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  • How to eager load sibling data using LINQ to SQL?

    - by Scott
    The goal is to issue the fewest queries to SQL Server using LINQ to SQL without using anonymous types. The return type for the method will need to be IList<Child1>. The relationships are as follows: Parent Child1 Child2 Grandchild1 Parent Child1 is a one-to-many relationship Child1 Grandchild1 is a one-to-n relationship (where n is zero to infinity) Parent Child2 is a one-to-n relationship (where n is zero to infinity) I am able to eager load the Parent, Child1 and Grandchild1 data resulting in one query to SQL Server. This query with load options eager loads all of the data, except the sibling data (Child2): DataLoadOptions loadOptions = new DataLoadOptions(); loadOptions.LoadWith<Child1>(o => o.GrandChild1List); loadOptions.LoadWith<Child1>(o => o.Parent); dataContext.LoadOptions = loadOptions; IQueryable<Child1> children = from child in dataContext.Child1 select child; I need to load the sibling data as well. One approach I have tried is splitting the query into two LINQ to SQL queries and merging the result sets together (not pretty), however upon accessing the sibling data it is lazy loaded anyway. Adding the sibling load option will issue a query to SQL Server for each Grandchild1 and Child2 record (which is exactly what I am trying to avoid): DataLoadOptions loadOptions = new DataLoadOptions(); loadOptions.LoadWith<Child1>(o => o.GrandChild1List); loadOptions.LoadWith<Child1>(o => o.Parent); loadOptions.LoadWith<Parent>(o => o.Child2List); dataContext.LoadOptions = loadOptions; IQueryable<Child1> children = from child in dataContext.Child1 select child; exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=1 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=2 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=3 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=4 I've also written LINQ to SQL queries to join in all of the data in hopes that it would eager load the data, however when the LINQ to SQL EntitySet of Child2 or Grandchild1 are accessed it lazy loads the data. The reason for returning the IList<Child1> is to hydrate business objects. My thoughts are I am either: Approaching this problem the wrong way. Have the option of calling a stored procedure? My organization should not be using LINQ to SQL as an ORM? Any help is greatly appreciated. Thank you, -Scott

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  • Data validation best practices: how can I better construct user feedback?

    - by Cory Larson
    Data validation, whether it be domain object, form, or any other type of input validation, could theoretically be part of any development effort, no matter its size or complexity. I sometimes find myself writing informational or error messages that might seem harsh or demanding to unsuspecting users, and frankly I feel like there must be a better way to describe the validation problem to the user. I know that this topic is subjective and argumentative. StackOverflow might not be the proper channel for diving into this subject, but like I've mentioned, we all run into this at some point or another. There are so many StackExchange sites now; if there is a better one, feel free to share! Basically, I'm looking for good resources on data validation and user feedback that results from it at a theoretical level. Topics and questions I'm interested in are: Content Should I be describing what the user did correctly or incorrectly, or simply what was expected? How much detail can the user read before they get annoyed? (e.g. Is "Username cannot exceed 20 characters." enough, or should it be described more fully, such as "The username cannot be empty, and must be at least 6 characters but cannot exceed 30 characters."?) Grammar How do I decide between phrases like "must not," "may not," or "cannot"? Delivery This can depend on the project, but how should the information be delivered to the user? Should it be obtrusive (e.g. JavaScript alerts) or friendly? Should they be displayed prominently? Immediately (i.e. without confirmation steps, etc.)? Logging Do you bother logging validation errors? Internationalization Some cultures prefer or better understand directness over subtlety and vice-versa (e.g. "Don't do that!" vs. "Please check what you've done."). How do I cater to the majority of users? I may edit this list as I think more about the topic, but I'm genuinely interest in proper user feedback techniques. I'm looking for things like research results, poll results, etc. I've developed and refined my own techniques over the years that users seem to be okay with, but I work in an environment where the users prefer to adapt to what you give them over speaking up about things they don't like. I'm interested in hearing your experiences in addition to any resources to which you may be able to point me.

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  • Microsoft Introduces WebMatrix

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

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  • How to convert an object to the serialized syntax for data in jquery.ajax function?

    - by Matthew
    I have an object that I want to send with my jquery.ajax function but I can't find anything that will convert it to the serialized format I need. $.ajax({ type: 'post', url: 'www.example.com', data: MyObject, success: function(data) { $('.data').html(data) } }) MyObject = [ { "UserId": "2", "UserLevel": "5", "FirstName": "Matthew" }, { "UserId": "4", "UserLevel": "5", "FirstName": "Craig" } ]

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  • Increase Performance of VS 2010 by using a SSD

    - by System.Data
    After searching on the internet for performance improvements when using Visual Studio 2010 with a solid state hard drive, I heard a lot of different opinions. A lot of people said that there isn't really a benefit when using a SSD, but in contrast others said the exact opposite. I am a bit confused with the contrasting opinions and I cannot really make a decision whether buying a SSD would make a difference. What are your experiences with this issue and which SSD did you use?

