Search Results

Search found 24900 results on 996 pages for 'call me steve'.

Page 485/996 | < Previous Page | 481 482 483 484 485 486 487 488 489 490 491 492  | Next Page >

• How to fix Solr - Server is shutting down issue?

  - by Krunal

  I was having a running Solr 4.1 on Windows Server 2008 R2. The Solr is deployed on Tomcat. However, today it stops suddenly, and while accessing Solr it gives following error. HTTP Status 503 - Server is shutting down type Status report message Server is shutting down description The requested service is not currently available. On further looking into Logs, we got following: Log File: tomcat7-stderr.2013-05-09.txt May 09, 2013 8:00:40 PM org.apache.solr.core.CoreContainer finalize SEVERE: CoreContainer was not shutdown prior to finalize(), indicates a bug -- POSSIBLE RESOURCE LEAK!!! instance=2221663 Log File: catalina.2013-05-09.txt May 09, 2013 7:59:25 PM org.apache.solr.core.SolrResourceLoader <init> INFO: new SolrResourceLoader for directory: 'c:\solrdir\' May 09, 2013 7:59:29 PM org.apache.solr.common.SolrException log SEVERE: Exception during parsing file: null:org.xml.sax.SAXParseException; systemId: file:/c:/solr/solr.xml; lineNumber: 2; columnNumber: 6; The processing instruction target matching "[xX][mM][lL]" is not allowed. at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source) at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLScanner.scanPIData(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanPIData(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLScanner.scanPI(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source) at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source) at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(Unknown Source) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(Unknown Source) at org.apache.solr.core.Config.<init>(Config.java:121) at org.apache.solr.core.CoreContainer.load(CoreContainer.java:428) at org.apache.solr.core.CoreContainer.load(CoreContainer.java:404) at org.apache.solr.core.CoreContainer$Initializer.initialize(CoreContainer.java:336) at org.apache.solr.servlet.SolrDispatchFilter.init(SolrDispatchFilter.java:98) at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:281) at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:262) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:107) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4656) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5309) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633) at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:977) at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1655) at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) May 09, 2013 7:59:29 PM org.apache.solr.servlet.SolrDispatchFilter init SEVERE: Could not start Solr. Check solr/home property and the logs May 09, 2013 7:59:29 PM org.apache.solr.common.SolrException log SEVERE: null:org.apache.solr.common.SolrException: at org.apache.solr.core.CoreContainer.load(CoreContainer.java:431) at org.apache.solr.core.CoreContainer.load(CoreContainer.java:404) at org.apache.solr.core.CoreContainer$Initializer.initialize(CoreContainer.java:336) at org.apache.solr.servlet.SolrDispatchFilter.init(SolrDispatchFilter.java:98) at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:281) at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:262) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:107) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4656) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5309) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633) at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:977) at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1655) at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: org.xml.sax.SAXParseException; systemId: file:/c:/solrdir/solr.xml; lineNumber: 2; columnNumber: 6; The processing instruction target matching "[xX][mM][lL]" is not allowed. at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source) at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLScanner.scanPIData(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanPIData(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLScanner.scanPI(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(Unknown Source) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source) at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source) at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(Unknown Source) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(Unknown Source) at org.apache.solr.core.Config.<init>(Config.java:121) at org.apache.solr.core.CoreContainer.load(CoreContainer.java:428) ... 20 more May 09, 2013 7:59:29 PM org.apache.solr.servlet.SolrDispatchFilter init INFO: SolrDispatchFilter.init() done May 09, 2013 7:59:29 PM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory C:\Program Files (x86)\Apache Software Foundation\Tomcat 7.0\webapps\docs May 09, 2013 7:59:30 PM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory C:\Program Files (x86)\Apache Software Foundation\Tomcat 7.0\webapps\manager May 09, 2013 7:59:30 PM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory C:\Program Files (x86)\Apache Software Foundation\Tomcat 7.0\webapps\ROOT May 09, 2013 7:59:30 PM org.apache.coyote.AbstractProtocol start INFO: Starting ProtocolHandler ["http-bio-8983"] May 09, 2013 7:59:30 PM org.apache.coyote.AbstractProtocol start INFO: Starting ProtocolHandler ["ajp-bio-8009"] May 09, 2013 7:59:30 PM org.apache.catalina.startup.Catalina start INFO: Server startup in 9578 ms May 09, 2013 8:00:40 PM org.apache.solr.core.CoreContainer finalize SEVERE: CoreContainer was not shutdown prior to finalize(), indicates a bug -- POSSIBLE RESOURCE LEAK!!! instance=2221663 Any idea what could be wrong and how to fix?

  Read the article

• Python version issues

  - by MidnightLightning

  I have a Mac which uses MacPorts to have multiple versions of Python installed and use the python_select application to switch between them. Currently, this Mac has OS 10.6.6, which comes with Python 2.6.1 installed as /usr/bin/python. Using MacPorts, I've installed the python27, python31, and python_select ports and now have this issue: python_select seems to not be switching the default python properly: $ which python /usr/bin/python $ python -V Python 2.6.1 $ /usr/bin/python -V Python 2.6.1 $ sudo python_select python27 Selecting version "python27" for python $ which python /opt/local/bin/python $ ls -l /opt/local/bin/python lrwxr-xr-x 1 root admin 24B Mar 18 10:24 /opt/local/bin/python -> /opt/local/bin/python2.7 $ python -V Python 2.6.1 # <-- Wrong!!! $ /opt/local/bin/python -V Python 2.7.1 # <-- Why are you not default? So, after running python_select, which python seems to think that the /opt/local/bin version is going to be used, but in reality, it seems that the /usr/bin one is taking precedent unless I specifically call the /opt/local/bin one. Is there something I'm doing wrong?

  Read the article

• Using a WPF ListView as a DataGrid

  - by psheriff

  Many people like to view data in a grid format of rows and columns. WPF did not come with a data grid control that automatically creates rows and columns for you based on the object you pass it. However, the WPF Toolkit can be downloaded from CodePlex.com that does contain a DataGrid control. This DataGrid gives you the ability to pass it a DataTable or a Collection class and it will automatically figure out the columns or properties and create all the columns for you and display the data.The DataGrid control also supports editing and many other features that you might not always need. This means that the DataGrid does take a little more time to render the data. If you want to just display data (see Figure 1) in a grid format, then a ListView works quite well for this task. Of course, you will need to create the columns for the ListView, but with just a little generic code, you can create the columns on the fly just like the WPF Toolkit’s DataGrid. Figure 1: A List of Data using a ListView A Simple ListView ControlThe XAML below is what you would use to create the ListView shown in Figure 1. However, the problem with using XAML is you have to pre-define the columns. You cannot re-use this ListView except for “Product” data. <ListView x:Name="lstData"          ItemsSource="{Binding}">  <ListView.View>    <GridView>      <GridViewColumn Header="Product ID"                      Width="Auto"               DisplayMemberBinding="{Binding Path=ProductId}" />      <GridViewColumn Header="Product Name"                      Width="Auto"               DisplayMemberBinding="{Binding Path=ProductName}" />      <GridViewColumn Header="Price"                      Width="Auto"               DisplayMemberBinding="{Binding Path=Price}" />    </GridView>  </ListView.View></ListView> So, instead of creating the GridViewColumn’s in XAML, let’s learn to create them in code to create any amount of columns in a ListView. Create GridViewColumn’s From Data TableTo display multiple columns in a ListView control you need to set its View property to a GridView collection object. You add GridViewColumn objects to the GridView collection and assign the GridView to the View property. Each GridViewColumn object needs to be bound to a column or property name of the object that the ListView will be bound to. An ADO.NET DataTable object contains a collection of columns, and these columns have a ColumnName property which you use to bind to the GridViewColumn objects. Listing 1 shows a sample of reading and XML file into a DataSet object. After reading the data a GridView object is created. You can then loop through the DataTable columns collection and create a GridViewColumn object for each column in the DataTable. Notice the DisplayMemberBinding property is set to a new Binding to the ColumnName in the DataTable. C#private void FirstSample(){  // Read the data  DataSet ds = new DataSet();  ds.ReadXml(GetCurrentDirectory() + @"\Xml\Product.xml");    // Create the GridView  GridView gv = new GridView();   // Create the GridView Columns  foreach (DataColumn item in ds.Tables[0].Columns)  {    GridViewColumn gvc = new GridViewColumn();    gvc.DisplayMemberBinding = new Binding(item.ColumnName);    gvc.Header = item.ColumnName;    gvc.Width = Double.NaN;    gv.Columns.Add(gvc);  }   // Setup the GridView Columns  lstData.View = gv;  // Display the Data  lstData.DataContext = ds.Tables[0];} VB.NETPrivate Sub FirstSample()  ' Read the data  Dim ds As New DataSet()  ds.ReadXml(GetCurrentDirectory() & "\Xml\Product.xml")   ' Create the GridView  Dim gv As New GridView()   ' Create the GridView Columns  For Each item As DataColumn In ds.Tables(0).Columns    Dim gvc As New GridViewColumn()    gvc.DisplayMemberBinding = New Binding(item.ColumnName)    gvc.Header = item.ColumnName    gvc.Width = [Double].NaN    gv.Columns.Add(gvc)  Next   ' Setup the GridView Columns  lstData.View = gv  ' Display the Data  lstData.DataContext = ds.Tables(0)End SubListing 1: Loop through the DataTable columns collection to create GridViewColumn objects A Generic Method for Creating a GridViewInstead of having to write the code shown in Listing 1 for each ListView you wish to create, you can create a generic method that given any DataTable will return a GridView column collection. Listing 2 shows how you can simplify the code in Listing 1 by setting up a class called WPFListViewCommon and create a method called CreateGridViewColumns that returns your GridView. C#private void DataTableSample(){  // Read the data  DataSet ds = new DataSet();  ds.ReadXml(GetCurrentDirectory() + @"\Xml\Product.xml");   // Setup the GridView Columns  lstData.View =      WPFListViewCommon.CreateGridViewColumns(ds.Tables[0]);  lstData.DataContext = ds.Tables[0];} VB.NETPrivate Sub DataTableSample()  ' Read the data  Dim ds As New DataSet()  ds.ReadXml(GetCurrentDirectory() & "\Xml\Product.xml")   ' Setup the GridView Columns  lstData.View = _      WPFListViewCommon.CreateGridViewColumns(ds.Tables(0))  lstData.DataContext = ds.Tables(0)End SubListing 2: Call a generic method to create GridViewColumns. The CreateGridViewColumns MethodThe CreateGridViewColumns method will take a DataTable as a parameter and create a GridView object with a GridViewColumn object in its collection for each column in your DataTable. C#public static GridView CreateGridViewColumns(DataTable dt){  // Create the GridView  GridView gv = new GridView();  gv.AllowsColumnReorder = true;   // Create the GridView Columns  foreach (DataColumn item in dt.Columns)  {    GridViewColumn gvc = new GridViewColumn();    gvc.DisplayMemberBinding = new Binding(item.ColumnName);    gvc.Header = item.ColumnName;    gvc.Width = Double.NaN;    gv.Columns.Add(gvc);  }   return gv;} VB.NETPublic Shared Function CreateGridViewColumns _  (ByVal dt As DataTable) As GridView  ' Create the GridView  Dim gv As New GridView()  gv.AllowsColumnReorder = True   ' Create the GridView Columns  For Each item As DataColumn In dt.Columns    Dim gvc As New GridViewColumn()    gvc.DisplayMemberBinding = New Binding(item.ColumnName)    gvc.Header = item.ColumnName    gvc.Width = [Double].NaN    gv.Columns.Add(gvc)  Next   Return gvEnd FunctionListing 3: The CreateGridViewColumns method takes a DataTable and creates GridViewColumn objects in a GridView. By separating this method out into a class you can call this method anytime you want to create a ListView with a collection of columns from a DataTable. SummaryIn this blog you learned how to create a ListView that acts like a DataGrid. You are able to use a DataTable as both the source of the data, and for creating the columns for the ListView. In the next blog entry you will learn how to use the same technique, but for Collection classes. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "WPF ListView as a DataGrid" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".

  Read the article

• jQuery Templates and Data Linking (and Microsoft contributing to jQuery)

