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• Difference Between WCF WCF Ria, and Data Service

  - by Asim Sajjad

  What is the defference between the WCF Service , WCF Ria Services and the data servics.

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• How to invalidate a single data item in the .net cache in VB

  - by Craig

  I have the following .NET VB code to set and read objects in cache on a per user basis (i.e. a bit like session) '' Public Shared Sub CacheSet(ByVal Key As String, ByVal Value As Object) Dim userID As String = HttpContext.Current.User.Identity.Name HttpContext.Current.Cache(Key & "_" & userID) = Value End Sub Public Shared Function CacheGet(ByVal Key As Object) Dim returnData As Object = Nothing Dim userID As String = HttpContext.Current.User.Identity.Name returnData = HttpContext.Current.Cache(Key & "_" & userID) Return returnData End Function I use these functions to hold user data that I don't want to access the DB for all the time. However, when the data is updated, I want the cached item to be removed so it get created again. How do I make an Item I set disappear or set it to NOTHING or NULL? Craig

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• operator not defined for System.Data.SqlClient.SqlConnection and System.Data.SqlClient.SqlConnection

  - by Beta033

  i hope i'm just doing something wrong here. Ideally i'm trying to open the connection, open a transaction execute a ton of prebuilt sqlstatements (with parameters) against this connection then close the connection. ideally all in the same batch. It's easy enough to wrap this all in a for loop, however i'd like to use the forEach function of the list generic to set the connection as it'll probably be faster than my implementation of calling List.Item(i) in the loop but i get some strange errors. Dim sqlStatements As List(Of SqlCommand) = New List(Of SqlCommand) Dim conn As SqlClient.SqlConnection = New SqlConnection("...") sqlStatements.Item(0).Connection = conn 'Works sqlStatements.ForEach(Function(ByRef cmd As SqlCommand) cmd.Connection = conn) 'ERROR: Operator '=' is not defined for types 'System.Data.SqlClient.SqlConnection' 'and 'System.Data.SqlClient.SqlConnection What does this error really mean?

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• Can I develop for .NET Framework 4 in Visual Studio 2008?

  - by Zack Peterson

  My ASP.NET application runs in IIS on my web server and uses Microsoft .NET Framework 4 Beta 2. (Its Application Pool is set to .NET Framework version .NET Framework v4.0.21006.) It gives this new error: A potentially dangerous Request.Form value was detected from the client... This is due to a breaking change in .NET 4. To revert to the behavior of the ASP.NET 2.0 request validation feature, I added the following setting in the Web.config file: <httpRuntime requestValidationMode="2.0" /> Now Visual Studio 2008 throws a compile-time error: The 'requestValidationMode' attribute is not declared. And I can no longer debug on my development machine using the ASP.NET Development Server that comes with Visual Studio. I need Visual Studio and its ASP.NET Development Server to recognize the new .NET Framework 4 requestValidationMode attribute. How can I debug my application in .NET 4? Must I switch from Visual Studio 2008 to Visual Studio 2010 Beta 2?

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• Display post data !

  - by Comii

  I am trying to post data from vb.net application to web service asmx that is located on server! For posting data from vb.net application I am using this code: Public Function Post(ByVal url As String, ByVal data As String) As String Dim vystup As String = Nothing Try 'Our postvars Dim buffer As Byte() = Encoding.ASCII.GetBytes(data) 'Initialisation, we use localhost, change if appliable Dim WebReq As HttpWebRequest = DirectCast(WebRequest.Create(url), HttpWebRequest) 'Our method is post, otherwise the buffer (postvars) would be useless WebReq.Method = "POST" 'We use form contentType, for the postvars. WebReq.ContentType = "application/x-www-form-urlencoded" 'The length of the buffer (postvars) is used as contentlength. WebReq.ContentLength = buffer.Length 'We open a stream for writing the postvars Dim PostData As Stream = WebReq.GetRequestStream() 'Now we write, and afterwards, we close. Closing is always important! PostData.Write(buffer, 0, buffer.Length) PostData.Close() 'Get the response handle, we have no true response yet! Dim WebResp As HttpWebResponse = DirectCast(WebReq.GetResponse(), HttpWebResponse) 'Let's show some information about the response Console.WriteLine(WebResp.StatusCode) Console.WriteLine(WebResp.Server) 'Now, we read the response (the string), and output it. Dim Answer As Stream = WebResp.GetResponseStream() Dim _Answer As New StreamReader(Answer) 'Congratulations, you just requested your first POST page, you 'can now start logging into most login forms, with your application 'Or other examples. vystup = _Answer.ReadToEnd() Catch ex As Exception MessageBox.Show(ex.Message) End Try Return vystup.Trim() & vbLf End Function Now how i can retrieve this data in asmx service?

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• Parallelism in .NET – Part 13, Introducing the Task class

  - by Reed

  Once we’ve used a task-based decomposition to decompose a problem, we need a clean abstraction usable to implement the resulting decomposition.  Given that task decomposition is founded upon defining discrete tasks, .NET 4 has introduced a new API for dealing with task related issues, the aptly named Task class. The Task class is a wrapper for a delegate representing a single, discrete task within your decomposition.  We will go into various methods of construction for tasks later, but, when reduced to its fundamentals, an instance of a Task is nothing more than a wrapper around a delegate with some utility functionality added.  In order to fully understand the Task class within the new Task Parallel Library, it is important to realize that a task really is just a delegate – nothing more.  In particular, note that I never mentioned threading or parallelism in my description of a Task.  Although the Task class exists in the new System.Threading.Tasks namespace: Tasks are not directly related to threads or multithreading. Of course, Task instances will typically be used in our implementation of concurrency within an application, but the Task class itself does not provide the concurrency used.  The Task API supports using Tasks in an entirely single threaded, synchronous manner. Tasks are very much like standard delegates.  You can execute a task synchronously via Task.RunSynchronously(), or you can use Task.Start() to schedule a task to run, typically asynchronously.  This is very similar to using delegate.Invoke to execute a delegate synchronously, or using delegate.BeginInvoke to execute it asynchronously. The Task class adds some nice functionality on top of a standard delegate which improves usability in both synchronous and multithreaded environments. The first addition provided by Task is a means of handling cancellation via the new unified cancellation mechanism of .NET 4.  If the wrapped delegate within a Task raises an OperationCanceledException during it’s operation, which is typically generated via calling ThrowIfCancellationRequested on a CancellationToken, or if the CancellationToken used to construct a Task instance is flagged as canceled, the Task’s IsCanceled property will be set to true automatically.  This provides a clean way to determine whether a Task has been canceled, often without requiring specific exception handling. Tasks also provide a clean API which can be used for waiting on a task.  Although the Task class explicitly implements IAsyncResult, Tasks provide a nicer usage model than the traditional .NET Asynchronous Programming Model.  Instead of needing to track an IAsyncResult handle, you can just directly call Task.Wait() to block until a Task has completed.  Overloads exist for providing a timeout, a CancellationToken, or both to prevent waiting indefinitely.  In addition, the Task class provides static methods for waiting on multiple tasks – Task.WaitAll and Task.WaitAny, again with overloads providing time out options.  This provides a very simple, clean API for waiting on single or multiple tasks. Finally, Tasks provide a much nicer model for Exception handling.  If the delegate wrapped within a Task raises an exception, the exception will automatically get wrapped into an AggregateException and exposed via the Task.Exception property.  This exception is stored with the Task directly, and does not tear down the application.  Later, when Task.Wait() (or Task.WaitAll or Task.WaitAny) is called on this task, an AggregateException will be raised at that point if any of the tasks raised an exception.  For example, suppose we have the following code: Task taskOne = new Task( () => { throw new ApplicationException("Random Exception!"); }); Task taskTwo = new Task( () => { throw new ArgumentException("Different exception here"); }); // Start the tasks taskOne.Start(); taskTwo.Start(); try { Task.WaitAll(new[] { taskOne, taskTwo }); } catch (AggregateException e) { Console.WriteLine(e.InnerExceptions.Count); foreach (var inner in e.InnerExceptions) Console.WriteLine(inner.Message); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, our routine will print: 2 Different exception here Random Exception! Note that we had two separate tasks, each of which raised two distinctly different types of exceptions.  We can handle this cleanly, with very little code, in a much nicer manner than the Asynchronous Programming API.  We no longer need to handle TargetInvocationException or worry about implementing the Event-based Asynchronous Pattern properly by setting the AsyncCompletedEventArgs.Error property.  Instead, we just raise our exception as normal, and handle AggregateException in a single location in our calling code.