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  • Exception Handling Differences Between 32/64 Bit

    - by Alois Kraus
    I do quite a bit of debugging .NET applications but from time to time I see things that are impossible (at a first look). I may ask you dear reader what your mental exception handling model is. Exception handling is easy after all right? Lets suppose the following code:         private void F1(object sender, EventArgs e)         {             try             {                 F2();             }             catch (Exception ex)             {                 throw new Exception("even worse Exception");             }           }           private void F2()         {             try             {                 F3();             }             finally             {                 throw new Exception("other exception");             }         }           private void F3()         {             throw new NotImplementedException();         }   What will the call stack look like when you break into the catch(Exception) clause in Windbg (32 and 64 bit on .NET 3.5 SP1)? The mental model I have is that when an exception is thrown the stack frames are unwound until the catch handler can execute. An exception does propagate the call chain upwards.   So when F3 does throw an exception the control flow will resume at the finally handler in F2 which does throw another exception hiding the original one (that is nasty) and then the new Exception will be catched in F1 where the catch handler is executed. So we should see in the catch handler in F1 as call stack only the F1 stack frame right? Well lets try it out in Windbg. For this I created a simple Windows Forms application with one button which does execute the F1 method in its click handler. When you compile the application for 64 bit and the catch handler is reached you will find with the following commands in Windbg   Load sos extension from the same path where mscorwks was loaded in the current process .loadby sos mscorwks   Beak on clr exceptions sxe clr   Continue execution g   Dump mixed call stack container C++  and .NET Stacks interleaved 0:000> !DumpStack OS Thread Id: 0x1d8 (0) Child-SP         RetAddr          Call Site 00000000002c88c0 000007fefa68f0bd KERNELBASE!RaiseException+0x39 00000000002c8990 000007fefac42ed0 mscorwks!RaiseTheExceptionInternalOnly+0x295 00000000002c8a60 000007ff005dd7f4 mscorwks!JIT_Throw+0x130 00000000002c8c10 000007fefa6942e1 WindowsFormsApplication1!WindowsFormsApplication1.Form1.F1(System.Object, System.EventArgs)+0xb4 00000000002c8c60 000007fefa661012 mscorwks!ExceptionTracker::CallHandler+0x145 00000000002c8d60 000007fefa711a72 mscorwks!ExceptionTracker::CallCatchHandler+0x9e 00000000002c8df0 0000000077b055cd mscorwks!ProcessCLRException+0x25e 00000000002c8e90 0000000077ae55f8 ntdll!RtlpExecuteHandlerForUnwind+0xd 00000000002c8ec0 000007fefa637c1a ntdll!RtlUnwindEx+0x539 00000000002c9560 000007fefa711a21 mscorwks!ClrUnwindEx+0x36 00000000002c9a70 0000000077b0554d mscorwks!ProcessCLRException+0x20d 00000000002c9b10 0000000077ae5d1c ntdll!RtlpExecuteHandlerForException+0xd 00000000002c9b40 0000000077b1fe48 ntdll!RtlDispatchException+0x3cb 00000000002ca220 000007fefdaeaa7d ntdll!KiUserExceptionDispatcher+0x2e 00000000002ca7e0 000007fefa68f0bd KERNELBASE!RaiseException+0x39 00000000002ca8b0 000007fefac42ed0 mscorwks!RaiseTheExceptionInternalOnly+0x295 00000000002ca980 000007ff005dd8df mscorwks!JIT_Throw+0x130 00000000002cab30 000007fefa6942e1 WindowsFormsApplication1!WindowsFormsApplication1.Form1.F2()+0x9f 00000000002cab80 000007fefa71b5b3 mscorwks!ExceptionTracker::CallHandler+0x145 00000000002cac80 000007fefa70dcd0 mscorwks!ExceptionTracker::ProcessManagedCallFrame+0x683 00000000002caed0 000007fefa7119af mscorwks!ExceptionTracker::ProcessOSExceptionNotification+0x430 00000000002cbd90 0000000077b055cd mscorwks!ProcessCLRException+0x19b 00000000002cbe30 0000000077ae55f8 ntdll!RtlpExecuteHandlerForUnwind+0xd 00000000002cbe60 000007fefa637c1a ntdll!RtlUnwindEx+0x539 00000000002cc500 000007fefa711a21 mscorwks!ClrUnwindEx+0x36 00000000002cca10 0000000077b0554d mscorwks!ProcessCLRException+0x20d 00000000002ccab0 0000000077ae5d1c ntdll!RtlpExecuteHandlerForException+0xd 00000000002ccae0 0000000077b1fe48 ntdll!RtlDispatchException+0x3cb 00000000002cd1c0 000007fefdaeaa7d ntdll!KiUserExceptionDispatcher+0x2e 00000000002cd780 000007fefa68f0bd KERNELBASE!RaiseException+0x39 00000000002cd850 000007fefac42ed0 mscorwks!RaiseTheExceptionInternalOnly+0x295 00000000002cd920 000007ff005dd968 mscorwks!JIT_Throw+0x130 00000000002cdad0 000007ff005dd875 WindowsFormsApplication1!WindowsFormsApplication1.Form1.F3()+0x48 00000000002cdb10 000007ff005dd786 WindowsFormsApplication1!WindowsFormsApplication1.Form1.F2()+0x35 00000000002cdb60 000007ff005dbe6a WindowsFormsApplication1!WindowsFormsApplication1.Form1.F1(System.Object, System.EventArgs)+0x46 00000000002cdbc0 000007ff005dd452 System_Windows_Forms!System.Windows.Forms.Control.OnClick(System.EventArgs)+0x5a   Hm okaaay. I see my method F1 two times in this call stack. Looks like we did get some recursion bug. But that can´t be given the obvious code above. Let´s try the same thing in a 32 bit process.  