World. Time is: " + DateTime.Now.ToString() }; } public JsonResult HelloWorldJson() { return Json(new Person(), JsonRequestBehavior.AllowGet); } } For MVC all I have to do for a JSON response is return a JSON result. ASP.NET internally uses JavaScriptSerializer. ASP.NET WebAPI public class WebApiPerformanceController : ApiController { [HttpGet] public HttpResponseMessage HelloWorldCode() { return new HttpResponseMessage() { Content = new StringContent("Hello World. Time is: " + DateTime.Now.ToString(), Encoding.UTF8, "text/plain") }; } [HttpGet] public Person HelloWorldJson() { return new Person(); } [HttpGet] public HttpResponseMessage HelloWorldJson2() { var response = new HttpResponseMessage(HttpStatusCode.OK); response.Content = new ObjectContent<Person>(new Person(), GlobalConfiguration.Configuration.Formatters.JsonFormatter); return response; } } Testing and Results To run these data requests I used the following ab.exe commands:REM JSON RESPONSES ab.exe -n100000 -c20 http://localhost/aspnetperf/Handler.ashx?action=json > HandlerJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/MvcPerformance/HelloWorldJson > MvcJson.txt ab.exe -n100000 -c20 http://localhost/aspnetperf/api/HelloWorldJson > WebApiJson.txt ab.exe -n100000 -c20 http://localhost/AspNetPerf/WcfService.svc/HelloWorldJson > WcfJson.txt The results from this test run are a bit interesting in that the WebAPI test improved performance significantly over returning plain string content. Here are the results: The performance for each technology drops a little bit except for WebAPI which is up quite a bit! From this test it appears that WebAPI is actually significantly better performing returning a JSON response, rather than a plain string response. Snag with Apache Benchmark and 'Length Failures' I ran into a little snag with Apache Benchmark, which was reporting failures for my Web API requests when serializing. As the graph shows performance improved significantly from with JSON results from 5580 to 6530 or so which is a 15% improvement (while all others slowed down by 3-8%). However, I was skeptical at first because the WebAPI test reports showed a bunch of errors on about 10% of the requests. Check out this report: Notice the Failed Request count. What the hey? Is WebAPI failing on roughly 10% of requests when sending JSON? Turns out: No it's not! But it took some sleuthing to figure out why it reports these failures. At first I thought that Web API was failing, and so to make sure I re-ran the test with Fiddler attached and runiisning the ab.exe test by using the -X switch: ab.exe -n100 -c10 -X localhost:8888 http://localhost/aspnetperf/api/HelloWorldJson which showed that indeed all requests where returning proper HTTP 200 results with full content. However ab.exe was reporting the errors. After some closer inspection it turned out that the dates varying in size altered the response length in dynamic output. For example: these two results: {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.841926-10:00"} {"Id":10,"Name":"Rick","Entered":"2012-09-04T10:57:24.8519262-10:00"} are different in length for the number which results in 68 and 69 bytes respectively. The same URL produces different result lengths which is what ab.exe reports. I didn't notice at first bit the same is happening when running the ASHX handler with JSON.NET result since it uses the same serializer that varies the milliseconds. Moral: You can typically ignore Length failures in Apache Benchmark and when in doubt check the actual output with Fiddler. Note that the other failure values are accurate though. Another interesting Side Note: Perf drops over Time As I was running these tests repeatedly I was finding that performance steadily dropped from a startup peak to a 10-15% lower stable level. IOW, with Web API I'd start out with around 6500 req/sec and in subsequent runs it keeps dropping until it would stabalize somewhere around 5900 req/sec occasionally jumping lower. For these tests this is why I did the IIS RESET and warm up for individual tests. This is a little puzzling. Looking at Process Monitor while the test are running memory very quickly levels out as do handles and threads, on the first test run. Subsequent runs everything stays stable, but the performance starts going downwards. This applies to all the technologies - Handlers, Web Forms, MVC, Web API - curious to see if others test this and see similar results. Doing an IISRESET then resets everything and performance starts off at peak again… Summary As I stated at the outset, these were informal to satiate my curiosity not to prove that any technology is better or even faster than another. While there clearly are differences in performance the differences (other than WCF REST which was by far the slowest and the raw handler which was by far the highest) are relatively minor, so there is no need to feel that any one technology is a runaway standout in raw performance. Choosing a technology is about more than pure performance but also about the adequateness for the job and the easy of implementation. The strengths of each technology will make for any minor performance difference we see in these tests. However, to me it's important to get an occasional reality check and compare where new technologies are heading. Often times old stuff that's been optimized and designed for a time of less horse power can utterly blow the doors off newer tech and simple checks like this let you compare. Luckily we're seeing that much of the new stuff performs well even in V1.0 which is great. To me it was very interesting to see Web API perform relatively badly with plain string content, which originally led me to think that Web API might not be properly optimized just yet. For those that caught my Tweets late last week regarding WebAPI's slow responses was with String content which is in fact considerably slower. Luckily where it counts with serialized JSON and XML WebAPI actually performs better. But I do wonder what would make generic string content slower than serialized code? This stresses another point: Don't take a single test as the final gospel and don't extrapolate out from a single set of tests. Certainly Twitter can make you feel like a fool when you post something immediate that hasn't been fleshed out a little more <blush>. Egg on my face. As a result I ended up screwing around with this for a few hours today to compare different scenarios. Well worth the time… I hope you found this useful, if not for the results, maybe for the process of quickly testing a few requests for performance and charting out a comparison. Now onwards with more serious stuff… Resources Source Code on GitHub Apache HTTP Server Project (ab.exe is part of the binary distribution)© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET Web Api 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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XML transform element appearing in wrong place in document