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• Parallelism in .NET – Part 11, Divide and Conquer via Parallel.Invoke

  - by Reed

  Many algorithms are easily written to work via recursion.  For example, most data-oriented tasks where a tree of data must be processed are much more easily handled by starting at the root, and recursively “walking” the tree.  Some algorithms work this way on flat data structures, such as arrays, as well.  This is a form of divide and conquer: an algorithm design which is based around breaking up a set of work recursively, “dividing” the total work in each recursive step, and “conquering” the work when the remaining work is small enough to be solved easily. Recursive algorithms, especially ones based on a form of divide and conquer, are often a very good candidate for parallelization. This is apparent from a common sense standpoint.  Since we’re dividing up the total work in the algorithm, we have an obvious, built-in partitioning scheme.  Once partitioned, the data can be worked upon independently, so there is good, clean isolation of data. Implementing this type of algorithm is fairly simple.  The Parallel class in .NET 4 includes a method suited for this type of operation: Parallel.Invoke.  This method works by taking any number of delegates defined as an Action, and operating them all in parallel.  The method returns when every delegate has completed: Parallel.Invoke( () => { Console.WriteLine("Action 1 executing in thread {0}", Thread.CurrentThread.ManagedThreadId); }, () => { Console.WriteLine("Action 2 executing in thread {0}", Thread.CurrentThread.ManagedThreadId); }, () => { Console.WriteLine("Action 3 executing in thread {0}", Thread.CurrentThread.ManagedThreadId); } ); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Running this simple example demonstrates the ease of using this method.  For example, on my system, I get three separate thread IDs when running the above code.  By allowing any number of delegates to be executed directly, concurrently, the Parallel.Invoke method provides us an easy way to parallelize any algorithm based on divide and conquer.  We can divide our work in each step, and execute each task in parallel, recursively. For example, suppose we wanted to implement our own quicksort routine.  The quicksort algorithm can be designed based on divide and conquer.  In each iteration, we pick a pivot point, and use that to partition the total array.  We swap the elements around the pivot, then recursively sort the lists on each side of the pivot.  For example, let’s look at this simple, sequential implementation of quicksort: public static void QuickSort<T>(T[] array) where T : IComparable<T> { QuickSortInternal(array, 0, array.Length - 1); } private static void QuickSortInternal<T>(T[] array, int left, int right) where T : IComparable<T> { if (left >= right) { return; } SwapElements(array, left, (left + right) / 2); int last = left; for (int current = left + 1; current <= right; ++current) { if (array[current].CompareTo(array[left]) < 0) { ++last; SwapElements(array, last, current); } } SwapElements(array, left, last); QuickSortInternal(array, left, last - 1); QuickSortInternal(array, last + 1, right); } static void SwapElements<T>(T[] array, int i, int j) { T temp = array[i]; array[i] = array[j]; array[j] = temp; } Here, we implement the quicksort algorithm in a very common, divide and conquer approach.  Running this against the built-in Array.Sort routine shows that we get the exact same answers (although the framework’s sort routine is slightly faster).  On my system, for example, I can use framework’s sort to sort ten million random doubles in about 7.3s, and this implementation takes about 9.3s on average. Looking at this routine, though, there is a clear opportunity to parallelize.  At the end of QuickSortInternal, we recursively call into QuickSortInternal with each partition of the array after the pivot is chosen.  This can be rewritten to use Parallel.Invoke by simply changing it to: // Code above is unchanged... SwapElements(array, left, last); Parallel.Invoke( () => QuickSortInternal(array, left, last - 1), () => QuickSortInternal(array, last + 1, right) ); } This routine will now run in parallel.  When executing, we now see the CPU usage across all cores spike while it executes.  However, there is a significant problem here – by parallelizing this routine, we took it from an execution time of 9.3s to an execution time of approximately 14 seconds!  We’re using more resources as seen in the CPU usage, but the overall result is a dramatic slowdown in overall processing time. This occurs because parallelization adds overhead.  Each time we split this array, we spawn two new tasks to parallelize this algorithm!  This is far, far too many tasks for our cores to operate upon at a single time.  In effect, we’re “over-parallelizing” this routine.  This is a common problem when working with divide and conquer algorithms, and leads to an important observation: When parallelizing a recursive routine, take special care not to add more tasks than necessary to fully utilize your system. This can be done with a few different approaches, in this case.  Typically, the way to handle this is to stop parallelizing the routine at a certain point, and revert back to the serial approach.  Since the first few recursions will all still be parallelized, our “deeper” recursive tasks will be running in parallel, and can take full advantage of the machine.  This also dramatically reduces the overhead added by parallelizing, since we’re only adding overhead for the first few recursive calls.  There are two basic approaches we can take here.  The first approach would be to look at the total work size, and if it’s smaller than a specific threshold, revert to our serial implementation.  In this case, we could just check right-left, and if it’s under a threshold, call the methods directly instead of using Parallel.Invoke. The second approach is to track how “deep” in the “tree” we are currently at, and if we are below some number of levels, stop parallelizing.  This approach is a more general-purpose approach, since it works on routines which parse trees as well as routines working off of a single array, but may not work as well if a poor partitioning strategy is chosen or the tree is not balanced evenly. This can be written very easily.  If we pass a maxDepth parameter into our internal routine, we can restrict the amount of times we parallelize by changing the recursive call to: // Code above is unchanged... SwapElements(array, left, last); if (maxDepth < 1) { QuickSortInternal(array, left, last - 1, maxDepth); QuickSortInternal(array, last + 1, right, maxDepth); } else { --maxDepth; Parallel.Invoke( () => QuickSortInternal(array, left, last - 1, maxDepth), () => QuickSortInternal(array, last + 1, right, maxDepth)); } We no longer allow this to parallelize indefinitely – only to a specific depth, at which time we revert to a serial implementation.  By starting the routine with a maxDepth equal to Environment.ProcessorCount, we can restrict the total amount of parallel operations significantly, but still provide adequate work for each processing core. With this final change, my timings are much better.  On average, I get the following timings: Framework via Array.Sort: 7.3 seconds Serial Quicksort Implementation: 9.3 seconds Naive Parallel Implementation: 14 seconds Parallel Implementation Restricting Depth: 4.7 seconds Finally, we are now faster than the framework’s Array.Sort implementation.

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• What&rsquo;s New in ASP.NET 4.0 Part Two: WebForms and Visual Studio Enhancements

