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• Remove redundant xml namespaces from soapenv:Body

  - by drachenstern

  If you can tell me the magic google term that instantly gives me clarification, that would be helpful. Here's the part that's throwing an issue when I try to manually deserialize from a string: xsi:type="ns1:errorObject" xmlns:ns1="http://www.example.org/Version_3.0" xsi:type="ns2:errorObject" xmlns:ns2="http://www.example.org/Version_3.0" xsi:type="ns3:errorObject" xmlns:ns3="http://www.example.org/Version_3.0" Here's how I'm deserializing by hand to test it: (in an aspx.cs page with a label on the front to display the value in that I can verify by reading source) (second block of XML duplicates the first but without the extra namespaces) using System; using System.IO; using System.Text; using System.Xml; using System.Xml.Serialization; public partial class test : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { string sourceXml = @"<?xml version=""1.0""?> <InitiateActivityResponse xmlns=""http://www.example.org/Version_3.0""> <InitiateActivityResult> <errorObject errorString=""string 1"" eventTime=""2010-05-21T21:19:15.775Z"" nounType=""Object"" objectID=""object1"" xsi:type=""ns1:errorObject"" xmlns:ns1=""http://www.example.org/Version_3.0"" /> <errorObject errorString=""string 2"" eventTime=""2010-05-21T21:19:15.791Z"" nounType=""Object"" objectID=""object2"" xsi:type=""ns2:errorObject"" xmlns:ns2=""http://www.example.org/Version_3.0"" /> <errorObject errorString=""string 3"" eventTime=""2010-05-21T21:19:15.806Z"" nounType=""Object"" objectID=""object3"" xsi:type=""ns3:errorObject"" xmlns:ns3=""http://www.example.org/Version_3.0"" /> </InitiateActivityResult> </InitiateActivityResponse> "; sourceXml = @"<?xml version=""1.0""?> <InitiateActivityResponse xmlns=""http://www.example.org/Version_3.0""> <InitiateActivityResult> <errorObject errorString=""string 1"" eventTime=""2010-05-21T21:19:15.775Z"" nounType=""Object"" objectID=""object1"" /> <errorObject errorString=""string 2"" eventTime=""2010-05-21T21:19:15.791Z"" nounType=""Object"" objectID=""object2"" /> <errorObject errorString=""string 3"" eventTime=""2010-05-21T21:19:15.806Z"" nounType=""Object"" objectID=""object3"" /> </InitiateActivityResult> </InitiateActivityResponse> "; InitiateActivityResponse fragment = new InitiateActivityResponse(); Type t = typeof( InitiateActivityResponse ); StringBuilder sb = new StringBuilder(); TextWriter textWriter = new StringWriter( sb ); TextReader textReader = new StringReader( sourceXml ); XmlTextReader xmlTextReader = new XmlTextReader( textReader ); XmlSerializer xmlSerializer = new XmlSerializer( t ); object obj = xmlSerializer.Deserialize( xmlTextReader ); fragment = (InitiateActivityResponse)obj; xmlSerializer.Serialize( textWriter, fragment ); //I have a field on my public page that I write to from sb.ToString(); } } Consuming a webservice, I have a class like thus: (all examples foreshortened to as little as possible to show the problem, if boilerplate is missing, my apologies) (this is where I think I want to remove the troublespot) [System.Diagnostics.DebuggerStepThroughAttribute()] [System.ComponentModel.DesignerCategoryAttribute( "code" )] [System.Web.Services.WebServiceBindingAttribute( Name = "MyServerSoapSoapBinding", Namespace = "http://www.example.org/Version_3.0" )] public partial class MyServer : System.Web.Services.Protocols.SoapHttpClientProtocol { public MsgHeader msgHeader { get; set; } public MyServer () { this.Url = "localAddressOmittedOnPurpose"; } [System.Web.Services.Protocols.SoapHeaderAttribute( "msgHeader" )] [System.Web.Services.Protocols.SoapDocumentMethodAttribute( "http://www.example.org/Version_3.0/InitiateActivity", RequestNamespace = "http://www.example.org/Version_3.0", ResponseNamespace = "http://www.example.org/Version_3.0", Use = System.Web.Services.Description.SoapBindingUse.Literal, ParameterStyle = System.Web.Services.Protocols.SoapParameterStyle.Wrapped )] [return: System.Xml.Serialization.XmlElementAttribute( "InitiateActivityResponse" )] public InitiateActivityResponse InitiateActivity(string inputVar) { object[] results = Invoke( "InitiateActivity", new object[] { inputVar } ); return ( (InitiateActivityResponse)( results[0] ) ); } } Class descriptions [System.SerializableAttribute] [System.Diagnostics.DebuggerStepThroughAttribute] [System.ComponentModel.DesignerCategoryAttribute( "code" )] [XmlType( Namespace = "http://www.example.org/Version_3.0", TypeName = "InitiateActivityResponse" )] [XmlRoot( Namespace = "http://www.example.org/Version_3.0" )] public class InitiateActivityResponse { [XmlArray( ElementName = "InitiateActivityResult", IsNullable = true )] [XmlArrayItem( ElementName = "errorObject", IsNullable = false )] public errorObject[] errorObject { get; set; } } [System.SerializableAttribute] [System.Diagnostics.DebuggerStepThroughAttribute] [System.ComponentModel.DesignerCategoryAttribute( "code" )] [XmlTypeAttribute( Namespace = "http://www.example.org/Version_3.0" )] public class errorObject { private string _errorString; private System.DateTime _eventTime; private bool _eventTimeSpecified; private string _nounType; private string _objectID; [XmlAttributeAttribute] public string errorString { get { return _errorString; } set { _errorString = value; } } [XmlAttributeAttribute] public System.DateTime eventTime { get { return _eventTime; } set { _eventTime = value; } } [XmlIgnoreAttribute] public bool eventTimeSpecified { get { return _eventTimeSpecified; } set { _eventTimeSpecified = value; } } [XmlAttributeAttribute] public string nounType { get { return _nounType; } set { _nounType = value; } } [XmlAttributeAttribute] public string objectID { get { return _objectID; } set { _objectID = value; } } } SOAP as it's being received (as seen by Fiddler2) <?xml version="1.0" encoding="utf-8"?> <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <soapenv:Header> <MsgHeader soapenv:actor="http://schemas.xmlsoap.org/soap/actor/next" soapenv:mustUnderstand="0" AppName="AppName" AppVersion="1.0" Company="Company" Pwd="" UserID="" xmlns="http://www.example.org/Version_3.0"/> </soapenv:Header> <soapenv:Body> <InitiateActivityResponse xmlns="http://www.example.org/Version_3.0"> <InitiateActivityResult> <errorObject errorString="Explanatory string for request 1" eventTime="2010-05-24T21:21:37.477Z" nounType="Object" objectID="12345" xsi:type="ns1:errorObject" xmlns:ns1="http://www.example.org/Version_3.0"/> <errorObject errorString="Explanatory string for request 2" eventTime="2010-05-24T21:21:37.493Z" nounType="Object" objectID="45678" xsi:type="ns2:errorObject" xmlns:ns2="http://www.example.org/Version_3.0"/> <errorObject errorString="Explanatory string for request 3" eventTime="2010-05-24T21:21:37.508Z" nounType="Object" objectID="98765" xsi:type="ns3:errorObject" xmlns:ns3="http://www.example.org/Version_3.0"/> </InitiateActivityResult> </InitiateActivityResponse> </soapenv:Body> </soapenv:Envelope> Okay, what should I have not omitted? No I won't post the WSDL, it's hosted behind a firewall, for a vertical stack product. No, I can't change the data sender. Is this somehow automagically handled elsewhere and I just don't know what I don't know? I think I want to do some sort of message sink leading into this method, to intercept the soapenv:Body, but obviously this is for errors, so I'm not going to get errors every time. I'm not entirely sure how to handle this, but some pointers would be nice.