  - by ScottGu

  The jQuery library has a passionate community of developers, and it is now the most widely used JavaScript library on the web today. Two years ago I announced that Microsoft would begin offering product support for jQuery, and that we’d be including it in new versions of Visual Studio going forward. By default, when you create new ASP.NET Web Forms and ASP.NET MVC projects with VS 2010 you’ll find jQuery automatically added to your project. A few weeks ago during my second keynote at the MIX 2010 conference I announced that Microsoft would also begin contributing to the jQuery project.  During the talk, John Resig -- the creator of the jQuery library and leader of the jQuery developer team – talked a little about our participation and discussed an early prototype of a new client templating API for jQuery. In this blog post, I’m going to talk a little about how my team is starting to contribute to the jQuery project, and discuss some of the specific features that we are working on such as client-side templating and data linking (data-binding). Contributing to jQuery jQuery has a fantastic developer community, and a very open way to propose suggestions and make contributions.  Microsoft is following the same process to contribute to jQuery as any other member of the community. As an example, when working with the jQuery community to improve support for templating to jQuery my team followed the following steps: We created a proposal for templating and posted the proposal to the jQuery developer forum (http://forum.jquery.com/topic/jquery-templates-proposal and http://forum.jquery.com/topic/templating-syntax ). After receiving feedback on the forums, the jQuery team created a prototype for templating and posted the prototype at the Github code repository (http://github.com/jquery/jquery-tmpl ). We iterated on the prototype, creating a new fork on Github of the templating prototype, to suggest design improvements. Several other members of the community also provided design feedback by forking the templating code. There has been an amazing amount of participation by the jQuery community in response to the original templating proposal (over 100 posts in the jQuery forum), and the design of the templating proposal has evolved significantly based on community feedback. The jQuery team is the ultimate determiner on what happens with the templating proposal – they might include it in jQuery core, or make it an official plugin, or reject it entirely.  My team is excited to be able to participate in the open source process, and make suggestions and contributions the same way as any other member of the community. jQuery Template Support Client-side templates enable jQuery developers to easily generate and render HTML UI on the client.  Templates support a simple syntax that enables either developers or designers to declaratively specify the HTML they want to generate.  Developers can then programmatically invoke the templates on the client, and pass JavaScript objects to them to make the content rendered completely data driven.  These JavaScript objects can optionally be based on data retrieved from a server. Because the jQuery templating proposal is still evolving in response to community feedback, the final version might look very different than the version below. This blog post gives you a sense of how you can try out and use templating as it exists today (you can download the prototype by the jQuery core team at http://github.com/jquery/jquery-tmpl or the latest submission from my team at http://github.com/nje/jquery-tmpl).  jQuery Client Templates You create client-side jQuery templates by embedding content within a <script type="text/html"> tag.  For example, the HTML below contains a <div> template container, as well as a client-side jQuery “contactTemplate” template (within the <script type="text/html"> element) that can be used to dynamically display a list of contacts: The {{= name }} and {{= phone }} expressions are used within the contact template above to display the names and phone numbers of “contact” objects passed to the template. We can use the template to display either an array of JavaScript objects or a single object. The JavaScript code below demonstrates how you can render a JavaScript array of “contact” object using the above template. The render() method renders the data into a string and appends the string to the “contactContainer” DIV element: When the page is loaded, the list of contacts is rendered by the template.  All of this template rendering is happening on the client-side within the browser:   Templating Commands and Conditional Display Logic The current templating proposal supports a small set of template commands - including if, else, and each statements. The number of template commands was deliberately kept small to encourage people to place more complicated logic outside of their templates. Even this small set of template commands is very useful though. Imagine, for example, that each contact can have zero or more phone numbers. The contacts could be represented by the JavaScript array below: The template below demonstrates how you can use the if and each template commands to conditionally display and loop the phone numbers for each contact: If a contact has one or more phone numbers then each of the phone numbers is displayed by iterating through the phone numbers with the each template command: The jQuery team designed the template commands so that they are extensible. If you have a need for a new template command then you can easily add new template commands to the default set of commands. Support for Client Data-Linking The ASP.NET team recently submitted another proposal and prototype to the jQuery forums (http://forum.jquery.com/topic/proposal-for-adding-data-linking-to-jquery). This proposal describes a new feature named data linking. Data Linking enables you to link a property of one object to a property of another object - so that when one property changes the other property changes.  Data linking enables you to easily keep your UI and data objects synchronized within a page. If you are familiar with the concept of data-binding then you will be familiar with data linking (in the proposal, we call the feature data linking because jQuery already includes a bind() method that has nothing to do with data-binding). Imagine, for example, that you have a page with the following HTML <input> elements: The following JavaScript code links the two INPUT elements above to the properties of a JavaScript “contact” object that has a “name” and “phone” property: When you execute this code, the value of the first INPUT element (#name) is set to the value of the contact name property, and the value of the second INPUT element (#phone) is set to the value of the contact phone property. The properties of the contact object and the properties of the INPUT elements are also linked – so that changes to one are also reflected in the other. Because the contact object is linked to the INPUT element, when you request the page, the values of the contact properties are displayed: More interesting, the values of the linked INPUT elements will change automatically whenever you update the properties of the contact object they are linked to. For example, we could programmatically modify the properties of the “contact” object using the jQuery attr() method like below: Because our two INPUT elements are linked to the “contact” object, the INPUT element values will be updated automatically (without us having to write any code to modify the UI elements): Note that we updated the contact object above using the jQuery attr() method. In order for data linking to work, you must use jQuery methods to modify the property values. Two Way Linking The linkBoth() method enables two-way data linking. The contact object and INPUT elements are linked in both directions. When you modify the value of the INPUT element, the contact object is also updated automatically. For example, the following code adds a client-side JavaScript click handler to an HTML button element. When you click the button, the property values of the contact object are displayed using an alert() dialog: The following demonstrates what happens when you change the value of the Name INPUT element and click the Save button. Notice that the name property of the “contact” object that the INPUT element was linked to was updated automatically: The above example is obviously trivially simple.  Instead of displaying the new values of the contact object with a JavaScript alert, you can imagine instead calling a web-service to save the object to a database. The benefit of data linking is that it enables you to focus on your data and frees you from the mechanics of keeping your UI and data in sync. Converters The current data linking proposal also supports a feature called converters. A converter enables you to easily convert the value of a property during data linking. For example, imagine that you want to represent phone numbers in a standard way with the “contact” object phone property. In particular, you don’t want to include special characters such as ()- in the phone number - instead you only want digits and nothing else. In that case, you can wire-up a converter to convert the value of an INPUT element into this format using the code below: Notice above how a converter function is being passed to the linkFrom() method used to link the phone property of the “contact” object with the value of the phone INPUT element. This convertor function strips any non-numeric characters from the INPUT element before updating the phone property.  Now, if you enter the phone number (206) 555-9999 into the phone input field then the value 2065559999 is assigned to the phone property of the contact object: You can also use a converter in the opposite direction also. For example, you can apply a standard phone format string when displaying a phone number from a phone property. Combining Templating and Data Linking Our goal in submitting these two proposals for templating and data linking is to make it easier to work with data when building websites and applications with jQuery. Templating makes it easier to display a list of database records retrieved from a database through an Ajax call. Data linking makes it easier to keep the data and user interface in sync for update scenarios. Currently, we are working on an extension of the data linking proposal to support declarative data linking. We want to make it easy to take advantage of data linking when using a template to display data. For example, imagine that you are using the following template to display an array of product objects: Notice the {{link name}} and {{link price}} expressions. These expressions enable declarative data linking between the SPAN elements and properties of the product objects. The current jQuery templating prototype supports extending its syntax with custom template commands. In this case, we are extending the default templating syntax with a custom template command named “link”. The benefit of using data linking with the above template is that the SPAN elements will be automatically updated whenever the underlying “product” data is updated.  Declarative data linking also makes it easier to create edit and insert forms. For example, you could create a form for editing a product by using declarative data linking like this: Whenever you change the value of the INPUT elements in a template that uses declarative data linking, the underlying JavaScript data object is automatically updated. Instead of needing to write code to scrape the HTML form to get updated values, you can instead work with the underlying data directly – making your client-side code much cleaner and simpler. Downloading Working Code Examples of the Above Scenarios You can download this .zip file to get with working code examples of the above scenarios.  The .zip file includes 4 static HTML page: Listing1_Templating.htm – Illustrates basic templating. Listing2_TemplatingConditionals.htm – Illustrates templating with the use of the if and each template commands. Listing3_DataLinking.htm – Illustrates data linking. Listing4_Converters.htm – Illustrates using a converter with data linking. You can un-zip the file to the file-system and then run each page to see the concepts in action. Summary We are excited to be able to begin participating within the open-source jQuery project.  We’ve received lots of encouraging feedback in response to our first two proposals, and we will continue to actively contribute going forward.  These features will hopefully make it easier for all developers (including ASP.NET developers) to build great Ajax applications. Hope this helps, Scott P.S. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu]

  Read the article

• SQLAuthority News – Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning Training

  - by pinaldave

  Last 3 days to register for the courses. This is one time offer with big discount. The deadline for the course registration is 5th May, 2010. There are two different courses are offered by Solid Quality Mentors 1) Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning – Pinal Dave Date: May 12-14, 2010 Price: Rs. 14,000/person for 3 days Discount Code: ‘SQLAuthority.com’ Effective Price: Rs. 11,000/person for 3 days 2) SharePoint 2010 – Joy Rathnayake Date: May 10-11, 2010 Price: Rs. 11,000/person for 3 days Discount Code: ‘SQLAuthority.com’ Effective Price: Rs. 8,000/person for 2 days Download the complete PDF brochure. To register, either send an email to [email protected] or call +91 95940 43399. Feel free to drop me an email at pinal “at” SQLAuthority.com for any additional information and clarification. Training Venue: Abridge Solutions, #90/B/C/3/1, Ganesh GHR & MSY Plaza, Vittalrao Nagar, Near Image Hospital, Madhapur, Hyderabad – 500 081. Additionally there is special program of SolidQ India Insider. This is only available to first few registrants of the courses only. Read more details about the course here. Read my TechEd India 2010 experience here. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Technology

  Read the article

• Parallelism in .NET – Part 4, Imperative Data Parallelism: Aggregation

  - by Reed

  In the article on simple data parallelism, I described how to perform an operation on an entire collection of elements in parallel.  Often, this is not adequate, as the parallel operation is going to be performing some form of aggregation. Simple examples of this might include taking the sum of the results of processing a function on each element in the collection, or finding the minimum of the collection given some criteria.  This can be done using the techniques described in simple data parallelism, however, special care needs to be taken into account to synchronize the shared data appropriately.  The Task Parallel Library has tools to assist in this synchronization. The main issue with aggregation when parallelizing a routine is that you need to handle synchronization of data.  Since multiple threads will need to write to a shared portion of data.  Suppose, for example, that we wanted to parallelize a simple loop that looked for the minimum value within a dataset: double min = double.MaxValue; foreach(var item in collection) { double value = item.PerformComputation(); min = System.Math.Min(min, value); } .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 seems like a good candidate for parallelization, but there is a problem here.  If we just wrap this into a call to Parallel.ForEach, we’ll introduce a critical race condition, and get the wrong answer.  Let’s look at what happens here: // Buggy code! Do not use! double min = double.MaxValue; Parallel.ForEach(collection, item => { double value = item.PerformComputation(); min = System.Math.Min(min, value); }); This code has a fatal flaw: min will be checked, then set, by multiple threads simultaneously.  Two threads may perform the check at the same time, and set the wrong value for min.  Say we get a value of 1 in thread 1, and a value of 2 in thread 2, and these two elements are the first two to run.  If both hit the min check line at the same time, both will determine that min should change, to 1 and 2 respectively.  If element 1 happens to set the variable first, then element 2 sets the min variable, we’ll detect a min value of 2 instead of 1.  This can lead to wrong answers. Unfortunately, fixing this, with the Parallel.ForEach call we’re using, would require adding locking.  We would need to rewrite this like: // Safe, but slow double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach(collection, item => { double value = item.PerformComputation(); lock(syncObject) min = System.Math.Min(min, value); }); This will potentially add a huge amount of overhead to our calculation.  Since we can potentially block while waiting on the lock for every single iteration, we will most likely slow this down to where it is actually quite a bit slower than our serial implementation.  The problem is the lock statement – any time you use lock(object), you’re almost assuring reduced performance in a parallel situation.  This leads to two observations I’ll make: When parallelizing a routine, try to avoid locks. That being said: Always add any and all required synchronization to avoid race conditions. These two observations tend to be opposing forces – we often need to synchronize our algorithms, but we also want to avoid the synchronization when possible.  Looking at our routine, there is no way to directly avoid this lock, since each element is potentially being run on a separate thread, and this lock is necessary in order for our routine to function correctly every time. However, this isn’t the only way to design this routine to implement this algorithm.  Realize that, although our collection may have thousands or even millions of elements, we have a limited number of Processing Elements (PE).  Processing Element is the standard term for a hardware element which can process and execute instructions.  This typically is a core in your processor, but many modern systems have multiple hardware execution threads per core.  The Task Parallel Library will not execute the work for each item in the collection as a separate work item. Instead, when Parallel.ForEach executes, it will partition the collection into larger “chunks” which get processed on different threads via the ThreadPool.  This helps reduce the threading overhead, and help the overall speed.  In general, the Parallel class will only use one thread per PE in the system. Given the fact that there are typically fewer threads than work items, we can rethink our algorithm design.  We can parallelize our algorithm more effectively by approaching it differently.  Because the basic aggregation we are doing here (Min) is communitive, we do not need to perform this in a given order.  We knew this to be true already – otherwise, we wouldn’t have been able to parallelize this routine in the first place.  With this in mind, we can treat each thread’s work independently, allowing each thread to serially process many elements with no locking, then, after all the threads are complete, “merge” together the results. This can be accomplished via a different set of overloads in the Parallel class: Parallel.ForEach<TSource,TLocal>.  The idea behind these overloads is to allow each thread to begin by initializing some local state (TLocal).  The thread will then process an entire set of items in the source collection, providing that state to the delegate which processes an individual item.  Finally, at the end, a separate delegate is run which allows you to handle merging that local state into your final results. To rewriting our routine using Parallel.ForEach<TSource,TLocal>, we need to provide three delegates instead of one.  The most basic version of this function is declared as: public static ParallelLoopResult ForEach<TSource, TLocal>( IEnumerable<TSource> source, Func<TLocal> localInit, Func<TSource, ParallelLoopState, TLocal, TLocal> body, Action<TLocal> localFinally ) The first delegate (the localInit argument) is defined as Func<TLocal>.  This delegate initializes our local state.  It should return some object we can use to track the results of a single thread’s operations. The second delegate (the body argument) is where our main processing occurs, although now, instead of being an Action<T>, we actually provide a Func<TSource, ParallelLoopState, TLocal, TLocal> delegate.  This delegate will receive three arguments: our original element from the collection (TSource), a ParallelLoopState which we can use for early termination, and the instance of our local state we created (TLocal).  It should do whatever processing you wish to occur per element, then return the value of the local state after processing is completed. The third delegate (the localFinally argument) is defined as Action<TLocal>.  This delegate is passed our local state after it’s been processed by all of the elements this thread will handle.  This is where you can merge your final results together.  This may require synchronization, but now, instead of synchronizing once per element (potentially millions of times), you’ll only have to synchronize once per thread, which is an ideal situation. Now that I’ve explained how this works, lets look at the code: // Safe, and fast! double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach( collection, // First, we provide a local state initialization delegate. () => double.MaxValue, // Next, we supply the body, which takes the original item, loop state, // and local state, and returns a new local state (item, loopState, localState) => { double value = item.PerformComputation(); return System.Math.Min(localState, value); }, // Finally, we provide an Action<TLocal>, to "merge" results together localState => { // This requires locking, but it's only once per used thread lock(syncObj) min = System.Math.Min(min, localState); } ); Although this is a bit more complicated than the previous version, it is now both thread-safe, and has minimal locking.  This same approach can be used by Parallel.For, although now, it’s Parallel.For<TLocal>.  When working with Parallel.For<TLocal>, you use the same triplet of delegates, with the same purpose and results. Also, many times, you can completely avoid locking by using a method of the Interlocked class to perform the final aggregation in an atomic operation.  The MSDN example demonstrating this same technique using Parallel.For uses the Interlocked class instead of a lock, since they are doing a sum operation on a long variable, which is possible via Interlocked.Add. By taking advantage of local state, we can use the Parallel class methods to parallelize algorithms such as aggregation, which, at first, may seem like poor candidates for parallelization.  Doing so requires careful consideration, and often requires a slight redesign of the algorithm, but the performance gains can be significant if handled in a way to avoid excessive synchronization.

