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  • SQL Server and Hyper-V Dynamic Memory Part 2

    - by SQLOS Team
    Part 1 of this series was an introduction and overview of Hyper-V Dynamic Memory. This part looks at SQL Server memory management and how the SQL engine responds to changing OS memory conditions.   Part 2: SQL Server Memory Management As with any Windows process, sqlserver.exe has a virtual address space (VAS) of 4GB on 32-bit and 8TB in 64-bit editions. Pages in its VAS are mapped to pages in physical memory when the memory is committed and referenced for the first time. The collection of VAS pages that have been recently referenced is known as the Working Set. How and when SQL Server allocates virtual memory and grows its working set depends on the memory model it uses. SQL Server supports three basic memory models:   1. Conventional Memory Model   The Conventional model is the default SQL Server memory model and has the following properties: - Dynamic - can grow or shrink its working set in response to load and external (operating system) memory conditions. - OS uses 4K pages – (not to be confused with SQL Server “pages” which are 8K regions of committed memory).- Pageable - Can be paged out to disk by the operating system.   2. Locked Page Model The locked page memory model is set when SQL Server is started with "Lock Pages in Memory" privilege*. It has the following characteristics: - Dynamic - can grow or shrink its working set in the same way as the Conventional model.- OS uses 4K pages - Non-Pageable – When memory is committed it is locked in memory, meaning that it will remain backed by physical memory and will not be paged out by the operating system. A common misconception is to interpret "locked" as non-dynamic. A SQL Server instance using the locked page memory model will grow and shrink (allocate memory and release memory) in response to changing workload and OS memory conditions in the same way as it does with the conventional model.   This is an important consideration when we look at Hyper-V Dynamic Memory – “locked” memory works perfectly well with “dynamic” memory.   * Note in “Denali” (Standard Edition and above), and in SQL 2008 R2 64-bit (Enterprise and above editions) the Lock Pages in Memory privilege is all that is required to set this model. In 2008 R2 64-Bit standard edition it also requires trace flag 845 to be set, in 2008 R2 32-bit editions it requires sp_configure 'awe enabled' 1.   3. Large Page Model The Large page model is set using trace flag 834 and potentially offers a small performance boost for systems that are configured with large pages. It is characterized by: - Static - memory is allocated at startup and does not change. - OS uses large (>2MB) pages - Non-Pageable The large page model is supported with Hyper-V Dynamic Memory (and Hyper-V also supports large pages), but you get no benefit from using Dynamic Memory with this model since SQL Server memory does not grow or shrink. The rest of this article will focus on the locked and conventional SQL Server memory models.   When does SQL Server grow? For “dynamic” configurations (Conventional and Locked memory models), the sqlservr.exe process grows – allocates and commits memory from the OS – in response to a workload. As much memory is allocated as is required to optimally run the query and buffer data for future queries, subject to limitations imposed by:   - SQL Server max server memory setting. If this configuration option is set, the buffer pool is not allowed to grow to more than this value. In SQL Server 2008 this value represents single page allocations, and in “Denali” it represents any size page allocations and also managed CLR procedure allocations.   - Memory signals from OS. The operating system sets a signal on memory resource notification objects to indicate whether it has memory available or whether it is low on available memory. If there is only 32MB free for every 4GB of memory a low memory signal is set, which continues until 64MB/4GB is free. If there is 96MB/4GB free the operating system sets a high memory signal. SQL Server only allocates memory when the high memory signal is set.   To summarize, for SQL Server to grow you need three conditions: a workload, max server memory setting higher than the current allocation, high memory signals from the OS.    When does SQL Server shrink caches? SQL Server as a rule does not like to return memory to the OS, but it will shrink its caches in response to memory pressure. Memory pressure can be divided into “internal” and “external”.   - External memory pressure occurs when the operating system is running low on memory and low memory signals are set. The SQL Server Resource Monitor checks for low memory signals approximately every 5 seconds and it will attempt to free memory until the signals stop.   To free memory SQL Server does the following: ·         Frees unused memory. ·         Notifies Memory Manager Clients to release memory o   Caches – Free unreferenced cache objects. o   Buffer pool - Based on oldest access times.   The freed memory is released back to the operating system. This process continues until the low memory resource notifications stop.    - Internal memory pressure occurs when the size of different caches and allocations increase but the SQL Server process needs to keep its total memory within a target value. For example if max server memory is set and certain caches are growing large, it will cause SQL to free memory for re-use internally, but not to release memory back to the OS. If you lower the value of max server memory you will generate internal memory pressure that will cause SQL to release memory back to the OS.    Memory pressure handling has not changed much since SQL 2005 and it was described in detail in a blog post by Slava Oks.   Note that SQL Server Express is an exception to the above behavior. Unlike other editions it does not assume it is the most important process running on the system but tries to be more “desktop” friendly. It will empty its working set after a period of inactivity.   How does SQL Server respond to changing OS memory?    In SQL Server 2005 support for Hot-Add memory was introduced. This feature, available in Enterprise and above editions, allows the server to make use of any extra physical memory that was added after SQL Server started. Being able to add physical memory when the system is running is limited to specialized hardware, but with the Hyper-V Dynamic Memory feature, when new memory is allocated to a guest virtual machine, it looks like hot-add physical memory to the guest. What this means is that thanks to the hot-add memory feature, SQL Server 2005 and higher can dynamically grow if more “physical” memory is granted to a guest VM by Hyper-V dynamic memory.   SQL Server checks OS memory every second and dynamically adjusts its “target” (based on available OS memory and max server memory) accordingly.   In “Denali” Standard Edition will also have sqlserver.exe support for hot-add memory when running virtualized (i.e. detecting and acting on Hyper-V Dynamic Memory allocations).   How does a SQL Server workload in a guest VM impact Hyper-V dynamic memory scheduling?   When a SQL workload causes the sqlserver.exe process to grow its working set, the Hyper-V memory scheduler will detect memory pressure in the guest VM and add memory to it. SQL Server will then detect the extra memory and grow according to workload demand. In our tests we have seen this feedback process cause a guest VM to grow quickly in response to SQL workload - we are still working on characterizing this ramp-up.    How does SQL Server respond when Hyper-V removes memory from a guest VM through ballooning?   If pressure from other VM's cause Hyper-V Dynamic Memory to take memory away from a VM through ballooning (allocating memory with a virtual device driver and returning it to the host OS), Windows Memory Manager will page out unlocked portions of memory and signal low resource notification events. When SQL Server detects these events it will shrink memory until the low memory notifications stop (see cache shrinking description above).    This raises another question. Can we make SQL Server release memory more readily and hence behave more "dynamically" without compromising performance? In certain circumstances where the application workload is predictable it may be possible to have a job which varies "max server memory" according to need, lowering it when the engine is inactive and raising it before a period of activity. This would have limited applicaability but it is something we're looking into.   What Memory Management changes are there in SQL Server “Denali”?   In SQL Server “Denali” (aka SQL11) the Memory Manager has been re-written to be more efficient. The main changes are summarized in this post. An important change with respect to Hyper-V Dynamic Memory support is that now the max server memory setting includes any size page allocations and managed CLR procedure allocations it now represents a closer approximation to total sqlserver.exe memory usage. This makes it easier to calculate a value for max server memory, which becomes important when configuring virtual machines to work well with Hyper-V Dynamic Memory Startup and Maximum RAM settings.   Another important change is no more AWE or hot-add support for 32-bit edition. This means if you're running a 32-bit edition of Denali you're limited to a 4GB address space and will not be able to take advantage of dynamically added OS memory that wasn't present when SQL Server started (though Hyper-V Dynamic Memory is still a supported configuration).   In part 3 we’ll develop some best practices for configuring and using SQL Server with Dynamic Memory. Originally posted at http://blogs.msdn.com/b/sqlosteam/

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  • SharePoint Apps and Windows Azure

    - by ScottGu
    Last Monday I had an opportunity to present as part of the keynote of this year’s SharePoint Conference.  My segment of the keynote covered the new SharePoint Cloud App Model we are introducing as part of the upcoming SharePoint 2013 and Office 365 releases.  This new app model for SharePoint is additive to the full trust solutions developers write today, and is built around three core tenants: Simplifying the development model and making it consistent between the on-premises version of SharePoint and SharePoint Online provided with Office 365. Making the execution model loosely coupled – and enabling developers to build apps and write code that can run outside of the core SharePoint service. This makes it easy to deploy SharePoint apps using Windows Azure, and avoid having to worry about breaking SharePoint and the apps within it when something is upgraded.  This new loosely coupled model also enables developers to write SharePoint applications that can leverage the full capabilities of the .NET Framework – including ASP.NET Web Forms 4.5, ASP.NET MVC 4, ASP.NET Web API, EF 5, Async, and more. Implementing this loosely coupled model using standard web protocols – like OAuth, JSON, and REST APIs – that enable developers to re-use skills and tools, and easily integrate SharePoint with Web and Mobile application architectures. A video of my talk + demos is now available to watch online: In the talk I walked through building an app from scratch – it showed off how easy it is to build solutions using new SharePoint application, and highlighted a web + workflow + mobile scenario that integrates SharePoint with code hosted on Windows Azure (all built using Visual Studio 2012 and ASP.NET 4.5 – including MVC and Web API). The new SharePoint Cloud App Model is something that I think is pretty exciting, and it is going to make it a lot easier to build SharePoint apps using the full power of both Windows Azure and the .NET Framework.  Using Windows Azure to easily extend SaaS based solutions like Office 365 is also a really natural fit and one that is going to offer a bunch of great developer opportunities.  Hope this helps, Scott  P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • iPhone Open GL ES using FBX - How do I import animations from FBX into iPhone?

    - by Dominic Tancredi
    I've been researching this extensively. We have a game that's 90% complete, using custom game logic in iPhone 4.0. We've been asked to import a 3D model and have it animate when various events happen in the game. I've put together an OpenGL view (based on Eagl and several examples), and used Blender to import the model, as well as Jeff LeMarche's script to export the .h file. After much trial, it worked, and I was able to show a rotating model (unskinned). However, the 3d artist hadn't UV unwrapped the model, so provided me a new model, this one as a Maya file, along with animation in a FBX format, a .obj file, and .tga texture unwrapped. My question is : how can I use FBX inside OpenGL ES inside iPhone to run through animations? And what's the pipeline to get this Maya file into Blender to be able to create a .h file. I've tried the obj2opengl however the model is missing normals (did it have it in the first place?) and the skin isn't applying at all (possibly a code issue, something I think I can fix). I'm trying to use Jeff LeMarche's animation tutorial but can't figure out how to get the model files into a proper .h file for use. Any advice?

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  • 3DS Max 2012 OBJ file import missing polygons

    - by Vit
    I started learning OpenGL. I got to a point I want to import some "real" objects. After "Googling" I decided I will go with OBJ file for start, since it is simple to understand, and there are plenty of tutorials on how to read them properly. I have from university access to 3DS Max 2012. So I tried to create very simple model (just deformated cube) and exporting it using OBJ file, just to vertices and triangles for the moment, without textures, so I can examine its structure by myself. But if I imported it right back to 3DS from OBJ file, now it renders somewhat strange, like its smoothen, and with lightsource, even I have none in scene. But the geometry, its wireframe is intact. So I thought maybe it is problem of exporting only vertices and triangles so I downloaded Enterprise-D model from internet, exported with everything on (normals, textures everything), and again imported it. Now, some polygons are missing. So, I want to ask, am I doing something terribly wrong, or is there some incompatibility issue between .max and .obj file ? Even it is only simple textured model without any lightsources, animation etc.? Thanks. Edit: I tried objects with MeshLab, the first, deformated cube was absolutelly OK. But still bothers me that 3DS Max doesen´t render it properly. In Enterprise-D model, there are polygons missing even in MeshLab. I uploaded rar archive with .max model of Enterprise, same .obj model exported from 3DS, and obj model of deformated cube. Download here (2.5 MB, filesonic).

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  • how to make HLSL effect just for lighning without texture mapping?

    - by naprox
    I'm new to XNA, i created an effect and just want to use lightning but in default effect that XNA create we should do texture mapping or the model appears 'RED', because of this lines of code in the effect file: float4 PixelShaderFunction(VertexShaderOutput input) : COLOR0 { float4 output = float4(1,0,0,1); return output; } and if i want to see my model (appear like when i use basiceffect) must do texture mapping by UV coordinates. but my model does not have UV coordinates assigned or its UV coordinates is not exported. and if i do texture mapping i got error. (i do texture mapping by this line of code in vertexshaderfunction and other necessary codes) output.UV= input.UV i have many of this models and want to work with them.(my models are in .FBX format) when i use Bassiceffect i have no problem and model appears correctly. how can i use "just" lightnings in my custom effects? and don't do texture mapping (because i have no UV coordinates in my models) and my model be look like when i use BasicEffect? if you need my complete code Here it is: http://www.mediafire.com/?4jexhd4ulm2icm2 here is inside of my Model Using BasicEffect http://i.imgur.com/ygP2h.jpg?1 and this is my code for drawing with or without BasicEffect inside of my draw() method: Matrix baseWorld = Matrix.CreateScale(Scale) * Matrix.CreateFromYawPitchRoll(Rotation.Y, Rotation.X, Rotation.Z) * Matrix.CreateTranslation(Position); foreach(ModelMesh mesh in Model.Meshes) { Matrix localWorld = ModelTransforms[mesh.ParentBone.Index] * baseWorld; foreach(ModelMeshPart part in mesh.MeshParts) { Effect effect = part.Effect; if (effect is BasicEffect) { ((BasicEffect)effect).World = localWorld; ((BasicEffect)effect).View = View; ((BasicEffect)effect).Projection = Projection; ((BasicEffect)effect).EnableDefaultLighting(); } else { setEffectParameter(effect, "World", localWorld); setEffectParameter(effect, "View", View); setEffectParameter(effect, "Projection", Projection); setEffectParameter(effect, "CameraPosition", CameraPosition); } } mesh.Draw(); } setEffectParameter is another method that sets effect parameter if i use my custom effect.