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• Web Browser Control &ndash; Specifying the IE Version

  - by Rick Strahl

  I use the Internet Explorer Web Browser Control in a lot of my applications to display document type layout. HTML happens to be one of the most common document formats and displaying data in this format – even in desktop applications, is often way easier than using normal desktop technologies. One issue the Web Browser Control has that it’s perpetually stuck in IE 7 rendering mode by default. Even though IE 8 and now 9 have significantly upgraded the IE rendering engine to be more CSS and HTML compliant by default the Web Browser control will have none of it. IE 9 in particular – with its much improved CSS support and basic HTML 5 support is a big improvement and even though the IE control uses some of IE’s internal rendering technology it’s still stuck in the old IE 7 rendering by default. This applies whether you’re using the Web Browser control in a WPF application, a WinForms app, a FoxPro or VB classic application using the ActiveX control. Behind the scenes all these UI platforms use the COM interfaces and so you’re stuck by those same rules. Rendering Challenged To see what I’m talking about here are two screen shots rendering an HTML 5 doctype page that includes some CSS 3 functionality – rounded corners and border shadows - from an earlier post. One uses IE 9 as a standalone browser, and one uses a simple WPF form that includes the Web Browser control. IE 9 Browser:   Web Browser control in a WPF form: The IE 9 page displays this HTML correctly – you see the rounded corners and shadow displayed. Obviously the latter rendering using the Web Browser control in a WPF application is a bit lacking. Not only are the new CSS features missing but the page also renders in Internet Explorer’s quirks mode so all the margins, padding etc. behave differently by default, even though there’s a CSS reset applied on this page. If you’re building an application that intends to use the Web Browser control for a live preview of some HTML this is clearly undesirable. Feature Delegation via Registry Hacks Fortunately starting with Internet Explore 8 and later there’s a fix for this problem via a registry setting. You can specify a registry key to specify which rendering mode and version of IE should be used by that application. These are not global mind you – they have to be enabled for each application individually. There are two different sets of keys for 32 bit and 64 bit applications. 32 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION Value Key: yourapplication.exe 64 bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION Value Key: yourapplication.exe The value to set this key to is (taken from MSDN here) as decimal values: 9999 (0x270F) Internet Explorer 9. Webpages are displayed in IE9 Standards mode, regardless of the !DOCTYPE directive. 9000 (0x2328) Internet Explorer 9. Webpages containing standards-based !DOCTYPE directives are displayed in IE9 mode. 8888 (0x22B8) Webpages are displayed in IE8 Standards mode, regardless of the !DOCTYPE directive. 8000 (0x1F40) Webpages containing standards-based !DOCTYPE directives are displayed in IE8 mode. 7000 (0x1B58) Webpages containing standards-based !DOCTYPE directives are displayed in IE7 Standards mode.   The added key looks something like this in the Registry Editor: With this in place my Html Html Help Builder application which has wwhelp.exe as its main executable now works with HTML 5 and CSS 3 documents in the same way that Internet Explorer 9 does. Incidentally I accidentally added an ‘empty’ DWORD value of 0 to my EXE name and that worked as well giving me IE 9 rendering. Although not documented I suspect 0 (or an invalid value) will default to the installed browser. Don’t have a good way to test this but if somebody could try this with IE 8 installed that would be great: What happens when setting 9000 with IE 8 installed? What happens when setting 0 with IE 8 installed? Don’t forget to add Keys for Host Environments If you’re developing your application in Visual Studio and you run the debugger you may find that your application is still not rendering right, but if you run the actual generated EXE from Explorer or the OS command prompt it works. That’s because when you run the debugger in Visual Studio it wraps your application into a debugging host container. For this reason you might want to also add another registry key for yourapp.vshost.exe on your development machine. If you’re developing in Visual FoxPro make sure you add a key for vfp9.exe to see the rendering adjustments in the Visual FoxPro development environment. Cleaner HTML - no more HTML mangling! There are a number of additional benefits to setting up rendering of the Web Browser control to the IE 9 engine (or even the IE 8 engine) beyond the obvious rendering functionality. IE 9 actually returns your HTML in something that resembles the original HTML formatting, as opposed to the IE 7 default format which mangled the original HTML content. If you do the following in the WPF application: private void button2_Click(object sender, RoutedEventArgs e) { dynamic doc = this.webBrowser.Document; MessageBox.Show(doc.body.outerHtml); } you get different output depending on the rendering mode active. With the default IE 7 rendering you get: <BODY><DIV> <H1>Rounded Corners and Shadows - Creating Dialogs in CSS</H1> <DIV class=toolbarcontainer><A class=hoverbutton href="./"><IMG src="../../css/images/home.gif"> Home</A> <A class=hoverbutton href="RoundedCornersAndShadows.htm"><IMG src="../../css/images/refresh.gif"> Refresh</A> </DIV> <DIV class=containercontent> <FIELDSET><LEGEND>Plain Box</LEGEND><!