  Read the article

• HP Network Utility Error

  - by William Ricci

  Using the HP Network Utility to team 2 ports on Windows 2008 R2 Standard results in this error:----- An error occurred when making a call into the operating system. Happens on either of two cards that are installed. This happened before and after upgrading to PSP 9.10. Uninstalled the HP Network Configuration Utility and re-installed version 10.65.0.6. Updated NIC drivers. NC382i DP - HP Broadcom 1Gb Multifunction Driver 7.4.23.0 (from 6.2.9.0) NC365T - Intel E1R 11.14.80.0 (from 11.14.49.0)

  Read the article

• SQL SERVER – The Difference between Dual Core vs. Core 2 Duo

  - by pinaldave

  I have decided that I would not write on this subject until I have received a total of 25 questions on this subject. Here are a few questions from the list: Questions: What is the difference between Dual Core and Core 2 Duo? Which one is recommended for SQL Server: Core 2 Duo or Dual Core? Can I upgrade my Dual Core to Core 2 Duo? If Dual Core has 2 CPUs, how many CPUs does Core 2 Duo have? Is it true that Core 2 Duo and Dual Core meant the same thing? Well, let us see the answer. Optimistically, I would be directing everybody to this blog post if I receive a question of the same kind sometime in the future. To verify the information that I provide, visit Intel’s site. For additional information regarding the subject, visit Wikipedia. My Answer: Any computer that has two CPUs or two “cores“ is known as Dual Core. Core Duo is a brand name of Intel for Dual Core. Core 2 Duo is simply a higher version of Core Duo. (e.g. for Pentium brand, it`s like Pentium I, Pentium II, etc.) The computer I am using now has Core 2 Duo. Intel has launched a new brand, which they call i3, i5, and i7.  Here, the numbers are not related to the number of cores; rather, they show the range of the CPU. I3 is of low range and i7 is of high range. Feel free to add more details by adding valuable comments here. And if you still want to ask why I created this blog post, well, I mentioned that I was waiting for 25 questions threshold to hit, before I write about this subject which I didn`t really plan to write about. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology

  Read the article

• External USB drive is failing

  - by dma_k

  I have an external USB 2.0 drive WD My Book Mirror Edition, running in RAID 1 (mirroring) mode. A while ago the hard drive started to fail: it stops responding (directories are not listed returning an error after a big timeout). Sometimes it works for weeks before a failure, sometimes – few hours. Small write operations (like removing few files or editing a small file) do not harm, but when copying large files to the drive over the network, or creating the archive locally, the kernel dumps. Also interesting to note that once kernel has failed, Linux does not want to reboot normally (reboot hangs); when Linux box is shutdown with power button, WD drive does not go to sleep mode (as it usually does): leds continue to run, pressing and holding the "shutdown" button on drive's back panel does not do anything; only unplugging the power cord helps. Here goes the boot log: Aug 16 00:32:21 kernel: [ 1.514106] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver Aug 16 00:32:21 kernel: [ 1.657738] ehci_hcd 0000:00:1d.7: PCI INT A -> GSI 23 (level, low) -> IRQ 23 Aug 16 00:32:21 kernel: [ 1.673747] ehci_hcd 0000:00:1d.7: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 1.673751] ehci_hcd 0000:00:1d.7: EHCI Host Controller Aug 16 00:32:21 kernel: [ 1.725224] ehci_hcd 0000:00:1d.7: new USB bus registered, assigned bus number 1 Aug 16 00:32:21 kernel: [ 1.741647] ehci_hcd 0000:00:1d.7: using broken periodic workaround Aug 16 00:32:21 kernel: [ 1.761790] ehci_hcd 0000:00:1d.7: cache line size of 32 is not supported Aug 16 00:32:21 kernel: [ 1.761873] ehci_hcd 0000:00:1d.7: irq 23, io mem 0xfdfff000 Aug 16 00:32:21 kernel: [ 1.796043] ehci_hcd 0000:00:1d.7: USB 2.0 started, EHCI 1.00 Aug 16 00:32:21 kernel: [ 1.879069] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002 Aug 16 00:32:21 kernel: [ 1.895446] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 1.911796] usb usb1: Product: EHCI Host Controller Aug 16 00:32:21 kernel: [ 1.928015] usb usb1: Manufacturer: Linux 2.6.32-5-686 ehci_hcd Aug 16 00:32:21 kernel: [ 1.944331] usb usb1: SerialNumber: 0000:00:1d.7 Aug 16 00:32:21 kernel: [ 1.961285] usb usb1: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 1.994412] hub 1-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 2.010864] hub 1-0:1.0: 8 ports detected Aug 16 00:32:21 kernel: [ 2.085939] uhci_hcd: USB Universal Host Controller Interface driver Aug 16 00:32:21 kernel: [ 2.191945] uhci_hcd 0000:00:1d.0: PCI INT A -> GSI 23 (level, low) -> IRQ 23 Aug 16 00:32:21 kernel: [ 2.226029] uhci_hcd 0000:00:1d.0: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 2.226034] uhci_hcd 0000:00:1d.0: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.243237] uhci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 2 Aug 16 00:32:21 kernel: [ 2.260390] uhci_hcd 0000:00:1d.0: irq 23, io base 0x0000fe00 Aug 16 00:32:21 kernel: [ 2.277517] usb usb2: New USB device found, idVendor=1d6b, idProduct=0001 Aug 16 00:32:21 kernel: [ 2.294815] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 2.312173] usb usb2: Product: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.329534] usb usb2: Manufacturer: Linux 2.6.32-5-686 uhci_hcd Aug 16 00:32:21 kernel: [ 2.346828] usb usb2: SerialNumber: 0000:00:1d.0 Aug 16 00:32:21 kernel: [ 2.412989] usb usb2: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 2.430651] usb 1-2: new high speed USB device using ehci_hcd and address 2 Aug 16 00:32:21 kernel: [ 2.449046] hub 2-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 2.466514] hub 2-0:1.0: 2 ports detected Aug 16 00:32:21 kernel: [ 2.484639] uhci_hcd 0000:00:1d.1: PCI INT B -> GSI 19 (level, low) -> IRQ 19 Aug 16 00:32:21 kernel: [ 2.537750] uhci_hcd 0000:00:1d.1: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 2.537756] uhci_hcd 0000:00:1d.1: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.555085] uhci_hcd 0000:00:1d.1: new USB bus registered, assigned bus number 3 Aug 16 00:32:21 kernel: [ 2.572231] uhci_hcd 0000:00:1d.1: irq 19, io base 0x0000fd00 Aug 16 00:32:21 kernel: [ 2.589593] usb usb3: New USB device found, idVendor=1d6b, idProduct=0001 Aug 16 00:32:21 kernel: [ 2.606869] usb usb3: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 2.624134] usb usb3: Product: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.641329] usb usb3: Manufacturer: Linux 2.6.32-5-686 uhci_hcd Aug 16 00:32:21 kernel: [ 2.658505] usb usb3: SerialNumber: 0000:00:1d.1 Aug 16 00:32:21 kernel: [ 2.675843] usb usb3: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 2.692864] hub 3-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 2.709651] hub 3-0:1.0: 2 ports detected Aug 16 00:32:21 kernel: [ 2.727378] uhci_hcd 0000:00:1d.2: PCI INT C -> GSI 18 (level, low) -> IRQ 18 Aug 16 00:32:21 kernel: [ 2.768252] uhci_hcd 0000:00:1d.2: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 2.768258] uhci_hcd 0000:00:1d.2: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.806679] uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus number 4 Aug 16 00:32:21 kernel: [ 2.824117] uhci_hcd 0000:00:1d.2: irq 18, io base 0x0000fc00 Aug 16 00:32:21 kernel: [ 2.841405] usb 1-2: New USB device found, idVendor=1058, idProduct=1104 Aug 16 00:32:21 kernel: [ 2.858448] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 Aug 16 00:32:21 kernel: [ 2.875347] usb 1-2: Product: My Book Aug 16 00:32:21 kernel: [ 2.892113] usb 1-2: Manufacturer: Western Digital Aug 16 00:32:21 kernel: [ 2.908915] usb 1-2: SerialNumber: 575532553130303530353538 Aug 16 00:32:21 kernel: [ 2.943242] usb usb4: New USB device found, idVendor=1d6b, idProduct=0001 Aug 16 00:32:21 kernel: [ 2.960405] usb usb4: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 2.977615] usb usb4: Product: UHCI Host Controller Aug 16 00:32:21 kernel: [ 2.994687] usb usb4: Manufacturer: Linux 2.6.32-5-686 uhci_hcd Aug 16 00:32:21 kernel: [ 3.011711] usb usb4: SerialNumber: 0000:00:1d.2 Aug 16 00:32:21 kernel: [ 3.029589] usb usb4: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 3.082027] sd 2:0:0:0: [sda] Attached SCSI disk Aug 16 00:32:21 kernel: [ 3.103953] usb 1-2: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 3.122625] hub 4-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 3.140484] hub 4-0:1.0: 2 ports detected Aug 16 00:32:21 kernel: [ 3.161680] uhci_hcd 0000:00:1d.3: PCI INT D -> GSI 16 (level, low) -> IRQ 16 Aug 16 00:32:21 kernel: [ 3.181257] uhci_hcd 0000:00:1d.3: setting latency timer to 64 Aug 16 00:32:21 kernel: [ 3.181263] uhci_hcd 0000:00:1d.3: UHCI Host Controller Aug 16 00:32:21 kernel: [ 3.198614] uhci_hcd 0000:00:1d.3: new USB bus registered, assigned bus number 5 Aug 16 00:32:21 kernel: [ 3.216012] uhci_hcd 0000:00:1d.3: irq 16, io base 0x0000fb00 Aug 16 00:32:21 kernel: [ 3.249877] Uniform CD-ROM driver Revision: 3.20 Aug 16 00:32:21 kernel: [ 3.267765] usb usb5: New USB device found, idVendor=1d6b, idProduct=0001 Aug 16 00:32:21 kernel: [ 3.284947] usb usb5: New USB device strings: Mfr=3, Product=2, SerialNumber=1 Aug 16 00:32:21 kernel: [ 3.302023] usb usb5: Product: UHCI Host Controller Aug 16 00:32:21 kernel: [ 3.319215] usb usb5: Manufacturer: Linux 2.6.32-5-686 uhci_hcd Aug 16 00:32:21 kernel: [ 3.336298] usb usb5: SerialNumber: 0000:00:1d.3 Aug 16 00:32:21 kernel: [ 3.368377] Initializing USB Mass Storage driver... Aug 16 00:32:21 kernel: [ 3.390652] usbcore: registered new interface driver hiddev Aug 16 00:32:21 kernel: [ 3.408109] scsi4 : SCSI emulation for USB Mass Storage devices Aug 16 00:32:21 kernel: [ 3.425281] sr 0:0:1:0: Attached scsi CD-ROM sr0 Aug 16 00:32:21 kernel: [ 3.438978] sr 0:0:1:0: Attached scsi generic sg0 type 5 Aug 16 00:32:21 kernel: [ 3.456328] usbcore: registered new interface driver usb-storage Aug 16 00:32:21 kernel: [ 3.474564] usb-storage: device found at 2 Aug 16 00:32:21 kernel: [ 3.474567] usb-storage: waiting for device to settle before scanning Aug 16 00:32:21 kernel: [ 3.475320] sd 2:0:0:0: Attached scsi generic sg1 type 0 Aug 16 00:32:21 kernel: [ 3.492587] USB Mass Storage support registered. Aug 16 00:32:21 kernel: [ 3.510930] usb usb5: configuration #1 chosen from 1 choice Aug 16 00:32:21 kernel: [ 3.531076] hub 5-0:1.0: USB hub found Aug 16 00:32:21 kernel: [ 3.548399] hub 5-0:1.0: 2 ports detected Aug 16 00:32:21 kernel: [ 3.591743] input: Western Digital My Book as /devices/pci0000:00/0000:00:1d.7/usb1/1-2/1-2:1.1/input/input2 Aug 16 00:32:21 kernel: [ 3.609515] generic-usb 0003:1058:1104.0001: input,hidraw0: USB HID v1.11 Device [Western Digital My Book] on usb-0000:00:1d.7-2/input1 Aug 16 00:32:21 kernel: [ 3.627466] usbcore: registered new interface driver usbhid Aug 16 00:32:21 kernel: [ 8.581664] usb-storage: device scan complete Aug 16 00:32:21 kernel: [ 8.624270] scsi 4:0:0:0: Direct-Access WD My Book 1008 PQ: 0 ANSI: 4 Aug 16 00:32:21 kernel: [ 8.655135] scsi 4:0:0:1: Enclosure WD My Book Device 1008 PQ: 0 ANSI: 4 Aug 16 00:32:21 kernel: [ 8.675393] sd 4:0:0:0: Attached scsi generic sg2 type 0 Aug 16 00:32:21 kernel: [ 8.698669] scsi 4:0:0:1: Attached scsi generic sg3 type 13 Aug 16 00:32:21 kernel: [ 8.723370] sd 4:0:0:0: [sdb] 1953513472 512-byte logical blocks: (1.00 TB/931 GiB) Aug 16 00:32:21 kernel: [ 8.750477] sd 4:0:0:0: [sdb] Write Protect is off Aug 16 00:32:21 kernel: [ 8.769411] sd 4:0:0:0: [sdb] Mode Sense: 10 00 00 00 Aug 16 00:32:21 kernel: [ 8.769414] sd 4:0:0:0: [sdb] Assuming drive cache: write through Aug 16 00:32:21 kernel: [ 8.822971] sd 4:0:0:0: [sdb] Assuming drive cache: write