  - by Rick Strahl

  In the last installment I talked about the core changes in the ASP.NET runtime that I’ve been taking advantage of. In this column, I’ll cover the changes to the Web Forms engine and some of the cool improvements in Visual Studio that make Web and general development easier. WebForms The WebForms engine is the area that has received most significant changes in ASP.NET 4.0. Probably the most widely anticipated features are related to managing page client ids and of ViewState on WebForm pages. Take Control of Your ClientIDs Unique ClientID generation in ASP.NET has been one of the most complained about “features” in ASP.NET. Although there’s a very good technical reason for these unique generated ids - they guarantee unique ids for each and every server control on a page - these unique and generated ids often get in the way of client-side JavaScript development and CSS styling as it’s often inconvenient and fragile to work with the long, generated ClientIDs. In ASP.NET 4.0 you can now specify an explicit client id mode on each control or each naming container parent control to control how client ids are generated. By default, ASP.NET generates mangled client ids for any control contained in a naming container (like a Master Page, or a User Control for example). The key to ClientID management in ASP.NET 4.0 are the new ClientIDMode and ClientIDRowSuffix properties. ClientIDMode supports four different ClientID generation settings shown below. For the following examples, imagine that you have a Textbox control named txtName inside of a master page control container on a WebForms page. <%@Page Language="C#"      MasterPageFile="~/Site.Master"     CodeBehind="WebForm2.aspx.cs"     Inherits="WebApplication1.WebForm2"  %> <asp:Content ID="content"  ContentPlaceHolderID="content"               runat="server"               ClientIDMode="Static" >       <asp:TextBox runat="server" ID="txtName" /> </asp:Content> The four available ClientIDMode values are: AutoID This is the existing behavior in ASP.NET 1.x-3.x where full naming container munging takes place. <input name="ctl00$content$txtName" type="text"        id="ctl00_content_txtName" /> This should be familiar to any ASP.NET developer and results in fairly unpredictable client ids that can easily change if the containership hierarchy changes. For example, removing the master page changes the name in this case, so if you were to move a block of script code that works against the control to a non-Master page, the script code immediately breaks. Static This option is the most deterministic setting that forces the control’s ClientID to use its ID value directly. No naming container naming at all is applied and you end up with clean client ids: <input name="ctl00$content$txtName"         type="text" id="txtName" /> Note that the name property which is used for postback variables to the server still is munged, but the ClientID property is displayed simply as the ID value that you have assigned to the control. This option is what most of us want to use, but you have to be clear on that because it can potentially cause conflicts with other controls on the page. If there are several instances of the same naming container (several instances of the same user control for example) there can easily be a client id naming conflict. Note that if you assign Static to a data-bound control, like a list child control in templates, you do not get unique ids either, so for list controls where you rely on unique id for child controls, you’ll probably want to use Predictable rather than Static. I’ll write more on this a little later when I discuss ClientIDRowSuffix. Predictable The previous two values are pretty self-explanatory. Predictable however, requires some explanation. To me at least it’s not in the least bit predictable. MSDN defines this value as follows: This algorithm is used for controls that are in data-bound controls. The ClientID value is generated by concatenating the ClientID value of the parent naming container with the ID value of the control. If the control is a data-bound control that generates multiple rows, the value of the data field specified in the ClientIDRowSuffix property is added at the end. For the GridView control, multiple data fields can be specified. If the ClientIDRowSuffix property is blank, a sequential number is added at the end instead of a data-field value. Each segment is separated by an underscore character (_). The key that makes this value a bit confusing is that it relies on the parent NamingContainer’s ClientID to build its own ClientID value. This effectively means that the value is not predictable at all but rather very tightly coupled to the parent naming container’s ClientIDMode setting. For my simple textbox example, if the ClientIDMode property of the parent naming container (Page in this case) is set to “Predictable” you’ll get this: <input name="ctl00$content$txtName" type="text"         id="content_txtName" /> which gives an id that based on walking up to the currently active naming container (the MasterPage content container) and starting the id formatting from there downward. Think of this as a semi unique name that’s guaranteed unique only for the naming container. If, on the other hand, the Page is set to “AutoID” you get the following with Predictable on txtName: <input name="ctl00$content$txtName" type="text"         id="ctl00_content_txtName" /> The latter is effectively the same as if you specified AutoID because it inherits the AutoID naming from the Page and Content Master Page control of the page. But again - predictable behavior always depends on the parent naming container and how it generates its id, so the id may not always be exactly the same as the AutoID generated value because somewhere in the NamingContainer chain the ClientIDMode setting may be set to a different value. For example, if you had another naming container in the middle that was set to Static you’d end up effectively with an id that starts with the NamingContainers id rather than the whole ctl000_content munging. The most common use for Predictable is likely to be for data-bound controls, which results in each data bound item getting a unique ClientID. Unfortunately, even here the behavior can be very unpredictable depending on which data-bound control you use - I found significant differences in how template controls in a GridView behave from those that are used in a ListView control. For example, GridView creates clean child ClientIDs, while ListView still has a naming container in the ClientID, presumably because of the template container on which you can’t set ClientIDMode. Predictable is useful, but only if all naming containers down the chain use this setting. Otherwise you’re right back to the munged ids that are pretty unpredictable. Another property, ClientIDRowSuffix, can be used in combination with ClientIDMode of Predictable to force a suffix onto list client controls. For example: <asp:GridView runat="server" ID="gvItems"              AutoGenerateColumns="false"             ClientIDMode="Static"              ClientIDRowSuffix="Id">     <Columns>     <asp:TemplateField>         <ItemTemplate>             <asp:Label runat="server" id="txtName"                        Text='<%# Eval("Name") %>'                   ClientIDMode="Predictable"/>         </ItemTemplate>     </asp:TemplateField>     <asp:TemplateField>         <ItemTemplate>         <asp:Label runat="server" id="txtId"                     Text='<%# Eval("Id") %>'                     ClientIDMode="Predictable" />         </ItemTemplate>     </asp:TemplateField>     </Columns>  </asp:GridView> generates client Ids inside of a column in the master page described earlier: <td>     <span id="txtName_0">Rick</span> </td> where the value after the underscore is the ClientIDRowSuffix field - in this case “Id” of the item data bound to the control. Note that all of the child controls require ClientIDMode=”Predictable” in order for the ClientIDRowSuffix to be applied, and the parent GridView controls need to be set to Static either explicitly or via Naming Container inheritance to give these simple names. It’s a bummer that ClientIDRowSuffix doesn’t work with Static to produce this automatically. Another real problem is that other controls process the ClientIDMode differently. For example, a ListView control processes the Predictable ClientIDMode differently and produces the following with the Static ListView and Predictable child controls: <span id="ctrl0_txtName_0">Rick</span> I couldn’t even figure out a way using ClientIDMode to get a simple ID that also uses a suffix short of falling back to manually generated ids using <%= %> expressions instead. Given the inconsistencies inside of list controls using <%= %>, ids for the ListView might not be a bad idea anyway. Inherit The final setting is Inherit, which is the default for all controls except Page. This means that controls by default inherit the parent naming container’s ClientIDMode setting. For more detailed information on ClientID behavior and different scenarios you can check out a blog post of mine on this subject: http://www.west-wind.com/weblog/posts/54760.aspx. ClientID Enhancements Summary The ClientIDMode property is a welcome addition to ASP.NET 4.0. To me this is probably the most useful WebForms feature as it allows me to generate clean IDs simply by setting ClientIDMode="Static" on either the page or inside of Web.config (in the Pages section) which applies the setting down to the entire page which is my 95% scenario. For the few cases when it matters - for list controls and inside of multi-use user controls or custom server controls) - I can use Predictable or even AutoID to force controls to unique names. For application-level page development, this is easy to accomplish and provides maximum usability for working with client script code against page controls. ViewStateMode Another area of large criticism for WebForms is ViewState. ViewState is used internally by ASP.NET to persist page-level changes to non-postback properties on controls as pages post back to the server. It’s a useful mechanism that works great for the overall mechanics of WebForms, but it can also cause all sorts of overhead for page operation as ViewState can very quickly get out of control and consume huge amounts of bandwidth in your page content. ViewState can also wreak havoc with client-side scripting applications that modify control properties that are tracked by ViewState, which can produce very unpredictable results on a Postback after client-side updates. Over the years in my own development, I’ve often turned off ViewState on pages to reduce overhead. Yes, you lose some functionality, but you can easily implement most of the common functionality in non-ViewState workarounds. Relying less on heavy ViewState controls and sticking with simpler controls or raw HTML constructs avoids getting around ViewState problems. In ASP.NET 3.x and prior, it wasn’t easy to control ViewState - you could turn it on or off and if you turned it off at the page or web.config level, you couldn’t turn it back on for specific controls. In short, it was an all or nothing approach. With ASP.NET 4.0, the new ViewStateMode property gives you more control. It allows you to disable ViewState globally either on the page or web.config level and then turn it back on for specific controls that might need it. ViewStateMode only works when EnableViewState="true" on the page or web.config level (which is the default). You can then use ViewStateMode of Disabled, Enabled or Inherit to control the ViewState settings on the page. If you’re shooting for minimal ViewState usage, the ideal situation is to set ViewStateMode to disabled on the Page or web.config level and only turn it back on particular controls: <%@Page Language="C#"      CodeBehind="WebForm2.aspx.cs"     Inherits="Westwind.WebStore.WebForm2"        ClientIDMode="Static"                ViewStateMode="Disabled"     EnableViewState="true"  %> <!-- this control has viewstate  --> <asp:TextBox runat="server" ID="txtName"  ViewStateMode="Enabled" />       <!-- this control has no viewstate - it inherits  from parent container --> <asp:TextBox runat="server" ID="txtAddress" /> Note that the EnableViewState="true" at the Page level isn’t required since it’s the default, but it’s important that the value is true. ViewStateMode has no effect if EnableViewState="false" at the page level. The main benefit of ViewStateMode is that it allows you to more easily turn off ViewState for most of the page and enable only a few key controls that might need it. For me personally, this is a perfect combination as most of my WebForm apps can get away without any ViewState at all. But some controls - especially third party controls - often don’t work well without ViewState enabled, and now it’s much easier to selectively enable controls rather than the old way, which required you to pretty much turn off ViewState for all controls that you didn’t want ViewState on. Inline HTML Encoding HTML encoding is an important feature to prevent cross-site scripting attacks in data entered by users on your site. In order to make it easier to create HTML encoded content, ASP.NET 4.0 introduces a new Expression syntax using <%: %> to encode string values. The encoding expression syntax looks like this: <%: "<script type='text/javascript'>" +     "alert('Really?');</script>" %> which produces properly encoded HTML: &lt;script type=&#39;text/javascript&#39; &gt;alert(&#39;Really?