- by Mike

I am having some problems with an XML transform and need some help. The stylesheet should iterate through all suffix elements and place the contents without the suffix tag next to the last text node within its first ancestor quote-block element (see desired ouput). It works when only a single suffix is present, but not when 2 are present, when 2 are present it places both suffixes next to each other in the last text node of the first quote-block. Any ideas? I have tried limiting the selections to ancestor::quote-block[1] in various places but that doesn't have the desired effect. Source XML <paragraph> <para> <quote-block> <list prefix-rules="specified"> <item prefix="“B42"> <para id="0a84d149-91b7-4012-ac6d-9f4eb8ed6c37">In June 2000, EME and EWS reached an agreement to negotiate towards a direct contract for coal haulage by rail (on a DIY basis), which would replace the previous indirect E2E arrangements that EME had in place with ECSL. An internal EWS e-mail noted: <quote-block> <quote-para>‘We did the deal with Edison Mission yesterday morning for LBT-Fiddlers @ £[…]/tonne as agreed. This rate until 16th September pending a contract.</quote-para> <quote-para><emphasis strength="strong">Enron are now off our hands so far as Edison are concerned. The Enron flows we have left are to British Energy’s station at Eggborough; from Immingham, Redcar and Hull</emphasis>. Also to Enron’s own power station at Wilton – 250,000 tonnes/year. I think we are stuck Enron [sic] on the Eggborough traffic until next April when British Energy will, hopefully take over their own coal procurement. <emphasis strength="strong">But we have got them out of Fiddlers Ferry and Ferrybridge – a big step forward</emphasis>.’</quote-para> <suffix>(Emphasis added.)</suffix> </quote-block> </para> </item> <item prefix="B43"> <para id="d64a5a72-0a02-476f-9a7b-7c07bbc93a8a">This e-mail is evidence of both EWS’s intent and, indeed, its success in stopping ECSL from carrying out indirect supplies to EME, one of the new generating companies.”</para> </item> </list> <suffix>(emphasis in original)</suffix> </quote-block> </para> </paragraph> Stylesheet <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://xml.sm.com/schema/cases/report" xmlns:sm="http://xml.sm.com/functions" xmlns:saxon="http://saxon.sf.net/" xpath-default-namespace="http://sm.com/schema/cases/report" exclude-result-prefixes="xs sm" version="2.0"> <xsl:output method="xml" indent="no"/> <xsl:template match="/"> <xsl:apply-templates/> </xsl:template> <xsl:template match="*"> <xsl:copy> <xsl:copy-of select="@*"/> <xsl:apply-templates/> </xsl:copy> </xsl:template>  <xsl:template match="*[*:quote-block and descendant::*:suffix]"> <xsl:call-template name="process-quote-block"/> </xsl:template>  <xsl:template match="*[*:quote and descendant::*:suffix]"> <xsl:call-template name="process-quote-block"/> </xsl:template>  <xsl:template name="process-quote-block"> <xsl:variable name="quoteBlockCopy"> <xsl:copy-of select="."/> </xsl:variable> <xsl:apply-templates select="$quoteBlockCopy" mode="append-suffix"> <xsl:with-param name="suffix" select="sm:get-suffix-note(.)"/> <xsl:with-param name="end-node" select="sm:get-last-text-node($quoteBlockCopy)"/> </xsl:apply-templates> </xsl:template>  <xsl:template match="*[*:quote-block and descendant::*:suffix][ancestor::*:quote-block[1]]" mode="create-copy"> <xsl:call-template name="process-quote-block"/> </xsl:template>  <xsl:template match="*[*:quote and descendant::*:suffix]" mode="create-copy"> <xsl:call-template name="process-quote-block"/> </xsl:template>  <xsl:template match="*" mode="append-suffix"> <xsl:param name="suffix"/> <xsl:param name="end-node"/> <xsl:copy> <xsl:copy-of select="@*"/> <xsl:apply-templates mode="append-suffix"> <xsl:with-param name="suffix" select="$suffix"/> <xsl:with-param name="end-node" select="$end-node"/> </xsl:apply-templates> </xsl:copy> </xsl:template>  <xsl:template match="text()[normalize-space() != '']" mode="append-suffix"> <xsl:param name="suffix"/> <xsl:param name="end-node"/> <xsl:choose> <xsl:when test="count(. | $end-node) = 1"> <xsl:value-of select="."/> <xsl:apply-templates select="$suffix"/> </xsl:when> <xsl:otherwise>  <xsl:value-of select="."/> </xsl:otherwise> </xsl:choose> </xsl:template>  <xsl:template match="*:suffix" mode="append-suffix"/> <xsl:function name="sm:get-suffix-note"> <xsl:param name="node"/> <xsl:sequence select="$node/descendant::*:suffix/node()"/> </xsl:function> <xsl:function name="sm:get-last-text-node">  <xsl:param name="node"/> <xsl:sequence select="reverse($node//text()[not(ancestor::*:suffix) and normalize-space() != ''])[1]"/> </xsl:function> </xsl:stylesheet> Current Output XML <paragraph> <para> <quote-block> <list prefix-rules="specified"> <item prefix="“B42"> <para id="0a84d149-91b7-4012-ac6d-9f4eb8ed6c37">In June 2000, EME and EWS reached an agreement to negotiate towards a direct contract for coal haulage by rail (on a DIY basis), which would replace the previous indirect E2E arrangements that EME had in place with ECSL. An internal EWS e-mail noted: <quote-block> <quote-para>‘We did the deal with Edison Mission yesterday morning for LBT-Fiddlers @ £[…]/tonne as agreed. This rate until 16th September pending a contract.</quote-para> <quote-para><emphasis strength="strong">Enron are now off our hands so far as Edison are concerned. The Enron flows we have left are to British Energy’s station at Eggborough; from Immingham, Redcar and Hull</emphasis>. Also to Enron’s own power station at Wilton – 250,000 tonnes/year. I think we are stuck Enron [sic] on the Eggborough traffic until next April when British Energy will, hopefully take over their own coal procurement. <emphasis strength="strong">But we have got them out of Fiddlers Ferry and Ferrybridge – a big step forward</emphasis>.’</quote-para> </quote-block> </para> </item> <item prefix="B43"> <para id="d64a5a72-0a02-476f-9a7b-7c07bbc93a8a">This e-mail is evidence of both EWS’s intent and, indeed, its success in stopping ECSL from carrying out indirect supplies to EME, one of the new generating companies.”(Emphasis added.)(emphasis in original)</para> </item> </list> </quote-block> </para> </paragraph> Desired Ouput <paragraph> <para> <quote-block> <list prefix-rules="specified"> <item prefix="“B42"> <para id="0a84d149-91b7-4012-ac6d-9f4eb8ed6c37">In June 2000, EME and EWS reached an agreement to negotiate towards a direct contract for coal haulage by rail (on a DIY basis), which would replace the previous indirect E2E arrangements that EME had in place with ECSL. An internal EWS e-mail noted: <quote-block> <quote-para>‘We did the deal with Edison Mission yesterday morning for LBT-Fiddlers @ £[…]/tonne as agreed. This rate until 16th September pending a contract.</quote-para> <quote-para><emphasis strength="strong">Enron are now off our hands so far as Edison are concerned. The Enron flows we have left are to British Energy’s station at Eggborough; from Immingham, Redcar and Hull</emphasis>. Also to Enron’s own power station at Wilton – 250,000 tonnes/year. I think we are stuck Enron [sic] on the Eggborough traffic until next April when British Energy will, hopefully take over their own coal procurement. <emphasis strength="strong">But we have got them out of Fiddlers Ferry and Ferrybridge – a big step forward</emphasis>.’(Emphasis added.)</quote-para> </quote-block> </para> </item> <item prefix="B43"> <para id="d64a5a72-0a02-476f-9a7b-7c07bbc93a8a">This e-mail is evidence of both EWS’s intent and, indeed, its success in stopping ECSL from carrying out indirect supplies to EME, one of the new generating companies.”(emphasis in original)</para> </item> </list> </quote-block> </para> </paragraph>