through Aug 16 00:32:21 kernel: [ 8.841978] sdb: sdb1 Aug 16 00:32:21 kernel: [ 8.905580] sd 4:0:0:0: [sdb] Assuming drive cache: write through Aug 16 00:32:21 kernel: [ 8.924173] sd 4:0:0:0: [sdb] Attached SCSI disk Aug 16 00:32:21 kernel: [ 11.600492] XFS mounting filesystem sdb1 Aug 16 00:32:21 kernel: [ 12.222948] Ending clean XFS mount for filesystem: sdb1 After a while the following appears in a log: Aug 16 09:30:56 kernel: [32359.112029] usb 1-2: reset high speed USB device using ehci_hcd and address 2 Aug 16 09:31:59 kernel: [32422.112035] usb 1-2: reset high speed USB device using ehci_hcd and address 2 Aug 16 09:33:00 kernel: [32483.112029] usb 1-2: reset high speed USB device using ehci_hcd and address 2 And then it is followed by few kernel dumps, which I think, are not good: Aug 16 09:33:40 kernel: [32520.428027] INFO: task xfssyncd:1002 blocked for more than 120 seconds. Aug 16 09:33:40 kernel: [32520.462689] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 16 09:33:40 kernel: [32520.497422] xfssyncd D c3d84a60 0 1002 2 0x00000000 Aug 16 09:33:40 kernel: [32520.532117] f6c9aa80 00000046 c1132742 c3d84a60 00000286 c1418100 c1418100 00000000 Aug 16 09:33:40 kernel: [32520.566867] f6c9ac3c c2808100 00000000 f653b18b 00001d76 00000001 f6c9aa80 c3c3f0e0 Aug 16 09:33:40 kernel: [32520.601343] 08e59242 f6c9ac3c 2e41392b 00000000 08e59242 00000000 c3f7fb48 0067385a Aug 16 09:33:40 kernel: [32520.635533] Call Trace: Aug 16 09:33:40 kernel: [32520.668991] [<c1132742>] ? cfq_set_request+0x0/0x290 Aug 16 09:33:40 kernel: [32520.702804] [<c126b532>] ? io_schedule+0x5f/0x98 Aug 16 09:33:40 kernel: [32520.736555] [<c1128be0>] ? get_request_wait+0xcb/0x146 Aug 16 09:33:40 kernel: [32520.770360] [<c10437ba>] ? autoremove_wake_function+0x0/0x2d Aug 16 09:33:40 kernel: [32520.804110] [<c112907c>] ? __make_request+0x2cc/0x3d9 Aug 16 09:33:40 kernel: [32520.837713] [<c1128230>] ? blk_peek_request+0x135/0x143 Aug 16 09:33:40 kernel: [32520.871265] [<f8582987>] ? scsi_dispatch_cmd+0x185/0x1e5 [scsi_mod] Aug 16 09:33:40 kernel: [32520.904407] [<c1127cf1>] ? generic_make_request+0x266/0x2b4 Aug 16 09:33:40 kernel: [32520.937007] [<c10cf821>] ? bvec_alloc_bs+0x95/0xaf Aug 16 09:33:40 kernel: [32520.969033] [<c1127dfb>] ? submit_bio+0xbc/0xd6 Aug 16 09:33:40 kernel: [32521.000485] [<c10cffd1>] ? bio_add_page+0x28/0x2e Aug 16 09:33:40 kernel: [32521.031403] [<f8918d38>] ? _xfs_buf_ioapply+0x206/0x22b [xfs] Aug 16 09:33:40 kernel: [32521.061888] [<f89197bd>] ? xfs_buf_iorequest+0x38/0x60 [xfs] Aug 16 09:33:40 kernel: [32521.091845] [<f8907230>] ? xlog_bdstrat_cb+0x16/0x3d [xfs] Aug 16 09:33:40 kernel: [32521.121222] [<f8905781>] ? XFS_bwrite+0x32/0x64 [xfs] Aug 16 09:33:40 kernel: [32521.150007] [<f89059be>] ? xlog_sync+0x20b/0x311 [xfs] Aug 16 09:33:40 kernel: [32521.178214] [<f89112fc>] ? xfs_trans_ail_tail+0x12/0x27 [xfs] Aug 16 09:33:40 kernel: [32521.205914] [<f8906261>] ? xlog_state_sync_all+0xa2/0x141 [xfs] Aug 16 09:33:40 kernel: [32521.233074] [<f8906611>] ? _xfs_log_force+0x51/0x68 [xfs] Aug 16 09:33:40 kernel: [32521.259664] [<c103abaf>] ? process_timeout+0x0/0x5 Aug 16 09:33:40 kernel: [32521.285662] [<f8906636>] ? xfs_log_force+0xe/0x27 [xfs] Aug 16 09:33:40 kernel: [32521.311171] [<f89202df>] ? xfs_sync_worker+0x17/0x5c [xfs] Aug 16 09:33:40 kernel: [32521.336117] [<f891fbb7>] ? xfssyncd+0x134/0x17d [xfs] Aug 16 09:33:40 kernel: [32521.360498] [<f891fa83>] ? xfssyncd+0x0/0x17d [xfs] Aug 16 09:33:40 kernel: [32521.384211] [<c1043588>] ? kthread+0x61/0x66 Aug 16 09:33:40 kernel: [32521.407890] [<c1043527>] ? kthread+0x0/0x66 Aug 16 09:33:40 kernel: [32521.430876] [<c1003d47>] ? kernel_thread_helper+0x7/0x10 Aug 16 09:33:40 kernel: [32521.453394] INFO: task flush-8:16:12945 blocked for more than 120 seconds. Aug 16 09:33:40 kernel: [32521.476116] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 16 09:33:40 kernel: [32521.498579] flush-8:16 D 00000000 0 12945 2 0x00000000 Aug 16 09:33:40 kernel: [32521.520649] f4e4d540 00000046 e412e940 00000000 00000002 c1418100 c1418100 c14136ac Aug 16 09:33:40 kernel: [32521.542426] f4e4d6fc c2808100 00000000 00000000 000008b4 00000001 f4e4d540 c3c3f0e0 Aug 16 09:33:40 kernel: [32521.563745] 02e905a8 f4e4d6fc 007a5399 00000000 02e905a8 00000000 f4e2db48 00670b98 Aug 16 09:33:40 kernel: [32521.585077] Call Trace: Aug 16 09:33:40 kernel: [32521.605790] [<c126b532>] ? io_schedule+0x5f/0x98 Aug 16 09:33:40 kernel: [32521.626184] [<c1128be0>] ? get_request_wait+0xcb/0x146 Aug 16 09:33:40 kernel: [32521.646133] [<c10437ba>] ? autoremove_wake_function+0x0/0x2d Aug 16 09:33:40 kernel: [32521.665659] [<c112907c>] ? __make_request+0x2cc/0x3d9 Aug 16 09:33:40 kernel: [32521.684716] [<f891796e>] ? xfs_convert_page+0x30a/0x331 [xfs] Aug 16 09:33:40 kernel: [32521.703366] [<c1127cf1>] ? generic_make_request+0x266/0x2b4 Aug 16 09:33:40 kernel: [32521.721644] [<c10cf821>] ? bvec_alloc_bs+0x95/0xaf Aug 16 09:33:40 kernel: [32521.739465] [<c1127dfb>] ? submit_bio+0xbc/0xd6 Aug 16 09:33:40 kernel: [32521.756896] [<c10cfa45>] ? bio_alloc_bioset+0x7b/0xba Aug 16 09:33:40 kernel: [32521.774046] [<f8917af0>] ? xfs_submit_ioend_bio+0x3b/0x44 [xfs] Aug 16 09:33:40 kernel: [32521.790694] [<f8917ba3>] ? xfs_submit_ioend+0xaa/0xc4 [xfs] Aug 16 09:33:40 kernel: [32521.806736] [<f891817d>] ? xfs_page_state_convert+0x5c0/0x61c [xfs] Aug 16 09:33:40 kernel: [32521.822859] [<c113705b>] ? __lookup_tag+0x8e/0xee Aug 16 09:33:40 kernel: [32521.838958] [<f891840d>] ? xfs_vm_writepage+0x91/0xc4 [xfs] Aug 16 09:33:40 kernel: [32521.855039] [<c108bbcc>] ? __writepage+0x8/0x22 Aug 16 09:33:40 kernel: [32521.871067] [<c108c17b>] ? write_cache_pages+0x1af/0x29f Aug 16 09:33:40 kernel: [32521.886616] [<c108bbc4>] ? __writepage+0x0/0x22 Aug 16 09:33:40 kernel: [32521.901593] [<c108c285>] ? generic_writepages+0x1a/0x21 Aug 16 09:33:40 kernel: [32521.916455] [<f8918338>] ? xfs_vm_writepages+0x0/0x38 [xfs] Aug 16 09:33:40 kernel: [32521.931484] [<c108c2a5>] ? do_writepages+0x19/0x25 Aug 16 09:33:40 kernel: [32521.946648] [<c10c80d9>] ? writeback_single_inode+0xc7/0x273 Aug 16 09:33:40 kernel: [32521.961675] [<c10c8c44>] ? writeback_inodes_wb+0x3dd/0x49c Aug 16 09:33:40 kernel: [32521.976831] [<c10c8e18>] ? wb_writeback+0x115/0x178 Aug 16 09:33:40 kernel: [32521.991778] [<c10c901f>] ? wb_do_writeback+0x121/0x131 Aug 16 09:33:40 kernel: [32522.006538] [<c103abaf>] ? process_timeout+0x0/0x5 Aug 16 09:33:40 kernel: [32522.021091] [<c10c9050>] ? bdi_writeback_task+0x21/0x89 Aug 16 09:33:40 kernel: [32522.035493] [<c10979e5>] ? bdi_start_fn+0x59/0xa4 Aug 16 09:33:40 kernel: [32522.049765] [<c109798c>] ? bdi_start_fn+0x0/0xa4 Aug 16 09:33:40 kernel: [32522.063792] [<c1043588>] ? kthread+0x61/0x66 Aug 16 09:33:40 kernel: [32522.077612] [<c1043527>] ? kthread+0x0/0x66 Aug 16 09:33:40 kernel: [32522.091260] [<c1003d47>] ? kernel_thread_helper+0x7/0x10 Aug 16 09:33:40 kernel: [32522.104966] INFO: task smartctl:13098 blocked for more than 120 seconds. Aug 16 09:33:40 kernel: [32522.118883] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Aug 16 09:33:40 kernel: [32522.133012] smartctl D 00000020 0 13098 13097 0x00000000 Aug 16 09:33:40 kernel: [32522.147221] e50b9540 00000086 c11d28a8 00000020 00000770 c1418100 c1418100 c14136ac Aug 16 09:33:40 kernel: [32522.161720] e50b96fc c2808100 00000000 e53e8800 00000000 00000020 c3cec000 c13886c0 Aug 16 09:33:40 kernel: [32522.176217] f99dab68 e50b96fc 007a4f1e 00000001 c4082f24 c4082ed8 00000001 c3c3f0e0 Aug 16 09:33:40 kernel: [32522.190737] Call Trace: Aug 16 09:33:40 kernel: [32522.205038] [<c11d28a8>] ? __netdev_alloc_skb+0x14/0x2d Aug 16 09:33:40 kernel: [32522.219605] [<c126b799>] ? schedule_timeout+0x20/0xb0 Aug 16 09:33:40 kernel: [32522.234144] [<c112820d>] ? blk_peek_request+0x112/0x143 Aug 16 09:33:40 kernel: [32522.248649] [<f85873b6>] ? scsi_request_fn+0x3c1/0x47a [scsi_mod] Aug 16 09:33:40 kernel: [32522.263233] [<c103aba8>] ? del_timer+0x55/0x5c Aug 16 09:33:40 kernel: [32522.277773] [<c126b6a2>] ? wait_for_common+0xa4/0x100 Aug 16 09:33:40 kernel: [32522.292342] [<c102cd8d>] ? default_wake_function+0x0/0x8 Aug 16 09:33:40 kernel: [32522.306958] [<c112b3d1>] ? blk_execute_rq+0x8b/0xb2 Aug 16 09:33:40 kernel: [32522.321569] [<c112b2ac>] ? blk_end_sync_rq+0x0/0x23 Aug 16 09:33:40 kernel: [32522.336070] [<c112b58b>] ? blk_recount_segments+0x13/0x20 Aug 16 09:33:40 kernel: [32522.350583] [<c1127307>] ? blk_rq_bio_prep+0x44/0x74 Aug 16 09:33:40 kernel: [32522.365059] [<c112b0b2>] ? blk_rq_map_kern+0xc5/0xee Aug 16 09:33:40 kernel: [32522.379439] [<c112e2a5>] ? sg_scsi_ioctl+0x221/0x2aa Aug 16 09:33:40 kernel: [32522.393801] [<c112e672>] ? scsi_cmd_ioctl+0x344/0x39a Aug 16 09:33:40 kernel: [32522.408140] [<c1024c87>] ? update_curr+0x106/0x1b3 Aug 16 09:33:40 kernel: [32522.422566] [<c1024c87>] ? update_curr+0x106/0x1b3 Aug 16 09:33:40 kernel: [32522.436832] [<f87676aa>] ? sd_ioctl+0x90/0xb5 [sd_mod] Aug 16 09:33:40 kernel: [32522.451228] [<c112c35f>] ? __blkdev_driver_ioctl+0x53/0x63 Aug 16 09:33:40 kernel: [32522.465689] [<c112cbbf>] ? blkdev_ioctl+0x850/0x891 Aug 16 09:33:40 kernel: [32522.479982] [<c1020474>] ? __wake_up_common+0x34/0x59 Aug 16 09:33:40 kernel: [32522.494138] [<c10244cd>] ? complete+0x28/0x36 Aug 16 09:33:40 kernel: [32522.507986] [<c1086c64>] ? find_get_page+0x1f/0x81 Aug 16 09:33:40 kernel: [32522.521671] [<c10abed5>] ? add_partial+0xe/0x40 Aug 16 09:33:40 kernel: [32522.535285] [<c1086e68>] ? lock_page+0x8/0x1d Aug 16 09:33:40 kernel: [32522.548797] [<c1087432>] ? filemap_fault+0xb5/0x2e6 Aug 16 09:33:40 kernel: [32522.562141] [<c109941c>] ? __do_fault+0x381/0x3b1 Aug 16 09:33:40 kernel: [32522.575441] [<c10d0c30>] ? block_ioctl+0x27/0x2c Aug 16 09:33:40 kernel: [32522.588708] [<c10d0c09>] ? block_ioctl+0x0/0x2c Aug 16 09:33:40 kernel: [32522.601858] [<c10bcd78>] ? vfs_ioctl+0x1c/0x5f Aug 16 09:33:40 kernel: [32522.614917] [<c10bd30c>] ? do_vfs_ioctl+0x4aa/0x4e5 Aug 16 09:33:40 kernel: [32522.627961] [<c10350db>] ? __do_softirq+0x115/0x151 Aug 16 09:33:40 kernel: [32522.640901] [<c126e270>] ? do_page_fault+0x2f1/0x307 Aug 16 09:33:40 kernel: [32522.653803] [<c10bd388>] ? sys_ioctl+0x41/0x58 Aug 16 09:33:40 kernel: [32522.666674] [<c10030fb>] ? sysenter_do_call+0x12/0x28 Then again few messages reset high speed USB device using ehci_hcd and address 2. I have browsed and read similar error reports here and there and I tried: I have upgraded the kernel from v2.6.26-2 to 2.6.32-5, which has not solved the problem. They say, this might a cable problem. I have tried to replace the USB-to-miniUSB cable (that connects external drive with computer) with another one. No changes. Somebody suggests to try another USB port. I have only 4 external USB ports, tried another one with no success. They say to try uhci_hcd. I have unmounted the device, unloaded ehci_hcd and mounted again. The difference was that now in log I get reset full speed USB device using uhci_hcd and address 2 and similar kernel dumps after a while. They say to echo 128 > /sys/block/sdb/device/max_sectors. I tried it with ehci_hcd with no success (note: I have issued this command after the drive was mounted but before using it actively). I have lauched smartmond and checking periodically the output of smartctl: drive temperature is OK, number of bad sectors and uncorrectable errors is 0. Nothing suspicious is reported by S.M.A.R.T. except maybe the following: Aug 16 12:40:12 kernel: [43715.314566] program smartctl is using a deprecated SCSI ioctl, please convert it to SG_IO Aug 16 12:40:13 kernel: [43715.705622] program smartctl is using a deprecated SCSI ioctl, please convert it to SG_IO Of course, I have not tried all combinations of above. But unfortunately, I am run out of cardinal ideas. If anybody can advice something specific about the problem, you are very welcome.