&#39;);&lt;/script&gt; Effectively this is a shortcut to: <%= HttpUtility.HtmlEncode( "<script type='text/javascript'>" + "alert('Really?');</script>") %> Of course the <%: %> syntax can also evaluate expressions just like <%= %> so the more common scenario applies this expression syntax against data your application is displaying. Here’s an example displaying some data model values: <%: Model.Address.Street %> This snippet shows displaying data from your application’s data store or more importantly, from data entered by users. Anything that makes it easier and less verbose to HtmlEncode text is a welcome addition to avoid potential cross-site scripting attacks. Although I listed Inline HTML Encoding here under WebForms, anything that uses the WebForms rendering engine including ASP.NET MVC, benefits from this feature. ScriptManager Enhancements The ASP.NET ScriptManager control in the past has introduced some nice ways to take programmatic and markup control over script loading, but there were a number of shortcomings in this control. The ASP.NET 4.0 ScriptManager has a number of improvements that make it easier to control script loading and addresses a few of the shortcomings that have often kept me from using the control in favor of manual script loading. The first is the AjaxFrameworkMode property which finally lets you suppress loading the ASP.NET AJAX runtime. Disabled doesn’t load any ASP.NET AJAX libraries, but there’s also an Explicit mode that lets you pick and choose the library pieces individually and reduce the footprint of ASP.NET AJAX script included if you are using the library. There’s also a new EnableCdn property that forces any script that has a new WebResource attribute CdnPath property set to a CDN supplied URL. If the script has this Attribute property set to a non-null/empty value and EnableCdn is enabled on the ScriptManager, that script will be served from the specified CdnPath. [assembly: WebResource(    "Westwind.Web.Resources.ww.jquery.js",    "application/x-javascript",    CdnPath =  "http://mysite.com/scripts/ww.jquery.min.js")] Cool, but a little too static for my taste since this value can’t be changed at runtime to point at a debug script as needed, for example. Assembly names for loading scripts from resources can now be simple names rather than fully qualified assembly names, which make it less verbose to reference scripts from assemblies loaded from your bin folder or the assembly reference area in web.config: <asp:ScriptManager runat="server" id="Id"          EnableCdn="true"         AjaxFrameworkMode="disabled">     <Scripts>         <asp:ScriptReference          Name="Westwind.Web.Resources.ww.jquery.js"         Assembly="Westwind.Web" />     </Scripts>        </asp:ScriptManager> The ScriptManager in 4.0 also supports script combining via the CompositeScript tag, which allows you to very easily combine scripts into a single script resource served via ASP.NET. Even nicer: You can specify the URL that the combined script is served with. Check out the following script manager markup that combines several static file scripts and a script resource into a single ASP.NET served resource from a static URL (allscripts.js): <asp:ScriptManager runat="server" id="Id"          EnableCdn="true"         AjaxFrameworkMode="disabled">     <CompositeScript          Path="~/scripts/allscripts.js">         <Scripts>             <asp:ScriptReference                    Path="~/scripts/jquery.js" />             <asp:ScriptReference                    Path="~/scripts/ww.jquery.js" />             <asp:ScriptReference            Name="Westwind.Web.Resources.editors.js"                 Assembly="Westwind.Web" />         </Scripts>     </CompositeScript> </asp:ScriptManager> When you render this into HTML, you’ll see a single script reference in the page: <script src="scripts/allscripts.debug.js"          type="text/javascript"></script> All you need to do to make this work is ensure that allscripts.js and allscripts.debug.js exist in the scripts folder of your application - they can be empty but the file has to be there. This is pretty cool, but you want to be real careful that you use unique URLs for each combination of scripts you combine or else browser and server caching will easily screw you up royally. The script manager also allows you to override native ASP.NET AJAX scripts now as any script references defined in the Scripts section of the ScriptManager trump internal references. So if you want custom behavior or you want to fix a possible bug in the core libraries that normally are loaded from resources, you can now do this simply by referencing the script resource name in the Name property and pointing at System.Web for the assembly. Not a common scenario, but when you need it, it can come in real handy. Still, there are a number of shortcomings in this control. For one, the ScriptManager and ClientScript APIs still have no common entry point so control developers are still faced with having to check and support both APIs to load scripts so that controls can work on pages that do or don’t have a ScriptManager on the page. The CdnUrl is static and compiled in, which is very restrictive. And finally, there’s still no control over where scripts get loaded on the page - ScriptManager still injects scripts into the middle of the HTML markup rather than in the header or optionally the footer. This, in turn, means there is little control over script loading order, which can be problematic for control developers. MetaDescription, MetaKeywords Page Properties There are also a number of additional Page properties that correspond to some of the other features discussed in this column: ClientIDMode, ClientTarget and ViewStateMode. Another minor but useful feature is that you can now directly access the MetaDescription and MetaKeywords properties on the Page object to set the corresponding meta tags programmatically. Updating these values programmatically previously required either <%= %> expressions in the page markup or dynamic insertion of literal controls into the page. You can now just set these properties programmatically on the Page object in any Control derived class on the page or the Page itself: Page.MetaKeywords = "ASP.NET,4.0,New Features"; Page.MetaDescription = "This article discusses the new features in ASP.NET 4.0"; Note, that there’s no corresponding ASP.NET tag for the HTML Meta element, so the only way to specify these values in markup and access them is via the @Page tag: <%@Page Language="C#"      CodeBehind="WebForm2.aspx.cs"     Inherits="Westwind.WebStore.WebForm2"      ClientIDMode="Static"                MetaDescription="Article that discusses what's                      new in ASP.NET 4.0"     MetaKeywords="ASP.NET,4.0,New Features" %> Nothing earth shattering but quite convenient. Visual Studio 2010 Enhancements for Web Development For Web development there are also a host of editor enhancements in Visual Studio 2010. Some of these are not Web specific but they are useful for Web developers in general. Text Editors Throughout Visual Studio 2010, the text editors have all been updated to a new core engine based on WPF which provides some interesting new features for various code editors including the nice ability to zoom in and out with Ctrl-MouseWheel to quickly change the size of text. There are many more API options to control the editor and although Visual Studio 2010 doesn’t yet use many of these features, we can look forward to enhancements in add-ins and future editor updates from the various language teams that take advantage of the visual richness that WPF provides to editing. On the negative side, I’ve noticed that occasionally the code editor and especially the HTML and JavaScript editors will lose the ability to use various navigation keys like arrows, back and delete keys, which requires closing and reopening the documents at times. This issue seems to be well documented so I suspect this will be addressed soon with a hotfix or within the first service pack. Overall though, the code editors work very well, especially given that they were re-written completely using WPF, which was one of my big worries when I first heard about the complete redesign of the editors. Multi-Targeting Visual Studio now targets all versions of the .NET framework from 2.0 forward. You can use Visual Studio 2010 to work on your ASP.NET 2, 3.0 and 3.5 applications which is a nice way to get your feet wet with the new development environment without having to make changes to existing applications. It’s nice to have one tool to work in for all the different versions. Multi-Monitor Support One cool feature of Visual Studio 2010 is the ability to drag windows out of the Visual Studio environment and out onto the desktop including onto another monitor easily. Since Web development often involves working with a host of designers at the same time - visual designer, HTML markup window, code behind and JavaScript editor - it’s really nice to be able to have a little more screen real estate to work on each of these editors. Microsoft made a welcome change in the environment. IntelliSense Snippets for HTML and JavaScript Editors The HTML and JavaScript editors now finally support IntelliSense scripts to create macro-based template expansions that have been in the core C# and Visual Basic code editors since Visual Studio 2005. Snippets allow you to create short XML-based template definitions that can act as static macros or real templates that can have replaceable values that can be embedded into the expanded text. The XML syntax for these snippets is straight forward and it’s pretty easy to create custom snippets manually. You can easily create snippets using XML and store them in your custom snippets folder (C:\Users\rstrahl\Documents\Visual Studio 2010\Code Snippets\Visual Web Developer\My HTML Snippets and My JScript Snippets), but it helps to use one of the third-party tools that exist to simplify the process for you. I use SnippetEditor, by Bill McCarthy, which makes short work of creating snippets interactively (http://snippeteditor.codeplex.com/). Note: You may have to manually add the Visual Studio 2010 User specific Snippet folders to this tool to see existing ones you’ve created. Code snippets are some of the biggest time savers and HTML editing more than anything deals with lots of repetitive tasks that lend themselves to text expansion. Visual Studio 2010 includes a slew of built-in snippets (that you can also customize!) and you can create your own very easily. If you haven’t done so already, I encourage you to spend a little time examining your coding patterns and find the repetitive code that you write and convert it into snippets. I’ve been using CodeRush for this for years, but now you can do much of the basic expansion natively for HTML and JavaScript snippets. jQuery Integration Is Now Native jQuery is a popular JavaScript library and recently Microsoft has recently stated that it will become the primary client-side scripting technology to drive higher level script functionality in various ASP.NET Web projects that Microsoft provides. In Visual Studio 2010, the default full project template includes jQuery as part of a new project including the support files that provide IntelliSense (-vsdoc files). IntelliSense support for jQuery is now also baked into Visual Studio 2010, so unlike Visual Studio 2008 which required a separate download, no further installs are required for a rich IntelliSense experience with jQuery. Summary ASP.NET 4.0 brings many useful improvements to the platform, but thankfully most of the changes are incremental changes that don’t compromise backwards compatibility and they allow developers to ease into the new features one feature at a time. None of the changes in ASP.NET 4.0 or Visual Studio 2010 are monumental or game changers. The bigger features are language and .NET Framework changes that are also optional. This ASP.NET and tools release feels more like fine tuning and getting some long-standing kinks worked out of the platform. It shows that the ASP.NET team is dedicated to paying attention to community feedback and responding with changes to the platform and development environment based on this feedback. If you haven’t gotten your feet wet with ASP.NET 4.0 and Visual Studio 2010, there’s no reason not to give it a shot now - the ASP.NET 4.0 platform is solid and Visual Studio 2010 works very well for a brand new release. Check it out. © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• Data Services Update for .NET 3.5 SP1…