0:000> !DumpStack OS Thread Id: 0x33e4 (0) Current frame: KERNELBASE!RaiseException+0x58 ChildEBP RetAddr  Caller,Callee 0028ed38 767db727 KERNELBASE!RaiseException+0x58, calling ntdll!RtlRaiseException 0028ed4c 68b9008c mscorwks!Binder::RawGetClass+0x20, calling mscorwks!Module::LookupTypeDef 0028ed5c 68b904ff mscorwks!Binder::IsClass+0x23, calling mscorwks!Binder::RawGetClass 0028ed68 68bfb96f mscorwks!Binder::IsException+0x14, calling mscorwks!Binder::IsClass 0028ed78 68bfb996 mscorwks!IsExceptionOfType+0x23, calling mscorwks!Binder::IsException 0028ed80 68bfbb1c mscorwks!RaiseTheExceptionInternalOnly+0x2a8, calling KERNEL32!RaiseExceptionStub 0028eda8 68ba0713 mscorwks!Module::ResolveStringRef+0xe0, calling mscorwks!BaseDomain::GetStringObjRefPtrFromUnicodeString 0028edc8 68b91e8d mscorwks!SetObjectReferenceUnchecked+0x19 0028ede0 68c8e910 mscorwks!JIT_Throw+0xfc, calling mscorwks!RaiseTheExceptionInternalOnly 0028ee44 68c8e734 mscorwks!JIT_StrCns+0x22, calling mscorwks!LazyMachStateCaptureState 0028ee54 68c8e865 mscorwks!JIT_Throw+0x1e, calling mscorwks!LazyMachStateCaptureState 0028eea4 02ffaecd (MethodDesc 0x7af08c +0x7d WindowsFormsApplication1.Form1.F1(System.Object, System.EventArgs)), calling mscorwks!JIT_Throw 0028eeec 02ffaf19 (MethodDesc 0x7af098 +0x29 WindowsFormsApplication1.Form1.F2()), calling 06370634 0028ef58 02ffae37 (MethodDesc 0x7a7bb0 +0x4f System.Windows.Forms.Control.OnClick(System.EventArgs))   That does look more familar. The call stack has been unwound and we do see only some frames into the history where the debugger was smart enough to find out that we have called F2 from F1. The exception handling on 64 bit systems does work quite differently which seems to have the nice property to remember the called methods not only during the first pass of exception filter clauses (during first pass all catch handler are called if they are going to catch the exception which is about to be thrown)  but also when the actual stack unwind has taken place. This makes it possible to follow not only the call stack right at the moment but also to look into the “history” of the catch/finally clauses. In a 64 bit process you only need to look at the ExceptionTracker to find out if a catch or finally handler was called. The two frames ProcessManagedCallFrame/CallHandler does indicate a finally clause whereas CallCatchHandler/CallHandler indicates a catch clause. That was a interesting one. Oh and by the way if you manage to load the Microsoft symbols you can also find out the hidden exception which. When you encounter in the call stack a line 0016eb34 75b79617 KERNELBASE!RaiseException+0x58 ====> Exception Code e0434f4d cxr@16e850 exr@16e838 Then it is a good idea to execute .exr 16e838 !analyze –v to find out more. In the managed world it is even easier since we can dump the objects allocated on the stack which have not yet been garbage collected to look at former method parameters. The command !dso which is the abbreviation for dump stack objects will give you 0:000> !dso OS Thread Id: 0x46c (0) ESP/REG  Object   Name 0016dd4c 020737f0 System.Exception 0016dd98 020737f0 System.Exception 0016dda8 01f5c6cc System.Windows.Forms.Button 0016ddac 01f5d2b8 System.EventHandler 0016ddb0 02071744 System.Windows.Forms.MouseEventArgs 0016ddc0 01f5d2b8 System.EventHandler 0016ddcc 01f5c6cc System.Windows.Forms.Button 0016dddc 020737f0 System.Exception 0016dde4 01f5d2b8 System.EventHandler 0016ddec 02071744 System.Windows.Forms.MouseEventArgs 0016de40 020737f0 System.Exception 0016de80 02071744 System.Windows.Forms.MouseEventArgs 0016de8c 01f5d2b8 System.EventHandler 0016de90 01f5c6cc System.Windows.Forms.Button 0016df10 02073784 System.SByte[] 0016df5c 02073684 System.NotImplementedException 0016e2a0 02073684 System.NotImplementedException 0016e2e8 01ed69f4 System.Resources.ResourceManager From there it is easy to do 0:000> !pe 02073684 Exception object: 02073684 Exception type: System.NotImplementedException Message: Die Methode oder der Vorgang sind nicht implementiert. InnerException: <none> StackTrace (generated):     SP       IP       Function     0016ECB0 006904AD WindowsFormsApplication2!WindowsFormsApplication2.Form1.F3()+0x35     0016ECC0 00690411 WindowsFormsApplication2!WindowsFormsApplication2.Form1.F2()+0x29     0016ECF0 0069038F WindowsFormsApplication2!WindowsFormsApplication2.Form1.F1(System.Object, System.EventArgs)+0x3f StackTraceString: <none> HResult: 80004001 to see the former exception. That´s all for today.