  Read the article

• ASP.NET GZip Encoding Caveats

  - by Rick Strahl

  GZip encoding in ASP.NET is pretty easy to accomplish using the built-in GZipStream and DeflateStream classes and applying them to the Response.Filter property.  While applying GZip and Deflate behavior is pretty easy there are a few caveats that you have watch out for as I found out today for myself with an application that was throwing up some garbage data. But before looking at caveats let’s review GZip implementation for ASP.NET. ASP.NET GZip/Deflate Basics Response filters basically are applied to the Response.OutputStream and transform it as data is written to it through the ASP.NET Response object. So a Response.Write eventually gets written into the output stream which if a filter is also written through the filter stream’s interface. To perform the actual GZip (and Deflate) encoding typically used by Web pages .NET includes the GZipStream and DeflateStream stream classes which can be readily assigned to the Repsonse.OutputStream. With these two stream classes in place it’s almost trivially easy to create a couple of reusable methods that allow you to compress your HTTP output. In my standard WebUtils utility class (from the West Wind West Wind Web Toolkit) created two static utility methods – IsGZipSupported and GZipEncodePage – that check whether the client supports GZip encoding and then actually encodes the current output (note that although the method includes ‘Page’ in its name this code will work with any ASP.NET output). /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } /// <summary> /// Sets up the current page or handler to use GZip through a Response.Filter /// IMPORTANT: /// You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if (IsGZipSupported()) { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (AcceptEncoding.Contains("deflate")) { Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "deflate"); } else { Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "gzip"); } } } As you can see the actual assignment of the Filter is as simple as: Response.Filter = new DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); which applies the filter to the OutputStream. You also need to ensure that your response reflects the new GZip or Deflate encoding and ensure that any pages that are cached in Proxy servers can differentiate between pages that were encoded with the various different encodings (or no encoding). To use this utility function now is trivially easy: In any ASP.NET code that wants to compress its Response output you simply use: protected void Page_Load(object sender, EventArgs e) { WebUtils.GZipEncodePage(); Entry = WebLogFactory.GetEntry(); var entries = Entry.GetLastEntries(App.Configuration.ShowEntryCount, "pk,Title,SafeTitle,Body,Entered,Feedback,Location,ShowTopAd", "TEntries"); if (entries == null) throw new ApplicationException("Couldn't load WebLog Entries: " + Entry.ErrorMessage); this.repEntries.DataSource = entries; this.repEntries.DataBind(); } Here I use an ASP.NET page, but the above WebUtils.GZipEncode() method call will work in any ASP.NET application type including HTTP Handlers. The only requirement is that the filter needs to be applied before any other output is sent to the OutputStream. For example, in my CallbackHandler service implementation by default output over a certain size is GZip encoded. The output that is generated is JSON or XML and if the output is over 5k in size I apply WebUtils.GZipEncode(): if (sbOutput.Length > GZIP_ENCODE_TRESHOLD) WebUtils.GZipEncodePage(); Response.ContentType = ControlResources.STR_JsonContentType; HttpContext.Current.Response.Write(sbOutput.ToString()); Ok, so you probably get the idea: Encoding GZip/Deflate content is pretty easy. Hold on there Hoss –Watch your Caching Or is it? There are a few caveats that you need to watch out for when dealing with GZip content. The fist issue is that you need to deal with the fact that some clients don’t support GZip or Deflate content. Most modern browsers support it, but if you have a programmatic Http client accessing your content GZip/Deflate support is by no means guaranteed. For example, WinInet Http clients don’t support GZip out of the box – it has to be explicitly implemented. Other low level HTTP clients on other platforms too don’t support GZip out of the box. The problem is that your application, your Web Server and Proxy Servers on the Internet might be caching your generated content. If you return content with GZip once and then again without, either caching is not applied or worse the wrong type of content is returned back to the client from a cache or proxy. The result is an unreadable response for *some clients* which is also very hard to debug and fix once in production. You already saw the issue of Proxy servers addressed in the GZipEncodePage() function: // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); This ensures that any Proxy servers also check for the Content-Encoding HTTP Header to cache their content – not just the URL. The same thing applies if you do OutputCaching in your own ASP.NET code. If you generate output for GZip on an OutputCached page the GZipped content will be cached (either by ASP.NET’s cache or in some cases by the IIS Kernel Cache). But what if the next client doesn’t support GZip? She’ll get served a cached GZip page that won’t decode and she’ll get a page full of garbage. Wholly undesirable. To fix this you need to add some custom OutputCache rules by way of the GetVaryByCustom() HttpApplication method in your global_ASAX file: public override string GetVaryByCustomString(HttpContext context, string custom) { // Override Caching for compression if (custom == "GZIP") { string acceptEncoding = HttpContext.Current.Response.Headers["Content-Encoding"]; if (string.IsNullOrEmpty(acceptEncoding)) return ""; else if (acceptEncoding.Contains("gzip")) return "GZIP"; else if (acceptEncoding.Contains("deflate")) return "DEFLATE"; return ""; } return base.GetVaryByCustomString(context, custom); } In a page that use Output caching you then specify: <%@ OutputCache Duration="180" VaryByParam="none" VaryByCustom="GZIP" %> To use that custom rule. It’s all Fun and Games until ASP.NET throws an Error Ok, so you’re up and running with GZip, you have your caching squared away and your pages that you are applying it to are jamming along. Then BOOM, something strange happens and you get a lovely garbled page that look like this: Lovely isn’t it? What’s happened here is that I have WebUtils.GZipEncode() applied to my page, but there’s an error in the page. The error falls back to the ASP.NET error handler and the error handler removes all existing output (good) and removes all the custom HTTP headers I’ve set manually (usually good, but very bad here). Since I applied the Response.Filter (via GZipEncode) the output is now GZip encoded, but ASP.NET has removed my Content-Encoding header, so the browser receives the GZip encoded content without a notification that it is encoded as GZip. The result is binary output. Here’s what Fiddler says about the raw HTTP header output when an error occurs when GZip encoding was applied: HTTP/1.1 500 Internal Server Error Cache-Control: private Content-Type: text/html; charset=utf-8 Date: Sat, 30 Apr 2011 22:21:08 GMT Content-Length: 2138 Connection: close ?`I?%&/m?{J?J??t??` … binary output striped here Notice: no Content-Encoding header and that’s why we’re seeing this garbage. ASP.NET has stripped the Content-Encoding header but left our filter intact. So how do we fix this? In my applications I typically have a global Application_Error handler set up and in this case I’ve been using that. One thing that you can do in the Application_Error handler is explicitly clear out the Response.Filter and set it to null at the top: protected void Application_Error(object sender, EventArgs e) { // Remove any special filtering especially GZip filtering Response.Filter = null; … } And voila I get my Yellow Screen of Death or my custom generated error output back via uncompressed content. BTW, the same is true for Page level errors handled in Page_Error or ASP.NET MVC Error handling methods in a controller. Another and possibly even better solution is to check whether a filter is attached just before the headers are sent to the client as pointed out by Adam Schroeder in the comments: protected void Application_PreSendRequestHeaders() { // ensure that if GZip/Deflate Encoding is applied that headers are set // also works when error occurs if filters are still active HttpResponse response = HttpContext.Current.Response; if (response.Filter is GZipStream && response.Headers["Content-encoding"] != "gzip") response.AppendHeader("Content-encoding", "gzip"); else if (response.Filter is DeflateStream && response.Headers["Content-encoding"] != "deflate") response.AppendHeader("Content-encoding", "deflate"); } This uses the Application_PreSendRequestHeaders() pipeline event to check for compression encoding in a filter and adjusts the content accordingly. This is actually a better solution since this is generic – it’ll work regardless of how the content is cleaned up. For example, an error Response.Redirect() or short error display might get changed and the filter not cleared and this code actually handles that. Sweet, thanks Adam. It’s unfortunate that ASP.NET doesn’t natively clear out Response.Filters when an error occurs just as it clears the Response and Headers. I can’t see where leaving a Filter in place in an error situation would make any sense, but hey - this is what it is and it’s easy enough to fix as long as you know where to look. Riiiight! IIS and GZip I should also mention that IIS 7 includes good support for compression natively. If you can defer encoding to let IIS perform it for you rather than doing it in your code by all means you should do it! Especially any static or semi-dynamic content that can be made static should be using IIS built-in compression. Dynamic caching is also supported but is a bit more tricky to judge in terms of performance and footprint. John Forsyth has a great article on the benefits and drawbacks of IIS 7 compression which gives some detailed performance comparisons and impact reviews. I’ll post another entry next with some more info on IIS compression since information on it seems to be a bit hard to come by. Related Content Built-in GZip/Deflate Compression in IIS 7.x HttpWebRequest and GZip Responses © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET   IIS7  

  Read the article

• openGL ES - change the render mode from RENDERMODE_WHEN_DIRTY to RENDERMODE_CONTINUOUSLY on touch

  - by Sid

  i want to change the rendermode from RENDERMODE_WHEN_DIRTY to RENDERMODE_CONTINUOUSLY when i touch the screen. WHAT i Need : Initially the object should be stationary. after touching the screen, it should move automatically. The motion of my object is a projectile motion ans it is working fine. what i get : Force close and a NULL pointer exception. My code : public class BallThrowGLSurfaceView extends GLSurfaceView{ MyRender _renderObj; Context context; GLSurfaceView glView; public BallThrowGLSurfaceView(Context context) { super(context); // TODO Auto-generated constructor stub _renderObj = new MyRender(context); this.setRenderer(_renderObj); this.setRenderMode(RENDERMODE_WHEN_DIRTY); this.requestFocus(); this.setFocusableInTouchMode(true); glView = new GLSurfaceView(context.getApplicationContext()); } @Override public boolean onTouchEvent(MotionEvent event) { // TODO Auto-generated method stub if (event != null) { if (event.getAction() == MotionEvent.ACTION_DOWN) { if (_renderObj != null) { Log.i("renderObj", _renderObj + "lll"); // Ensure we call switchMode() on the OpenGL thread. // queueEvent() is a method of GLSurfaceView that will do this for us. queueEvent(new Runnable() { public void run() { glView.setRenderMode(RENDERMODE_CONTINUOUSLY); } }); return true; } } } return super.onTouchEvent(event); } } PS : i know that i am making some silly mistakes in this, but cannot figure out what it really is.

  Read the article

• Resolve a URL from a Partial View (ASP.NET MVC)

  Working on an ASP.NET MVC application and needed the ability to resolve a URL from a partial view. For example, I have an image I want to display, but I need to resolve the virtual path (say, ~/Content/Images/New.png) into a relative path that the browser can use, such as ../../Content/Images/New.png or /MyAppName/Content/Images/New.png. Astandard view derives from the System.Web.UI.Page class, meaning you have access to the ResolveUrl and ResolveClientUrl methods. Consequently, you can write markup/code like the following:' /The problem is that the above code does not work as expected in a partial view. What's a little confusing is that while the above code compiles and the page, when visited through a browser, renders, the call to Page.ResolveClientUrl returns precisely what you pass in, ~/Content/Images/New.png, in this instance. The browser doesn't know what to do with ~, it presumes it's part of the URL, so it sends the request to the server for the image with the ~ in the URL, which results in a broken image.I did a bit of searching online and found this handy tip from Stephen Walther - Using ResolveUrl in an HTML Helper. In a nutshell, Stephen shows how to create an extension method for the HtmlHelper class that uses the UrlHelper class to resolve a URL. Specifically, Stephen shows how to add an Image extension method to HtmlHelper. I incorporated Stephen's code into my codebase and also created a more generic extension method, which I named ResolveUrl.public static MvcHtmlString ResolveUrl(this HtmlHelper htmlHelper, string url) { var urlHelper = new UrlHelper(htmlHelper.ViewContext.RequestContext); return MvcHtmlString.Create(urlHelper.Content(url)); }With this method in place you can resolve a URL in a partial view like so:' /Or you could use Stephen's Html.Image extension method (althoughmy more generic Html.ResolveUrl method could be used in non-image related scenarios where you needed to get a relative URL from a virtual one in a partial view). Thanks for the helpful tip, Stephen!Happy Programming!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

  Read the article

• Resolve a URL from a Partial View (ASP.NET MVC)

  Working on an ASP.NET MVC application and needed the ability to resolve a URL from a partial view. For example, I have an image I want to display, but I need to resolve the virtual path (say, ~/Content/Images/New.png) into a relative path that the browser can use, such as ../../Content/Images/New.png or /MyAppName/Content/Images/New.png. Astandard view derives from the System.Web.UI.Page class, meaning you have access to the ResolveUrl and ResolveClientUrl methods. Consequently, you can write markup/code like the following:' /The problem is that the above code does not work as expected in a partial view. What's a little confusing is that while the above code compiles and the page, when visited through a browser, renders, the call to Page.ResolveClientUrl returns precisely what you pass in, ~/Content/Images/New.png, in this instance. The browser doesn't know what to do with ~, it presumes it's part of the URL, so it sends the request to the server for the image with the ~ in the URL, which results in a broken image.I did a bit of searching online and found this handy tip from Stephen Walther - Using ResolveUrl in an HTML Helper. In a nutshell, Stephen shows how to create an extension method for the HtmlHelper class that uses the UrlHelper class to resolve a URL. Specifically, Stephen shows how to add an Image extension method to HtmlHelper. I incorporated Stephen's code into my codebase and also created a more generic extension method, which I named ResolveUrl.public static MvcHtmlString ResolveUrl(this HtmlHelper htmlHelper, string url) { var urlHelper = new UrlHelper(htmlHelper.ViewContext.RequestContext); return MvcHtmlString.Create(urlHelper.Content(url)); }With this method in place you can resolve a URL in a partial view like so:' /Or you could use Stephen's Html.Image extension method (althoughmy more generic Html.ResolveUrl method could be used in non-image related scenarios where you needed to get a relative URL from a virtual one in a partial view). Thanks for the helpful tip, Stephen!Happy Programming!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