  - by joelvarty

  I have started writing OData style services for a couple of clients, and I noticed that a lot of the classes in the API were missing… That’s because I needed to download the update, just having .net 3.5 sp1 wasn’t enough.. http://blogs.msdn.com/astoriateam/archive/2010/01/27/data-services-update-for-net-3-5-sp1-available-for-download.aspx   More later - joel

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• Oracle's Social Services Solution: The Citizen Demo

  - by michael.seback

  See how Oracle's Social Services Solution can transform interactions between the public and government agencies. Watch "The Citizen" demo here

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• Connect to QuickBooks from PowerBuilder using RSSBus ADO.NET Data Provider

  - by dataintegration

  The RSSBus ADO.NET providers are easy-to-use, standards based controls that can be used from any platform or development technology that supports Microsoft .NET, including Sybase PowerBuilder. In this article we show how to use the RSSBus ADO.NET Provider for QuickBooks in PowerBuilder. A similar approach can be used from PowerBuilder with other RSSBus ADO.NET Data Providers to access data from Salesforce, SharePoint, Dynamics CRM, Google, OData, etc. In this article we will show how to create a basic PowerBuilder application that performs CRUD operations using the RSSBus ADO.NET Provider for QuickBooks. Step 1: Open PowerBuilder and create a new WPF Window Application solution. Step 2: Add all the Visual Controls needed for the connection properties. Step 3: Add the DataGrid control from the .NET controls. Step 4:Configure the columns of the DataGrid control as shown below. The column bindings will depend on the table. <DataGrid AutoGenerateColumns="False" Margin="13,249,12,14" Name="datagrid1" TabIndex="70" ItemsSource="{Binding}"> <DataGrid.Columns> <DataGridTextColumn x:Name="idColumn" Binding="{Binding Path=ID}" Header="ID" Width="SizeToHeader" /> <DataGridTextColumn x:Name="nameColumn" Binding="{Binding Path=Name}" Header="Name" Width="SizeToHeader" /> ... </DataGrid.Columns> </DataGrid> Step 5:Add a reference to the RSSBus ADO.NET Provider for QuickBooks assembly. Step 6:Optional: Set the QBXML Version to 6. Some of the tables in QuickBooks require a later version of QuickBooks to support updates and deletes. Please check the help for details. Connect the DataGrid: Once the visual elements have been configured, developers can use standard ADO.NET objects like Connection, Command, and DataAdapter to populate a DataTable with the results of a SQL query: System.Data.RSSBus.QuickBooks.QuickBooksConnection conn conn = create System.Data.RSSBus.QuickBooks.QuickBooksConnection(connectionString) System.Data.RSSBus.QuickBooks.QuickBooksCommand comm comm = create System.Data.RSSBus.QuickBooks.QuickBooksCommand(command, conn) System.Data.DataTable table table = create System.Data.DataTable System.Data.RSSBus.QuickBooks.QuickBooksDataAdapter dataAdapter dataAdapter = create System.Data.RSSBus.QuickBooks.QuickBooksDataAdapter(comm) dataAdapter.Fill(table) datagrid1.ItemsSource=table.DefaultView The code above can be used to bind data from any query (set this in command), to the DataGrid. The DataGrid should have the same columns as those returned from the SELECT statement. PowerBuilder Sample Project The included sample project includes the steps outlined in this article. You will also need the QuickBooks ADO.NET Data Provider to make the connection. You can download a free trial here.

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• Develop JavaScript API to expose web services [closed]

  - by Apps

  We are planning to develop a JavaScript API to expose some of our J2EE based services. We are doing this keeping Google Maps API in mind. Can someone please suggested where we should start and the approaches that we need to follow to create a useful and extensible JavaScript API? These are the things that we are considering to achieve. It should be very simple for others to use our API. We feel Google Maps API is like that. We should be able to release the updates of the APIs without affecting the existing implementations. We should have enough security measures so that not all can use these services. Please suggest us if there are any books that can guide us through. Any suggestion will be greatly helpful for us. Please let me know if my question is not clear or you need any further information.

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• How does ASP.Net MVC differ from Classic ASP (not ASP.Net--the original ASP)

  - by LuftMensch

  I'm trying to get a high-level understanding of ASP.Net MVC, and it has started to occur to me that it looks a lot like the original ASP script. Back in the day, we were organizing our "model"/business logic code into VBScript classes, or into VB COM components. Of course, now we have the additional power of c# and the .net framework classes. Besides the high-level oo and other capabilities in c# and .Net, what are the other major differences between the original ASP and ASP.Net MVC?

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• ASP.NET: With C# or C# + VB.NET?

  - by Sahat

  I am currently reading Beginning ASP.NET 4: in C# and VB (Wrox Programmer to Programmer) and it comes with both C# and VB.NET source code. I am definitely planning to use C# in the future for most of my projects. But VB.NET - is it really worth learning side-by-side with C#? Are there such cases when VB.NET is preferred over C#?

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• ASP.NET with C# or VB.NET + C#?