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  • I can't access Page.RouteData or Response.RedirectPermanent in web forms upgraded from 3.5 to 4.0 ?

    - by Barbaros Alp
    Hi, I have upgraded my web application from 3.5 to 4.0 to get benefits of the new features of ASP.NET 4.0. When i try to get Route Data Values; Page.RouteData.Values["customerId"] with this code i couldn't reach the RouteData.Values collection the Page class doesnt contain a member called routedata. I also have the same issue with Response.RedirectPermanent... What might be the reason ? Thanks in advance

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  • How to apply Data Oriented Design with Object Oriented Programming?

    - by Pombal
    I've read lots of articles about Data Oriented Design (DOD) and I understand it but I can't design an Object Oriented Programming (OOP) system with DOD in mind, I think my OOP education is blocking me. How should I think to mix the two? The objective is to have a nice OOP interface while using DOD behind the scenes. I saw this too but didn't help much: http://stackoverflow.com/questions/3872354/how-to-apply-dop-and-keep-a-nice-user-interface

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  • Ajax problem not displaying data using multiple javascript calls...

    - by Ronedog
    I'm writing an app that uses ajax to retrieve data from a mysql db using php. Because of the nature of the app, the user clicks an href link that has an "onclick" event used to call the javascript/ajax. I'm retrieving the data from mysql, then calling a separate php function which creates a small html table with the necessary data in it. The new table gets passed back to the responseText and is displayed inside a div tag. The tables only have around 10-20 rows of data in them. This functionality is working fine and displays the data in html form exactly as it needs to be on the page. The problem is this. the HREF "onclick" event needs to run multiple scripts one right after the other. The first script updates the "existing" data and inside the "update_existing" function is a call to refresh a section of the page with the updated HTML from the responseText. Then when that is done a "display_html" function is called which also updates a different section of the page with it's newly created HTML table. The event looks like this: Update This string gets built dynamically using php with parameters supplied, but for this example I simply took the parameters out so it didn't get confusing. The "update_existion() function actually calls the display_html() function which updates a section of the page as needed. I need to update a different section of the page on the same click of the mouse right after the update, which is why I'm calling the display_html() again, right after it. The problem is only the last call is being updated on my screen. In other words, the 2nd function call "display_html()" executes and displays the refreshed data just fine, but the previous call to update_existing() runs and updates the database properly, but doesn't display on the screen unless I press the browsers "refresh" button, which of course displays the new data exactly how I want it to, but I don't want the users to have to press the "refresh" button. I tried adding multiple "display_html() calls one right after the other, separating all of them with the semicolon and learned that only the very last function call actually refreshed the div element on the html page with the table information, although all the previous display_html() calls worked, they couldn't be seen on the page without a refresh of the browser. Is this a problem with javascript, or the ajax call, or is this a limitation in the DOM that only allows one element to be updated at a time. The ajax call is asynchroneous, but I've tried both, only async works period. This is the same in both Firefox and Internet Explorer Any ideas what's going on and how to get around it so I can run these multiple scripts?