  Read the article

• Implementing a generic repository for WCF data services

  - by cibrax

  The repository implementation I am going to discuss here is not exactly what someone would call repository in terms of DDD, but it is an abstraction layer that becomes handy at the moment of unit testing the code around this repository. In other words, you can easily create a mock to replace the real repository implementation. The WCF Data Services update for .NET 3.5 introduced a nice feature to support two way data bindings, which is very helpful for developing WPF or Silverlight based application but also for implementing the repository I am going to talk about. As part of this feature, the WCF Data Services Client library introduced a new collection DataServiceCollection<T> that implements INotifyPropertyChanged to notify the data context (DataServiceContext) about any change in the association links. This means that it is not longer necessary to manually set or remove the links in the data context when an item is added or removed from a collection. Before having this new collection, you basically used the following code to add a new item to a collection. Order order = new Order {   Name = "Foo" }; OrderItem item = new OrderItem {   Name = "bar",   UnitPrice = 10,   Qty = 1 }; var context = new OrderContext(); context.AddToOrders(order); context.AddToOrderItems(item); context.SetLink(item, "Order", order); context.SaveChanges(); Now, thanks to this new collection, everything is much simpler and similar to what you have in other ORMs like Entity Framework or L2S. Order order = new Order {   Name = "Foo" }; OrderItem item = new OrderItem {   Name = "bar",   UnitPrice = 10,   Qty = 1 }; order.Items.Add(item); var context = new OrderContext(); context.AddToOrders(order); context.SaveChanges(); In order to use this new feature, you first need to enable V2 in the data service, and then use some specific arguments in the datasvcutil tool (You can find more information about this new feature and how to use it in this post). DataSvcUtil /uri:"http://localhost:3655/MyDataService.svc/" /out:Reference.cs /dataservicecollection /version:2.0 Once you use those two arguments, the generated proxy classes will use DataServiceCollection<T> rather than a simple ObjectCollection<T>, which was the default collection in V1. There are some aspects that you need to know to use this feature correctly. 1. All the entities retrieved directly from the data context with a query track the changes and report those to the data context automatically. 2. A entity created with “new” does not track any change in the properties or associations. In order to enable change tracking in this entity, you need to do the following trick. public Order CreateOrder() {   var collection = new DataServiceCollection<Order>(this.context);   var order = new Order();   collection.Add(order);   return order; } You basically need to create a collection, and add the entity to that collection with the “Add” method to enable change tracking on that entity. 3. If you need to attach an existing entity (For example, if you created the entity with the “new” operator rather than retrieving it from the data context with a query) to a data context for tracking changes, you can use the “Load” method in the DataServiceCollection. var order = new Order {   Id = 1 }; var collection = new DataServiceCollection<Order>(this.context); collection.Load(order); In this case, the order with Id = 1 must exist on the data source exposed by the Data service. Otherwise, you will get an error because the entity did not exist. These cool extensions methods discussed by Stuart Leeks in this post to replace all the magic strings in the “Expand” operation with Expression Trees represent another feature I am going to use to implement this generic repository. Thanks to these extension methods, you could replace the following query with magic strings by a piece of code that only uses expressions. Magic strings, var customers = dataContext.Customers .Expand("Orders")         .Expand("Orders/Items") Expressions, var customers = dataContext.Customers .Expand(c => c.Orders.SubExpand(o => o.Items)) That query basically returns all the customers with their orders and order items. Ok, now that we have the automatic change tracking support and the expression support for explicitly loading entity associations, we are ready to create the repository. The interface for this repository looks like this,public interface IRepository { T Create<T>() where T : new(); void Update<T>(T entity); void Delete<T>(T entity); IQueryable<T> RetrieveAll<T>(params Expression<Func<T, object>>[] eagerProperties); IQueryable<T> Retrieve<T>(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] eagerProperties); void Attach<T>(T entity); void SaveChanges(); } The Retrieve and RetrieveAll methods are used to execute queries against the data service context. While both methods receive an array of expressions to load associations explicitly, only the Retrieve method receives a predicate representing the “where” clause. The following code represents the final implementation of this repository.public class DataServiceRepository: IRepository { ResourceRepositoryContext context; public DataServiceRepository() : this (new DataServiceContext()) { } public DataServiceRepository(DataServiceContext context) { this.context = context; } private static string ResolveEntitySet(Type type) { var entitySetAttribute = (EntitySetAttribute)type.GetCustomAttributes(typeof(EntitySetAttribute), true).FirstOrDefault(); if (entitySetAttribute != null) return entitySetAttribute.EntitySet; return null; } public T Create<T>() where T : new() { var collection = new DataServiceCollection<T>(this.context); var entity = new T(); collection.Add(entity); return entity; } public void Update<T>(T entity) { this.context.UpdateObject(entity); } public void Delete<T>(T entity) { this.context.DeleteObject(entity); } public void Attach<T>(T entity) { var collection = new DataServiceCollection<T>(this.context); collection.Load(entity); } public IQueryable<T> Retrieve<T>(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] eagerProperties) { var entitySet = ResolveEntitySet(typeof(T)); var query = context.CreateQuery<T>(entitySet); foreach (var e in eagerProperties) { query = query.Expand(e); } return query.Where(predicate); } public IQueryable<T> RetrieveAll<T>(params Expression<Func<T, object>>[] eagerProperties) { var entitySet = ResolveEntitySet(typeof(T)); var query = context.CreateQuery<T>(entitySet); foreach (var e in eagerProperties) { query = query.Expand(e); } return query; } public void SaveChanges() { this.context.SaveChanges(SaveChangesOptions.Batch); } } For instance, you can use the following code to retrieve customers with First name equal to “John”, and all their orders in a single call. repository.Retrieve<Customer>(    c => c.FirstName == “John”, //Where    c => c.Orders.SubExpand(o => o.Items)); In case, you want to have some pre-defined queries that you are going to use across several places, you can put them in an specific class. public static class CustomerQueries {   public static Expression<Func<Customer, bool>> LastNameEqualsTo(string lastName)   {     return c => c.LastName == lastName;   } } And then, use it with the repository. repository.Retrieve<Customer>(    CustomerQueries.LastNameEqualsTo("foo"),    c => c.Orders.SubExpand(o => o.Items));

  Read the article

• Pluralsight Meet the Author Podcast on Structuring JavaScript Code

  - by dwahlin

  I had the opportunity to talk with Fritz Onion from Pluralsight about one of my recent courses titled Structuring JavaScript Code for one of their Meet the Author podcasts. We talked about why JavaScript patterns are important for building more re-useable and maintainable apps, pros and cons of different patterns, and how to go about picking a pattern as a project is started. The course provides a solid walk-through of converting what I call “Function Spaghetti Code” into more modular code that’s easier to maintain, more re-useable, and less susceptible to naming conflicts. Patterns covered in the course include the Prototype Pattern, Revealing Module Pattern, and Revealing Prototype Pattern along with several other tips and techniques that can be used. Meet the Author:  Dan Wahlin on Structuring JavaScript Code   The transcript from the podcast is shown below: [Fritz]  Hello, this is Fritz Onion with another Pluralsight author interview. Today we’re talking with Dan Wahlin about his new course, Structuring JavaScript Code. Hi, Dan, it’s good to have you with us today. [Dan]  Thanks for having me, Fritz. [Fritz]  So, Dan, your new course, which came out in December of 2011 called Structuring JavaScript Code, goes into several patterns of usage in JavaScript as well as ways of organizing your code and what struck me about it was all the different techniques you described for encapsulating your code. I was wondering if you could give us just a little insight into what your motivation was for creating this course and sort of why you decided to write it and record it. [Dan]  Sure. So, I got started with JavaScript back in the mid 90s. In fact, back in the days when browsers that most people haven’t heard of were out and we had JavaScript but it wasn’t great. I was on a project in the late 90s that was heavy, heavy JavaScript and we pretty much did what I call in the course function spaghetti code where you just have function after function, there’s no rhyme or reason to how those functions are structured, they just kind of flow and it’s a little bit hard to do maintenance on it, you really don’t get a lot of reuse as far as from an object perspective. And so coming from an object-oriented background in JAVA and C#, I wanted to put something together that highlighted kind of the new way if you will of writing JavaScript because most people start out just writing functions and there’s nothing with that, it works, but it’s definitely not a real reusable solution. So the course is really all about how to move from just kind of function after function after function to the world of more encapsulated code and more reusable and hopefully better maintenance in the process. [Fritz]  So I am sure a lot of people have had similar experiences with their JavaScript code and will be looking forward to seeing what types of patterns you’ve put forth. Now, a couple I noticed in your course one is you start off with the prototype pattern. Do you want to describe sort of what problem that solves and how you go about using it within JavaScript? [Dan]  Sure. So, the patterns that are covered such as the prototype pattern and the revealing module pattern just as two examples, you know, show these kind of three things that I harp on throughout the course of encapsulation, better maintenance, reuse, those types of things. The prototype pattern specifically though has a couple kind of pros over some of the other patterns and that is the ability to extend your code without touching source code and what I mean by that is let’s say you’re writing a library that you know either other teammates or other people just out there on the Internet in general are going to be using. With the prototype pattern, you can actually write your code in such a way that we’re leveraging the JavaScript property and by doing that now you can extend my code that I wrote without touching my source code script or you can even override my code and perform some new functionality. Again, without touching my code.  And so you get kind of the benefit of the almost like inheritance or overriding in object oriented languages with this prototype pattern and it makes it kind of attractive that way definitely from a maintenance standpoint because, you know, you don’t want to modify a script I wrote because I might roll out version 2 and now you’d have to track where you change things and it gets a little tricky. So with this you just override those pieces or extend them and get that functionality and that’s kind of some of the benefits that that pattern offers out of the box. [Fritz]  And then the revealing module pattern, how does that differ from the prototype pattern and what problem does that solve differently? [Dan]  Yeah, so the prototype pattern and there’s another one that’s kind of really closely lined with revealing module pattern called the revealing prototype pattern and it also uses the prototype key word but it’s very similar to the one you just asked about the revealing module pattern. [Fritz]  Okay. [Dan]  This is a really popular one out there. In fact, we did a project for Microsoft that was very, very heavy JavaScript. It was an HMTL5 jQuery type app and we use this pattern for most of the structure if you will for the JavaScript code and what it does in a nutshell is allows you to get that encapsulation so you have really a single function wrapper that wraps all your other child functions but it gives you the ability to do public versus private members and this is kind of a sort of debate out there on the web. Some people feel that all JavaScript code should just be directly accessible and others kind of like to be able to hide their, truly their private stuff and a lot of people do that. You just put an underscore in front of your field or your variable name or your function name and that kind of is the defacto way to say hey, this is private. With the revealing module pattern you can do the equivalent of what objective oriented languages do and actually have private members that you literally can’t get to as an external consumer of the JavaScript code and then you can expose only those members that you want to be public. Now, you don’t get the benefit though of the prototype feature, which is I can’t easily extend the revealing module pattern type code if you don’t like something I’m doing, chances are you’re probably going to have to tweak my code to fix that because we’re not leveraging prototyping but in situations where you’re writing apps that are very specific to a given target app, you know, it’s not a library, it’s not going to be used in other apps all over the place, it’s a pattern I actually like a lot, it’s very simple to get going and then if you do like that public/private feature, it’s available to you. [Fritz]  Yeah, that’s interesting. So it’s almost, you can either go private by convention just by using a standard naming convention or you can actually enforce it by using the prototype pattern. [Dan]  Yeah, that’s exactly right. [Fritz]  So one of the things that I know I run across in JavaScript and I’m curious to get your take on is we do have all these different techniques of encapsulation and each one is really quite different when you’re using closures versus simply, you know, referencing member variables and adding them to your objects that the syntax changes with each pattern and the usage changes. So what would you recommend for people starting out in a brand new JavaScript project? Should they all sort of decide beforehand on what patterns they’re going to stick to or do you change it based on what part of the library you’re working on? I know that’s one of the points of confusion in this space. [Dan]  Yeah, it’s a great question. In fact, I just had a company ask me about that. So which one do I pick and, of course, there’s not one answer fits all. [Fritz]  Right. [Dan]  So it really depends what you just said is absolutely in my opinion correct, which is I think as a, especially if you’re on a team or even if you’re just an individual a team of one, you should go through and pick out which pattern for this particular project you think is best. Now if it were me, here’s kind of the way I think of it. If I were writing a let’s say base library that several web apps are going to use or even one, but I know that there’s going to be some pieces that I’m not really sure on right now as I’m writing I and I know people might want to hook in that and have some better extension points, then I would look at either the prototype pattern or the revealing prototype. Now, really just a real quick summation between the two the revealing prototype also gives you that public/private stuff like the revealing module pattern does whereas the prototype pattern does not but both of the prototype patterns do give you the benefit of that extension or that hook capability. So, if I were writing a library that I need people to override things or I’m not even sure what I need them to override, I want them to have that option, I’d probably pick a prototype, one of the prototype patterns. If I’m writing some code that is very unique to the app and it’s kind of a one off for this app which is what I think a lot of people are kind of in that mode as writing custom apps for customers, then my personal preference is the revealing module pattern you could always go with the module pattern as well which is very close but I think the revealing module patterns a little bit cleaner and we go through that in the course and explain kind of the syntax there and the differences. [Fritz]  Great, that makes a lot of sense. [Fritz]  I appreciate you taking the time, Dan, and I hope everyone takes a chance to look at your course and sort of make these decisions for themselves in their next JavaScript project. Dan’s course is, Structuring JavaScript Code and it’s available now in the Pluralsight Library. So, thank you very much, Dan. [Dan]  Thanks for having me again.

  Read the article

• Wine MFC80.DLL Issue

  - by Kush

  I am getting the following error when trying to run winetricks vcrun2005. "vcrun2005 install completed, but installed file /home/compuz/.wine/dosdevices/c:/windows/winsxs/x86_Microsoft.VC80.MFC_1fc8b3b9a1e18e3b_8.0.50727.6195_x-ww_150c9e8b/mfc80.dll not found" I then tried the following command: winetricks dlls list | grep mfc80 This gave the following output: vcrun2005 Visual C++ 2005 libraries (mfc80,msvcp80,msvcr80) (Microsoft, 2011) [downloadable,cached] Here mfc80 is colored red. This is the complete log: $ winetricks vcrun2005 Executing w_do_call vcrun2005 Executing load_vcrun2005 Executing mkdir -p /home/compuz/.cache/winetricks/vcrun2005 Using native,builtin override for following DLLs: msvcr80 Executing winetricks_early_wine regedit C:\windows\Temp\_vcrun2005\override-dll.reg Executing wine vcredist_x86.EXE fixme:advapi:DecryptFileA "C:\\users\\compuz\\Temp\\IXP000.TMP\\" 00000000 wine: Call from 0x7bc49070 to unimplemented function SHLWAPI.dll.SHRegGetValueW, aborting err:module:attach_process_dlls "urlmon.dll" failed to initialize, aborting err:module:LdrInitializeThunk Main exe initialization for L"C:\\windows\\system32\\msiexec.exe" failed, status 80000100 ------------------------------------------------------ vcrun2005 install completed, but installed file /home/compuz/.wine/dosdevices/c:/windows/winsxs/x86_Microsoft.VC80.MFC_1fc8b3b9a1e18e3b_8.0.50727.6195_x-ww_150c9e8b/mfc80.dll not found How can I fix this issue?

  Read the article

• Ten - oh, wait, eleven - Eleven things you should know about the ASP.NET Fall 2012 Update