  - by Sahat

  I am currently reading Beginning ASP.NET 4: in C# and VB (Wrox Programmer to Programmer) and it comes with both C# and VB.NET source code. I am definitely planning to use C# in the future for most of my projects. But VB.NET - is it worth learning side-by-side with C#? Will there be a case when VB.NET is preferred over C#?

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• DomainDataSource DataPager with silverlight 3 DataGrid & .Net RIA Services

  - by Dennis Ward

  I have a simple datagrid example with silverlight 3, and am populating it with the .NET ria services using a DomainDataSource along with a DataPager declaratively (nothing in the code-behind), and am experiencing this problem: The LoadSize is 30, and the Page size is 15, and when the page is loaded, the 1st and 2nd page appear correctly, but when I go beyond the 2nd page, nothing shows up in the grid. This used to work in the silverlight 3 beta with the Mix 2009 preview of .NET Ria services, and I've got a really simple example and have verified that the Service on the web project gets called to load a new batch, but the grid doesn't show any data. Can anyone shed any light as to why grid displays data only for the initial load of data and not subsequent batches from the pager? Here's my xaml: <riaControls:DomainDataSource x:Name="ArtistSource" QueryName="GetArtist" AutoLoad="True" LoadSize="30" PageSize="15"> <riaControls:DomainDataSource.DomainContext> <domain:AdminContext /> </riaControls:DomainDataSource.DomainContext> </riaControls:DomainDataSource> <data:DataGrid Grid.Row="1" x:Name="ArtistDataGrid" ItemsSource="{Binding Data, ElementName=ArtistSource}"> </data:DataGrid> <StackPanel Grid.Row="2"> <data:DataPager Source="{Binding Data, ElementName=ArtistSource}" /> </StackPanel>

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• How to Put Javascript into an ASP.NET MVC View

  - by Maxim Z.

  I'm really new to ASP.NET MVC, and I'm trying to integrate some Javascript into a website I'm making as a test of this technology. My question is this: how can I insert Javascript code into a View? Let's say that I start out with the default ASP.NET MVC template. In terms of Views, this creates a Master page, a "Home" View, and an "About" view. The "Home" View, called Index.aspx, looks like this: <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %> <asp:Content ID="indexTitle" ContentPlaceHolderID="TitleContent" runat="server"> Home Page </asp:Content> <asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server"> <h2><%= Html.Encode(ViewData["Message"]) %></h2> <p> To learn more about ASP.NET MVC visit <a href="http://asp.net/mvc" title="ASP.NET MVC Website">http://asp.net/mvc</a>. </p> <p>Welcome to this testing site!</p> </asp:Content> Adding a <script> tag here didn't work. Where and how should I do it? P.S.: I have a feeling I'm missing something very basic... Thanks in advance!

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• New Big Data Appliance Security Features

  - by mgubar

  The Oracle Big Data Appliance (BDA) is an engineered system for big data processing.  It greatly simplifies the deployment of an optimized Hadoop Cluster – whether that cluster is used for batch or real-time processing.  The vast majority of BDA customers are integrating the appliance with their Oracle Databases and they have certain expectations – especially around security.  Oracle Database customers have benefited from a rich set of security features:  encryption, redaction, data masking, database firewall, label based access control – and much, much more.  They want similar capabilities with their Hadoop cluster.    Unfortunately, Hadoop wasn’t developed with security in mind.  By default, a Hadoop cluster is insecure – the antithesis of an Oracle Database.  Some critical security features have been implemented – but even those capabilities are arduous to setup and configure.  Oracle believes that a key element of an optimized appliance is that its data should be secure.  Therefore, by default the BDA delivers the “AAA of security”: authentication, authorization and auditing. Security Starts at Authentication A successful security strategy is predicated on strong authentication – for both users and software services.  Consider the default configuration for a newly installed Oracle Database; it’s been a long time since you had a legitimate chance at accessing the database using the credentials “system/manager” or “scott/tiger”.  The default Oracle Database policy is to lock accounts thereby restricting access; administrators must consciously grant access to users. Default Authentication in Hadoop By default, a Hadoop cluster fails the authentication test. For example, it is easy for a malicious user to masquerade as any other user on the system.  Consider the following scenario that illustrates how a user can access any data on a Hadoop cluster by masquerading as a more privileged user.  In our scenario, the Hadoop cluster contains sensitive salary information in the file /user/hrdata/salaries.txt.  When logged in as the hr user, you can see the following files.  Notice, we’re using the Hadoop command line utilities for accessing the data: $ hadoop fs -ls /user/hrdataFound 1 items-rw-r--r--   1 oracle supergroup         70 2013-10-31 10:38 /user/hrdata/salaries.txt$ hadoop fs -cat /user/hrdata/salaries.txtTom Brady,11000000Tom Hanks,5000000Bob Smith,250000Oprah,300000000 User DrEvil has access to the cluster – and can see that there is an interesting folder called “hrdata”.  $ hadoop fs -ls /user Found 1 items drwx------   - hr supergroup          0 2013-10-31 10:38 /user/hrdata However, DrEvil cannot view the contents of the folder due to lack of access privileges: $ hadoop fs -ls /user/hrdata ls: Permission denied: user=drevil, access=READ_EXECUTE, inode="/user/hrdata":oracle:supergroup:drwx------ Accessing this data will not be a problem for DrEvil. He knows that the hr user owns the data by looking at the folder’s ACLs. To overcome this challenge, he will simply masquerade as the hr user. On his local machine, he adds the hr user, assigns that user a password, and then accesses the data on the Hadoop cluster: $ sudo useradd hr $ sudo passwd $ su hr $ hadoop fs -cat /user/hrdata/salaries.txt Tom Brady,11000000 Tom Hanks,5000000 Bob Smith,250000 Oprah,300000000 Hadoop has not authenticated the user; it trusts that the identity that has been presented is indeed the hr user. Therefore, sensitive data has been easily compromised. Clearly, the default security policy is inappropriate and dangerous to many organizations storing critical data in HDFS. Big Data Appliance Provides Secure Authentication The BDA provides secure authentication to the Hadoop cluster by default – preventing the type of masquerading described above. It accomplishes this thru Kerberos integration. Figure 1: Kerberos Integration The Key Distribution Center (KDC) is a server that has two components: an authentication server and a ticket granting service. The authentication server validates the identity of the user and service. Once authenticated, a client must request a ticket from the ticket granting service – allowing it to access the BDA’s NameNode, JobTracker, etc. At installation, you simply point the BDA to an external KDC or automatically install a highly available KDC on the BDA itself. Kerberos will then provide strong authentication for not just the end user – but also for important Hadoop services running on the appliance. You can now guarantee that users are who they claim to be – and rogue services (like fake data nodes) are not added to the system. It is common for organizations to want to leverage existing LDAP servers for common user and group management. Kerberos integrates with LDAP servers – allowing the principals and encryption keys to be stored in the common repository. This simplifies the deployment and administration of the secure environment. Authorize Access to Sensitive Data Kerberos-based authentication ensures secure access to the system and the establishment of a trusted identity – a prerequisite for any authorization scheme. Once this identity is established, you need to authorize access to the data. HDFS will authorize access to files using ACLs with the authorization specification applied using classic Linux-style commands like chmod and chown (e.g. hadoop fs -chown oracle:oracle /user/hrdata changes the ownership of the /user/hrdata folder to oracle). Authorization is applied at the user or group level – utilizing group membership found in the Linux environment (i.e. /etc/group) or in the LDAP server. For SQL-based data stores – like Hive and Impala – finer grained access control is required. Access to databases, tables, columns, etc. must be controlled. And, you want to leverage roles to facilitate administration. Apache Sentry is a new project that delivers fine grained access control; both Cloudera and Oracle are the project’s founding members. Sentry satisfies the following three authorization requirements: Secure Authorization:  the ability to control access to data and/or privileges on data for authenticated users. Fine-Grained Authorization:  the ability to give users access to a subset of the data (e.g. column) in a database Role-Based Authorization:  the ability to create/apply template-based privileges based on functional roles. With Sentry, “all”, “select” or “insert” privileges are granted to an object. The descendants of that object automatically inherit that privilege. A collection of privileges across many objects may be aggregated into a role – and users/groups are then assigned that role. This leads to simplified administration of security across the system. Figure 2: Object Hierarchy – granting a privilege on the database object will be inherited by its tables and views. Sentry is currently used by both Hive and Impala – but it is a framework that other data sources can leverage when offering fine-grained authorization. For example, one can expect Sentry to deliver authorization capabilities to Cloudera Search in the near future. Audit Hadoop Cluster Activity Auditing is a critical component to a secure system and is oftentimes required for SOX, PCI and other regulations. The BDA integrates with Oracle Audit Vault and Database Firewall – tracking different types of activity taking place on the cluster: Figure 3: Monitored Hadoop services. At the lowest level, every operation that accesses data in HDFS is captured. The HDFS audit log identifies the user who accessed the file, the time that file was accessed, the type of access (read, write, delete, list, etc.) and whether or not that file access was successful. The other auditing features include: MapReduce:  correlate the MapReduce job that accessed the file Oozie:  describes who ran what as part of a workflow Hive:  captures changes were made to the Hive metadata The audit data is captured in the Audit Vault Server – which integrates audit activity from a variety of sources, adding databases (Oracle, DB2, SQL Server) and operating systems to activity from the BDA. Figure 4: Consolidated audit data across the enterprise.  Once the data is in the Audit Vault server, you can leverage a rich set of prebuilt and custom reports to monitor all the activity in the enterprise. In addition, alerts may be defined to trigger violations of audit policies. Conclusion Security cannot be considered an afterthought in big data deployments. Across most organizations, Hadoop is managing sensitive data that must be protected; it is not simply crunching publicly available information used for search applications. The BDA provides a strong security foundation – ensuring users are only allowed to view authorized data and that data access is audited in a consolidated framework.