-- Simple Box with rounded corners and shadow --> <DIV style="BORDER-BOTTOM: steelblue 2px solid; BORDER-LEFT: steelblue 2px solid; WIDTH: 550px; BORDER-TOP: steelblue 2px solid; BORDER-RIGHT: steelblue 2px solid" class="roundbox boxshadow"> <DIV style="BACKGROUND: khaki" class="boxcontenttext roundbox">Simple Rounded Corner Box. </DIV></DIV></FIELDSET> <FIELDSET><LEGEND>Box with Header</LEGEND> <DIV style="BORDER-BOTTOM: steelblue 2px solid; BORDER-LEFT: steelblue 2px solid; WIDTH: 550px; BORDER-TOP: steelblue 2px solid; BORDER-RIGHT: steelblue 2px solid" class="roundbox boxshadow"> <DIV class="gridheaderleft roundbox-top">Box with a Header</DIV> <DIV style="BACKGROUND: khaki" class="boxcontenttext roundbox-bottom">Simple Rounded Corner Box. </DIV></DIV></FIELDSET> <FIELDSET><LEGEND>Dialog Style Window</LEGEND> <DIV style="POSITION: relative; WIDTH: 450px" id=divDialog class="dialog boxshadow" jQuery16107208195684204002="2"> <DIV style="POSITION: relative" class=dialog-header> <DIV class=closebox></DIV>User Sign-in <DIV class=closebox jQuery16107208195684204002="3"></DIV></DIV> <DIV class=descriptionheader>This dialog is draggable and closable</DIV> <DIV class=dialog-content><LABEL>Username:</LABEL> <INPUT name=txtUsername value=" "> <LABEL>Password</LABEL> <INPUT name=txtPassword value=" "> <HR> <INPUT id=btnLogin value=Login type=button> </DIV> <DIV class=dialog-statusbar>Ready</DIV></DIV></FIELDSET> </DIV> <SCRIPT type=text/javascript>     $(document).ready(function () {         $("#divDialog")             .draggable({ handle: ".dialog-header" })             .closable({ handle: ".dialog-header",                 closeHandler: function () {                     alert("Window about to be closed.");                     return true;  // true closes - false leaves open                 }             });     }); </SCRIPT> </DIV></BODY> Now lest you think I’m out of my mind and create complete whacky HTML rooted in the last century, here’s the IE 9 rendering mode output which looks a heck of a lot cleaner and a lot closer to my original HTML of the page I’m accessing: <body> <div>         <h1>Rounded Corners and Shadows - Creating Dialogs in CSS</h1>     <div class="toolbarcontainer">         <a class="hoverbutton" href="./"> <img src="../../css/images/home.gif"> Home</a>         <a class="hoverbutton" href="RoundedCornersAndShadows.htm"> <img src="../../css/images/refresh.gif"> Refresh</a>     </div>         <div class="containercontent">     <fieldset>         <legend>Plain Box</legend>                <!-- Simple Box with rounded corners and shadow -->             <div style="border: 2px solid steelblue; width: 550px;" class="roundbox boxshadow">                              <div style="background: khaki;" class="boxcontenttext roundbox">                     Simple Rounded Corner Box.                 </div>             </div>     </fieldset>     <fieldset>         <legend>Box with Header</legend>         <div style="border: 2px solid steelblue; width: 550px;" class="roundbox boxshadow">                          <div class="gridheaderleft roundbox-top">Box with a Header</div>             <div style="background: khaki;" class="boxcontenttext roundbox-bottom">                 Simple Rounded Corner Box.             </div>         </div>     </fieldset>       <fieldset>         <legend>Dialog Style Window</legend>         <div style="width: 450px; position: relative;" id="divDialog" class="dialog boxshadow">             <div style="position: relative;" class="dialog-header">                 <div class="closebox"></div>                 User Sign-in             <div class="closebox"></div></div>             <div class="descriptionheader">This dialog is draggable and closable</div>                    <div class="dialog-content">                             <label>Username:</label>                 <input name="txtUsername" value=" " type="text">                 <label>Password</label>                 <input name="txtPassword" value=" " type="text">                                 <hr/>                                 <input id="btnLogin" value="Login" type="button">                        </div>             <div class="dialog-statusbar">Ready</div>         </div>     </fieldset>     </div> <script type="text/javascript">     $(document).ready(function () {         $("#divDialog")             .draggable({ handle: ".dialog-header" })             .closable({ handle: ".dialog-header",                 closeHandler: function () {                     alert("Window about to be closed.");                     return true;  // true closes - false leaves open                 }             });     }); </script>        </div> </body> IOW, in IE9 rendering mode IE9 is much closer (but not identical) to the original HTML from the page on the Web that we’re reading from. As a side note: Unfortunately, the browser feature emulation can't be applied against the Html Help (CHM) Engine in Windows which uses the Web Browser control (or COM interfaces anyway) to render Html Help content. I tried setting up hh.exe which is the help viewer, to use IE 9 rendering but a help file generated with CSS3 features will simply show in IE 7 mode. Bummer - this would have been a nice quick fix to allow help content