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On Writing Blogs

- by Tony Davis

Why are so many blogs about IT so difficult to read? Over at SQLServerCentral.com, we do a special subscription-only newsletter called Database Weekly. Every other week, it is my turn to look through all the blogs, news and events that might be of relevance to people working with databases. We provide the title, with the link, and a short abstract of what you can expect to read. It is a popular service with close to a million subscribers. You might think that this is a happy and fascinating task. Sometimes, yes. If a blog comes to the point quickly, and says something both interesting and original, then it has our immediate attention. If it backs up what it says with supporting material, then it is more-or-less home and dry, featured in DBW's list. If it also takes trouble over the formatting and presentation, maybe with an illustration or two and any code well-formatted, then we are agog with joy and it is marked as a must-visit destination in our blog roll. More often, however, a task that should be fun becomes a routine chore, and the effort of trawling so many badly-written blogs is enough to make any conscientious Health & Safety officer whistle through their teeth at the risk to the editor's spiritual and psychological well-being. And yet, frustratingly, most blogs could be improved very easily. There is, I believe, a simple formula for a successful blog. First, choose a single topic that is reasonably fresh and interesting. Second, get to the point quickly; explain in the first paragraph exactly what the blog is about, and then stay on topic. In writing the first paragraph, you must picture yourself as a pilot, hearing the smooth roar of the engines as your plane gracefully takes air. Too often, however, the accompanying sound is that of the engine stuttering before the plane veers off the runway into a field, and a wheel falls off. The author meanders around the topic without getting to the point, and takes frequent off-radar diversions to talk about themselves, or the weather, or which friends have recently tagged them. This might work if you're J.D Salinger, or James Joyce, but it doesn't help a technical blog. Sometimes, the writing is so convoluted that we are entirely defeated in our quest to shoehorn its meaning into a simple summary sentence. Finally, write simply, in plain English, and in a conversational way such that you can read it out loud, and sound natural. That's it! If you could also avoid any references to The Matrix then this is a bonus but is purely personal preference. Cheers, Tony.

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Book Review: Inside Windows Communicat?ion Foundation by Justin Smith

- by Sam Abraham

In gearing up for a new major project, I have taken it upon myself to research and review various aspects of our Microsoft stack of choice seeking new creative ways for us to leverage in our upcoming state-of-the-art solution projected to position us ahead of the competition. While I am a big supporter of search engines and online articles as a quick and usually reliable source of information, I have opted in my investigative quest to actually “hit the books”. I have also made it a habit to provide quick reviews for material I go over hoping this can be of help to someone who may be looking for items others may have had success using for reference. I have started a few months ago by investigating better ways to implementing, profiling and troubleshooting SQL Server 2008. My reference of choice was Itzik Ben-Gan et al’s “Inside Microsoft SQL Server 2008” series. While it has been a month since my last book review, this by no means meant that I have been sitting idle. It has been pretty challenging to balance research with the continuous flow of projects and deadlines all while balancing that with my family duties which, of course, always comes first. In this post, I will be providing a quick review of my latest reading: Inside Windows Communication Foundation by Justin Smith. This book has been on my reading list for a very long time and I am proud to have finally tackled it. Justin’s book presents a great coverage of WCF internals. His simple, concise and well-worded style has simplified the relatively complex internals of WCF and made it comprehensible. Justin opted to organize the book into three parts: an introduction to WCF, coverage of the Channel Layer and a look at WCF internals at the ServiceModel layer. Part I introduced the concepts and made the case behind WCF while covering a simplified version of WCF’s message patterns, endpoints and contracts. In Part II, Justin provided a thorough coverage of the internals of Messages, Channels and Channel Managers. Part III concluded this nice reading with coverage of Bindings, Contracts, Dispatchers and Clients. While one would not likely need to extend WCF at that low level of the API, an understanding of the inner-workings of WCF is a must to avoid pitfalls mainly caused by misinformation or erroneous assumptions. Problems can quickly arise in high-traffic hosted solutions, but most can be easily avoided with some minimal time investment and education. My next goal is to pay a closer look at WCF from the programmer’s API perspective now that I have acquired a better understanding of its inner working. Many thanks to the O’Reilly User Group Program and its support of our West Palm Beach Developers’ Group. Stay tuned for more… All the best, --Sam