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  • Museum of Modern Art Starts Video Game Collection; Acquires Myst, Pac-Man, and More

    - by Jason Fitzpatrick
    The Museum of Modern Art is weighing in on the video-games-as-art debate by starting a collection of iconic video games and putting them up for public display. Read on to see what games are included in the initial batch and the MoMA’s reasons behind starting a video game collection. Although the MoMA is slated to grow to over 40 titles, the seed batch is 14 titles including: Pac-Man, Tetris, Sim City 2000, Myst, Portal, and Dwarf Fortress. In the announcement they explain the motivation for building a video game collection: Are video games art? They sure are, but they are also design, and a design approach is what we chose for this new foray into this universe. The games are selected as outstanding examples of interaction design—a field that MoMA has already explored and collected extensively, and one of the most important and oft-discussed expressions of contemporary design creativity. Our criteria, therefore, emphasize not only the visual quality and aesthetic experience of each game, but also the many other aspects—from the elegance of the code to the design of the player’s behavior—that pertain to interaction design. In order to develop an even stronger curatorial stance, over the past year and a half we have sought the advice of scholars, digital conservation and legal experts, historians, and critics, all of whom helped us refine not only the criteria and the wish list, but also the issues of acquisition, display, and conservation of digital artifacts that are made even more complex by the games’ interactive nature. This acquisition allows the Museum to study, preserve, and exhibit video games as part of its Architecture and Design collection. The above quote is only a small snippet of a much lengthier look at the benefits of examining and preserving video games, hit up the link below to check out the full post including future titles the MoMA would like to include in their archive. Video Games: 14 in the Collection, for Starters [Inside/Out] How To Boot Your Android Phone or Tablet Into Safe Mode HTG Explains: Does Your Android Phone Need an Antivirus? How To Use USB Drives With the Nexus 7 and Other Android Devices

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  • Hosting the Razor Engine for Templating in Non-Web Applications