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  • Webcast: John Fowler Reveals The Next Step In Data Center Consolidation – June 27 At 10 AM PT

    - by Roxana Babiciu
    Completely integrated solutions are just better. But don't take our word for it - encourage your customers and prospects to join this live webcast featuring Oracle EVP John Fowler to find out why. Participants will learn how consolidating their existing data center to this new generation of solutions will simplify architectures, jump start application deployment and improve system performance - with easy self-service and private cloud capabilities.

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  • SQL Azure and Trust Services

    - by BuckWoody
    Microsoft is working on a new Windows Azure service called “Trust Services”. Trust Services takes a certificate you upload and uses it to encrypt and decrypt sensitive data in the cloud. Of course, like any security service, there’s a bit more to it than that. I’ll give you a quick overview of how you can use this product to protect data you send to SQL Azure. The primary issue with storing data in the cloud is that you are in an environment that isn’t under your control – in fact, that’s the benefit of being in a distributed computing environment in the first place. On premises you’re able to encrypt data you don’t want anyone else to see, using various methods such as passwords (not very strong) or certificates (stronger). When you use a certificate, it’s vital that you create (or procure) and protect it yourself. When you store data remotely, regardless of IaaS, PaaS or SaaS, you don’t own the machines where the data lives. That means if you use a certificate from the cloud vendor to encrypt the data, you have to trust that the data won’t be accessed by the vendor. In some cases having a signed agreement with the vendor that they won’t access your data is sufficient, in other cases that doesn’t meet the requirements your system has for security. With the new Trust Services service, the basic process is that you use a Portal to create a Trust Server using policies and other controls. You place a X.509 Certificate you create or procure in that server. Using the Software development Kit (SDK), the developer has access to an Application Layer Encryption Framework to set fields of data they want to encrypt. From there, the data can be stored in SQL Azure as a standard field – only it is encrypted before it ever arrives. The portion of the client software that decrypts the data uses the same service, so the authenticated user sees the data if they are allowed to do so. The data remains encrypted “at rest”.  You can learn more about this product and check it out in the SQL Azure labs at Microsoft Codename "Trust Services"

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  • how to make Sliding window model for data stream mining?

    - by zeedotcom
    we have a situation that a stream (data from sensor or click stream data at server) is coming with sliding window algorithm we have to store the last (say) 500 samples of data in memory. These samples are then used to create histograms, aggregations & capture information about anomalies in the input data stream. please tell me how to make such sliding window.

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  • Is it safer to use the same IV all times data are encrypted, or use a dynamic IV that is sent together the encrypted text? [closed]

    - by kiamlaluno
    When encrypting data that is then send to a server, is it better to always use the same IV, which is already known from the receiving server, or use a dynamic IV that is then sent to the receiving server? I am referring to the case the remote server receives data from another server, or from a client application, and executes operations on a database table, in the table row identified by the received data. Which of the following PHP snippets is preferable? $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND); $ks = mcrypt_enc_get_key_size($td); $key = substr(md5('very secret key'), 0, $ks); mcrypt_generic_init($td, $key, $iv); $encrypted = mcrypt_generic($td, 'This is very important data'); send_encripted_data(combine_iv_encrypted_text($iv, $encrypted)); $ks = mcrypt_enc_get_key_size($td); $key = substr(md5('very secret key'), 0, $ks); mcrypt_generic_init($td, $key, $iv); send_encripted_data(mcrypt_generic($td, 'This is very important data')); In which way is one of the snippets more vulnerable than the other one?

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  • Zelda-style Top-down RPG. Storing data for each tile type

    - by Delerat
    I'm creating a Zelda-style RPG using Tiled, C#, and MonoGame. When my code parses the .tmx file, it will get a number to associate with each tile type based off of their position in the tile sheet. If I ever need to change my sprite sheet, this number will change for many of the tiles. How can I guarantee that when I parse my .tmx file, I will be able to know exactly what tile type I'm getting so that I can associate the proper data with it(transparency, animated, collision, etc.)?

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  • Best choise of gui platform/framework for 3d development [closed]

    - by Miguel P
    The title pretty much says it all, so I'm developing a 3d engine for Directx 11, and it's going good so far. I started using .net forms as a GUI, but then(Of curiosity), i jumped to MFC, and the app looked great, but in my perspective, MFC is badly written, and it's too complicated, meaning that some things just took forever, while it would have taken a few seconds in .net forms. But my real question is: If i want to make an Editor for a 3d scene, where directx renders in the form( This was accomplished in .net forms), what would be the best choise of gui platform/framework? MFC,.net forms, Qt, etc....

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  • How to record streaming camera video and auto-erase old data before drive fills up?