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How can I resolve Hibernate 3's ConstraintViolationException when updating a Persistent Entity's Col

- by Tim Visher

I'm trying to discover why two nearly identical class sets are behaving different from Hibernate 3's perspective. I'm fairly new to Hibernate in general and I'm hoping I'm missing something fairly obvious about the mappings or timing issues or something along those lines but I spent the whole day yesterday staring at the two sets and any differences that would lead to one being able to be persisted and the other not completely escaped me. I appologize in advance for the length of this question but it all hinges around some pretty specific implementation details. I have the following class mapped with Annotations and managed by Hibernate 3.? (if the specific specific version turns out to be pertinent, I'll figure out what it is). Java version is 1.6. ... @Embeddable public class JobStateChange implements Comparable<JobStateChange> { @Temporal(TemporalType.TIMESTAMP) @Column(nullable = false) private Date date; @Enumerated(EnumType.STRING) @Column(nullable = false, length = JobState.FIELD_LENGTH) private JobState state; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "acting_user_id", nullable = false) private User actingUser; public JobStateChange() { } @Override public int compareTo(final JobStateChange o) { return this.date.compareTo(o.date); } @Override public boolean equals(final Object obj) { if (this == obj) { return true; } else if (!(obj instanceof JobStateChange)) { return false; } JobStateChange candidate = (JobStateChange) obj; return this.state == candidate.state && this.actingUser.equals(candidate.getUser()) && this.date.equals(candidate.getDate()); } @Override public int hashCode() { return this.state.hashCode() + this.actingUser.hashCode() + this.date.hashCode(); } } It is mapped as a Hibernate CollectionOfElements in the class Job as follows: ... @Entity @Table( name = "job", uniqueConstraints = { @UniqueConstraint( columnNames = { "agency", //Job Name "payment_type", //Job Name "payment_file", //Job Name "date_of_payment", "payment_control_number", "truck_number" }) }) public class Job implements Serializable { private static final long serialVersionUID = -1131729422634638834L; ... @org.hibernate.annotations.CollectionOfElements @JoinTable(name = "job_state", joinColumns = @JoinColumn(name = "job_id")) @Sort(type = SortType.NATURAL) private final SortedSet<JobStateChange> stateChanges = new TreeSet<JobStateChange>(); ... public void advanceState( final User actor, final Date date) { JobState nextState; LOGGER.debug("Current state of {} is {}.", this, this.getCurrentState()); if (null == this.currentState) { nextState = JobState.BEGINNING; } else { if (!this.isAdvanceable()) { throw new IllegalAdvancementException(this.currentState.illegalAdvancementStateMessage); } if (this.currentState.isDivergent()) { nextState = this.currentState.getNextState(this); } else { nextState = this.currentState.getNextState(); } } JobStateChange stateChange = new JobStateChange(nextState, actor, date); this.setCurrentState(stateChange.getState()); this.stateChanges.add(stateChange); LOGGER.debug("Advanced {} to {}", this, this.getCurrentState()); } private void setCurrentState(final JobState jobState) { this.currentState = jobState; } boolean isAdvanceable() { return this.getCurrentState().isAdvanceable(this); } ... @Override public boolean equals(final Object obj) { if (obj == this) { return true; } else if (!(obj instanceof Job)) { return false; } Job otherJob = (Job) obj; return this.getName().equals(otherJob.getName()) && this.getDateOfPayment().equals(otherJob.getDateOfPayment()) && this.getPaymentControlNumber().equals(otherJob.getPaymentControlNumber()) && this.getTruckNumber().equals(otherJob.getTruckNumber()); } @Override public int hashCode() { return this.getName().hashCode() + this.getDateOfPayment().hashCode() + this.getPaymentControlNumber().hashCode() + this.getTruckNumber().hashCode(); } ... } The purpose of JobStateChange is to record when the Job moves through a series of State Changes that are outline in JobState as enums which know about advancement and decrement rules. The interface used to advance Jobs through a series of states is to call Job.advanceState() with a Date and a User. If the Job is advanceable according to rules coded in the enum, then a new StateChange is added to the SortedSet and everyone's happy. If not, an IllegalAdvancementException is thrown. The DDL this generates is as follows: ... drop table job; drop table job_state; ... create table job ( id bigint generated by default as identity, current_state varchar(25), date_of_payment date not null, beginningCheckNumber varchar(8) not null, item_count integer, agency varchar(10) not null, payment_file varchar(25) not null, payment_type varchar(25) not null, endingCheckNumber varchar(8) not null, payment_control_number varchar(4) not null, truck_number varchar(255) not null, wrapping_system_type varchar(15) not null, printer_id bigint, primary key (id), unique (agency, payment_type, payment_file, date_of_payment, payment_control_number, truck_number) ); create table job_state ( job_id bigint not null, acting_user_id bigint not null, date timestamp not null, state varchar(25) not null, primary key (job_id, acting_user_id, date, state) ); ... alter table job add constraint FK19BBD12FB9D70 foreign key (printer_id) references printer; alter table job_state add constraint FK57C2418FED1F0D21 foreign key (acting_user_id) references app_user; alter table job_state add constraint FK57C2418FABE090B3 foreign key (job_id) references job; ... The database is seeded with the following data prior to running tests ... insert into job (id, agency, payment_type, payment_file, payment_control_number, date_of_payment, beginningCheckNumber, endingCheckNumber, item_count, current_state, printer_id, wrapping_system_type, truck_number) values (-3, 'RRB', 'Monthly', 'Monthly','4501','1998-12-01 08:31:16' , '00000001','00040000', 40000, 'UNASSIGNED', null, 'KERN', '02'); insert into job_state (job_id, acting_user_id, date, state) values (-3, -1, '1998-11-30 08:31:17', 'UNASSIGNED'); ... After the database schema is automatically generated and rebuilt by the Hibernate tool. The following test runs fine up until the call to Session.flush() ... @ContextConfiguration(locations = { "/applicationContext-data.xml", "/applicationContext-service.xml" }) public class JobDaoIntegrationTest extends AbstractTransactionalJUnit4SpringContextTests { @Autowired private JobDao jobDao; @Autowired private SessionFactory sessionFactory; @Autowired private UserService userService; @Autowired private PrinterService printerService; ... @Test public void saveJob_JobAdvancedToAssigned_AllExpectedStateChanges() { //Get an unassigned Job Job job = this.jobDao.getJob(-3L); assertEquals(JobState.UNASSIGNED, job.getCurrentState()); Date advancedToUnassigned = new GregorianCalendar(1998, 10, 30, 8, 31, 17).getTime(); assertEquals(advancedToUnassigned, job.getStateChange(JobState.UNASSIGNED).getDate()); //Satisfy advancement constraints and advance job.setPrinter(this.printerService.getPrinter(-1L)); Date advancedToAssigned = new Date(); job.advanceState( this.userService.getUserByUsername("admin"), advancedToAssigned); assertEquals(JobState.ASSIGNED, job.getCurrentState()); assertEquals(advancedToUnassigned, job.getStateChange(JobState.UNASSIGNED).getDate()); assertEquals(advancedToAssigned, job.getStateChange(JobState.ASSIGNED).getDate()); //Persist