  - by Jon Galloway

  Today, just a little over two months after the big ASP.NET 4.5 / ASP.NET MVC 4 / ASP.NET Web API / Visual Studio 2012 / Web Matrix 2 release, the first preview of the ASP.NET Fall 2012 Update is out. Here's what you need to know: There are no new framework bits in this release - there's no change or update to ASP.NET Core, ASP.NET MVC or Web Forms features. This means that you can start using it without any updates to your server, upgrade concerns, etc. This update is really an update to the project templates and Visual Studio tooling, conceptually similar to the ASP.NET MVC 3 Tools Update. It's a relatively lightweight install. It's a 41MB download. I've installed it many times and usually takes 5-7 minutes; it's never required a reboot. It adds some new project templates to ASP.NET MVC: Facebook Application and Single Page Application templates. It adds a lot of cool enhancements to ASP.NET Web API. It adds some tooling that makes it easy to take advantage of features like SignalR, Friendly URLs, and Windows Azure Authentication. Most of the new features are installed via NuGet packages. Since ASP.NET is open source, nightly NuGet packages are available, and the roadmap is published, most of this has really been publicly available for a while. The official name of this drop is the ASP.NET Fall 2012 Update BUILD Prerelease. Please do not attempt to say that ten times fast. While the EULA doesn't prohibit it, it WILL legally change your first name to Scott. As with all new releases, you can find out everything you need to know about the Fall Update at http://asp.net/vnext (especially the release notes!) I'm going to be showing all of this off, assisted by special guest code monkey Scott Hanselman, this Friday at BUILD: Bleeding edge ASP.NET: See what is next for MVC, Web API, SignalR and more… (and I've heard it will be livestreamed). Let's look at some of those things in more detail. No new bits ASP.NET 4.5, MVC 4 and Web API have a lot of great core features. I see the goal of this update release as making it easier to put those features to use to solve some useful scenarios by taking advantage of NuGet packages and template code. If you create a new ASP.NET MVC application using one of the new templates, you'll see that it's using the ASP.NET MVC 4 RTM NuGet package (4.0.20710.0): This means you can install and use the Fall Update without any impact on your existing projects and no worries about upgrading or compatibility. New Facebook Application Template ASP.NET MVC 4 (and ASP.NET 4.5 Web Forms) included the ability to authenticate your users via OAuth and OpenID, so you could let users log in to your site using a Facebook account. One of the new changes in the Fall Update is a new template that makes it really easy to create full Facebook applications. You could create Facebook application in ASP.NET already, you'd just need to go through a few steps: Search around to find a good Facebook NuGet package, like the Facebook C# SDK (written by my friend Nathan Totten and some other Facebook SDK brainiacs). Read the Facebook developer documentation to figure out how to authenticate and integrate with them. Write some code, debug it and repeat until you got something working. Get started with the application you'd originally wanted to write. What this template does for you: eliminate steps 1-3. Erik Porter, Nathan and some other experts built out the Facebook Application template so it automatically pulls in and configures the Facebook NuGet package and makes it really easy to take advantage of it in an ASP.NET MVC application. One great example is the the way you access a Facebook user's information. Take a look at the following code in a File / New / MVC / Facebook Application site. First, the Home Controller Index action: [FacebookAuthorize(Permissions = "email")] public ActionResult Index(MyAppUser user, FacebookObjectList<MyAppUserFriend> userFriends) { ViewBag.Message = "Modify this template to jump-start your Facebook application using ASP.NET MVC."; ViewBag.User = user; ViewBag.Friends = userFriends.Take(5); return View(); } First, notice that there's a FacebookAuthorize attribute which requires the user is authenticated via Facebook and requires permissions to access their e-mail address. It binds to two things: a custom MyAppUser object and a list of friends. Let's look at the MyAppUser code: using Microsoft.AspNet.Mvc.Facebook.Attributes; using Microsoft.AspNet.Mvc.Facebook.Models; // Add any fields you want to be saved for each user and specify the field name in the JSON coming back from Facebook // https://developers.facebook.com/docs/reference/api/user/ namespace MvcApplication3.Models { public class MyAppUser : FacebookUser { public string Name { get; set; } [FacebookField(FieldName = "picture", JsonField = "picture.data.url")] public string PictureUrl { get; set; } public string Email { get; set; } } } You can add in other custom fields if you want, but you can also just bind to a FacebookUser and it will automatically pull in the available fields. You can even just bind directly to a FacebookUser and check for what's available in debug mode, which makes it really easy to explore. For more information and some walkthroughs on creating Facebook applications, see: Deploying your first Facebook App on Azure using ASP.NET MVC Facebook Template (Yao Huang Lin) Facebook Application Template Tutorial (Erik Porter) Single Page Application template Early releases of ASP.NET MVC 4 included a Single Page Application template, but it was removed for the official release. There was a lot of interest in it, but it was kind of complex, as it handled features for things like data management. The new Single Page Application template that ships with the Fall Update is more lightweight. It uses Knockout.js on the client and ASP.NET Web API on the server, and it includes a sample application that shows how they all work together. I think the real benefit of this application is that it shows a good pattern for using ASP.NET Web API and Knockout.js. For instance, it's easy to end up with a mess of JavaScript when you're building out a client-side application. This template uses three separate JavaScript files (delivered via a Bundle, of course): todoList.js - this is where the main client-side logic lives todoList.dataAccess.js - this defines how the client-side application interacts with the back-end services todoList.bindings.js - this is where you set up events and overrides for the Knockout bindings - for instance, hooking up jQuery validation and defining some client-side events This is a fun one to play with, because you can just create a new Single Page Application and hit F5. Quick, easy install (with one gotcha) One of the cool engineering changes for this release is a big update to the installer to make it more lightweight and efficient. I've been running nightly builds of this for a few weeks to prep for my BUILD demos, and the install has been really quick and easy to use. The install takes about 5 minutes, has never required a reboot for me, and the uninstall is just as simple. There's one gotcha, though. In this preview release, you may hit an issue that will require you to uninstall and re-install the NuGet VSIX package. The problem comes up when you create a new MVC application and see this dialog: The solution, as explained in the release notes, is to uninstall and re-install the NuGet VSIX package: Start Visual Studio 2012 as an Administrator Go to Tools->Extensions and Updates and uninstall NuGet. Close Visual Studio Navigate to the ASP.NET Fall 2012 Update installation folder: For Visual Studio 2012: Program Files\Microsoft ASP.NET\ASP.NET Web Stack\Visual Studio 2012 For Visual Studio 2012 Express for Web: Program Files\Microsoft ASP.NET\ASP.NET Web Stack\Visual Studio Express 2012 for Web Double click on the NuGet.Tools.vsix to reinstall NuGet This took me under a minute to do, and I was up and running. ASP.NET Web API Update Extravaganza! Uh, the Web API team is out of hand. They added a ton of new stuff: OData support, Tracing, and API Help Page generation. OData support Some people like OData. Some people start twitching when you mention it. If you're in the first group, this is for you. You can add a [Queryable] attribute to an API that returns an IQueryable<Whatever> and you get OData query support from your clients. Then, without any extra changes to your client or server code, your clients can send filters like this: /Suppliers?$filter=Name eq ‘Microsoft’ For more information about OData support in ASP.NET Web API, see Alex James' mega-post about it: OData support in ASP.NET Web API ASP.NET Web API Tracing Tracing makes it really easy to leverage the .NET Tracing system from within your ASP.NET Web API's. If you look at the \App_Start\WebApiConfig.cs file in new ASP.NET Web API project, you'll see a call to TraceConfig.Register(config). That calls into some code in the new \App_Start\TraceConfig.cs file: public static void Register(HttpConfiguration configuration) { if (configuration == null) { throw new ArgumentNullException("configuration"); } SystemDiagnosticsTraceWriter traceWriter = new SystemDiagnosticsTraceWriter() { MinimumLevel = TraceLevel.Info, IsVerbose = false }; configuration.Services.Replace(typeof(ITraceWriter), traceWriter); } As you can see, this is using the standard trace system, so you can extend it to any other trace listeners you'd like. To see how it works with the built in diagnostics trace writer, just run the application call some API's, and look at the Visual Studio Output window: iisexpress.exe Information: 0 : Request, Method=GET, Url=http://localhost:11147/api/Values, Message='http://localhost:11147/api/Values' iisexpress.exe Information: 0 : Message='Values', Operation=DefaultHttpControllerSelector.SelectController iisexpress.exe Information: 0 : Message='WebAPI.Controllers.ValuesController', Operation=DefaultHttpControllerActivator.Create iisexpress.exe Information: 0 : Message='WebAPI.Controllers.ValuesController', Operation=HttpControllerDescriptor.CreateController iisexpress.exe Information: 0 : Message='Selected action 'Get()'', Operation=ApiControllerActionSelector.SelectAction iisexpress.exe Information: 0 : Operation=HttpActionBinding.ExecuteBindingAsync iisexpress.exe Information: 0 : Operation=QueryableAttribute.ActionExecuting iisexpress.exe Information: 0 : Message='Action returned 'System.String[]'', Operation=ReflectedHttpActionDescriptor.ExecuteAsync iisexpress.exe Information: 0 : Message='Will use same 'JsonMediaTypeFormatter' formatter', Operation=JsonMediaTypeFormatter.GetPerRequestFormatterInstance iisexpress.exe Information: 0 : Message='Selected formatter='JsonMediaTypeFormatter', content-type='application/json; charset=utf-8'', Operation=DefaultContentNegotiator.Negotiate iisexpress.exe Information: 0 : Operation=ApiControllerActionInvoker.InvokeActionAsync, Status=200 (OK) iisexpress.exe Information: 0 : Operation=QueryableAttribute.ActionExecuted, Status=200 (OK) iisexpress.exe Information: 0 : Operation=ValuesController.ExecuteAsync, Status=200 (OK) iisexpress.exe Information: 0 : Response, Status=200 (OK), Method=GET, Url=http://localhost:11147/api/Values, Message='Content-type='application/json; charset=utf-8', content-length=unknown' iisexpress.exe Information: 0 : Operation=JsonMediaTypeFormatter.WriteToStreamAsync iisexpress.exe Information: 0 : Operation=ValuesController.Dispose API Help Page When you create a new ASP.NET Web API project, you'll see an API link in the header: Clicking the API link shows generated help documentation for your ASP.NET Web API controllers: And clicking on any of those APIs shows specific information: What's great is that this information is dynamically generated, so if you add your own new APIs it will automatically show useful and up to date help. This system is also completely extensible, so you can generate documentation in other formats or customize the HTML help as much as you'd like. The Help generation code is all included in an ASP.NET MVC Area: SignalR SignalR is a really slick open source project that was started by some ASP.NET team members in their spare time to add real-time communications capabilities to ASP.NET - and .NET applications in general. It allows you to handle long running communications channels between your server and multiple connected clients using the best communications channel they can both support - websockets if available, falling back all the way to old technologies like long polling if necessary for old browsers. SignalR remains an open source project, but now it's being included in ASP.NET (also open source, hooray!). That means there's real, official ASP.NET engineering work being put into SignalR, and it's even easier to use in an ASP.NET application. Now in any ASP.NET project type, you can right-click / Add / New Item... SignalR Hub or Persistent Connection. And much more... There's quite a bit more. You can find more info at http://asp.net/vnext, and we'll be adding more content as fast as we can. Watch my BUILD talk to see as I demonstrate these and other features in the ASP.NET Fall 2012 Update, as well as some other even futurey-er stuff!

  Read the article

• SQLAuthority News – Pluralsight Course Review – Practices for Software Startups – Part 1 of 2

  - by pinaldave

  This is first part of the two part series of Practices for Software Startup Pluralsight Course. The course is written by Stephen Forte (Blog | Twitter). Stephen Forte is the Chief Strategy Officer of the venture backed company, Telerik, a leading vendor of developer and team productivity tools. Stephen is also a Certified Scrum Master, Certified Scrum Professional, PMP, and also speaks regularly at industry conferences around the world. He has written several books on application and database development.  Stephen is also a board member of the Scrum Alliance. Startups – Everybodies Dream Start-up companies are an important topic right now – everyone wants to start their own business.  It is also important to remember that all companies were a start up at one point – from your corner store to the giants like Microsoft and Apple.  Research proves that not every start-up succeeds, in fact, most will fail before their first year.  There are many reasons for this, and this could be due to the fact that there are many stages to a start-up company, and stumbling at any of these stages can lead to failure.  It is important to understand what makes a start-up company succeed at all its hurdles to become successful.  It is even important to define success.  For most start-ups this would mean becoming their own independently functioning company or to be bought out for a hefty profit by a larger company.  The idea of making a hefty profit by living your dream is extremely important, and you can even think of start-ups as the new craze.  That’s why studying them is so important – they are very popular, but things have changed a lot since their inception. Starting the Startups Beginning a start-up company used to be difficult, but now facilities and information is widely available, and it is much easier.  But that means it is much easier to fail, also.  Previously to start your own company, everything was planned and organized, resources were ensured and backed up before beginning; even the idea of starting your own business was a big thing.  Now anybody can do it, and the steps are simple and outlines everywhere – you can get online software and easily outsource , cloud source, or crowdsource a lot of your material.  But without the type of planning previously required, things can often go badly. New Products – New Ideas – New World There are so many fantastic new products, but they don’t reach success all the time.  I find start-up companies very interesting, and whenever I meet someone who is interested in the subject or already starting their own company, I always ask what they are doing, their plans, goals, market, etc.  I am sorry to say that in most cases, they cannot answer my questions.  It is true that many fantastic ideas fail because of bad decisions.  These bad decisions were not made intentionally, but people were simply unaware of what they should be doing.  This will always lead to failure.  But I am happy to say that all these issues can be gone because Pluralsight is now offering a course all about start-ups by Stephen Forte.  Stephen is a start up leader.  He has successfully started many companies and most are still going strong, or have gone on to even bigger and better things. Beginning Course on Startup I have always thought start-ups are a fascinating subject, and decided to take his course, but it is three hours long.  This would be hard to fit into my busy work day all at once, so I decided to do half of his course before my daughter wakes up, and the other half after she goes to sleep.  The course is divided into six modules, so this would be easy to do.  I began the first chapter early in the morning, at 5 am.  Stephen jumped right into the middle of the subject in the very first module – designing your business plan.  The first question you will have to answer to yourself, to others, and to investors is: What is your product and when will we be able to see it?  So a very important concept is a “minimal viable product.”  This means setting goals for yourself and your product.  We all have large dreams, but your minimal viable product doesn’t have to be your final vision at the very first.  For example: Apple is a giant company, but it is still evolving.  Steve Jobs didn’t envision the iPhone 6 at the very beginning.  He had to start at the first iPhone and do his market research, and the idea evolved into the technology you see now.  So for yourself, you should decide a beginning and stop point.  Do your market research.  Determine who you want to reach, what audience you want for your product.  You can have a great idea that simply will not work in the market, do need, bottlenecks, lack of resources, or competition.  There is a lot of research that needs to be done before you even write a business plan, and Stephen covers it in the very first chapter. The Team – Unique Key to Success After jumping right into the subject in the very first module, I wondered what Stephen could have in store for me for the rest of the course.  Chapter number two is building a team.  Having a team is important regardless of what your startup is.  You can be a true visionary with endless ideas and energy, but one person can still not do everything.  It is important to decide from the very beginning if you will have cofounders, team leaders, and how many employees you’ll need.  Even more important, you’ll need to decide what kind of team you want – what personalities, skills, and type of energy you want each of your employees to bring.  Do you want to have an A+ team with a B- idea, or do you have a B- idea that needs an A+ team to sell it?  Stephen asks all the hard questions!  I was especially impressed by his insight on developing.  You have to decide if you need developers, how many, and what their skills should be. I found this insight extremely useful for everyday usage, not just for start-up companies.  I would apply this kind of information in management at any position.  An amazing team will build an amazing product – and that doesn’t matter if you’re a start-up company or a small team working for a much larger business. Customer Development – The Ultimate Obective Chapter three was about customer development. According to Stephen, there are four different steps to develop a customer base.  The first question to ask yourself is if you are envisioning a large customer base buying a few products each, or a small, dedicated base that buys a lot of your product – quantity vs. Quality.  He also discusses how to earn, retain, and get more customers.  He also says that each customer should be placed in a different role – some will be like investors, who regularly spend with you and invest their money in your business.  It is then your job to take that investment and turn it into a better product in the future.  You need to deal with their money properly – think of it is as theirs as investors, not yours as profit.  At the end of this module I felt that only Stephen could provide this kind of insight, and then he listed all the resources he took his information from.  I have never seen a group of people so passionate about their customers. It was indeed a long day for me. In tomorrow’s part 2 we will discuss rest of the three module and also will see a quick video of the Practices for Software Startup Pluralsight Course. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Best Practices, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• Beware: Upgrade to ASP.NET MVC 2.0 with care if you use AntiForgeryToken

  - by James Crowley

  If you're thinking of upgrading to MVC 2.0, and you take advantage of the AntiForgeryToken support then be careful - you can easily kick out all active visitors after the upgrade until they restart their browser. Why's this?For the anti forgery validation to take place, ASP.NET MVC uses a session cookie called "__RequestVerificationToken_Lw__". This gets checked for and de-serialized on any page where there is an AntiForgeryToken() call. However, the format of this validation cookie has apparently changed between MVC 1.0 and MVC 2.0. What this means is that when you make to switch on your production server to MVC 2.0, suddenly all your visitors session cookies are invalid, resulting in calls to AntiForgeryToken() throwing exceptions (even on a standard GET request) when de-serializing it: [InvalidCastException: Unable to cast object of type 'System.Web.UI.Triplet' to type 'System.Object[]'.]   System.Web.Mvc.AntiForgeryDataSerializer.Deserialize(String serializedToken) +104[HttpAntiForgeryException (0x80004005): A required anti-forgery token was not supplied or was invalid.]   System.Web.Mvc.AntiForgeryDataSerializer.Deserialize(String serializedToken) +368   System.Web.Mvc.HtmlHelper.GetAntiForgeryTokenAndSetCookie(String salt, String domain, String path) +209   System.Web.Mvc.HtmlHelper.AntiForgeryToken(String salt, String domain, String path) +16   System.Web.Mvc.HtmlHelper.AntiForgeryToken() +10  <snip> So you've just kicked all your active users out of your site with exceptions until they think to restart their browser (to clear the session cookies). The only work around for now is to either write some code that wipes this cookie - or disable use of AntiForgeryToken() in your MVC 2.0 site until you're confident all session cookies will have expired. That in itself isn't very straightforward, given how frequently people tend to hibernate/standby their machines - the session cookie will only clear once the browser has been shut down and re-opened. Hope this helps someone out there!