    - by Rick Strahl
    Microsoft’s new Razor HTML Rendering Engine that is currently shipping with ASP.NET MVC previews can be used outside of ASP.NET. Razor is an alternative view engine that can be used instead of the ASP.NET Page engine that currently works with ASP.NET WebForms and MVC. It provides a simpler and more readable markup syntax and is much more light weight in terms of functionality than the full blown WebForms Page engine, focusing only on features that are more along the lines of a pure view engine (or classic ASP!) with focus on expression and code rendering rather than a complex control/object model. Like the Page engine though, the parser understands .NET code syntax which can be embedded into templates, and behind the scenes the engine compiles markup and script code into an executing piece of .NET code in an assembly. Although it ships as part of the ASP.NET MVC and WebMatrix the Razor Engine itself is not directly dependent on ASP.NET or IIS or HTTP in any way. And although there are some markup and rendering features that are optimized for HTML based output generation, Razor is essentially a free standing template engine. And what’s really nice is that unlike the ASP.NET Runtime, Razor is fairly easy to host inside of your own non-Web applications to provide templating functionality. Templating in non-Web Applications? Yes please! So why might you host a template engine in your non-Web application? Template rendering is useful in many places and I have a number of applications that make heavy use of it. One of my applications – West Wind Html Help Builder - exclusively uses template based rendering to merge user supplied help text content into customizable and executable HTML markup templates that provide HTML output for CHM style HTML Help. This is an older product and it’s not actually using .NET at the moment – and this is one reason I’m looking at Razor for script hosting at the moment. For a few .NET applications though I’ve actually used the ASP.NET Runtime hosting to provide templating and mail merge style functionality and while that works reasonably well it’s a very heavy handed approach. It’s very resource intensive and has potential issues with versioning in various different versions of .NET. The generic implementation I created in the article above requires a lot of fix up to mimic an HTTP request in a non-HTTP environment and there are a lot of little things that have to happen to ensure that the ASP.NET runtime works properly most of it having nothing to do with the templating aspect but just satisfying ASP.NET’s requirements. The Razor Engine on the other hand is fairly light weight and completely decoupled from the ASP.NET runtime and the HTTP processing. Rather it’s a pure template engine whose sole purpose is to render text templates. Hosting this engine in your own applications can be accomplished with a reasonable amount of code (actually just a few lines with the tools I’m about to describe) and without having to fake HTTP requests. It’s also much lighter on resource usage and you can easily attach custom properties to your base template implementation to easily pass context from the parent application into templates all of which was rather complicated with ASP.NET runtime hosting. Installing the Razor Template Engine You can get Razor as part of the MVC 3 (RC and later) or Web Matrix. Both are available as downloadable components from the Web Platform Installer Version 3.0 (!important – V2 doesn’t show these components). If you already have that version of the WPI installed just fire it up. You can get the latest version of the Web Platform Installer from here: http://www.microsoft.com/web/gallery/install.aspx Once the platform Installer 3.0 is installed install either MVC 3 or ASP.NET Web Pages. Once installed you’ll find a System.Web.Razor assembly in C:\Program Files\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\Assemblies\System.Web.Razor.dll which you can add as a reference to your project. Creating a Wrapper The basic Razor Hosting API is pretty simple and you can host Razor with a (large-ish) handful of lines of code. I’ll show the basics of it later in this article. However, if you want to customize the rendering and handle assembly and namespace includes for the markup as well as deal with text and file inputs as well as forcing Razor to run in a separate AppDomain so you can unload the code-generated assemblies and deal with assembly caching for re-used templates little more work is required to create something that is more easily reusable. For this reason I created a Razor Hosting wrapper project that combines a bunch of this functionality into an easy to use hosting class, a hosting factory that can load the engine in a separate AppDomain and a couple of hosting containers that provided folder based and string based caching for templates for an easily embeddable and reusable engine with easy to use syntax. If you just want the code and play with the samples and source go grab the latest code from the Subversion Repository at: http://www.west-wind.com:8080/svn/articles/trunk/RazorHosting/ or a snapshot from: http://www.west-wind.com/files/tools/RazorHosting.zip Getting Started Before I get into how hosting with Razor works, let’s take a look at how you can get up and running quickly with the wrapper classes provided. It only takes a few lines of code. The easiest way to use these Razor Hosting Wrappers is to use one of the two HostContainers provided. One is for hosting Razor scripts in a directory and rendering them as relative paths from these script files on disk. The other HostContainer serves razor scripts from string templates… Let’s start with a very simple template that displays some simple expressions, some code blocks and demonstrates rendering some data from contextual data that you pass to the template in the form of a ‘context’. Here’s a simple Razor template: @using System.Reflection Hello @Context.FirstName! Your entry was entered on: @Context.Entered @{ // Code block: Update the host Windows Form passed in through the context Context.WinForm.Text = "Hello World from Razor at " + DateTime.Now.ToString(); } AppDomain Id: @AppDomain.CurrentDomain.FriendlyName Assembly: @Assembly.GetExecutingAssembly().FullName Code based output: @{ // Write output with Response object from code string output = string.Empty; for (int i = 0; i < 10; i++) { output += i.ToString() + " "; } Response.Write(output); } Pretty easy to see what’s going on here. The only unusual thing in this code is the Context object which is an arbitrary object I’m passing from the host to the template by way of the template base class. I’m also displaying the current AppDomain and the executing Assembly name so you can see how compiling and running a template actually loads up new assemblies. Also note that as part of my context I’m passing a reference to the current Windows Form down to the template and changing the title from within the script. It’s a silly example, but it demonstrates two-way communication between host and template and back which can be very powerful. The easiest way to quickly render this template is to use the RazorEngine<TTemplateBase> class. The generic parameter specifies a template base class type that is used by Razor internally to generate the class it generates from a template. The default implementation provided in my RazorHosting wrapper is RazorTemplateBase. Here’s a simple one that renders from a string and outputs a string: var engine = new RazorEngine<RazorTemplateBase>(); // we can pass any object as context - here create a custom context var context = new CustomContext() { WinForm = this, FirstName = "Rick", Entered = DateTime.Now.AddDays(-10) }; string output = engine.RenderTemplate(this.txtSource.Text new string[] { "System.Windows.Forms.dll" }, context); if (output == null) this.txtResult.Text = "*** ERROR:\r\n" + engine.ErrorMessage; else this.txtResult.Text = output; Simple enough. This code renders a template from a string input and returns a result back as a string. It  creates a custom context and passes that to the template which can then access the Context’s properties. Note that anything passed as ‘context’ must be serializable (or MarshalByRefObject) – otherwise you get an exception when passing the reference over AppDomain boundaries (discussed later). Passing a context is optional, but is a key feature in being able to share data between the host application and the template. Note that we use the Context object to access FirstName, Entered and even the host Windows Form object which is used in the template to change the Window caption from within the script! In the code above all the work happens in the RenderTemplate method which provide a variety of overloads to read and write to and from strings, files and TextReaders/Writers. Here’s another example that renders from a file input using a TextReader: using (reader = new StreamReader("templates\\simple.csHtml", true)) { result = host.RenderTemplate(reader, new string[] { "System.Windows.Forms.dll" }, this.CustomContext); } RenderTemplate() is fairly high level and it handles loading of the runtime, compiling into an assembly and rendering of the template. If you want more control you can use the lower level methods to control each step of the way which is important for the HostContainers I’ll discuss later. Basically for those scenarios you want to separate out loading of the engine, compiling into an assembly and then rendering the template from the assembly. Why? So we can keep assemblies cached. In the code above a new assembly is created for each template rendered which is inefficient and uses up resources. Depending on the size of your templates and how often you fire them you can chew through memory very quickly. This slighter lower level approach is only a couple of extra steps: // we can pass any object as context - here create a custom context var context = new CustomContext() { WinForm = this, FirstName = "Rick", Entered = DateTime.Now.AddDays(-10) }; var engine = new RazorEngine<RazorTemplateBase>(); string assId = null; using (StringReader reader = new StringReader(this.txtSource.Text)) { assId = engine.ParseAndCompileTemplate(new string[] { "System.Windows.Forms.dll" }, reader); } string output = engine.RenderTemplateFromAssembly(assId, context); if (output == null) this.txtResult.Text = "*** ERROR:\r\n" + engine.ErrorMessage; else this.txtResult.Text = output; The difference here is that you can capture the assembly – or rather an Id to it – and potentially hold on to it to render again later assuming the template hasn’t changed. The HostContainers take advantage of this feature to cache the assemblies based on certain criteria like a filename and file time step or a string hash that if not change indicate that an assembly can be reused. Note that ParseAndCompileTemplate returns an assembly Id rather than the assembly itself. This is done so that that the assembly always stays in the host’s AppDomain and is not passed across AppDomain boundaries which would cause load failures. We’ll talk more about this in a minute but for now just realize that assemblies references are stored in a list and are accessible by this ID to allow locating and re-executing of the assembly based on that id. Reuse of the assembly avoids recompilation overhead and creation of yet another assembly that loads into the current AppDomain. You can play around with several different versions of the above code in the main sample form:   Using Hosting Containers for more Control and Caching The above examples simply render templates into assemblies each and every time they are executed. While this works and is even reasonably fast, it’s not terribly efficient. If you render templates more than once it would be nice if you could cache the generated assemblies for example to avoid re-compiling and creating of a new assembly each time. Additionally it would be nice to load template assemblies into a separate AppDomain optionally to be able to be able to unload assembli es and also to protect your host application from scripting attacks with malicious template code. Hosting containers provide also provide a wrapper around the RazorEngine<T> instance, a factory (which allows creation in separate AppDomains) and an easy way to start and stop the container ‘runtime’. The Razor Hosting samples provide two hosting containers: RazorFolderHostContainer and StringHostContainer. The folder host provides a simple runtime environment for a folder structure similar in the way that the ASP.NET runtime handles a virtual directory as it’s ‘application' root. Templates are loaded from disk in relative paths and the resulting assemblies are cached unless the template on disk is changed. The string host also caches templates based on string hashes – if the same string is passed a second time a cached version of the assembly is used. Here’s how HostContainers work. I’ll use the FolderHostContainer because it’s likely the most common way you’d use templates – from disk based templates that can be easily edited and maintained on disk. The first step is to create an instance of it and keep it around somewhere (in the example it’s attached as a property to the Form): RazorFolderHostContainer Host = new RazorFolderHostContainer(); public RazorFolderHostForm() { InitializeComponent(); // The base path for templates - templates are rendered with relative paths // based on this path. Host.TemplatePath = Path.Combine(Environment.CurrentDirectory, TemplateBaseFolder); // Add any assemblies you want reference in your templates Host.ReferencedAssemblies.Add("System.Windows.Forms.dll"); // Start up the host container Host.Start(); } Next anytime you want to render a template you can use simple code like this: private void RenderTemplate(string fileName) { // Pass the template path via the Context var relativePath = Utilities.GetRelativePath(fileName, Host.TemplatePath); if (!Host.RenderTemplate(relativePath, this.Context, Host.RenderingOutputFile)) { MessageBox.Show("Error: " + Host.ErrorMessage); return; } this.webBrowser1.Navigate("file://" + Host.RenderingOutputFile); } You can also render the output to a string instead of to a file: string result = Host.RenderTemplateToString(relativePath,context); Finally if you want to release the engine and shut down the hosting AppDomain you can simply do: Host.Stop(); Stopping the AppDomain and restarting it (ie. calling Stop(); followed by Start()) is also a nice way to release all resources in the AppDomain. The FolderBased domain also supports partial Rendering based on root path based relative paths with the same caching characteristics as the main templates. From within a template you can call out to a partial like this: @RenderPartial(@"partials\PartialRendering.cshtml", Context) where partials\PartialRendering.cshtml is a relative to the template root folder. The folder host example lets you load up templates from disk and display the result in a Web Browser control which demonstrates using Razor HTML output from templates that contain HTML syntax which happens to me my target scenario for Html Help Builder.   The Razor Engine Wrapper Project The project I created to wrap Razor hosting has a fair bit of code and a number of classes associated with it. Most of the components are internally used and as you can see using the final RazorEngine<T> and HostContainer classes is pretty easy. The classes are extensible and I suspect developers will want to build more customized host containers for their applications. Host containers are the key to wrapping up all functionality – Engine, BaseTemplate, AppDomain Hosting, Caching etc in a logical piece that is ready to be plugged into an application. When looking at the code there are a couple of core features provided: Core Razor Engine Hosting This is the core Razor hosting which provides the basics of loading a template, compiling it into an assembly and executing it. This is fairly straightforward, but without a host container that can cache assemblies based on some criteria templates are recompiled and re-created each time which is inefficient (although pretty fast). The base engine wrapper implementation also supports hosting the Razor runtime in a separate AppDomain for security and the ability to unload it on demand. Host Containers The engine hosting itself doesn’t provide any sort of ‘runtime’ service like picking up files from disk, caching assemblies and so forth. So my implementation provides two HostContainers: RazorFolderHostContainer and RazorStringHostContainer. The FolderHost works off a base directory and loads templates based on relative paths (sort of like the ASP.NET runtime does off a virtual). The HostContainers also deal with caching of template assemblies – for the folder host the file date is tracked and checked for updates and unless the template is changed a cached assembly is reused. The StringHostContainer similiarily checks string hashes to figure out whether a particular string template was previously compiled and executed. The HostContainers also act as a simple startup environment and a single reference to easily store and reuse in an application. TemplateBase Classes The template base classes are the base classes that from which the Razor engine generates .NET code. A template is parsed into a class with an Execute() method and the class is based on this template type you can specify. RazorEngine<TBaseTemplate> can receive this type and the HostContainers default to specific templates in their base implementations. Template classes are customizable to allow you to create templates that provide application specific features and interaction from the template to your host application. How does the RazorEngine wrapper work? You can browse the source code in the links above or in the repository or download the source, but I’ll highlight some key features here. Here’s part of the RazorEngine implementation that can be used to host the runtime and that demonstrates the key code required to host the Razor runtime. The RazorEngine class is implemented as a generic class to reflect the Template base class type: public class RazorEngine<TBaseTemplateType> : MarshalByRefObject where TBaseTemplateType : RazorTemplateBase The generic type is used to internally provide easier access to the template type and assignments on it as part of the template processing. The class also inherits MarshalByRefObject to allow execution over AppDomain boundaries – something that all the classes discussed here need to do since there is much interaction between the host and the template. The first two key methods deal with creating a template assembly: /// <summary> /// Creates an instance of the RazorHost with various options applied. /// Applies basic namespace imports and the name of the class to generate /// </summary> /// <param name="generatedNamespace"></param> /// <param name="generatedClass"></param> /// <returns></returns> protected RazorTemplateEngine CreateHost(string generatedNamespace, string generatedClass) { Type baseClassType = typeof(TBaseTemplateType); RazorEngineHost host = new RazorEngineHost(new CSharpRazorCodeLanguage()); host.DefaultBaseClass = baseClassType.FullName; host.DefaultClassName = generatedClass; host.DefaultNamespace = generatedNamespace; host.NamespaceImports.Add("System"); host.NamespaceImports.Add("System.Text"); host.NamespaceImports.Add("System.Collections.Generic"); host.NamespaceImports.Add("System.Linq"); host.NamespaceImports.Add("System.IO"); return new RazorTemplateEngine(host); } /// <summary> /// Parses and compiles a markup template into an assembly and returns /// an assembly name. The name is an ID that can be passed to /// ExecuteTemplateByAssembly which picks up a cached instance of the /// loaded assembly. /// /// </summary> /// <param name="namespaceOfGeneratedClass">The namespace of the class to generate from the template</param> /// <param name="generatedClassName">The name of the class to generate from the template</param> /// <param name="ReferencedAssemblies">Any referenced assemblies by dll name only. Assemblies must be in execution path of host or in GAC.</param> /// <param name="templateSourceReader">Textreader that loads the template</param> /// <remarks> /// The actual assembly isn't returned here to allow for cross-AppDomain /// operation. If the assembly was returned it would fail for cross-AppDomain /// calls. /// </remarks> /// <returns>An assembly Id. The Assembly is cached in memory and can be used with RenderFromAssembly.</returns> public string ParseAndCompileTemplate( string namespaceOfGeneratedClass, string generatedClassName, string[] ReferencedAssemblies, TextReader templateSourceReader) { RazorTemplateEngine engine = CreateHost(namespaceOfGeneratedClass, generatedClassName); // Generate the template class as CodeDom GeneratorResults razorResults = engine.GenerateCode(templateSourceReader); // Create code from the codeDom and compile CSharpCodeProvider codeProvider = new CSharpCodeProvider(); CodeGeneratorOptions options = new CodeGeneratorOptions(); // Capture Code Generated as a string for error info // and debugging LastGeneratedCode = null; using (StringWriter writer = new StringWriter()) { codeProvider.GenerateCodeFromCompileUnit(razorResults.GeneratedCode, writer, options); LastGeneratedCode = writer.ToString(); } CompilerParameters compilerParameters = new CompilerParameters(ReferencedAssemblies); // Standard Assembly References compilerParameters.ReferencedAssemblies.Add("System.dll"); compilerParameters.ReferencedAssemblies.Add("System.Core.dll"); compilerParameters.ReferencedAssemblies.Add("Microsoft.CSharp.dll"); // dynamic support! // Also add the current assembly so RazorTemplateBase is available compilerParameters.ReferencedAssemblies.Add(Assembly.GetExecutingAssembly().CodeBase.Substring(8)); compilerParameters.GenerateInMemory = Configuration.CompileToMemory; if (!Configuration.CompileToMemory) compilerParameters.OutputAssembly = Path.Combine(Configuration.TempAssemblyPath, "_" + Guid.NewGuid().ToString("n") + ".dll"); CompilerResults compilerResults = codeProvider.CompileAssemblyFromDom(compilerParameters, razorResults.GeneratedCode); if (compilerResults.Errors.Count > 0) { var compileErrors = new StringBuilder(); foreach (System.CodeDom.Compiler.CompilerError compileError in compilerResults.Errors) compileErrors.Append(String.Format(Resources.LineX0TColX1TErrorX2RN, compileError.Line, compileError.Column, compileError.ErrorText)); this.SetError(compileErrors.ToString() + "\r\n" + LastGeneratedCode); return null; } AssemblyCache.Add(compilerResults.CompiledAssembly.FullName, compilerResults.CompiledAssembly); return compilerResults.CompiledAssembly.FullName; } Think of the internal CreateHost() method as setting up the assembly generated from each template. Each template compiles into a separate assembly. It sets up namespaces, and assembly references, the base class used and the name and namespace for the generated class. ParseAndCompileTemplate() then calls the CreateHost() method to receive the template engine generator which effectively generates a CodeDom from the template – the template is turned into .NET code. The code generated from our earlier example looks something like this: //------------------------------------------------------------------------------ // <auto-generated> // This code was generated by a tool. // Runtime Version:4.0.30319.1 // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ namespace RazorTest { using System; using System.Text; using System.Collections.Generic; using System.Linq; using System.IO; using System.Reflection; public class RazorTemplate : RazorHosting.RazorTemplateBase { #line hidden public RazorTemplate() { } public override void Execute() { WriteLiteral("Hello "); Write(Context.FirstName); WriteLiteral("! Your entry was entered on: "); Write(Context.Entered); WriteLiteral("\r\n\r\n"); // Code block: Update the host Windows Form passed in through the context Context.WinForm.Text = "Hello World from Razor at " + DateTime.Now.ToString(); WriteLiteral("\r\nAppDomain Id:\r\n "); Write(AppDomain.CurrentDomain.FriendlyName); WriteLiteral("\r\n \r\nAssembly:\r\n "); Write(Assembly.GetExecutingAssembly().FullName); WriteLiteral("\r\n\r\nCode based output: \r\n"); // Write output with Response object from code string output = string.Empty; for (int i = 0; i < 10; i++) { output += i.ToString() + " "; } } } } Basically the template’s body is turned into code in an Execute method that is called. Internally the template’s Write method is fired to actually generate the output. Note that the class inherits from RazorTemplateBase which is the generic parameter I used to specify the base class when creating an instance in my RazorEngine host: var engine = new RazorEngine<RazorTemplateBase>(); This template class must be provided and it must implement an Execute() and Write() method. Beyond that you can create any class you chose and attach your own properties. My RazorTemplateBase class implementation is very simple: public class RazorTemplateBase : MarshalByRefObject, IDisposable { /// <summary> /// You can pass in a generic context object /// to use in your template code /// </summary> public dynamic Context { get; set; } /// <summary> /// Class that generates output. Currently ultra simple /// with only Response.Write() implementation. /// </summary> public RazorResponse Response { get; set; } public object HostContainer {get; set; } public object Engine { get; set; } public RazorTemplateBase() { Response = new RazorResponse(); } public