to DB this.sessionFactory.getCurrentSession().flush(); ... } ... } The error thrown is SQLCODE=-803, SQLSTATE=23505: could not insert collection rows: [jaci.model.job.Job.stateChanges#-3] org.hibernate.exception.ConstraintViolationException: could not insert collection rows: [jaci.model.job.Job.stateChanges#-3] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:94) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.persister.collection.AbstractCollectionPersister.insertRows(AbstractCollectionPersister.java:1416) at org.hibernate.action.CollectionUpdateAction.execute(CollectionUpdateAction.java:86) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:170) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027) at jaci.dao.JobDaoIntegrationTest.saveJob_JobAdvancedToAssigned_AllExpectedStateChanges(JobDaoIntegrationTest.java:98) at org.springframework.test.context.junit4.SpringTestMethod.invoke(SpringTestMethod.java:160) at org.springframework.test.context.junit4.SpringMethodRoadie.runTestMethod(SpringMethodRoadie.java:233) at org.springframework.test.context.junit4.SpringMethodRoadie$RunBeforesThenTestThenAfters.run(SpringMethodRoadie.java:333) at org.springframework.test.context.junit4.SpringMethodRoadie.runWithRepetitions(SpringMethodRoadie.java:217) at org.springframework.test.context.junit4.SpringMethodRoadie.runTest(SpringMethodRoadie.java:197) at org.springframework.test.context.junit4.SpringMethodRoadie.run(SpringMethodRoadie.java:143) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.invokeTestMethod(SpringJUnit4ClassRunner.java:160) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:97) Caused by: com.ibm.db2.jcc.b.lm: DB2 SQL Error: SQLCODE=-803, SQLSTATE=23505, SQLERRMC=1;ACI_APP.JOB_STATE, DRIVER=3.50.152 at com.ibm.db2.jcc.b.wc.a(wc.java:575) at com.ibm.db2.jcc.b.wc.a(wc.java:57) at com.ibm.db2.jcc.b.wc.a(wc.java:126) at com.ibm.db2.jcc.b.tk.b(tk.java:1593) at com.ibm.db2.jcc.b.tk.c(tk.java:1576) at com.ibm.db2.jcc.t4.db.k(db.java:353) at com.ibm.db2.jcc.t4.db.a(db.java:59) at com.ibm.db2.jcc.t4.t.a(t.java:50) at com.ibm.db2.jcc.t4.tb.b(tb.java:200) at com.ibm.db2.jcc.b.uk.Gb(uk.java:2355) at com.ibm.db2.jcc.b.uk.e(uk.java:3129) at com.ibm.db2.jcc.b.uk.zb(uk.java:568) at com.ibm.db2.jcc.b.uk.executeUpdate(uk.java:551) at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:46) at org.hibernate.persister.collection.AbstractCollectionPersister.insertRows(AbstractCollectionPersister.java:1389) Therein lies my problem… A nearly identical Class set (in fact, so identical that I've been chomping at the bit to make it a single class that serves both business entities) runs absolutely fine. It is identical except for name. Instead of Job it's Web. Instead of JobStateChange it's WebStateChange. Instead of JobState it's WebState. Both Job and Web's SortedSet of StateChanges are mapped as a Hibernate CollectionOfElements. Both are @Embeddable. Both are SortType.Natural. Both are backed by an Enumeration with some advancement rules in it. And yet when a nearly identical test is run for Web, no issue is discovered and the data flushes fine. For the sake of brevity I won't include all of the Web classes here, but I will include the test and if anyone wants to see the actual sources, I'll include them (just leave a comment). The data seed: insert into web (id, stock_type, pallet, pallet_id, date_received, first_icn, last_icn, shipment_id, current_state) values (-1, 'PF', '0011', 'A', '2008-12-31 08:30:02', '000000001', '000080000', -1, 'UNSTAGED'); insert into web_state (web_id, date, state, acting_user_id) values (-1, '2008-12-31 08:30:03', 'UNSTAGED', -1); The test: ... @ContextConfiguration(locations = { "/applicationContext-data.xml", "/applicationContext-service.xml" }) public class WebDaoIntegrationTest extends AbstractTransactionalJUnit4SpringContextTests { @Autowired private WebDao webDao; @Autowired private UserService userService; @Autowired private SessionFactory sessionFactory; ... @Test public void saveWeb_WebAdvancedToNewState_AllExpectedStateChanges() { Web web = this.webDao.getWeb(-1L); Date advancedToUnstaged = new GregorianCalendar(2008, 11, 31, 8, 30, 3).getTime(); assertEquals(WebState.UNSTAGED, web.getCurrentState()); assertEquals(advancedToUnstaged, web.getState(WebState.UNSTAGED).getDate()); Date advancedToStaged = new Date(); web.advanceState( this.userService.getUserByUsername("admin"), advancedToStaged); this.sessionFactory.getCurrentSession().flush(); web = this.webDao.getWeb(web.getId()); assertEquals( "Web should have moved to STAGED State.", WebState.STAGED, web.getCurrentState()); assertEquals(advancedToUnstaged, web.getState(WebState.UNSTAGED).getDate()); assertEquals(advancedToStaged, web.getState(WebState.STAGED).getDate()); assertNotNull(web.getState(WebState.UNSTAGED)); assertNotNull(web.getState(WebState.STAGED)); } ... } As you can see, I assert that the Web was reconstituted the way I expect, I advance it, flush it to the DB, and then re-get it and verify that the states are as I expect. Everything works perfectly. Not so with Job. A possibly pertinent detail: the reconstitution code works fine if I cease to map JobStateChange.data as a TIMESTAMP and instead as a DATE, and ensure that all of the StateChanges always occur on different Dates. The problem is that this particular business entity can go through many state changes in a single day and so it needs to be sorted by time stamp rather than by date. If I don't do this then I can't sort the StateChanges correctly. That being said, WebStateChange.date is also mapped as a TIMESTAMP and so I again remain absolutely befuddled as to where this error is arising from. I tried to do a fairly thorough job of giving all of the technical details of the implementation but as this particular question is very implementation specific, if I missed anything just let me know in the comments and I'll include it. Thanks so much for your help! UPDATE: Since it turns out to be important to the solution of my problem, I have to include the pertinent bits of the WebStateChange class as well. ... @Embeddable public class WebStateChange implements Comparable<WebStateChange> { @Temporal(TemporalType.TIMESTAMP) @Column(nullable = false) private Date date; @Enumerated(EnumType.STRING) @Column(nullable = false, length = WebState.FIELD_LENGTH) private WebState state; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "acting_user_id", nullable = false) private User actingUser; ... WebStateChange( final WebState state, final User actingUser, final Date date) { ExceptionUtils.illegalNullArgs(state, actingUser, date); this.state = state; this.actingUser = actingUser; this.date = new Date(date.getTime()); } @Override public int compareTo(final WebStateChange otherStateChange) { return this.date.compareTo(otherStateChange.date); } @Override public boolean equals(final Object candidate) { if (this == candidate) { return true; } else if (!(candidate instanceof WebStateChange)) { return false; } WebStateChange candidateWebState = (WebStateChange) candidate; return this.getState() == candidateWebState.getState() && this.getUser().equals(candidateWebState.getUser()) && this.getDate().equals(candidateWebState.getDate()); } @Override public int hashCode() { return this.getState().hashCode() + this.getUser().hashCode() + this.getDate().hashCode(); } ... }