  Read the article

• Spritebatch not working in winforms

  - by CodingMadeEasy

  I'm using the Winforms sample on the app hub and everything is working fine except my spritebatch won't draw anything unless I call Invalidate in the Draw method. I have this in my initialize method: Application.Idle += delegate { Invalidate(); }; I used a breakpoint and it is indeed invalidating my program and it is calling my draw method. I get no errors with the spritebatch and all the textures are loaded I just don't see anything on the screen. Here's the code I have: protected override void Draw() { GraphicsDevice.Clear(Color.CornflowerBlue); spriteBatch.Begin(); tileSheet.Draw(spriteBatch); foreach (Image img in selector) img.Draw(spriteBatch); spriteBatch.End(); } But when I do this: protected override void Draw() { GraphicsDevice.Clear(Color.CornflowerBlue); spriteBatch.Begin(); tileSheet.Draw(spriteBatch); foreach (Image img in selector) img.Draw(spriteBatch); spriteBatch.End(); Invalidate(); } then all of a sudden the drawing starts to work! but the problem is that it freezes everything else and only that control gets updated. What can I do to fix this? It's really frustrating.

  Read the article

• Connecting Dell PowerVault NAS to ESXi

  - by Matt Fitz

  Just got a Dell PowerVault NAS storage device running Windows Storage Server Standard which includes NFS. When I try and connect the ESXi server I get the following message: Call "HostDatastoreSystem.CreateNasDatastore" for object "ha-datastoresystem" on ESXi "powerhouse" failed. Operation failed, diagnostics report: Unable to complete Sysinfo operation. Please see the VMkernel log file for more details. I am pretty sure it is a username/password type thing. Not sure were to begin though. Also, I am planning on using "Username Mapping" instead of Active Directory. Any ideas would be greatly appreciated

  Read the article

• Uploading documents to WSS (Windows Sharepoint Services) using SSIS

  - by Randy Aldrich Paulo

  Recently I was tasked to create an SSIS application that will query a database, split the results with certain criteria and create CSV file for every result and upload the file to a Sharepoint Document Library site. I've search the web and compiled the steps I've taken to build the solution. Summary: A) Create a proxy class of WSS Copy.asmx. B) Create a wrapper class for the proxy class and add a mechanism to check if the file is existing and delete method. C) Create an SSIS and call the wrapper class to transfer the files.   A) Creating Proxy Class 1) Go to Visual Studio Command Prompt type wsdl http://[sharepoint site]/_vti_bin/Copy.asmx this will generate the proxy class (Copy.cs) that will be added to the solution. 2) Add Copy.cs to solution and create another constructor for Copy() that will accept additional parameters url, userName, password and domain.   public Copy(string url, string userName, string password, string domain) { this.Url = url; this.Credentials = new System.Net.NetworkCredential(userName, password, domain); } 3) Add a namespace.     B) Wrapper Class Create a C# new library that references the Proxy Class.         C) Create SSIS SSIS solution is composed of:   1) Execute SQL Task, returns a single column rows containing the criteria. 2) Foreach Loop Container - loops per result from query (SQL Task) and creates a CSV file on a certain folder. 3) Script Task - calls the wrapper class to upload CSV files located on a certain folder to targer WSS Document Library Note: I've created another overload of CopyFiles that accepts a Directory Info instead of file location that loops thru the contents of the folder. Designer View Variable View

  Read the article

• Installing a php extension (xdiff) from pecl on Linux

  - by wilsonsilva

  I was getting this error on my php script: Fatal error: Call to undefined function xdiff_file_diff() I realised that I didn't had the xdiff extension installed. When I tried to install it using the install pecl xdiff command, I got this errors (among other lines): configure: WARNING: You will need re2c 0.13.4 or later if you want to regenerate PHP configure: error: Please reinstall the libxdiff distribution Then I installed re2c and libxdiff: wget http://www.compdigitec.com/labs/files/re2c_0135_redhat.rpm wget ftp://ftp.task.gda.pl/vol/vol1/ftp.pld-linux.org/dists/2.0/PLD/i386/PLD/RPMS/libxdiff-0.7-1.i386.rpm rpm -ivh re2c_0135_redhat.rpm rpm -ivh libxdiff-0.7-1.i386 But after that I still get the same errors. PS: I've Googled a LOT and I found a couple of people with this problem but they didn't get an answer either :(

  Read the article

• .NET Weak Event Handlers – Part II

  - by João Angelo

  On the first part of this article I showed two possible ways to create weak event handlers. One using reflection and the other using a delegate. For this performance analysis we will further differentiate between creating a delegate by providing the type of the listener at compile time (Explicit Delegate) vs creating the delegate with the type of the listener being only obtained at runtime (Implicit Delegate). As expected, the performance between reflection/delegate differ significantly. With the reflection based approach, creating a weak event handler is just storing a MethodInfo reference while with the delegate based approach there is the need to create the delegate which will be invoked later. So, at creating the weak event handler reflection clearly wins, but what about when the handler is invoked. No surprises there, performing a call through reflection every time a handler is invoked is costly. In conclusion, if you want good performance when creating handlers that only sporadically get triggered use reflection, otherwise use the delegate based approach. The explicit delegate approach always wins against the implicit delegate, but I find the syntax for the latter much more intuitive. // Implicit delegate - The listener type is inferred at runtime from the handler parameter public static EventHandler WrapInDelegateCall(EventHandler handler); public static EventHandler<TArgs> WrapInDelegateCall<TArgs>(EventHandler<TArgs> handler) where TArgs : EventArgs; // Explicite delegate - TListener is the type that defines the handler public static EventHandler WrapInDelegateCall<TListener>(EventHandler handler); public static EventHandler<TArgs> WrapInDelegateCall<TArgs, TListener>(EventHandler<TArgs> handler) where TArgs : EventArgs;

  Read the article

• Back to Basics: When does a .NET Assembly Dependency get loaded

  - by Rick Strahl

  When we work on typical day to day applications, it's easy to forget some of the core features of the .NET framework. For me personally it's been a long time since I've learned about some of the underlying CLR system level services even though I rely on them on a daily basis. I often think only about high level application constructs and/or high level framework functionality, but the low level stuff is often just taken for granted. Over the last week at DevConnections I had all sorts of low level discussions with other developers about the inner workings of this or that technology (especially in light of my Low Level ASP.NET Architecture talk and the Razor Hosting talk). One topic that came up a couple of times and ended up a point of confusion even amongst some seasoned developers (including some folks from Microsoft <snicker>) is when assemblies actually load into a .NET process. There are a number of different ways that assemblies are loaded in .NET. When you create a typical project assemblies usually come from: The Assembly reference list of the top level 'executable' project The Assembly references of referenced projects Dynamically loaded at runtime via AppDomain/Reflection loading In addition .NET automatically loads mscorlib (most of the System namespace) the boot process that hosts the .NET runtime in EXE apps, or some other kind of runtime hosting environment (runtime hosting in servers like IIS, SQL Server or COM Interop). In hosting environments the runtime host may also pre-load a bunch of assemblies on its own (for example the ASP.NET host requires all sorts of assemblies just to run itself, before ever routing into your user specific code). Assembly Loading The most obvious source of loaded assemblies is the top level application's assembly reference list. You can add assembly references to a top level application and those assembly references are then available to the application. In a nutshell, referenced assemblies are not immediately loaded - they are loaded on the fly as needed. So regardless of whether you have an assembly reference in a top level project, or a dependent assembly assemblies typically load on an as needed basis, unless explicitly loaded by user code. The same is true of dependent assemblies. To check this out I ran a simple test: I have a utility assembly Westwind.Utilities which is a general purpose library that can work in any type of project. Due to a couple of small requirements for encoding and a logging piece that allows logging Web content (dependency on HttpContext.Current) this utility library has a dependency on System.Web. Now System.Web is a pretty large assembly and generally you'd want to avoid adding it to a non-Web project if it can be helped. So I created a Console Application that loads my utility library: You can see that the top level Console app a reference to Westwind.Utilities and System.Data (beyond the core .NET libs). The Westwind.Utilities project on the other hand has quite a few dependencies including System.Web. I then add a main program that accesses only a simple utillity method in the Westwind.Utilities library that doesn't require any of the classes that access System.Web: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.ReadLine(); } StringUtils.NewStringId() calls into Westwind.Utilities, but it doesn't rely on System.Web. Any guesses what the assembly list looks like when I stop the code on the ReadLine() command? I'll wait here while you think about it… … … So, when I stop on ReadLine() and then fire up Process Explorer and check the assembly list I get: We can see here that .NET has not actually loaded any of the dependencies of the Westwind.Utilities assembly. Also not loaded is the top level System.Data reference even though it's in the dependent assembly list of the top level project. Since this particular function I called only uses core System functionality (contained in mscorlib) there's in fact nothing else loaded beyond the main application and my Westwind.Utilities assembly that contains the method accessed. None of the dependencies of Westwind.Utilities loaded. If you were to open the assembly in a disassembler like Reflector or ILSpy, you would however see all the compiled in dependencies. The referenced assemblies are in the dependency list and they are loadable, but they are not immediately loaded by the application. In other words the C# compiler and .NET linker are smart enough to figure out the dependencies based on the code that actually is referenced from your application and any dependencies cascading down into the dependencies from your top level application into the referenced assemblies. In the example above the usage requirement is pretty obvious since I'm only calling a single static method and then exiting the app, but in more complex applications these dependency relationships become very complicated - however it's all taken care of by the compiler and linker figuring out what types and members are actually referenced and including only those assemblies that are in fact referenced in your code or required by any of your dependencies. The good news here is: That if you are referencing an assembly that has a dependency on something like System.Web in a few places that are not actually accessed by any of your code or any dependent assembly code that you are calling, that assembly is never loaded into memory! Some Hosting Environments pre-load Assemblies The load behavior can vary however. In Console and desktop applications we have full control over assembly loading so we see the core CLR behavior. However other environments like ASP.NET for example will preload referenced assemblies explicitly as part of the startup process - primarily to minimize load conflicts. Specifically ASP.NET pre-loads all assemblies referenced in the assembly list and the /bin folder. So in Web applications it definitely pays to minimize your top level assemblies if they are not used. Understanding when Assemblies Load To clarify and see it actually happen what I described in the first example , let's look at a couple of other scenarios. To see assemblies loading at runtime in real time lets create a utility function to print out loaded assemblies to the console: public static void PrintAssemblies() { var assemblies = AppDomain.CurrentDomain.GetAssemblies(); foreach (var assembly in assemblies) { Console.WriteLine(assembly.GetName()); } } Now let's look at the first scenario where I have class method that references internally uses System.Web. In the first scenario lets add a method to my main program like this: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.ReadLine(); PrintAssemblies(); } public static void WebLogEntry() { var entry = new WebLogEntry(); entry.UpdateFromRequest(); Console.WriteLine(entry.QueryString); } UpdateFromWebRequest() internally accesses HttpContext.Current to read some information of the ASP.NET Request object so it clearly needs a reference System.Web to work. In this first example, the method that holds the calling code is never called, but exists as a static method that can potentially be called externally at some point. What do you think will happen here with the assembly loading? Will System.Web load in this example? No - it doesn't. Because the WebLogEntry() method is never called by the mainline application (or anywhere else) System.Web is not loaded. .NET dynamically loads assemblies as code that needs it is called. No code references the WebLogEntry() method and so System.Web is never loaded. Next, let's add the call to this method, which should trigger System.Web to be loaded because a dependency exists. Let's change the code to: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.WriteLine("--- Before:"); PrintAssemblies(); WebLogEntry(); Console.WriteLine("--- After:"); PrintAssemblies(); Console.ReadLine(); } public static void WebLogEntry() { var entry = new WebLogEntry(); entry.UpdateFromRequest(); Console.WriteLine(entry.QueryString); } Looking at the code now, when do you think System.Web will be loaded? Will the before list include it? Yup System.Web gets loaded, but only after it's actually referenced. In fact, just until before the call to UpdateFromRequest() System.Web is not loaded - it only loads when the method is actually called and requires the reference in the executing code. Moral of the Story So what have we learned - or maybe remembered again? Dependent Assembly References are not pre-loaded when an application starts (by default) Dependent Assemblies that are not referenced by executing code are never loaded Dependent Assemblies are just in time loaded when first referenced in code All of this is nothing new - .NET has always worked like this. But it's good to have a refresher now and then and go through the exercise of seeing it work in action. It's not one of those things we think about everyday, and as I found out last week, I couldn't remember exactly how it worked since it's been so long since I've learned about this. And apparently I'm not the only one as several other people I had discussions with in relation to loaded assemblies also didn't recall exactly what should happen or assumed incorrectly that just having a reference automatically loads the assembly. The moral of the story for me is: Trying at all costs to eliminate an assembly reference from a component is not quite as important as it's often made out to be. For example, the Westwind.Utilities module described above has a logging component, including a Web specific logging entry that supports pulling information from the active HTTP Context. Adding that feature requires a reference to System.Web. Should I worry about this in the scope of this library? Probably not, because if I don't use that one class of nearly a hundred, System.Web never gets pulled into the parent process. IOW, System.Web only loads when I use that specific feature and if I am, well I clearly have to be running in a Web environment anyway to use it realistically. The alternative would be considerably uglier: Pulling out the WebLogEntry class and sticking it into another assembly and breaking up the logging code. In this case - definitely not worth it. So, .NET definitely goes through some pretty nifty optimizations to ensure that it loads only what it needs and in most cases you can just rely on .NET to do the right thing. Sometimes though assembly loading can go wrong (especially when signed and versioned local assemblies are involved), but that's subject for a whole other post…© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  CSharp   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

  Read the article

< Previous Page | 481 482 483 484 485 486 487 488 489 490 491 492  | Next Page >