virtual void Write(object value) { Response.Write(value); } public virtual void WriteLiteral(object value) { Response.Write(value); } /// <summary> /// Razor Parser implements this method /// </summary> public virtual void Execute() {} public virtual void Dispose() { if (Response != null) { Response.Dispose(); Response = null; } } } Razor fills in the Execute method when it generates its subclass and uses the Write() method to output content. As you can see I use a RazorResponse() class here to generate output. This isn’t necessary really, as you could use a StringBuilder or StringWriter() directly, but I prefer using Response object so I can extend the Response behavior as needed. The RazorResponse class is also very simple and merely acts as a wrapper around a TextWriter: public class RazorResponse : IDisposable { /// <summary> /// Internal text writer - default to StringWriter() /// </summary> public TextWriter Writer = new StringWriter(); public virtual void Write(object value) { Writer.Write(value); } public virtual void WriteLine(object value) { Write(value); Write("\r\n"); } public virtual void WriteFormat(string format, params object[] args) { Write(string.Format(format, args)); } public override string ToString() { return Writer.ToString(); } public virtual void Dispose() { Writer.Close(); } public virtual void SetTextWriter(TextWriter writer) { // Close original writer if (Writer != null) Writer.Close(); Writer = writer; } } The Rendering Methods of RazorEngine At this point I’ve talked about the assembly generation logic and the template implementation itself. What’s left is that once you’ve generated the assembly is to execute it. The code to do this is handled in the various RenderXXX methods of the RazorEngine class. Let’s look at the lowest level one of these which is RenderTemplateFromAssembly() and a couple of internal support methods that handle instantiating and invoking of the generated template method: public string RenderTemplateFromAssembly( string assemblyId, string generatedNamespace, string generatedClass, object context, TextWriter outputWriter) { this.SetError(); Assembly generatedAssembly = AssemblyCache[assemblyId]; if (generatedAssembly == null) { this.SetError(Resources.PreviouslyCompiledAssemblyNotFound); return null; } string className = generatedNamespace + "." + generatedClass; Type type; try { type = generatedAssembly.GetType(className); } catch (Exception ex) { this.SetError(Resources.UnableToCreateType + className + ": " + ex.Message); return null; } // Start with empty non-error response (if we use a writer) string result = string.Empty; using(TBaseTemplateType instance = InstantiateTemplateClass(type)) { if (instance == null) return null; if (outputWriter != null) instance.Response.SetTextWriter(outputWriter); if (!InvokeTemplateInstance(instance, context)) return null; // Capture string output if implemented and return // otherwise null is returned if (outputWriter == null) result = instance.Response.ToString(); } return result; } protected virtual TBaseTemplateType InstantiateTemplateClass(Type type) { TBaseTemplateType instance = Activator.CreateInstance(type) as TBaseTemplateType; if (instance == null) { SetError(Resources.CouldnTActivateTypeInstance + type.FullName); return null; } instance.Engine = this; // If a HostContainer was set pass that to the template too instance.HostContainer = this.HostContainer; return instance; } /// <summary> /// Internally executes an instance of the template, /// captures errors on execution and returns true or false /// </summary> /// <param name="instance">An instance of the generated template</param> /// <returns>true or false - check ErrorMessage for errors</returns> protected virtual bool InvokeTemplateInstance(TBaseTemplateType instance, object context) { try { instance.Context = context; instance.Execute(); } catch (Exception ex) { this.SetError(Resources.TemplateExecutionError + ex.Message); return false; } finally { // Must make sure Response is closed instance.Response.Dispose(); } return true; } The RenderTemplateFromAssembly method basically requires the namespace and class to instantate and creates an instance of the class using InstantiateTemplateClass(). It then invokes the method with InvokeTemplateInstance(). These two methods are broken out because they are re-used by various other rendering methods and also to allow subclassing and providing additional configuration tasks to set properties and pass values to templates at execution time. In the default mode instantiation sets the Engine and HostContainer (discussed later) so the template can call back into the template engine, and the context is set when the template method is invoked. The various RenderXXX methods use similar code although they create the assemblies first. If you’re after potentially cashing assemblies the method is the one to call and that’s exactly what the two HostContainer classes do. More on that in a minute, but before we get into HostContainers let’s talk about AppDomain hosting and the like. Running Templates in their own AppDomain With the RazorEngine class above, when a template is parsed into an assembly and executed the assembly is created (in memory or on disk – you can configure that) and cached in the current AppDomain. In .NET once an assembly has been loaded it can never be unloaded so if you’re loading lots of templates and at some time you want to release them there’s no way to do so. If however you load the assemblies in a separate AppDomain that new AppDomain can be unloaded and the assemblies loaded in it with it. In order to host the templates in a separate AppDomain the easiest thing to do is to run the entire RazorEngine in a separate AppDomain. Then all interaction occurs in the other AppDomain and no further changes have to be made. To facilitate this there is a RazorEngineFactory which has methods that can instantiate the RazorHost in a separate AppDomain as well as in the local AppDomain. The host creates the remote instance and then hangs on to it to keep it alive as well as providing methods to shut down the AppDomain and reload the engine. Sounds complicated but cross-AppDomain invocation is actually fairly easy to implement. Here’s some of the relevant code from the RazorEngineFactory class. Like the RazorEngine this class is generic and requires a template base type in the generic class name: public class RazorEngineFactory<TBaseTemplateType> where TBaseTemplateType : RazorTemplateBase Here are the key methods of interest: /// <summary> /// Creates an instance of the RazorHost in a new AppDomain. This /// version creates a static singleton that that is cached and you /// can call UnloadRazorHostInAppDomain to unload it. /// </summary> /// <returns></returns> public static RazorEngine<TBaseTemplateType> CreateRazorHostInAppDomain() { if (Current == null) Current = new RazorEngineFactory<TBaseTemplateType>(); return Current.GetRazorHostInAppDomain(); } public static void UnloadRazorHostInAppDomain() { if (Current != null) Current.UnloadHost(); Current = null; } /// <summary> /// Instance method that creates a RazorHost in a new AppDomain. /// This method requires that you keep the Factory around in /// order to keep the AppDomain alive and be able to unload it. /// </summary> /// <returns></returns> public RazorEngine<TBaseTemplateType> GetRazorHostInAppDomain() { LocalAppDomain = CreateAppDomain(null); if (LocalAppDomain == null) return null; /// Create the instance inside of the new AppDomain /// Note: remote domain uses local EXE's AppBasePath!!! RazorEngine<TBaseTemplateType> host = null; try { Assembly ass = Assembly.GetExecutingAssembly(); string AssemblyPath = ass.Location; host = (RazorEngine<TBaseTemplateType>) LocalAppDomain.CreateInstanceFrom(AssemblyPath, typeof(RazorEngine<TBaseTemplateType>).FullName).Unwrap(); } catch (Exception ex) { ErrorMessage = ex.Message; return null; } return host; } /// <summary> /// Internally creates a new AppDomain in which Razor templates can /// be run. /// </summary> /// <param name="appDomainName"></param> /// <returns></returns> private AppDomain CreateAppDomain(string appDomainName) { if (appDomainName == null) appDomainName = "RazorHost_" + Guid.NewGuid().ToString("n"); AppDomainSetup setup = new AppDomainSetup(); // *** Point at current directory setup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory; AppDomain localDomain = AppDomain.CreateDomain(appDomainName, null, setup); return localDomain; } /// <summary> /// Allow unloading of the created AppDomain to release resources /// All internal resources in the AppDomain are released including /// in memory compiled Razor assemblies. /// </summary> public void UnloadHost() { if (this.LocalAppDomain != null) { AppDomain.Unload(this.LocalAppDomain); this.LocalAppDomain = null; } } The static CreateRazorHostInAppDomain() is the key method that startup code usually calls. It uses a Current singleton instance to an instance of itself that is created cross AppDomain and is kept alive because it’s static. GetRazorHostInAppDomain actually creates a cross-AppDomain instance which first creates a new AppDomain and then loads the RazorEngine into it. The remote Proxy instance is returned as a result to the method and can be used the same as a local instance. The code to run with a remote AppDomain is simple: private RazorEngine<RazorTemplateBase> CreateHost() { if (this.Host != null) return this.Host; // Use Static Methods - no error message if host doesn't load this.Host = RazorEngineFactory<RazorTemplateBase>.CreateRazorHostInAppDomain(); if (this.Host == null) { MessageBox.Show("Unable to load Razor Template Host", "Razor Hosting", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); } return this.Host; } This code relies on a local reference of the Host which is kept around for the duration of the app (in this case a form reference). To use this you’d simply do: this.Host = CreateHost(); if (host == null) return; string result = host.RenderTemplate( this.txtSource.Text, new string[] { "System.Windows.Forms.dll", "Westwind.Utilities.dll" }, this.CustomContext); if (result == null) { MessageBox.Show(host.ErrorMessage, "Template Execution Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); return; } this.txtResult.Text = result; Now all templates run in a remote AppDomain and can be unloaded with simple code like this: RazorEngineFactory<RazorTemplateBase>.UnloadRazorHostInAppDomain(); this.Host = null; One Step further – Providing a caching ‘Runtime’ Once we can load templates in a remote AppDomain we can add some additional functionality like assembly caching based on application specific features. One of my typical scenarios is to render templates out of a scripts folder. So all templates live in a folder and they change infrequently. So a Folder based host that can compile these templates once and then only recompile them if something changes would be ideal. Enter host containers which are basically wrappers around the RazorEngine<t> and RazorEngineFactory<t>. They provide additional logic for things like file caching based on changes on disk or string hashes for string based template inputs. The folder host also provides for partial rendering logic through a custom template base implementation. There’s a base implementation in RazorBaseHostContainer, which provides the basics for hosting a RazorEngine, which includes the ability to start and stop the engine, cache assemblies and add references: public abstract class RazorBaseHostContainer<TBaseTemplateType> : MarshalByRefObject where TBaseTemplateType : RazorTemplateBase, new() { public RazorBaseHostContainer() { UseAppDomain = true; GeneratedNamespace = "__RazorHost"; } /// <summary> /// Determines whether the Container hosts Razor /// in a separate AppDomain. Seperate AppDomain /// hosting allows unloading and releasing of /// resources. /// </summary> public bool UseAppDomain { get; set; } /// <summary> /// Base folder location where the AppDomain /// is hosted. By default uses the same folder /// as the host application. /// /// Determines where binary dependencies are /// found for assembly references. /// </summary> public string BaseBinaryFolder { get; set; } /// <summary> /// List of referenced assemblies as string values. /// Must be in GAC or in the current folder of the host app/ /// base BinaryFolder /// </summary> public List<string> ReferencedAssemblies = new List<string>(); /// <summary> /// Name of the generated namespace for template classes /// </summary> public string GeneratedNamespace {get; set; } /// <summary> /// Any error messages /// </summary> public string ErrorMessage { get; set; } /// <summary> /// Cached instance of the Host. Required to keep the /// reference to the host alive for multiple uses. /// </summary> public RazorEngine<TBaseTemplateType> Engine; /// <summary> /// Cached instance of the Host Factory - so we can unload /// the host and its associated AppDomain. /// </summary> protected RazorEngineFactory<TBaseTemplateType> EngineFactory; /// <summary> /// Keep track of each compiled assembly /// and when it was compiled. /// /// Use a hash of the string to identify string /// changes. /// </summary> protected Dictionary<int, CompiledAssemblyItem> LoadedAssemblies = new Dictionary<int, CompiledAssemblyItem>(); /// <summary> /// Call to start the Host running. Follow by a calls to RenderTemplate to /// render individual templates. Call Stop when done. /// </summary> /// <returns>true or false - check ErrorMessage on false </returns> public virtual bool Start() { if (Engine == null) { if (UseAppDomain) Engine = RazorEngineFactory<TBaseTemplateType>.CreateRazorHostInAppDomain(); else Engine = RazorEngineFactory<TBaseTemplateType>.CreateRazorHost(); Engine.Configuration.CompileToMemory = true; Engine.HostContainer = this; if (Engine == null) { this.ErrorMessage = EngineFactory.ErrorMessage; return false; } } return true; } /// <summary> /// Stops the Host and releases the host AppDomain and cached /// assemblies. /// </summary> /// <returns>true or false</returns> public bool Stop() { this.LoadedAssemblies.Clear(); RazorEngineFactory<RazorTemplateBase>.UnloadRazorHostInAppDomain(); this.Engine = null; return true; } … } This base class provides most of the mechanics to host the runtime, but no application specific implementation for rendering. There are rendering functions but they just call the engine directly and provide no caching – there’s no context to decide how to cache and reuse templates. The key methods are Start and Stop and their main purpose is to start a new AppDomain (optionally) and shut it down when requested. The RazorFolderHostContainer – Folder Based Runtime Hosting Let’s look at the more application specific RazorFolderHostContainer implementation which is defined like this: public class RazorFolderHostContainer : RazorBaseHostContainer<RazorTemplateFolderHost> Note that a customized RazorTemplateFolderHost class template is used for this implementation that supports partial rendering in form of a RenderPartial() method that’s available to templates. The folder host’s features are: Render templates based on a Template Base Path (a ‘virtual’ if you will) Cache compiled assemblies based on the relative path and file time stamp File changes on templates cause templates to be recompiled into new assemblies Support for partial rendering using base folder relative pathing As shown in the startup examples earlier host containers require some startup code with a HostContainer tied to a persistent property (like a Form property): // The base path for templates - templates are rendered with relative paths // based on this path. HostContainer.TemplatePath = Path.Combine(Environment.CurrentDirectory, TemplateBaseFolder); // Default output rendering disk location HostContainer.RenderingOutputFile = Path.Combine(HostContainer.TemplatePath, "__Preview.htm"); // Add any assemblies you want reference in your templates HostContainer.ReferencedAssemblies.Add("System.Windows.Forms.dll"); // Start up the host container HostContainer.Start(); Once that’s done, you can render templates with the host container: // Pass the template path for full filename seleted with OpenFile Dialog // relativepath is: subdir\file.cshtml or file.cshtml or ..\file.cshtml var relativePath = Utilities.GetRelativePath(fileName, HostContainer.TemplatePath); if (!HostContainer.RenderTemplate(relativePath, Context, HostContainer.RenderingOutputFile)) { MessageBox.Show("Error: " + HostContainer.ErrorMessage); return; } webBrowser1.Navigate("file://" + HostContainer.RenderingOutputFile); The most critical task of the RazorFolderHostContainer implementation is to retrieve a template from disk, compile and cache it and then deal with deciding whether subsequent requests need to re-compile the template or simply use a cached version. Internally the GetAssemblyFromFileAndCache() handles this task: /// <summary> /// Internally checks if a cached assembly exists and if it does uses it /// else creates and compiles one. Returns an assembly Id to be /// used with the LoadedAssembly list. /// </summary> /// <param name="relativePath"></param> /// <param name="context"></param> /// <returns></returns> protected virtual CompiledAssemblyItem GetAssemblyFromFileAndCache(string relativePath) { string fileName = Path.Combine(TemplatePath, relativePath).ToLower(); int fileNameHash = fileName.GetHashCode(); if (!File.Exists(fileName)) { this.SetError(Resources.TemplateFileDoesnTExist + fileName); return null; } CompiledAssemblyItem item = null; this.LoadedAssemblies.TryGetValue(fileNameHash, out item); string assemblyId = null; // Check for cached instance if (item != null) { var fileTime = File.GetLastWriteTimeUtc(fileName); if (fileTime <= item.CompileTimeUtc) assemblyId = item.AssemblyId; } else item = new CompiledAssemblyItem(); // No cached instance - create assembly and cache if (assemblyId == null) { string safeClassName = GetSafeClassName(fileName); StreamReader reader = null; try { reader = new StreamReader(fileName, true); } catch (Exception ex) { this.SetError(Resources.ErrorReadingTemplateFile + fileName); return null; } assemblyId = Engine.ParseAndCompileTemplate(this.ReferencedAssemblies.ToArray(), reader); // need to ensure reader is closed if (reader != null) reader.Close(); if (assemblyId == null) { this.SetError(Engine.ErrorMessage); return null; } item.AssemblyId = assemblyId; item.CompileTimeUtc = DateTime.UtcNow; item.FileName = fileName; item.SafeClassName = safeClassName; this.LoadedAssemblies[fileNameHash] = item; } return item; } This code uses a LoadedAssembly dictionary which is comprised of a structure that holds a reference to a compiled assembly, a full filename and file timestamp and an assembly id. LoadedAssemblies (defined on the base class shown earlier) is essentially a cache for compiled assemblies and they are identified by a hash id. In the case of files the hash is a GetHashCode() from the full filename of the template. The template is checked for in the cache and if not found the file stamp is checked. If that’s newer than the cache’s compilation date the template is recompiled otherwise the version in the cache is used. All the core work defers to a RazorEngine<T> instance to ParseAndCompileTemplate(). The three rendering specific methods then are rather simple implementations with just a few lines of code dealing with parameter and return value parsing: /// <summary> /// Renders a template to a TextWriter. Useful to write output into a stream or /// the Response object. Used for partial rendering. /// </summary> /// <param name="relativePath">Relative path to the file in the folder structure</param> /// <param name="context">Optional context object or null</param> /// <param name="writer">The textwriter to write output into</param> /// <returns></returns> public bool RenderTemplate(string relativePath, object context, TextWriter writer) { // Set configuration data that is to be passed to the template (any object) Engine.TemplatePerRequestConfigurationData = new RazorFolderHostTemplateConfiguration() { TemplatePath = Path.Combine(this.TemplatePath, relativePath), TemplateRelativePath = relativePath, }; CompiledAssemblyItem item = GetAssemblyFromFileAndCache(relativePath); if (item == null) { writer.Close(); return false; } try { // String result will be empty as output will be rendered into the // Response object's stream output. However a null result denotes // an error string result = Engine.RenderTemplateFromAssembly(item.AssemblyId, context, writer); if (result == null) { this.SetError(Engine.ErrorMessage); return false; } } catch (Exception ex) { this.SetError(ex.Message); return false; } finally { writer.Close(); } return true; } /// <summary> /// Render a template from a source file on disk to a specified outputfile. /// </summary> /// <param name="relativePath">Relative path off the template root folder. Format: path/filename.cshtml</param> /// <param name="context">Any object that will be available in the template as a dynamic of this.Context</param> /// <param name="outputFile">Optional - output file where output is written to. If not specified the /// RenderingOutputFile property is used instead /// </param> /// <returns>true if rendering succeeds, false on failure - check ErrorMessage</returns> public bool RenderTemplate(string relativePath, object context, string outputFile) { if (outputFile == null) outputFile = RenderingOutputFile; try { using (StreamWriter writer = new StreamWriter(outputFile, false, Engine.Configuration.OutputEncoding, Engine.Configuration.StreamBufferSize)) { return RenderTemplate(relativePath, context, writer); } } catch (Exception ex) { this.SetError(ex.Message); return false; } return true; } /// <summary> /// Renders a template to string. Useful for RenderTemplate /// </summary> /// <param name="relativePath"></param> /// <param name="context"></param> /// <returns></returns> public string RenderTemplateToString(string relativePath, object context) { string result = string.Empty; try { using (StringWriter writer = new StringWriter()) { // String result will be empty as output will be rendered into the // Response object's stream output. However a null result denotes // an error if (!RenderTemplate(relativePath, context, writer)) { this.SetError(Engine.ErrorMessage); return null; } result = writer.ToString(); } } catch (Exception ex) { this.SetError(ex.Message); return null; } return result; } The idea is that you can create custom host container implementations that do exactly what you want fairly easily. Take a look at both the RazorFolderHostContainer and RazorStringHostContainer classes for the basic concepts you can use to create custom implementations. Notice also that you can set the engine’s PerRequestConfigurationData() from the host container: // Set configuration data that is to be passed to the template (any object) Engine.TemplatePerRequestConfigurationData = new RazorFolderHostTemplateConfiguration() { TemplatePath = Path.Combine(this.TemplatePath, relativePath), TemplateRelativePath = relativePath, }; which when set to a non-null value is passed to the Template’s InitializeTemplate() method. This method receives an object parameter which you can cast as needed: public override void InitializeTemplate(object configurationData) { // Pick up configuration data and stuff into Request object RazorFolderHostTemplateConfiguration config = configurationData as RazorFolderHostTemplateConfiguration; this.Request.TemplatePath = config.TemplatePath; this.Request.TemplateRelativePath = config.TemplateRelativePath; } With this data you can then configure any custom properties or objects on your main template class. It’s an easy way to pass data from the HostContainer all the way down into the template. The type you use is of type object so you have to cast it yourself, and it must be serializable since it will likely run in a separate AppDomain. This might seem like an ugly way to pass data around – normally I’d use an event delegate to call back from the engine to the host, but since this is running over AppDomain boundaries events get really tricky and passing a template instance back up into the host over AppDomain boundaries doesn’t work due to serialization issues. So it’s easier to pass the data from the host down into the template using this rather clumsy approach of set and forward. It’s ugly, but it’s something that can be hidden in the host container implementation as I’ve done here. It’s also not something you have to do in every implementation so this is kind of an edge case, but I know I’ll need to pass a bunch of data in some of my applications and this will be the easiest way to do so. Summing Up Hosting the Razor runtime is something I got jazzed up about quite a bit because I have an immediate need for this type of templating/merging/scripting capability in an application I’m working on. I’ve also been using templating in many apps and it’s always been a pain to deal with. The Razor engine makes this whole experience a lot cleaner and more light weight and with these wrappers I can now plug .NET based templating into my code literally with a few lines of code. That’s something to cheer about… I hope some of you will find this useful as well… Resources The examples and code require that you download the Razor runtimes. Projects are for Visual Studio 2010 running on .NET 4.0 Platform Installer 3.0 (install WebMatrix or MVC 3 for Razor Runtimes) Latest Code in Subversion Repository Download Snapshot of the Code Documentation (CHM Help File) © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  .NET  