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• .net 4.5 Asp Mvc -> Error 403.14- IIS 7 - Windows Server 2008 R2

  - by Boas Enkler

  When I want to deploy an MVC 4 (.net 4.5) application to my iis i got the 403.14 calling me that the content ist not browseable. This also occurs when i deploy the unchanged mvc 4 template. when using the mvc 4 template with .net 4.0 everything works. I checked the other posts but can't figure out the solution. ist set i ran aspnet_regiss -i which completed without any errors. the only strange thing is that .net 4.5 is installed in the .net 4.0 directory %windows%/microsoft.net/Framework64/4.0.30319 From this folder i also ran aspnet_regiis. to ensure that 4.5 is installed i restarted the .net 4.5 setup and it tells me taht it is installes Also the apppools show me 4.0.30319 as version. There is an other application targeting mvc with 4.5 which runs. but i don't know wether it was created with a 4.0 templated and retargeted to 4.5 Any hints? The app.config is the unchanged default from the mvc 4 template. I just tested to create a subfolder which i convert to an application. placing the site there makes it working. But why not on root folder?

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• How to present a stable data model in a public API that allows internal data structures to be changed without breaking the public view of the data?

  - by Max Palmer

  I am in the process of developing an application that allows users to write C# scripts. These scripts allow users to call selected methods and to access and manipulate data in a document. This works well, however, in the development version, scripts access the document's (internal) data structures directly. This means that if we were to change the internal data model/structure, there is a good chance that someone's script will no longer compile. We obviously want to prevent this breaking change from happening, but still want to allow the user to write sensible C# code (whilst not restricting how we develop our internal data model as a result). We therefore need to decouple our scripting API and its data structures from our internal methods and data structures. We've a few ideas as to how we might allow the user to access a what is effectively a stable public version of the document's internal data*, but I wanted to throw the question out there to someone who might have some real experience of this problem. NB our internal document's data structure is quite complex and it could be quite difficult to wrap. We know we want to expose as little as possible in our public API, especially as once it's out there, it's out there for good. Can anyone help? How do scripting languages / APIs decouple their public API and data structures from their internal data structures? Is there no real alternative to having to write a complex interaction layer? If we need to do this, what's a good approach or pattern for wrapping complex data structures that include nested objects, including collections? I've looked at the API facade pattern, which looks like it's trying to address these kinds of issues, but are there alternatives? *One idea is to build a data facade that is kept stable across versions of our application. The facade exposes a set of facade data objects that are used in the script code. These maintain backwards compatibility and wrap access to our internal document's data model.

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• Parallelism in .NET – Part 14, The Different Forms of Task

  - by Reed

  Before discussing Task creation and actual usage in concurrent environments, I will briefly expand upon my introduction of the Task class and provide a short explanation of the distinct forms of Task.  The Task Parallel Library includes four distinct, though related, variations on the Task class. In my introduction to the Task class, I focused on the most basic version of Task.  This version of Task, the standard Task class, is most often used with an Action delegate.  This allows you to implement for each task within the task decomposition as a single delegate. Typically, when using the new threading constructs in .NET 4 and the Task Parallel Library, we use lambda expressions to define anonymous methods.  The advantage of using a lambda expression is that it allows the Action delegate to directly use variables in the calling scope.  This eliminates the need to make separate Task classes for Action<T>, Action<T1,T2>, and all of the other Action<…> delegate types.  As an example, suppose we wanted to make a Task to handle the ”Show Splash” task from our earlier decomposition.  Even if this task required parameters, such as a message to display, we could still use an Action delegate specified via a lambda: // Store this as a local variable string messageForSplashScreen = GetSplashScreenMessage(); // Create our task Task showSplashTask = new Task( () => { // We can use variables in our outer scope, // as well as methods scoped to our class! this.DisplaySplashScreen(messageForSplashScreen); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This provides a huge amount of flexibility.  We can use this single form of task for any task which performs an operation, provided the only information we need to track is whether the task has completed successfully or not.  This leads to my first observation: Use a Task with a System.Action delegate for any task for which no result is generated. This observation leads to an obvious corollary: we also need a way to define a task which generates a result.  The Task Parallel Library provides this via the Task<TResult> class. Task<TResult> subclasses the standard Task class, providing one additional feature – the ability to return a value back to the user of the task.  This is done by switching from providing an Action delegate to providing a Func<TResult> delegate.  If we decompose our problem, and we realize we have one task where its result is required by a future operation, this can be handled via Task<TResult>.  For example, suppose we want to make a task for our “Check for Update” task, we could do: Task<bool> checkForUpdateTask = new Task<bool>( () => { return this.CheckWebsiteForUpdate(); }); Later, we would start this task, and perform some other work.  At any point in the future, we could get the value from the Task<TResult>.Result property, which will cause our thread to block until the task has finished processing: // This uses Task<bool> checkForUpdateTask generated above... // Start the task, typically on a background thread checkForUpdateTask.Start(); // Do some other work on our current thread this.DoSomeWork(); // Discover, from our background task, whether an update is available // This will block until our task completes bool updateAvailable = checkForUpdateTask.Result; This leads me to my second observation: Use a Task<TResult> with a System.Func<TResult> delegate for any task which generates a result. Task and Task<TResult> provide a much cleaner alternative to the previous Asynchronous Programming design patterns in the .NET framework.  Instead of trying to implement IAsyncResult, and providing BeginXXX() and EndXXX() methods, implementing an asynchronous programming API can be as simple as creating a method that returns a Task or Task<TResult>.  The client side of the pattern also is dramatically simplified – the client can call a method, then either choose to call task.Wait() or use task.Result when it needs to wait for the operation’s completion. While this provides a much cleaner model for future APIs, there is quite a bit of infrastructure built around the current Asynchronous Programming design patterns.  In order to provide a model to work with existing APIs, two other forms of Task exist.  There is a constructor for Task which takes an Action<Object> and a state parameter.  In addition, there is a constructor for creating a Task<TResult> which takes a Func<Object, TResult> as well as a state parameter.  When using these constructors, the state parameter is stored in the Task.AsyncState property. While these two overloads exist, and are usable directly, I strongly recommend avoiding this for new development.  The two forms of Task which take an object state parameter exist primarily for interoperability with traditional .NET Asynchronous Programming methodologies.  Using lambda expressions to capture variables from the scope of the creator is a much cleaner approach than using the untyped state parameters, since lambda expressions provide full type safety without introducing new variables.