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Mathematica Programming Language–An Introduction

- by JoshReuben

The Mathematica http://www.wolfram.com/mathematica/ programming model consists of a kernel computation engine (or grid of such engines) and a front-end of notebook instances that communicate with the kernel throughout a session. The programming model of Mathematica is incredibly rich & powerful – besides numeric calculations, it supports symbols (eg Pi, I, E) and control flow logic. obviously I could use this as a simple calculator: 5 * 10 --> 50 but this language is much more than that! for example, I could use control flow logic & setup a simple infinite loop: x=1; While [x>0, x=x,x+1] Different brackets have different purposes: square brackets for function arguments: Cos[x] round brackets for grouping: (1+2)*3 curly brackets for lists: {1,2,3,4} The power of Mathematica (as opposed to say Matlab) is that it gives exact symbolic answers instead of a rounded numeric approximation (unless you request it): Mathematica lets you define scoped variables (symbols): a=1; b=2; c=a+b --> 5 these variables can contain symbolic values – you can think of these as partially computed functions: use Clear[x] or Remove[x] to zero or dereference a variable. To compute a numerical approximation to n significant digits (default n=6), use N[x,n] or the //N prefix: Pi //N -->3.14159 N[Pi,50] --> 3.1415926535897932384626433832795028841971693993751 The kernel uses % to reference the lastcalculation result, %% the 2nd last, %%% the 3rd last etc –> clearer statements: eg instead of: Sqrt[Pi+Sqrt[Sqrt[Pi+Sqrt[Pi]]] do: Sqrt[Pi]; Sqrt[Pi+%]; Sqrt[Pi+%] The help system supports wildcards, so I can search for functions like so: ?Inv* Mathematica supports some very powerful programming constructs and a rich function library that allow you to do things that you would have to write allot of code for in a language like C++. the Factor function – factorization: Factor[x^3 – 6*x^2 +11x – 6] --> (-3+x) (-2+x) (-1+x) the Solve function – find the roots of an equation: Solve[x^3 – 2x + 1 == 0] --> the Expand function – express (1+x)^10 in polynomial form: Expand[(1+x)^10] --> 1+10x+45x^2+120x^3+210x^4+252x^5+210x^6+120x^7+45x^8+10x^9+x^10 the Prime function – what is the 1000th prime? Prime[1000] -->7919 Mathematica also has some powerful graphics capabilities: the Plot function – plot the graph of y=Sin x in a single period: Plot[Sin[x], {x,0,2*Pi}] you can also plot 3D surfaces of functions using Plot3D function