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  • Knockoutjs - stringify to handling observables and custom events

    - by Renso
    Goal: Once you viewmodel has been built and populated with data, at some point it goal of it all is to persist the data to the database (or some other media). Regardless of where you want to save it, your client-side viewmodel needs to be converted to a JSON string and sent back to the server. Environment considerations: jQuery 1.4.3+ Knockoutjs version 1.1.2   How to: So let’s set the stage, you are using Knockoutjs and you have a viewmodel with some Knockout dependencies. You want to make sure it is in the proper JSON format and via ajax post it to the server for persistence.   First order of business is to deal with the viewmodel (JSON) object. To most the JSON stringifier sounds familiar. The JSON stringifier converts JavaScript data structures into JSON text. JSON does not support cyclic data structures, so be careful to not give cyclical structures to the JSON stringifier. You may ask, is this the best way to do it? What about those observables and other Knockout properties that I don’t want to persist or want their actual value persisted and not their function, etc. Not sure if you were aware, but KO already has a method; ko.utils.stringifyJson() - it's mostly just a wrapper around JSON.stringify. (which is native in some browsers, and can be made available by referencing json2.js in others). What does it do that the regular stringify does not is that it automatically converts observable, dependentObservable, or observableArray to their underlying value to JSON. Hold on! There is a new feature in this version of Knockout, the ko.toJSON. It is part of the core library and it will clone the view model’s object graph, so you don’t mess it up after you have stringified  it and unwrap all its observables. It's smart enough to avoid reference cycles. Since you are using the MVVM pattern it would assume you are not trying to reference DOM nodes from your view. Wait a minute. I can already see this info on the http://knockoutjs.com/examples/contactsEditor.html website, why mention it all here? First of this is a much nicer blog, no orange ? At this time, you may want to have a look at the blog and see what I am talking about. See the save event, how they stringify the view model’s contacts only? That’s cool but what if your view model is a representation of your object you want to persist, meaning it has no property that represents the json object you want to persist, it is the view model itself. The example in http://knockoutjs.com/examples/contactsEditor.html assumes you have a list of contacts you may want to persist. In the example here, you want to persist the view model itself. The viewmodel here looks something like this:     var myViewmodel = {         accountName: ko.observable(""),         accountType: ko.observable("Active")     };     myViewmodel.isItActive = ko.dependentObservable(function () {         return myViewmodel.accountType() == "Active";     });     myViewmodel.clickToSaveMe = function() {         SaveTheAccount();     }; Here is the function in charge of saving the account: Function SaveTheAccount() {     $.ajax({         data: ko.toJSON(viewmodel),         url: $('#ajaxSaveAccountUrl').val(),         type: "POST",         dataType: "json",         async: false,         success: function (result) {             if (result && result.Success == true) {                 $('#accountMessage').html('<span class="fadeMyContainerSlowly">The account has been saved</span>').show();                 FadeContainerAwaySlowly();             }         },         error: function (xmlHttpRequest, textStatus, errorThrown) {             alert('An error occurred: ' + errorThrown);         }     }); //ajax }; Try run this and your browser will eventually freeze up or crash. Firebug will tell you that you have a repetitive call to the first function call in your model that keeps firing infinitely.  What is happening is that Knockout serializes the view model to a JSON string by traversing the object graph and firing off the functions, again-and-again. Not sure why it does that, but it does. So what is the work around: Nullify your function calls and then post it:         var lightweightModel = viewmodel.clickToSaveMe = null;         data: ko.toJSON(lightweightModel), So then I traced the JSON string on the server and found it having issues with primitive types. C#, by the way. So I changed ko.toJSON(model) to ko.toJS(model), and that solved my problem. Of course you could just create a property on the viewmodel for the account itself, so you only have to serialize the property and not the entire viewmodel. If that is an option then that would be the way to go. If your view model contains other properties in the view model that you also want to post then that would not be an option and then you’ll know what to watch out for. Hope this helps.

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  • ASP.NET MVC3 checkbox dropdownlist create [migrated]

    - by user95381
    i'm new in asp.net MVC and I/m use view model to poppulate the dropdown list and group of checkboxes. I use SQL Server 2012, where have many to many relationships between Students - Books; Student - Cities. I need collect StudentName, one city and many books for one student. I have next questions: 1. How can I get the values from database to my StudentBookCityViewModel? 2. How can I save the values to my database in [HttpPost] Create method? Here is the code: MODEL public class Student { public int StudentId { get; set; } public string StudentName { get; set; } public ICollection<Book> Books { get; set; } public ICollection<City> Cities { get; set; } } public class Book { public int BookId { get; set; } public string BookName { get; set; } public bool IsSelected { get; set; } public ICollection<Student> Students { get; set; } } public class City { public int CityId { get; set; } public string CityName { get; set; } public bool IsSelected { get; set; } public ICollection<Student> Students { get; set; } } VIEW MODEL public class StudentBookCityViewModel { public string StudentName { get; set; } public IList<Book> Books { get; set; } public StudentBookCityViewModel() { Books = new[] { new Book {BookName = "Title1", IsSelected = false}, new Book {BookName = "Title2", IsSelected = false}, new Book {BookName = "Title3", IsSelected = false} }.ToList(); } public string City { get; set; } public IEnumerable<SelectListItem> CityValues { get { return new[] { new SelectListItem {Value = "Value1", Text = "Text1"}, new SelectListItem {Value = "Value2", Text = "Text2"}, new SelectListItem {Value = "Value3", Text = "Text3"} }; } } } Context public class EFDbContext : DbContext{ public EFDbContext(string connectionString) { Database.Connection.ConnectionString = connectionString; } public DbSet<Book> Books { get; set; } public DbSet<Student> Students { get; set; } public DbSet<City> Cities { get; set; } protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<Book>() .HasMany(x => x.Students).WithMany(x => x.Books) .Map(x => x.MapLeftKey("BookId").MapRightKey("StudentId").ToTable("StudentBooks")); modelBuilder.Entity<City>() .HasMany(x => x.Students).WithMany(x => x.Cities) .Map(x => x.MapLeftKey("CityId").MapRightKey("StudentId").ToTable("StudentCities")); } } Controller public ActionResult Create() { return View(); } [HttpPost] public ActionResult Create() { //I don't understand how I can save values to db context.SaveChanges(); return RedirectToAction("Index"); } View @model UsingEFNew.ViewModels.StudentBookCityViewModel @using (Html.BeginForm()) { Your Name: @Html.TextBoxFor(model = model.StudentName) <div>Genre:</div> <div> @Html.DropDownListFor(model => model.City, Model.CityValues) </div> <div>Books:</div> <div> @for (int i = 0; i < Model.Books.Count; i++) { <div> @Html.HiddenFor(x => x.Books[i].BookId) @Html.CheckBoxFor(x => x.Books[i].IsSelected) @Html.LabelFor(x => x.Books[i].IsSelected, Model.Books[i].BookName) </div> } </div> <div> <input id="btnSubmit" type="submit" value="Submit" /> </div> </div> }

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  • SOA, Governance, and Drugs

    Why is IT governance important in service oriented architecture (SOA)? IT Governance provides a framework for making appropriate decisions based on company guidelines and accepted standards. This framework also outlines each stakeholder’s responsibilities and authority when making important architectural or design decisions. Furthermore, this framework of governance defines parameters and constraints that are used to give context and perspective when making decisions. The use of governance as it applies to SOA ensures that specific design principles and patterns are used when developing and maintaining services. When governance is consistently applied systems the following benefits are achieved according to Anne Thomas Manes in 2010. Governance makes sure that services conform to standard interface patterns, common data modeling practices, and promotes the incorporation of existing system functionality by building on top of other available services across a system. Governance defines development standards based on proven design principles and patterns that promote reuse and composition. Governance provides developers a set of proven design principles, standards and practices that promote the reduction in system based component dependencies.  By following these guidelines, individual components will be easier to maintain. For me personally, I am a fan of IT governance, and feel that it valuable part of any corporate IT department. However, depending on how it is implemented can really affect the value of using IT governance.  Companies need to find a way to ensure that governance does not become extreme in its policies and procedures. I know for me personally, I would really dislike working under a completely totalitarian or laissez-faire version of governance. Developers need to be able to be creative in their designs and too much governance can really impede the design process and prevent the most optimal design from being developed. On the other hand, with no governance enforced, no standards will be followed and accepted design patterns will be ignored. I have personally had to spend a lot of time working on this particular scenario and I have found that the concept of code reuse and composition is almost nonexistent.  Based on this, too much time and money is wasted on redeveloping existing aspects of an application that already exist within the system as a whole. I think moving forward we will see a staggered form of IT governance, regardless if it is for SOA or IT in general.  Depending on the size of a company and the size of its IT department,  I can see IT governance as a layered approach in that the top layer will be defined by enterprise architects that focus on abstract concepts pertaining to high level design, general  guidelines, acceptable best practices, and recommended design patterns.  The next layer will be defined by solution architects or department managers that further expand on abstracted guidelines defined by the enterprise architects. This layer will contain further definitions as to when various design patterns, coding standards, and best practices are to be applied based on the context of the solutions that are being developed by the department. The final layer will be defined by the system designer or a solutions architect assed to a project in that they will define what design patterns will be used in a solution, naming conventions, as well as outline how a system will function based on the best practices defined by the previous layers. This layered approach allows for IT departments to be flexible in that system designers have creative leeway in designing solutions to meet the needs of the business, but they must operate within the confines of the abstracted IT governance guidelines.  A real world example of this can be seen in the United States as it pertains to governance of the people in that the US government defines rules and regulations in the abstract and then the state governments take these guidelines and applies them based on the will of the people in each individual state. Furthermore, the county or city governments are the ones that actually enforce these rules based on how they are interpreted by local community.  To further define my example, the United States government defines that marijuana is illegal. Each individual state has the option to determine this regulation as it wishes in that the state of Florida determines that all uses of the drug are illegal, but the state of California legally allows the use of marijuana for medicinal purposes only. Based on these accepted practices each local government enforces these rules in that a police officer will arrest anyone in the state of Florida for having this drug on them if they walk down the street, but in California if a person has a medical prescription for the drug they will not get arrested.  REFERENCESThomas Manes, Anne. (2010). Understanding SOA Governance: http://www.soamag.com/I40/0610-2.php

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  • Can YQL parse web sites requiring cookie-based authentication?