    - by nLinked
    I'm interested in making my own home CCTV system using Ubuntu. I want to get network cameras similar to this: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260745150596 I want a way to dump or record the live stream to a large hard drive, but have Ubuntu automatically delete the oldest parts of the video while the drive fills, so it can continue recording new data continuously. How can this auto-delete while recording be accomplished? I've searched and searched.

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  • What languages are the kids of today actually programming in? Does anyone have real data?

    - by Gaz Davidson
    Back in the 80s colleges were teaching Pascal because it is easy to learn, while myself and many others like me were learning BASIC because it was not only easy to learn but accessible and also fashionable (for an extremely liberal definition of fashion) It has just occurred to me that empirical data on the actual programming languages kids are choosing to use should be a good indicator of which language would be the ideal first choice for educators. Please note that this question is not "what do you think is a good programming language for kids?"

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  • Strange Flash AS3 xml Socket behavior

    - by Rnd_d
    I have a problem which I can't understand. To understand it I wrote a socket client on AS3 and a server on python/twisted, you can see the code of both applications below. Let's launch two clients at the same time, arrange them so that you can see both windows and press connection button in both windows. Then press and hold any button. What I'm expecting: Client with pressed button sends a message "some data" to the server, then the server sends this message to all the clients(including the original sender) . Then each client moves right the button 'connectButton' and prints a message to the log with time in the following format: "min:secs:milliseconds". What is going wrong: The motion is smooth in the client that sends the message, but in all other clients the motion is jerky. This happens because messages to those clients arrive later than to the original sending client. And if we have three clients (let's name them A,B,C) and we send a message from A, the sending time log of B and C will be the same. Why other clients recieve this messages later than the original sender? By the way, on ubuntu 10.04/chrome all the motion is smooth. Two clients are launched in separated chromes. windows screenshot Can't post linux screenshot, need more than 10 reputation to post more hyperlinks. Listing of log, four clients simultaneously: [16:29:33.280858] 62.140.224.1 >> some data [16:29:33.280912] 87.249.9.98 << some data [16:29:33.280970] 87.249.9.98 << some data [16:29:33.281025] 87.249.9.98 << some data [16:29:33.281079] 62.140.224.1 << some data [16:29:33.323267] 62.140.224.1 >> some data [16:29:33.323326] 87.249.9.98 << some data [16:29:33.323386] 87.249.9.98 << some data [16:29:33.323440] 87.249.9.98 << some data [16:29:33.323493] 62.140.224.1 << some data [16:29:34.123435] 62.140.224.1 >> some data [16:29:34.123525] 87.249.9.98 << some data [16:29:34.123593] 87.249.9.98 << some data [16:29:34.123648] 87.249.9.98 << some data [16:29:34.123702] 62.140.224.1 << some data AS3 client code package { import adobe.utils.CustomActions; import flash.display.Sprite; import flash.events.DataEvent; import flash.events.Event; import flash.events.IOErrorEvent; import flash.events.KeyboardEvent; import flash.events.MouseEvent; import flash.events.SecurityErrorEvent; import flash.net.XMLSocket; import flash.system.Security; import flash.text.TextField; public class Main extends Sprite { private var socket :XMLSocket; private var textField :TextField = new TextField; private var connectButton :TextField = new TextField; public function Main():void { if (stage) init(); else addEventListener(Event.ADDED_TO_STAGE, init); } private function init(event:Event = null):void { socket = new XMLSocket(); socket.addEventListener(Event.CONNECT, connectHandler); socket.addEventListener(DataEvent.DATA, dataHandler); stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler); addChild(textField); textField.y = 50; textField.width = 780; textField.height = 500; textField.border = true; connectButton.selectable = false; connectButton.border = true; connectButton.addEventListener(MouseEvent.MOUSE_DOWN, connectMouseDownHandler); connectButton.width = 105; connectButton.height = 20; connectButton.text = "click here to connect"; addChild(connectButton); } private function connectHandler(event:Event):void { textField.appendText("Connect\n"); textField.appendText("Press and hold any key\n"); } private function dataHandler(event:DataEvent):void { var now:Date = new Date(); textField.appendText(event.data + " time = " + now.getMinutes() + ":" + now.getSeconds() + ":" + now.getMilliseconds() + "\n"); connectButton.x += 2; } private function keyDownHandler(event:KeyboardEvent):void { socket.send("some data"); } private function connectMouseDownHandler(event:MouseEvent):void { var connectAddress:String = "ep1c.org"; var connectPort:Number = 13250; Security.loadPolicyFile("xmlsocket://" + connectAddress + ":" + String(connectPort)); socket.connect(connectAddress, connectPort); } } } Python server code from twisted.internet import reactor from twisted.internet.protocol import ServerFactory from twisted.protocols.basic import LineOnlyReceiver import datetime class EchoProtocol(LineOnlyReceiver): ##### name = "" id = 0 delimiter = chr(0) ##### def getName(self): return self.transport.getPeer().host def connectionMade(self): self.id = self.factory.getNextId() print "New connection from %s - id:%s" % (self.getName(), self.id) self.factory.clientProtocols[self.id] = self def connectionLost(self, reason): print "Lost connection from "+ self.getName() del self.factory.clientProtocols[self.id] self.factory.sendMessageToAllClients(self.getName() + " has disconnected.") def lineReceived(self, line): print "[%s] %s >> %s" % (datetime.datetime.now().time(), self, line) if line=="<policy-file-request/>": data = """<?xml version="1.0"?> <!DOCTYPE cross-domain-policy SYSTEM "http://www.adobe.com/xml/dtds/cross-domain-policy.dtd"> <!-- Policy file for xmlsocket://ep1c.org --> <cross-domain-policy> <allow-access-from domain="*" to-ports="%s" /> </cross-domain-policy>""" % PORT self.send(data) else: self.factory.sendMessageToAllClients( line ) def send(self, line): print "[%s] %s << %s" % (datetime.datetime.now().time(), self, line) if line: self.transport.write( str(line) + chr(0)) else: print "Nothing to send" def __str__(self): return self.getName() class ChatProtocolFactory(ServerFactory): protocol = EchoProtocol def __init__(self): self.clientProtocols = {} self.nextId = 0 def getNextId(self): id = self.nextId self.nextId += 1 return id def sendMessageToAllClients(self, msg): for client in self.clientProtocols: self.clientProtocols[client].send(msg) def sendMessageToClient(self, id, msg): self.clientProtocols[id].send(msg) PORT = 13250 print "Starting Server" factory = ChatProtocolFactory() reactor.listenTCP(PORT, factory) reactor.run()