served from CHM files to look better. HTML Editing leaves HTML formatting intact In the same vane, if you do any inline HTML editing in the control by setting content to be editable, IE 9’s control does a much more reasonable job of creating usable and somewhat valid HTML. It also leaves the original content alone other than the text your are editing or adding. No longer is the HTML output stripped of excess spaces and reformatted in IEs format. So if I do: private void button3_Click(object sender, RoutedEventArgs e) { dynamic doc = this.webBrowser.Document; doc.body.contentEditable = true; } and then make some changes to the document by typing into it using IE 9 mode, the document formatting stays intact and only the affected content is modified. The created HTML is reasonably clean (although it does lack proper XHTML formatting for things like <br/> <hr/>). This is very different from IE 7 mode which mangled the HTML as soon as the page was loaded into the control. Any editing you did stripped out all white space and lost all of your existing XHTML formatting. In IE 9 mode at least *most* of your original formatting stays intact. This is huge! In Html Help Builder I have supported HTML editing for a long time but the HTML mangling by the Web Browser control made it very difficult to edit the HTML later. Previously IE would mangle the HTML by stripping out spaces, upper casing all tags and converting many XHTML safe tags to its HTML 3 tags. Now IE leaves most of my document alone while editing, and creates cleaner and more compliant markup (with exception of self-closing elements like BR/HR). The end result is that I now have HTML editing in place that's much cleaner and actually capable of being manually edited. Caveats, Caveats, Caveats It wouldn't be Internet Explorer if there weren't some major compatibility issues involved in using this various browser version interaction. The biggest thing I ran into is that there are odd differences in some of the COM interfaces and what they return. I specifically ran into a problem with the document.selection.createRange() function which with IE 7 compatibility returns an expected text range object. When running in IE 8 or IE 9 mode however. I could not retrieve a valid text range with this code where loEdit is the WebBrowser control: loRange = loEdit.document.selection.CreateRange() The loRange object returned (here in FoxPro) had a length property of 0 but none of the other properties of the TextRange or TextRangeCollection objects were available. I figured this was due to some changed security settings but even after elevating the Intranet Security Zone and mucking with the other browser feature flags pertaining to security I had no luck. In the end I relented and used a JavaScript function in my editor document that returns a selection range object: function getselectionrange() { var range = document.selection.createRange(); return range; } and call that JavaScript function from my host applications code: *** Use a function in the document to get around HTML Editing issues loRange = loEdit.document.parentWindow.getselectionrange(.f.) and that does work correctly. This wasn't a big deal as I'm already loading a support script file into the editor page so all I had to do is add the function to this existing script file. You can find out more how to call script code in the Web Browser control from a host application in a previous post of mine. IE 8 and 9 also clamp down the security environment a little more than the default IE 7 control, so there may be other issues you run into. Other than the createRange() problem above I haven't seen anything else that is breaking in my code so far though and that's encouraging at least since it uses a lot of HTML document manipulation for the custom editor I've created (and would love to replace - any PROFESSIONAL alternatives anybody?) Registry Key Installation for your Application It’s important to remember that this registry setting is made per application, so most likely this is something you want to set up with your installer. Also remember that 32 and 64 bit settings require separate settings in the registry so if you’re creating your installer you most likely will want to set both keys in the registry preemptively for your application. I use Tarma Installer for all of my application installs and in Tarma I configure registry keys for both and set a flag to only install the latter key group in the 64 bit version: Because this setting is application specific you have to do this for every application you install unfortunately, but this also means that you can safely configure this setting in the registry because it is after only applied to your application. Another problem with install based installation is version detection. If IE 8 is installed I’d want 8000 for the value, if IE 9 is installed I want 9000. I can do this easily in code but in the installer this is much more difficult. I don’t have a good solution for this at the moment, but given that the app works with IE 7 mode now, IE 9 mode is just a bonus for the moment. If IE 9 is not installed and 9000 is used the default rendering will remain in use.   It sure would be nice if we could specify the IE rendering mode as a property, but I suspect the ActiveX container has to know before it loads what actual version to load up and once loaded can only load a single version of IE. This would account for this annoying application level configuration… Summary The registry feature emulation has been available for quite some time, but I just found out about it today and started experimenting around with it. I’m stoked to see that this is available as I’d pretty much given up in ever seeing any better rendering in the Web Browser control. Now at least my apps can take advantage of newer HTML features. Now if we could only get better HTML Editing support somehow <snicker>… ah can’t have everything.© Rick Strahl, West Wind Technologies, 2005-2011Posted in .NET  FoxPro  Windows  