    - by user249488
    First, my use case: I'm trying to use YQL's built in XPATH capabilities to scrape content from Yahoo! Fantasy Sports. It uses some sort of cookie-based authentication scheme. Basically, the sequence is: 1) Do an HTTP GET on the Yahoo! Login page 2) Parse the hidden inputs from the response and do an HTTP PUT with your Yahoo! Login on the form URL 3) Use the cookies returned from step 2 to GET any of the Fantasy Sports! websites that you have access to My question is, does YQL support doing this to scrape data? The only authentication based examples I've seen use OAuth, but I haven't seen any examples of using YQL to parse websites with cookie-based authentication schemes

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  • How does SWTBOT run a custom eclipse based application? I don't know how to specify my target application

    - by jlisam13
    I have an eclipse based application. I have heard of swtbot however I am having a hard time understanding how exactly does this tool run my application and how would I specify that. This eclipse based application has an executable and various configuration/plugin/features files. I have done the tutorials about swtbot and I have successfully completed them but they all just create a template application to test on. Is this even possible? If not do you guys have any alternatives for UI automation testing on eclipse based apps? Thanks.

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  • Should my web based app be a consumer of my api?

    - by seanbrant
    I will be developing a mobile app (iPhone) and a web based app (Django) soon. For the mobile app I will be creating a REST api (most likely using Django) to send data back and forth from phone to server. When I comes time to create the web based version does it make sense to just create it as any other client of the api. In other words both the mobile app and the web app will get there data from an external API over HTTP. Or should the web based app have direct access to the database that the api is using and just get its data that way?

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  • Problem with movieclip animation for tiles-based game platform !

    - by user209636
    Hi everybody, I'm a new member of this forum. I have some problem and i want to ask you. Recently, I have a project game tiles-based platform. I have coded completed my project game with simple graphics represent for character animation. But when i create flash animation then attach to tiles-based character of my game's project i have a problem. Because of tiles-based game with fixed tile sizes and my character animation have each width and height size for each frame. When i attach animation to character code. Example , with my game if i press key to move character , then my character will playing "moving" frame , because of this frame animation have difference width and height then my game function check collisions fail , I want to ask you how can i solve this problem ?. I want to learn some good pratice for making game . Thank ! Sorry for my english skill , i am not good at this

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  • Developing web apps using ASP.NET MVC 3, Razor and EF Code First - Part 2

    - by shiju
    In my previous post Developing web apps using ASP.NET MVC 3, Razor and EF Code First - Part 1, we have discussed on how to work with ASP.NET MVC 3 and EF Code First for developing web apps. We have created generic repository and unit of work with EF Code First for our ASP.NET MVC 3 application and did basic CRUD operations against a simple domain entity. In this post, I will demonstrate on working with domain entity with deep object graph, Service Layer and View Models and will also complete the rest of the demo application. In the previous post, we have done CRUD operations against Category entity and this post will be focus on Expense entity those have an association with Category entity. You can download the source code from http://efmvc.codeplex.com . The following frameworks will be used for this step by step tutorial.    1. ASP.NET MVC 3 RTM    2. EF Code First CTP 5    3. Unity 2.0 Domain Model Category Entity public class Category   {       public int CategoryId { get; set; }       [Required(ErrorMessage = "Name Required")]       [StringLength(25, ErrorMessage = "Must be less than 25 characters")]       public string Name { get; set;}       public string Description { get; set; }       public virtual ICollection<Expense> Expenses { get; set; }   } Expense Entity public class Expense     {                public int ExpenseId { get; set; }                public string  Transaction { get; set; }         public DateTime Date { get; set; }         public double Amount { get; set; }         public int CategoryId { get; set; }         public virtual Category Category { get; set; }     } We have two domain entities - Category and Expense. A single category contains a list of expense transactions and every expense transaction should have a Category. Repository class for Expense Transaction Let’s create repository class for handling CRUD operations for Expense entity public class ExpenseRepository : RepositoryBase<Expense>, IExpenseRepository     {     public ExpenseRepository(IDatabaseFactory databaseFactory)         : base(databaseFactory)         {         }                } public interface IExpenseRepository : IRepository<Expense> { } Service Layer If you are new to Service Layer, checkout Martin Fowler's article Service Layer . According to Martin Fowler, Service Layer defines an application's boundary and its set of available operations from the perspective of interfacing client layers. It encapsulates the application's business logic, controlling transactions and coordinating responses in the implementation of its operations. Controller classes should be lightweight and do not put much of business logic onto it. We can use the service layer as the business logic layer and can encapsulate the rules of the application. Let’s create a Service class for coordinates the transaction for Expense public interface IExpenseService {     IEnumerable<Expense> GetExpenses(DateTime startDate, DateTime ednDate);     Expense GetExpense(int id);             void CreateExpense(Expense expense);     void DeleteExpense(int id);     void SaveExpense(); } public class ExpenseService : IExpenseService {     private readonly IExpenseRepository expenseRepository;            private readonly IUnitOfWork unitOfWork;     public ExpenseService(IExpenseRepository expenseRepository, IUnitOfWork unitOfWork)     {                  this.expenseRepository = expenseRepository;         this.unitOfWork = unitOfWork;     }     public IEnumerable<Expense> GetExpenses(DateTime startDate, DateTime endDate)     {         var expenses = expenseRepository.GetMany(exp => exp.Date >= startDate && exp.Date <= endDate);         return expenses;     }     public void CreateExpense(Expense expense)     {         expenseRepository.Add(expense);         unitOfWork.Commit();     }     public Expense GetExpense(int id)     {         var expense = expenseRepository.GetById(id);         return expense;     }     public void DeleteExpense(int id)     {         var expense = expenseRepository.GetById(id);         expenseRepository.Delete(expense);         unitOfWork.Commit();     }     public void SaveExpense()     {         unitOfWork.Commit();     } }   View Model for Expense Transactions In real world ASP.NET MVC applications, we need to design model objects especially for our views. Our domain objects are mainly designed for the needs for domain model and it is representing the domain of our applications. On the other hand, View Model objects are designed for our needs for views. We have an Expense domain entity that has an association with Category. While we are creating a new Expense, we have to specify that in which Category belongs with the new Expense transaction. The user interface for Expense transaction will have form fields for representing the Expense entity and a CategoryId for representing the Category. So let's create view model for representing the need for Expense transactions. public class ExpenseViewModel {     public int ExpenseId { get; set; }       [Required(ErrorMessage = "Category Required")]     public int CategoryId { get; set; }       [Required(ErrorMessage = "Transaction Required")]     public string Transaction { get; set; }       [Required(ErrorMessage = "Date Required")]     public DateTime Date { get; set; }       [Required(ErrorMessage = "Amount Required")]     public double Amount { get; set; }       public IEnumerable<SelectListItem> Category { get; set; } } The ExpenseViewModel is designed for the purpose of View template and contains the all validation rules. It has properties for mapping values to Expense entity and a property Category for binding values to a drop-down for list values of Category. Create Expense transaction Let’s create action methods in the ExpenseController for creating expense transactions public ActionResult Create() {     var expenseModel = new ExpenseViewModel();     var categories = categoryService.GetCategories();     expenseModel.Category = categories.ToSelectListItems(-1);     expenseModel.Date = DateTime.Today;     return View(expenseModel); } [HttpPost] public ActionResult Create(ExpenseViewModel expenseViewModel) {                      if (!ModelState.IsValid)         {             var categories = categoryService.GetCategories();             expenseViewModel.Category = categories.ToSelectListItems(expenseViewModel.CategoryId);             return View("Save", expenseViewModel);         }         Expense expense=new Expense();         ModelCopier.CopyModel(expenseViewModel,expense);         expenseService.CreateExpense(expense);         return RedirectToAction("Index");              } In the Create action method for HttpGet request, we have created an instance of our View Model ExpenseViewModel with Category information for the drop-down list and passing the Model object to View template. The extension method ToSelectListItems is shown below   public static IEnumerable<SelectListItem> ToSelectListItems(         this IEnumerable<Category> categories, int  selectedId) {     return           categories.OrderBy(category => category.Name)                 .Select(category =>                     new SelectListItem                     {                         Selected = (category.CategoryId == selectedId),                         Text = category.Name,                         Value = category.CategoryId.ToString()                     }); } In the Create action method for HttpPost, our view model object ExpenseViewModel will map with posted form input values. We need to create an instance of Expense for the persistence purpose. So we need to copy values from ExpenseViewModel object to Expense object. ASP.NET MVC futures assembly provides a static class ModelCopier that can use for copying values between Model objects. ModelCopier class has two static methods - CopyCollection and CopyModel.CopyCollection method will copy values between two collection objects and CopyModel will copy values between two model objects. We have used CopyModel method of ModelCopier class for copying values from expenseViewModel object to expense object. Finally we did a call to CreateExpense method of ExpenseService class for persisting new expense transaction. List Expense Transactions We want to list expense transactions based on a date range. So let’s create action method for filtering expense transactions with a specified date range. public ActionResult Index(DateTime? startDate, DateTime? endDate) {     //If date is not passed, take current month's first and last dte     DateTime dtNow;     dtNow = DateTime.Today;     if (!startDate.HasValue)     {         startDate = new DateTime(dtNow.Year, dtNow.Month, 1);         endDate = startDate.Value.AddMonths(1).AddDays(-1);     }     //take last date of start date's month, if end date is not passed     if (startDate.HasValue && !endDate.HasValue)     {         endDate = (new DateTime(startDate.Value.Year, startDate.Value.Month, 1)).AddMonths(1).AddDays(-1);     }     var expenses = expenseService.GetExpenses(startDate.Value ,endDate.Value);     //if request is Ajax will return partial view     if (Request.IsAjaxRequest())     {         return PartialView("ExpenseList", expenses);     }     //set start date and end date to ViewBag dictionary     ViewBag.StartDate = startDate.Value.ToShortDateString();     ViewBag.EndDate = endDate.Value.ToShortDateString();     //if request is not ajax     return View(expenses); } We are using the above Index Action method for both Ajax requests and normal requests. If there is a request for Ajax, we will call the PartialView ExpenseList. Razor Views for listing Expense information Let’s create view templates in Razor for showing list of Expense information ExpenseList.cshtml @model IEnumerable<MyFinance.Domain.Expense>   <table>         <tr>             <th>Actions</th>             <th>Category</th>             <th>                 Transaction             </th>             <th>                 Date             </th>             <th>                 Amount             </th>         </tr>       @foreach (var item in Model) {              <tr>             <td>                 @Html.ActionLink("Edit", "Edit",new { id = item.ExpenseId })                 @Ajax.ActionLink("Delete", "Delete", new { id = item.ExpenseId }, new AjaxOptions { Confirm = "Delete Expense?", HttpMethod = "Post", UpdateTargetId = "divExpenseList" })             </td>              <td>                 @item.Category.Name             </td>             <td>                 @item.Transaction             </td>             <td>                 @String.Format("{0:d}", item.Date)             </td>             <td>                 @String.Format("{0:F}", item.Amount)             </td>         </tr>          }       </table>     <p>         @Html.ActionLink("Create New Expense", "Create") |         @Html.ActionLink("Create New Category", "Create","Category")     </p> Index.cshtml @using MyFinance.Helpers; @model IEnumerable<MyFinance.Domain.Expense> @{     ViewBag.Title = "Index"; }    <h2>Expense List</h2>    <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery-ui.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.ui.datepicker.js")" type="text/javascript"></script> <link href="@Url.Content("~/Content/jquery-ui-1.8.6.custom.css")" rel="stylesheet" type="text/css" />      @using (Ajax.BeginForm(new AjaxOptions{ UpdateTargetId="divExpenseList", HttpMethod="Get"})) {     <table>         <tr>         <td>         <div>           Start Date: @Html.TextBox("StartDate", Html.Encode(String.Format("{0:mm/dd/yyyy}", ViewData["StartDate"].ToString())), new { @class = "ui-datepicker" })         </div>         </td>         <td><div>            End Date: @Html.TextBox("EndDate", Html.Encode(String.Format("{0:mm/dd/yyyy}", ViewData["EndDate"].ToString())), new { @class = "ui-datepicker" })          </div></td>          <td> <input type="submit" value="Search By TransactionDate" /></td>         </tr>     </table>         }   <div id="divExpenseList">             @Html.Partial("ExpenseList", Model)     </div> <script type="text/javascript">     $().ready(function () {         $('.ui-datepicker').datepicker({             dateFormat: 'mm/dd/yy',             buttonImage: '@Url.Content("~/Content/calendar.gif")',             buttonImageOnly: true,             showOn: "button"         });     }); </script> Ajax search functionality using Ajax.BeginForm The search functionality of Index view is providing Ajax functionality using Ajax.BeginForm. The Ajax.BeginForm() method writes an opening <form> tag to the response. You can use this method in a using block. In that case, the method renders the closing </form> tag at the end of the using block and the form is submitted asynchronously by using JavaScript. The search functionality will call the Index Action method and this will return partial view ExpenseList for updating the search result. We want to update the response UI for the Ajax request onto divExpenseList element. So we have specified the UpdateTargetId as "divExpenseList" in the Ajax.BeginForm method. Add jQuery DatePicker Our search functionality is using a date range so we are providing two date pickers using jQuery datepicker. You need to add reference to the following JavaScript files to working with jQuery datepicker. jquery-ui.js jquery.ui.datepicker.js For theme support for datepicker, we can use a customized CSS class. In our example we have used a CSS file “jquery-ui-1.8.6.custom.css”. For more details about the datepicker component, visit jquery UI website at http://jqueryui.com/demos/datepicker . In the jQuery ready event, we have used following JavaScript function to initialize the UI element to show date picker. <script type="text/javascript">     $().ready(function () {         $('.ui-datepicker').datepicker({             dateFormat: 'mm/dd/yy',             buttonImage: '@Url.Content("~/Content/calendar.gif")',             buttonImageOnly: true,             showOn: "button"         });     }); </script>   Source Code You can download the source code from http://efmvc.codeplex.com/ . Summary In this two-part series, we have created a simple web application using ASP.NET MVC 3 RTM, Razor and EF Code First CTP 5. I have demonstrated patterns and practices  such as Dependency Injection, Repository pattern, Unit of Work, ViewModel and Service Layer. My primary objective was to demonstrate different practices and options for developing web apps using ASP.NET MVC 3 and EF Code First. You can implement these approaches in your own way for building web apps using ASP.NET MVC 3. I will refactor this demo app on later time.