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  • How can I optimize Apache to use 1GB of RAM on my website? [closed]

    - by Markon
    My VPS plan gives me 1GB of RAM burstable to 2GB. Of course I cannot use 2 GB, nor 1 GB, everyday, so I'm planning to optimize the performance of my webserver. The average of hits-per-hour is about 8'000-10'000. This means about 2 connections-per-second. Max hits-per-hour reached until now is about 60'000. That means about 16 connections-per-second. Unluckily my current apache configuration uses too much memory (when there are not connected clients - usually during the night - it uses about 1GB) so I've tried to customize the apache installation to fit to my needs. I'm using Ubuntu, kernel 2.6.18, with apache2-mpm-worker, since I've read it requires less memory, and fcgid ( + PHP). This is my /etc/apache2/apache2.conf: Timeout 45 KeepAlive on MaxKeepAliveRequests 100 KeepAliveTimeout 10 <IfModule mpm_worker_module> StartServer 2 MinSpareThreads 25 MaxSpareThreads 75 MaxClients 100 MaxRequestsPerChild 0 </IfModule> This is the output of ps aux: www-data 9547 0.0 0.3 423828 7268 ? Sl 20:09 0:00 /usr/sbin/apache2 -k start root 17714 0.0 0.1 76496 3712 ? Ss Feb05 0:00 /usr/sbin/apache2 -k start www-data 17716 0.0 0.0 75560 2048 ? S Feb05 0:00 /usr/sbin/apache2 -k start www-data 17746 0.0 0.1 76228 2384 ? S Feb05 0:00 /usr/sbin/apache2 -k start www-data 20126 0.0 0.3 424852 7588 ? Sl 19:24 0:02 /usr/sbin/apache2 -k start www-data 24260 0.0 0.3 424852 7580 ? Sl 19:42 0:01 /usr/sbin/apache2 -k start while this is ps aux for php5: www-data 7461 2.9 2.2 142172 47048 ? S 19:39 1:39 /usr/lib/cgi-bin/php5 www-data 23845 1.3 1.7 135744 35948 ? S 20:17 0:15 /usr/lib/cgi-bin/php5 www-data 23900 2.0 1.7 136692 36760 ? S 20:17 0:22 /usr/lib/cgi-bin/php5 www-data 27907 2.0 2.0 142272 43432 ? S 20:00 0:43 /usr/lib/cgi-bin/php5 www-data 27909 2.5 1.9 138092 40036 ? S 20:00 0:53 /usr/lib/cgi-bin/php5 www-data 27993 2.4 2.2 142336 47192 ? S 20:01 0:50 /usr/lib/cgi-bin/php5 www-data 27999 1.8 1.4 135932 31100 ? S 20:01 0:38 /usr/lib/cgi-bin/php5 www-data 28230 2.6 1.9 143436 39956 ? S 20:01 0:54 /usr/lib/cgi-bin/php5 www-data 30708 3.1 2.2 142508 46528 ? S 19:44 1:38 /usr/lib/cgi-bin/php5 As you can see it use a lot of memory. How can I reduce it to fit to just 1GB of RAM? PS: I also think about the switch to nginx, if Apache can't fit to my needs...