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Hadoop growing pains

- by Piotr Rodak

This post is not going to be about SQL Server. I have been reading recently more and more about “Big Data” – very catchy term that describes untamed increase of the data that mankind is producing each day and the struggle to capture the meaning of these data. Ten years ago, and perhaps even three years ago this need was not so recognized. Increasing number of smartphones and discernable trend of mainstream Internet traffic moving to the smartphone generated one means that there is bigger and bigger stream of information that has to be stored, transformed, analysed and perhaps monetized. The nature of this traffic makes if very difficult to wrap it into boundaries of relational database engines. The amount of data makes it near to impossible to process them in relational databases within reasonable time. This is where ‘cloud’ technologies come to play. I just read a good article about the growing pains of Hadoop, which became one of the leading players on distributed processing arena within last year or two. Toby Baer concludes in it that lack of enterprise ready toolsets hinders Hadoop’s apprehension in the enterprise world. While this is true, something else drew my attention. According to the article there are already about half of a dozen of commercially supported distributions of Hadoop. For me, who has not been involved into intricacies of open-source world, this is quite interesting observation. On one hand, it is good that there is competition as it is beneficial in the end to the customer. On the other hand, the customer is faced with difficulty of choosing the right distribution. In future, when Hadoop distributions fork even more, this choice will be even harder. The distributions will have overlapping sets of features, yet will be quite incompatible with each other. I suppose it will take a few years until leaders emerge and the market will begin to resemble what we see in Linux world. There are myriads of distributions, but only few are acknowledged by the industry as enterprise standard. Others are honed by bearded individuals with too much time to spend. In any way, the third fact I can’t help but notice about the proliferation of distributions of Hadoop is that IT professionals will have jobs. BuzzNet Tags: Hadoop,Big Data,Enterprise IT

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Hadoop growing pains

- by Piotr Rodak

This post is not going to be about SQL Server. I have been reading recently more and more about “Big Data” – very catchy term that describes untamed increase of the data that mankind is producing each day and the struggle to capture the meaning of these data. Ten years ago, and perhaps even three years ago this need was not so recognized. Increasing number of smartphones and discernable trend of mainstream Internet traffic moving to the smartphone generated one means that there is bigger and bigger stream of information that has to be stored, transformed, analysed and perhaps monetized. The nature of this traffic makes if very difficult to wrap it into boundaries of relational database engines. The amount of data makes it near to impossible to process them in relational databases within reasonable time. This is where ‘cloud’ technologies come to play. I just read a good article about the growing pains of Hadoop, which became one of the leading players on distributed processing arena within last year or two. Toby Baer concludes in it that lack of enterprise ready toolsets hinders Hadoop’s apprehension in the enterprise world. While this is true, something else drew my attention. According to the article there are already about half of a dozen of commercially supported distributions of Hadoop. For me, who has not been involved into intricacies of open-source world, this is quite interesting observation. On one hand, it is good that there is competition as it is beneficial in the end to the customer. On the other hand, the customer is faced with difficulty of choosing the right distribution. In future, when Hadoop distributions fork even more, this choice will be even harder. The distributions will have overlapping sets of features, yet will be quite incompatible with each other. I suppose it will take a few years until leaders emerge and the market will begin to resemble what we see in Linux world. There are myriads of distributions, but only few are acknowledged by the industry as enterprise standard. Others are honed by bearded individuals with too much time to spend. In any way, the third fact I can’t help but notice about the proliferation of distributions of Hadoop is that IT professionals will have jobs. BuzzNet Tags: Hadoop,Big Data,Enterprise IT

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JavaScript in different browsers