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  • ASP.NET MVC 3 Hosting :: How to Deploy Web Apps Using ASP.NET MVC 3, Razor and EF Code First - Part II

    - by mbridge
    In previous post, I have discussed on how to work with ASP.NET MVC 3 and EF Code First for developing web apps. In this post, I will demonstrate on working with domain entity with deep object graph, Service Layer and View Models and will also complete the rest of the demo application. In the previous post, we have done CRUD operations against Category entity and this post will be focus on Expense entity those have an association with Category entity. Domain Model Category Entity public class Category   {       public int CategoryId { get; set; }       [Required(ErrorMessage = "Name Required")]       [StringLength(25, ErrorMessage = "Must be less than 25 characters")]       public string Name { get; set;}       public string Description { get; set; }       public virtual ICollection<Expense> Expenses { get; set; }   } Expense Entity public class Expense     {                public int ExpenseId { get; set; }                public string  Transaction { get; set; }         public DateTime Date { get; set; }         public double Amount { get; set; }         public int CategoryId { get; set; }         public virtual Category Category { get; set; }     } We have two domain entities - Category and Expense. A single category contains a list of expense transactions and every expense transaction should have a Category. Repository class for Expense Transaction Let’s create repository class for handling CRUD operations for Expense entity public class ExpenseRepository : RepositoryBase<Expense>, IExpenseRepository     {     public ExpenseRepository(IDatabaseFactory databaseFactory)         : base(databaseFactory)         {         }                } public interface IExpenseRepository : IRepository<Expense> { } Service Layer If you are new to Service Layer, checkout Martin Fowler's article Service Layer . According to Martin Fowler, Service Layer defines an application's boundary and its set of available operations from the perspective of interfacing client layers. It encapsulates the application's business logic, controlling transactions and coordinating responses in the implementation of its operations. Controller classes should be lightweight and do not put much of business logic onto it. We can use the service layer as the business logic layer and can encapsulate the rules of the application. Let’s create a Service class for coordinates the transaction for Expense public interface IExpenseService {     IEnumerable<Expense> GetExpenses(DateTime startDate, DateTime ednDate);     Expense GetExpense(int id);             void CreateExpense(Expense expense);     void DeleteExpense(int id);     void SaveExpense(); } public class ExpenseService : IExpenseService {     private readonly IExpenseRepository expenseRepository;            private readonly IUnitOfWork unitOfWork;     public ExpenseService(IExpenseRepository expenseRepository, IUnitOfWork unitOfWork)     {                  this.expenseRepository = expenseRepository;         this.unitOfWork = unitOfWork;     }     public IEnumerable<Expense> GetExpenses(DateTime startDate, DateTime endDate)     {         var expenses = expenseRepository.GetMany(exp => exp.Date >= startDate && exp.Date <= endDate);         return expenses;     }     public void CreateExpense(Expense expense)     {         expenseRepository.Add(expense);         unitOfWork.Commit();     }     public Expense GetExpense(int id)     {         var expense = expenseRepository.GetById(id);         return expense;     }     public void DeleteExpense(int id)     {         var expense = expenseRepository.GetById(id);         expenseRepository.Delete(expense);         unitOfWork.Commit();     }     public void SaveExpense()     {         unitOfWork.Commit();     } } View Model for Expense Transactions In real world ASP.NET MVC applications, we need to design model objects especially for our views. Our domain objects are mainly designed for the needs for domain model and it is representing the domain of our applications. On the other hand, View Model objects are designed for our needs for views. We have an Expense domain entity that has an association with Category. While we are creating a new Expense, we have to specify that in which Category belongs with the new Expense transaction. The user interface for Expense transaction will have form fields for representing the Expense entity and a CategoryId for representing the Category. So let's create view model for representing the need for Expense transactions. public class ExpenseViewModel {     public int ExpenseId { get; set; }       [Required(ErrorMessage = "Category Required")]     public int CategoryId { get; set; }       [Required(ErrorMessage = "Transaction Required")]     public string Transaction { get; set; }       [Required(ErrorMessage = "Date Required")]     public DateTime Date { get; set; }       [Required(ErrorMessage = "Amount Required")]     public double Amount { get; set; }       public IEnumerable<SelectListItem> Category { get; set; } } The ExpenseViewModel is designed for the purpose of View template and contains the all validation rules. It has properties for mapping values to Expense entity and a property Category for binding values to a drop-down for list values of Category. Create Expense transaction Let’s create action methods in the ExpenseController for creating expense transactions public ActionResult Create() {     var expenseModel = new ExpenseViewModel();     var categories = categoryService.GetCategories();     expenseModel.Category = categories.ToSelectListItems(-1);     expenseModel.Date = DateTime.Today;     return View(expenseModel); } [HttpPost] public ActionResult Create(ExpenseViewModel expenseViewModel) {                      if (!ModelState.IsValid)         {             var categories = categoryService.GetCategories();             expenseViewModel.Category = categories.ToSelectListItems(expenseViewModel.CategoryId);             return View("Save", expenseViewModel);         }         Expense expense=new Expense();         ModelCopier.CopyModel(expenseViewModel,expense);         expenseService.CreateExpense(expense);         return RedirectToAction("Index");              } In the Create action method for HttpGet request, we have created an instance of our View Model ExpenseViewModel with Category information for the drop-down list and passing the Model object to View template. The extension method ToSelectListItems is shown below public static IEnumerable<SelectListItem> ToSelectListItems(         this IEnumerable<Category> categories, int  selectedId) {     return           categories.OrderBy(category => category.Name)                 .Select(category =>                     new SelectListItem                     {                         Selected = (category.CategoryId == selectedId),                         Text = category.Name,                         Value = category.CategoryId.ToString()                     }); } In the Create action method for HttpPost, our view model object ExpenseViewModel will map with posted form input values. We need to create an instance of Expense for the persistence purpose. So we need to copy values from ExpenseViewModel object to Expense object. ASP.NET MVC futures assembly provides a static class ModelCopier that can use for copying values between Model objects. ModelCopier class has two static methods - CopyCollection and CopyModel.CopyCollection method will copy values between two collection objects and CopyModel will copy values between two model objects. We have used CopyModel method of ModelCopier class for copying values from expenseViewModel object to expense object. Finally we did a call to CreateExpense method of ExpenseService class for persisting new expense transaction. List Expense Transactions We want to list expense transactions based on a date range. So let’s create action method for filtering expense transactions with a specified date range. public ActionResult Index(DateTime? startDate, DateTime? endDate) {     //If date is not passed, take current month's first and last dte     DateTime dtNow;     dtNow = DateTime.Today;     if (!startDate.HasValue)     {         startDate = new DateTime(dtNow.Year, dtNow.Month, 1);         endDate = startDate.Value.AddMonths(1).AddDays(-1);     }     //take last date of start date's month, if end date is not passed     if (startDate.HasValue && !endDate.HasValue)     {         endDate = (new DateTime(startDate.Value.Year, startDate.Value.Month, 1)).AddMonths(1).AddDays(-1);     }     var expenses = expenseService.GetExpenses(startDate.Value ,endDate.Value);     //if request is Ajax will return partial view     if (Request.IsAjaxRequest())     {         return PartialView("ExpenseList", expenses);     }     //set start date and end date to ViewBag dictionary     ViewBag.StartDate = startDate.Value.ToShortDateString();     ViewBag.EndDate = endDate.Value.ToShortDateString();     //if request is not ajax     return View(expenses); } We are using the above Index Action method for both Ajax requests and normal requests. If there is a request for Ajax, we will call the PartialView ExpenseList. Razor Views for listing Expense information Let’s create view templates in Razor for showing list of Expense information ExpenseList.cshtml @model IEnumerable<MyFinance.Domain.Expense>   <table>         <tr>             <th>Actions</th>             <th>Category</th>             <th>                 Transaction             </th>             <th>                 Date             </th>             <th>                 Amount             </th>         </tr>       @foreach (var item in Model) {              <tr>             <td>                 @Html.ActionLink("Edit", "Edit",new { id = item.ExpenseId })                 @Ajax.ActionLink("Delete", "Delete", new { id = item.ExpenseId }, new AjaxOptions { Confirm = "Delete Expense?", HttpMethod = "Post", UpdateTargetId = "divExpenseList" })             </td>              <td>                 @item.Category.Name             </td>             <td>                 @item.Transaction             </td>             <td>                 @String.Format("{0:d}", item.Date)             </td>             <td>                 @String.Format("{0:F}", item.Amount)             </td>         </tr>          }       </table>     <p>         @Html.ActionLink("Create New Expense", "Create") |         @Html.ActionLink("Create New Category", "Create","Category")     </p> Index.cshtml @using MyFinance.Helpers; @model IEnumerable<MyFinance.Domain.Expense> @{     ViewBag.Title = "Index"; }    <h2>Expense List</h2>    <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery-ui.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.ui.datepicker.js")" type="text/javascript"></script> <link href="@Url.Content("~/Content/jquery-ui-1.8.6.custom.css")" rel="stylesheet" type="text/css" />      @using (Ajax.BeginForm(new AjaxOptions{ UpdateTargetId="divExpenseList", HttpMethod="Get"})) {     <table>         <tr>         <td>         <div>           Start Date: @Html.TextBox("StartDate", Html.Encode(String.Format("{0:mm/dd/yyyy}", ViewData["StartDate"].ToString())), new { @class = "ui-datepicker" })         </div>         </td>         <td><div>            End Date: @Html.TextBox("EndDate", Html.Encode(String.Format("{0:mm/dd/yyyy}", ViewData["EndDate"].ToString())), new { @class = "ui-datepicker" })          </div></td>          <td> <input type="submit" value="Search By TransactionDate" /></td>         </tr>     </table>         }   <div id="divExpenseList">             @Html.Partial("ExpenseList", Model)     </div> <script type="text/javascript">     $().ready(function () {         $('.ui-datepicker').datepicker({             dateFormat: 'mm/dd/yy',             buttonImage: '@Url.Content("~/Content/calendar.gif")',             buttonImageOnly: true,             showOn: "button"         });     }); </script> Ajax search functionality using Ajax.BeginForm The search functionality of Index view is providing Ajax functionality using Ajax.BeginForm. The Ajax.BeginForm() method writes an opening <form> tag to the response. You can use this method in a using block. In that case, the method renders the closing </form> tag at the end of the using block and the form is submitted asynchronously by using JavaScript. The search functionality will call the Index Action method and this will return partial view ExpenseList for updating the search result. We want to update the response UI for the Ajax request onto divExpenseList element. So we have specified the UpdateTargetId as "divExpenseList" in the Ajax.BeginForm method. Add jQuery DatePicker Our search functionality is using a date range so we are providing two date pickers using jQuery datepicker. You need to add reference to the following JavaScript files to working with jQuery datepicker. - jquery-ui.js - jquery.ui.datepicker.js For theme support for datepicker, we can use a customized CSS class. In our example we have used a CSS file “jquery-ui-1.8.6.custom.css”. For more details about the datepicker component, visit jquery UI website at http://jqueryui.com/demos/datepicker . In the jQuery ready event, we have used following JavaScript function to initialize the UI element to show date picker. <script type="text/javascript">     $().ready(function () {         $('.ui-datepicker').datepicker({             dateFormat: 'mm/dd/yy',             buttonImage: '@Url.Content("~/Content/calendar.gif")',             buttonImageOnly: true,             showOn: "button"         });     }); </script> Summary In this two-part series, we have created a simple web application using ASP.NET MVC 3 RTM, Razor and EF Code First CTP 5. I have demonstrated patterns and practices  such as Dependency Injection, Repository pattern, Unit of Work, ViewModel and Service Layer. My primary objective was to demonstrate different practices and options for developing web apps using ASP.NET MVC 3 and EF Code First. You can implement these approaches in your own way for building web apps using ASP.NET MVC 3. I will refactor this demo app on later time.