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  • What are the commonly confused encodings that may result in identical test data?

    - by makerofthings7
    I'm fixing code that is using ASCIIEncoding in some places and UTF-8 encoding in other functions. Since we aren't using the UTF-8 features, all of our unit tests passed, but I want to create a heightened awareness of encodings that produce similar results and may not be fully tested. I don't want to limit this to just UTF-8 vs ASCII, since I think issue with code that handles ASN.1 fields and other code working with Base64. So, what are the commonly confused encodings that may result in identical test data?

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  • Can I avoid a threaded UDP socket in Python dropping data?

    - by 666craig
    First off, I'm new to Python and learning on the job, so be gentle! I'm trying to write a threaded Python app for Windows that reads data from a UDP socket (thread-1), writes it to file (thread-2), and displays the live data (thread-3) to a widget (gtk.Image using a gtk.gdk.pixbuf). I'm using queues for communicating data between threads. My problem is that if I start only threads 1 and 3 (so skip the file writing for now), it seems that I lose some data after the first few samples. After this drop it looks fine. Even by letting thread 1 complete before running thread 3, this apparent drop is still there. Apologies for the length of code snippet (I've removed the thread that writes to file), but I felt removing code would just prompt questions. Hope someone can shed some light :-) import socket import threading import Queue import numpy import gtk gtk.gdk.threads_init() import gtk.glade import pygtk class readFromUDPSocket(threading.Thread): def __init__(self, socketUDP, readDataQueue, packetSize, numScans): threading.Thread.__init__(self) self.socketUDP = socketUDP self.readDataQueue = readDataQueue self.packetSize = packetSize self.numScans = numScans def run(self): for scan in range(1, self.numScans + 1): buffer = self.socketUDP.recv(self.packetSize) self.readDataQueue.put(buffer) self.socketUDP.close() print 'myServer finished!' class displayWithGTK(threading.Thread): def __init__(self, displayDataQueue, image, viewArea): threading.Thread.__init__(self) self.displayDataQueue = displayDataQueue self.image = image self.viewWidth = viewArea[0] self.viewHeight = viewArea[1] self.displayData = numpy.zeros((self.viewHeight, self.viewWidth, 3), dtype=numpy.uint16) def run(self): scan = 0 try: while True: if not scan % self.viewWidth: scan = 0 buffer = self.displayDataQueue.get(timeout=0.1) self.displayData[:, scan, 0] = numpy.fromstring(buffer, dtype=numpy.uint16) self.displayData[:, scan, 1] = numpy.fromstring(buffer, dtype=numpy.uint16) self.displayData[:, scan, 2] = numpy.fromstring(buffer, dtype=numpy.uint16) gtk.gdk.threads_enter() self.myPixbuf = gtk.gdk.pixbuf_new_from_data(self.displayData.tostring(), gtk.gdk.COLORSPACE_RGB, False, 8, self.viewWidth, self.viewHeight, self.viewWidth * 3) self.image.set_from_pixbuf(self.myPixbuf) self.image.show() gtk.gdk.threads_leave() scan += 1 except Queue.Empty: print 'myDisplay finished!' pass def quitGUI(obj): print 'Currently active threads: %s' % threading.enumerate() gtk.main_quit() if __name__ == '__main__': # Create socket (IPv4 protocol, datagram (UDP)) and bind to address socketUDP = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) host = '192.168.1.5' port = 1024 socketUDP.bind((host, port)) # Data parameters samplesPerScan = 256 packetsPerSecond = 1200 packetSize = 512 duration = 1 # For now, set a fixed duration to log data numScans = int(packetsPerSecond * duration) # Create array to store data data = numpy.zeros((samplesPerScan, numScans), dtype=numpy.uint16) # Create queue for displaying from readDataQueue = Queue.Queue(numScans) # Build GUI from Glade XML file builder = gtk.Builder() builder.add_from_file('GroundVue.glade') window = builder.get_object('mainwindow') window.connect('destroy', quitGUI) view = builder.get_object('viewport') image = gtk.Image() view.add(image) viewArea = (1200, samplesPerScan) # Instantiate & start threads myServer = readFromUDPSocket(socketUDP, readDataQueue, packetSize, numScans) myDisplay = displayWithGTK(readDataQueue, image, viewArea) myServer.start() myDisplay.start() gtk.gdk.threads_enter() gtk.main() gtk.gdk.threads_leave() print 'gtk.main finished!'

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