- by PointsToShare

Adventures with JavaScript rendered in IE 8, Chrome 15, and Firefox 8.0 I have written a little monogram about the advantages of Math and wrote a few JavaScript applications to demonstrate them. I was a bit careless and used elements on the page in my JavaScript without using any of the GetElementsByXXXX methods to identify them. Say I had a text box named tbSeqNum into which I entered a number to be used in a computation. In my code I simply referred to its value by using it directly. Like here: Function Blah() { return tbSeqNum.value; } This ran fine in IE8. In IE, the elements are available as global variables. This is not the case in either Firefox or Chrome. In there one has to create the variable and only then use it. Assuming I also used tbSeqNum as the element’s ID, this works: Function Blah() { return GetElementById(“tbSeqNum”).value; } Naturally this corrected function also works in IE, so be warned. Also, coming from windows programming (I am long in the tooth and programmed long before the internet), I have a habit of putting an “Exit” button on my pages and setting their onclick to: onclick=”window.close()”. Again, this works fine in IE. In Firefox and chrome, it does not! There you can only close a window that you opened in the code. A window that was opened by navigation to a URL will not close. Before I deployed mu code to my website, I painfully removed all my Exit buttons. But my greatest surprise came when I tested my pages in the various browsers. In my code I do a comparison on the performance of two algorithms used to solve the same problem. One is brute force, the other uses a mathematical formula. The compare functions runs each many times and displays the time it took for each and also the ratio. Chrome runs JavaScript between 5 and 10 times faster than Firefox and between 50 and 100 times faster that IE. Wow!!! This difference is especially remarkable when the code uses iteration. I suspect that the JS engines in Chrome and Firefox simply cache the result of a function and if it is called again with the same parameters, it returns the cached result. To see it in action play run the “How Many Squares” page in www.mgsltns.com/games.htm The host is running on Unix, so the link is case sensitive. Last Note: IE9 runs JS a bit faster, but still lags behind almost as badly. That’s All Folks!

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Canonicalization of single, small pages like reviews or product categories [SEO]

- by Valorized

In general I pretty much like the idea of canonicalization. And in most cases, Google explains possible procedures in a clear way. For example: If I have duplicates because of parameters (eg: &sort=desc) it's clear to use the canonical for the site, provided the within the head-tag. However I'm wondering how to handle "small - no to say thin content - sites". What's my definition of a small site? An Example: On one of my main sites, we use a directory based url-structure. Let's see: example.com/ (root) example.com/category-abc/ example.com/category-abc/produkt-xy/ Moreover we provide on page, that includes all products example.com/all-categories/ (lists all products the same way as in the categories) In case of reviews, we use a similar structure: example.com/reviews/product-xy/ shows all review for one certain product example.com/reviews/product-xy/abc-your-product-is-great/ shows one certain review example.com/reviews/ shows all reviews for all products (latest first) Let's make it even more complicated: On every product site, there are the latest 2 reviews at the end of the page. So you see, a lot of potential duplicates. Q1: Should I create canonicals for a: example.com/category-abc/ to example.com/all-categories/ b: example.com/reviews/product-xy/abc-your-product-is-great/ to example.com/reviews/product-xy/ or to example.com/review/ or none of them? Q2: Can I link the collection of categories (all-categories/) and collection of all reviews (reviews/ and reviews/product-xy/) to the single category respectively to the single review. Example: example.com/reviews/ includes - let's say - 100 reviews. Can I somehow use a markup that tells search engines: "Hey, wait, you are now looking at a collection of 100 reviews - do not index this collection, you should rather prefer indexing every single review as a single page!". In HTML it might be something like that (which - of course - does not work, it's only to show you what I mean): <div class="review" rel="canonical" href="http://example.com/reviews/product-xz/abc-your-product-is-great/">HERE GOES THE REVIEW</div> Reason: I don't think it is a great user experience if the user searches for "your product is great" and lands on example.com/reviews/ instead of example.com/reviews/product-xy/abc-your-product-is-great/. On the first site, he will have to search and might stop because of frustration. The second result, however, might lead to a conversion. The same applies for categories. If the user is searching for category-Z, he might land on the all-categories page and he has to scroll down to the (last) category, to find what he searched for (Z). So what's best practice? What should I do? Thank you for your help!

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Is inline SQL still classed as bad practice now that we have Micro ORMs?

- by Grofit

This is a bit of an open ended question but I wanted some opinions, as I grew up in a world where inline SQL scripts were the norm, then we were all made very aware of SQL injection based issues, and how fragile the sql was when doing string manipulations all over the place. Then came the dawn of the ORM where you were explaining the query to the ORM and letting it generate its own SQL, which in a lot of cases was not optimal but was safe and easy. Another good thing about ORMs or database abstraction layers were that the SQL was generated with its database engine in mind, so I could use Hibernate/Nhibernate with MSSQL, MYSQL and my code never changed it was just a configuration detail. Now fast forward to current day, where Micro ORMs seem to be winning over more developers I was wondering why we have seemingly taken a U-Turn on the whole in-line sql subject. I must admit I do like the idea of no ORM config files and being able to write my query in a more optimal manner but it feels like I am opening myself back up to the old vulnerabilities such as SQL injection and I am also tying myself to one database engine so if I want my software to support multiple database engines I would need to do some more string hackery which seems to then start to make code unreadable and more fragile. (Just before someone mentions it I know you can use parameter based arguments with most micro orms which offers protection in most cases from sql injection) So what are peoples opinions on this sort of thing? I am using Dapper as my Micro ORM in this instance and NHibernate as my regular ORM in this scenario, however most in each field are quite similar. What I term as inline sql is SQL strings within source code. There used to be design debates over SQL strings in source code detracting from the fundamental intent of the logic, which is why statically typed linq style queries became so popular its still just 1 language, but with lets say C# and Sql in one page you have 2 languages intermingled in your raw source code now. Just to clarify, the SQL injection is just one of the known issues with using sql strings, I already mention you can stop this from happening with parameter based queries, however I highlight other issues with having SQL queries ingrained in your source code, such as the lack of DB Vendor abstraction as well as losing any level of compile time error capturing on string based queries, these are all issues which we managed to side step with the dawn of ORMs with their higher level querying functionality, such as HQL or LINQ etc (not all of the issues but most of them). So I am less focused on the individual highlighted issues and more the bigger picture of is it now becoming more acceptable to have SQL strings directly in your source code again, as most Micro ORMs use this mechanism. Here is a similar question which has a few different view points, although is more about the inline sql without the micro orm context: http://stackoverflow.com/questions/5303746/is-inline-sql-hard-coding

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