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  • Data Source Security Part 4

    - by Steve Felts
    So far, I have covered Client Identity and Oracle Proxy Session features, with WLS or database credentials.  This article will cover one more feature, Identify-based pooling.  Then, there is one more topic to cover - how these options play with transactions.Identity-based Connection Pooling An identity based pool creates a heterogeneous pool of connections.  This allows applications to use a JDBC connection with a specific DBMS credential by pooling physical connections with different DBMS credentials.  The DBMS credential is based on either the WebLogic user mapped to a database user or the database user directly, based on the “use database credentials” setting as described earlier. Using this feature enabled with “use database credentials” enabled seems to be what is proposed in the JDBC standard, basically a heterogeneous pool with users specified by getConnection(user, password). The allocation of connections is more complex if Enable Identity Based Connection Pooling attribute is enabled on the data source.  When an application requests a database connection, the WebLogic Server instance selects an existing physical connection or creates a new physical connection with requested DBMS identity. The following section provides information on how heterogeneous connections are created:1. At connection pool initialization, the physical JDBC connections based on the configured or default “initial capacity” are created with the configured default DBMS credential of the data source.2. An application tries to get a connection from a data source.3a. If “use database credentials” is not enabled, the user specified in getConnection is mapped to a DBMS credential, as described earlier.  If the credential map doesn’t have a matching user, the default DBMS credential is used from the datasource descriptor.3b. If “use database credentials” is enabled, the user and password specified in getConnection are used directly.4. The connection pool is searched for a connection with a matching DBMS credential.5. If a match is found, the connection is reserved and returned to the application.6. If no match is found, a connection is created or reused based on the maximum capacity of the pool: - If the maximum capacity has not been reached, a new connection is created with the DBMS credential, reserved, and returned to the application.- If the pool has reached maximum capacity, based on the least recently used (LRU) algorithm, a physical connection is selected from the pool and destroyed. A new connection is created with the DBMS credential, reserved, and returned to the application. It should be clear that finding a matching connection is more expensive than a homogeneous pool.  Destroying a connection and getting a new one is very expensive.  If you can use a normal homogeneous pool or one of the light-weight options (client identity or an Oracle proxy connection), those should be used instead of identity based pooling. Regardless of how physical connections are created, each physical connection in the pool has its own DBMS credential information maintained by the pool. Once a physical connection is reserved by the pool, it does not change its DBMS credential even if the current thread changes its WebLogic user credential and continues to use the same connection. To configure this feature, select Enable Identity Based Connection Pooling.  See http://docs.oracle.com/cd/E24329_01/apirefs.1211/e24401/taskhelp/jdbc/jdbc_datasources/EnableIdentityBasedConnectionPooling.html  "Enable identity-based connection pooling for a JDBC data source" in Oracle WebLogic Server Administration Console Help. You must make the following changes to use Logging Last Resource (LLR) transaction optimization with Identity-based Pooling to get around the problem that multiple users will be accessing the associated transaction table.- You must configure a custom schema for LLR using a fully qualified LLR table name. All LLR connections will then use the named schema rather than the default schema when accessing the LLR transaction table.  - Use database specific administration tools to grant permission to access the named LLR table to all users that could access this table via a global transaction. By default, the LLR table is created during boot by the user configured for the connection in the data source. In most cases, the database will only allow access to this user and not allow access to mapped users. Connections within Transactions Now that we have covered the behavior of all of these various options, it’s time to discuss the exception to all of the rules.  When you get a connection within a transaction, it is associated with the transaction context on a particular WLS instance. When getting a connection with a data source configured with non-XA LLR or 1PC (using the JTS driver) with global transactions, the first connection obtained within the transaction is returned on subsequent connection requests regardless of the values of username/password specified and independent of the associated proxy user session, if any. The connection must be shared among all users of the connection when using LLR or 1PC. For XA data sources, the first connection obtained within the global transaction is returned on subsequent connection requests within the application server, regardless of the values of username/password specified and independent of the associated proxy user session, if any.  The connection must be shared among all users of the connection within a global transaction within the application server/JVM.

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  • ASP.NET MVC - using model property as form, how can I post to action?

    - by Ryan Peters
    Consider the following model: public class BandProfileModel { public BandModel Band { get; set; } public IEnumerable<Relationship> Requests { get; set; } } and the following form: <% using (Html.BeginForm()) { %> <%: Html.EditorFor(m => m.Band) %> <input type="submit" value="Save Band" /> <% } %> which posts to the following action: public ActionResult EditPost(BandProfileModel m, string band) { // stuff is done here, but m is null? return View(m); } Basically, I only have one property on my model that is used in the form. The other property in BandProfleModel is just used in the UI for other data. I'm trying to update just the Band property, but for each post, the argument "m" is always null (specifically, the .Band property is null). It's posting just fine to the action, so it isn't a problem with my route. Just the data is null. The ID and name attributes of the fields are BAND_whatever and Band.whatever (whatever being a property of Band), so it seems like it would work... What am I doing wrong? How can I use just one property as part of a form, post back, and have values populated via the model binder for my BandProfileModel property in the action? Thanks.

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  • ILOG CPLEX: how to populate IloLPMatrix while using addGe to set up the model?

    - by downer
    I have a queatoin about IloLPMatrix and addGe. I was trying to follow the example of AdMIPex5.java to generate user defined cutting planes based on the solution to the LP relaxation. The difference is that eh initial MIP model is not read in from a mps file, but set up in the code using methods like addGe, addLe etc. I think this is why I ran into problems while copying the exampe to do the following. IloLPMatrix lp = (IloLPMatrix)cplex.LPMatrixIterator().next(); lp from the above line turns to be NULL. I am wondering 1. What is the relationship between IloLPMatrix and the addLe, addGe commands? I tried to addLPMatrix() to the model, and then used model.addGe methods. but the LPMatrix seems to be empty still. How do I populate the IloLPMatrix of the moel according to the value that I had set up using addGe and addLe. Is the a method to this easily, or do I have to set them up row by row myself? I was doing this to get the number of variables and their values by doing lp.getNumVars(). Is there other methods that I can use to get the number of variables and their values wihout doing these, since my system is set up by addLe, addGe etc? Thanks a lot for your help on this.

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  • Design patter to keep track UITableView rows correspondance to underlying data in constant time.

    - by DenNukem
    When my model changes I want to animate changes in UITableView by inserting/deleting rows. For that I need to know the ordinal of the given row (so I can construct NSIndexPath), which I find hard to do in better-than-linear time. For example, consider that I have a list of addressbook entries which are manualy sorted by the user, i.e. there is no ordering "key" that represents the sort order. There is also a corresponding UITableView that shows one row per addressbook entry. When UITableView queries the datasource I query the NSMUtableArray populated with my entries and return required data in constant time for each row. However, if there is a change in underlying model I am getting a notification "Joe Smith, id#123 has been removed". Now I have a dilemma. A naive approach would be to scan the array, determine the index at which Joe Smith is and then ask UITableView to remove that precise row from the view, also removing it form the array. However, the scan will take linear time to finish. Now I could have an NSDictionary which allows me to find Joe Smith in constant time, but that doesn't do me a lot of good because I still need to find his ordinal index within the array in order to instruct UITableView to remove that row, which is again a linear search. I could further decide to store each object's ordinal inside the object itself to make it constant, but it will become outdated after first such update as all subsequent index values will have changed due to removal of an object. So what is the correct design pattern to accurately reflect model changes in the UITableView in costant (or at least logarithmic) time?

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  • How do I repopulate the view model in ASP.NET MVC 2 after a validation error?

    - by Keltex
    I'm using ASP.NET MVC 2 and here's the issue. My View Model looks something like this. It includes some fields which are edited by the user and others which are used for display purposes. Here's a simple version public class MyModel { public decimal Price { get; set; } // for view purpose only [Required(ErrorMessage="Name Required")] public string Name { get; set; } } The controller looks something like this: public ActionResult Start(MyModel rec) { if (ModelState.IsValid) { Repository.SaveModel(rec); return RedirectToAction("NextPage"); } else { // validation error return View(rec); } } The issue is when there's a validation error and I call View(rec), I'm not sure the best way to populate my view model with the values that are displayed only. The old way of doing it, where I pass in a form collection, I would do something like this: public ActionResult Start(FormCollection collection) { var rec = Repository.LoadModel(); UpdateModel(rec); if (ModelState.IsValid) { Repository.SaveModel(rec); return RedirectToAction("NextPage"); } else { // validation error return View(rec); } } But doing this, I get an error on UpdateModel(rec): The model of type 'MyModel' could not be updated. Any ideas?

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  • Design pattern to keep track UITableView rows correspondance to underlying data in constant time.

    - by DenNukem
    When my model changes I want to animate changes in UITableView by inserting/deleting rows. For that I need to know the ordinal of the given row (so I can construct NSIndexPath), which I find hard to do in better-than-linear time. For example, consider that I have a list of addressbook entries which are manualy sorted by the user, i.e. there is no ordering "key" that represents the sort order. There is also a corresponding UITableView that shows one row per addressbook entry. When UITableView queries the datasource I query the NSMUtableArray populated with my entries and return required data in constant time for each row. However, if there is a change in underlying model I am getting a notification "Joe Smith, id#123 has been removed". Now I have a dilemma. A naive approach would be to scan the array, determine the index at which Joe Smith is and then ask UITableView to remove that precise row from the view, also removing it form the array. However, the scan will take linear time to finish. Now I could have an NSDictionary which allows me to find Joe Smith in constant time, but that doesn't do me a lot of good because I still need to find his ordinal index within the array in order to instruct UITableView to remove that row, which is again a linear search. I could further decide to store each object's ordinal inside the object itself to make it constant, but it will become outdated after first such update as all subsequent index values will have changed due to removal of an object. So what is the correct design pattern to accurately reflect model changes in the UITableView in costant (or at least logarithmic) time?

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  • generating images with php based on css3 gradient settings?

    - by thrice801
    Hi, Does anyone know if there is a php library, or if there isnt, have any input on how one would go about generating an image via php, from basic HTML element input settings, and CSS 3 gradient parameters. To give an example on why this would be useful, I have found as of a couple days ago, that laying out the wireframe for a webpage using basic Css3 gradient styling speeds up my design and development time by, well, alot. I cant design from photoshop, Ill spend hours tweaking stupid little things that only lead to me tweaking more stupid little things to compensate for stupid little changes. -- So, I had an epiphany to stop using photoshop until the end, and just focus on the main styling of elements, text-shadow, and borders for highlights, and I feel I am able to make super clean, more focused layout by being more restricted to the basics of graphic design with just css. Anyways, so Im planning on after I have the layouts done, to then recreate the graphics in photoshop, so that every browser is able to render the images. This wont take long, but as far as repeating it goes, if I could just do it with PHP, that would be incredible. For instance, take this style for example, which renders a clean looking ipad/pod ish menu/button gradient. [code] background: -moz-linear-gradient(top, #808080, #454545 50%, #313131 51%, #333333); background: -webkit-gradient(linear, left top, left bottom, color-stop(0, #808080), color-stop(.5, #454545), color-stop(.5, #313131), to(#333333));[/code] Basically what Im looking to do is take one or more inputs that control rendering the image as you see there. Take a width and a height input, and then render the image gradient accordingly, so I can save it, upload it and then use it in my designs. So ya, I know PHP has some image generation capabilities but I dont know to what extent, any input on the most effective way to go about doing this or whether it already exists, would be appreciated!

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  • backbone.js Model.get() returns undefined, scope using coffeescript + coffee toaster?

    - by benipsen
    I'm writing an app using coffeescript with coffee toaster (an awesome NPM module for stitching) that builds my app.js file. Lots of my application classes and templates require info about the current user so I have an instance of class User (extends Backbone.Model) stored as a property of my main Application class (extends Backbone.Router). As part of the initialization routine I grab the user from the server (which takes care of authentication, roles, account switching etc.). Here's that coffeescript: @user = new models.User @user.fetch() console.log(@user) console.log(@user.get('email')) The first logging statement outputs the correct Backbone.Model attributes object in the console just as it should: User _changing: false _escapedAttributes: Object _pending: Object _previousAttributes: Object _silent: Object attributes: Object account: Object created_on: "1983-12-13 00:00:00" email: "[email protected]" icon: "0" id: "1" last_login: "2012-06-07 02:31:38" name: "Ben Ipsen" roles: Object __proto__: Object changed: Object cid: "c0" id: "1" __proto__: ctor app.js:228 However, the second returns undefined despite the model attributes clearly being there in the console when logged. And just to make things even more interesting, typing "window.app.user.get('email')" into the console manually returns the expected value of "[email protected]"... ? Just for reference, here's how the initialize method compiles into my app.js file: Application.prototype.initialize = function() { var isMobile; isMobile = navigator.userAgent.match(/(iPhone|iPod|iPad|Android|BlackBerry)/); this.helpers = new views.DOMHelpers().initialize().setup_viewport(isMobile); this.user = new models.User(); this.user.fetch(); console.log(this.user); console.log(this.user.get('email')); return this; }; I initialize the Application controller in my static HTML like so: jQuery(document).ready(function(){ window.app = new controllers.Application(); }); Suggestions please and thank you!

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