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• SSRS ReportViewer 2010 Iframe IE Problem

  - by Phil

  Hello all, My problem relates to trying to include an SSRS (SQL Server) Report inside my MVC application. I've settled on the hybrid solution of having a WebForm with the ReportViewer Control in and then on my MVC View pages having an iframe reference this WebForm page. The tricky part is that the iframe needs to be dynamically populated with the report rather than using src due to posting parameters to the WebForm. It works perfectly in Firefox and Chrome, however IE throws a "Sys is Undefined" javascript error. Using src on the iframe works in IE, but I can't find a way to post parameters (don't want to use something like /Report.aspx?param1=test due to the possible length). Its a ASP.NET MVC 2 project, .NET 4, Visual Studio 2010 on Windows 7 x74 if its any help. So here is the code (I could provide the VS2010 project files if anyone wants them) In my webform: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Report.aspx.cs" Inherits="SSRSMVC.Views.Home.Report" %> <%@ Register Assembly="Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" Namespace="Microsoft.Reporting.WebForms" TagPrefix="rsweb" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <body> <form id="RSForm" runat="server"> <asp:ScriptManager ID="ScriptManager" runat="server" EnablePartialRendering="true" ScriptMode="Release"> </asp:ScriptManager> <asp:UpdatePanel ID="ReportViewerUP" runat="server"> <ContentTemplate> <rsweb:ReportViewer ID="ReportViewer" runat="server" Width="100%" Height="380px" ProcessingMode="Local" InteractivityPostBackMode="AlwaysAsynchronous" AsyncRendering="true"> <LocalReport ReportPath="Models\\TestReport.rdlc"> </LocalReport> </rsweb:ReportViewer> </ContentTemplate> </asp:UpdatePanel> </form> </body> </html> And Codebehind: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using Microsoft.Reporting.WebForms; namespace SSRSMVC.Views.Home { public partial class Report : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { string test = Request.Params["val1"]; ReportViewer.LocalReport.DataSources.Add(new ReportDataSource("DataSet1", new SSRSMVC.Models.DataProvider().GetData())); } } } } And lastly my View page, <script type="text/javascript"> $(window).load(function () { $.post('/Report.aspx', { val1: "Hello World" }, function (data) { var rv_frame = document.getElementById('Frame1'); rv_frame = (rv_frame.contentWindow) ? rv_frame.contentWindow : (rv_frame.contentDocument.document) ? rv_frame.contentDocument.document : rv_frame.contentDocument; rv_frame.document.open(); rv_frame.document.write(data); rv_frame.document.close(); }); }); </script>

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• How do I authenticate an ADO.NET Data Service?

  - by lsb

  Hi! I've created an ADO.Net Data Service hosted in a Azure worker role. I want to pass credentials from a simple console client to the service then validate them using a QueryInterceptor. Unfortunately, the credentials don't seem to be making it over the wire. The following is a simplified version of the code I'm using, starting with the DataService on the server: using System; using System.Data.Services; using System.Linq.Expressions; using System.ServiceModel; using System.Web; namespace Oslo.Worker { [ServiceBehavior(AddressFilterMode = AddressFilterMode.Any)] public class AdminService : DataService<OsloEntities> { public static void InitializeService( IDataServiceConfiguration config) { config.SetEntitySetAccessRule("*", EntitySetRights.All); config.SetServiceOperationAccessRule("*", ServiceOperationRights.All); } [QueryInterceptor("Pairs")] public Expression<Func<Pair, bool>> OnQueryPairs() { // This doesn't work!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! if (HttpContext.Current.User.Identity.Name != "ADMIN") throw new Exception("Ooops!"); return p => true; } } } Here's the AdminService I'm using to instantiate the AdminService in my Azure worker role: using System; using System.Data.Services; namespace Oslo.Worker { public class AdminHost : DataServiceHost { public AdminHost(Uri baseAddress) : base(typeof(AdminService), new Uri[] { baseAddress }) { } } } And finally, here's the client code. using System; using System.Data.Services.Client; using System.Net; using Oslo.Shared; namespace Oslo.ClientTest { public class AdminContext : DataServiceContext { public AdminContext(Uri serviceRoot, string userName, string password) : base(serviceRoot) { Credentials = new NetworkCredential(userName, password); } public DataServiceQuery<Order> Orders { get { return base.CreateQuery<Pair>("Orders"); } } } } I should mention that the code works great with the signal exception that the credentials are not being passed over the wire. Any help in this regard would be greatly appreciated! Thanks....

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• SQL Server 2008 Express + Reporting Services on Windows 7

  - by TimothyP

  I'm trying to install SQL Server Express 2008 and Reporting Services on a x64 Windows 7 Machine for development purposes. I've installed SQL Server 2008 Express with the Microsoft Web Platform Installer I had to manually enable the SQL Server Browser in the Sql Server Configuration Manager and tried to enable the SQL Server Agent but that simply doesn't work. Keeps throwing an RPC error: "The remote procedure call failed. [0x800706be]". The start mode is set to Disabled and I cannot change it. Even though I selected the SQL Server Express with advanced services in the web platform installer I could not find any reference to SQL Server Reporting Services so I used the SQL Server Installation Center x64 application to "upgrade" to SQL Server Express 2008 with advanced services... this installed many things but still I couldn't find any reference to SQL Server Reporting Services other than an application called: "Reporting Services Configuration Manager" This opens up a dialog called "Reporting Services Configuration Connection" which is asking for a server name (shows the name of my machine) and a Find button. When I click the find button I get: "Unable to connect to the Reporting Server WMI provider. Details: Invalid Namespace". I found some references on the web to solve this problem, but they refer to a directory: "%ProgamFiles%\Microsoft SQL Server\MSRS10.SQL2008\Reporting Services\" which does not exist anywhere on my system. (The directories for SQL Server are there, but there is no Reporting Services directory anywhere). What am I doing wrong here? Wasn't the web platform installer supposed to handle all this? Thnx for any advice. PS: Most google results refer to 2005 vs 2008 problems, but I never had 2005 installed on this system, it's a newly installed development machine.

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• .NET asmx web services: serialize object property as string property to support versioning

  - by mcliedtk

  I am in the process of upgrading our web services to support versioning. We will be publishing our versioned web services like so: http://localhost/project/services/1.0/service.asmx http://localhost/project/services/1.1/service.asmx One requirement of this versioning is that I am not allowed to break the original wsdl (the 1.0 wsdl). The challenge lies in how to shepherd the newly versioned classes through the logic that lies behind the web services (this logic includes a number of command and adapter classes). Note that upgrading to WCF is not an option at the moment. To illustrate this, let's consider an example with Blogs and Posts. Prior to the introduction of versions, we were passing concrete objects around instead of interfaces. So an AddPostToBlog command would take in a Post object instead of an IPost. // Old AddPostToBlog constructor. public AddPostToBlog(Blog blog, Post post) { // constructor body } With the introduction of versioning, I would like to maintain the original Post while adding a PostOnePointOne. Both Post and PostOnePointOne will implement the IPost interface (they are not extending an abstract class because that inheritance breaks the wsdl, though I suppose there may be a way around that via some fancy xml serialization tricks). // New AddPostToBlog constructor. public AddPostToBlog(Blog blog, IPost post) { // constructor body } This brings us to my question regarding serialization. The original Post class has an enum property named Type. For various cross-platform compatibility issues, we are changing our enums in our web services to strings. So I would like to do the following: // New IPost interface. public interface IPost { object Type { get; set; } } // Original Post object. public Post { // The purpose of this attribute would be to maintain how // the enum currently is serialized even though now the // type is an object instead of an enum (internally the // object actually is an enum here, but it is exposed as // an object to implement the interface). [XmlMagic(SerializeAsEnum)] object Type { get; set; } } // New version of Post object public PostOnePointOne { // The purpose of this attribute would be to force // serialization as a string even though it is an object. [XmlMagic(SerializeAsString)] object Type { get; set; } } The XmlMagic refers to an XmlAttribute or some other part of the System.Xml namespace that would allow me to control the type of the object property being serialized (depending on which version of the object I am serializaing). Does anyone know how to accomplish this?

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