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• Table sorting & pagination with jQuery and Razor in ASP.NET MVC

  - by hajan

  Introduction jQuery enjoys living inside pages which are built on top of ASP.NET MVC Framework. The ASP.NET MVC is a place where things are organized very well and it is quite hard to make them dirty, especially because the pattern enforces you on purity (you can still make it dirty if you want so ;) ). We all know how easy is to build a HTML table with a header row, footer row and table rows showing some data. With ASP.NET MVC we can do this pretty easy, but, the result will be pure HTML table which only shows data, but does not includes sorting, pagination or some other advanced features that we were used to have in the ASP.NET WebForms GridView. Ok, there is the WebGrid MVC Helper, but what if we want to make something from pure table in our own clean style? In one of my recent projects, I’ve been using the jQuery tablesorter and tablesorter.pager plugins that go along. You don’t need to know jQuery to make this work… You need to know little CSS to create nice design for your table, but of course you can use mine from the demo… So, what you will see in this blog is how to attach this plugin to your pure html table and a div for pagination and make your table with advanced sorting and pagination features.   Demo Project Resources The resources I’m using for this demo project are shown in the following solution explorer window print screen: Content/images – folder that contains all the up/down arrow images, pagination buttons etc. You can freely replace them with your own, but keep the names the same if you don’t want to change anything in the CSS we will built later. Content/Site.css – The main css theme, where we will add the theme for our table too Controllers/HomeController.cs – The controller I’m using for this project Models/Person.cs – For this demo, I’m using Person.cs class Scripts – jquery-1.4.4.min.js, jquery.tablesorter.js, jquery.tablesorter.pager.js – required script to make the magic happens Views/Home/Index.cshtml – Index view (razor view engine) the other items are not important for the demo. ASP.NET MVC 1. Model In this demo I use only one Person class which defines Person entity with several properties. You can use your own model, maybe one which will access data from database or any other resource. Person.cs public class Person {     public string Name { get; set; }     public string Surname { get; set; }     public string Email { get; set; }     public int? Phone { get; set; }     public DateTime? DateAdded { get; set; }     public int? Age { get; set; }     public Person(string name, string surname, string email,         int? phone, DateTime? dateadded, int? age)     {         Name = name;         Surname = surname;         Email = email;         Phone = phone;         DateAdded = dateadded;         Age = age;     } } 2. View In our example, we have only one Index.chtml page where Razor View engine is used. Razor view engine is my favorite for ASP.NET MVC because it’s very intuitive, fluid and keeps your code clean. 3. Controller Since this is simple example with one page, we use one HomeController.cs where we have two methods, one of ActionResult type (Index) and another GetPeople() used to create and return list of people. HomeController.cs public class HomeController : Controller {     //     // GET: /Home/     public ActionResult Index()     {         ViewBag.People = GetPeople();         return View();     }     public List<Person> GetPeople()     {         List<Person> listPeople = new List<Person>();                  listPeople.Add(new Person("Hajan", "Selmani", "[email protected]", 070070070,DateTime.Now, 25));                     listPeople.Add(new Person("Straight", "Dean", "[email protected]", 123456789, DateTime.Now.AddDays(-5), 35));         listPeople.Add(new Person("Karsen", "Livia", "[email protected]", 46874651, DateTime.Now.AddDays(-2), 31));         listPeople.Add(new Person("Ringer", "Anne", "[email protected]", null, DateTime.Now, null));         listPeople.Add(new Person("O'Leary", "Michael", "[email protected]", 32424344, DateTime.Now, 44));         listPeople.Add(new Person("Gringlesby", "Anne", "[email protected]", null, DateTime.Now.AddDays(-9), 18));         listPeople.Add(new Person("Locksley", "Stearns", "[email protected]", 2135345, DateTime.Now, null));         listPeople.Add(new Person("DeFrance", "Michel", "[email protected]", 235325352, DateTime.Now.AddDays(-18), null));         listPeople.Add(new Person("White", "Johnson", null, null, DateTime.Now.AddDays(-22), 55));         listPeople.Add(new Person("Panteley", "Sylvia", null, 23233223, DateTime.Now.AddDays(-1), 32));         listPeople.Add(new Person("Blotchet-Halls", "Reginald", null, 323243423, DateTime.Now, 26));         listPeople.Add(new Person("Merr", "South", "[email protected]", 3232442, DateTime.Now.AddDays(-5), 85));         listPeople.Add(new Person("MacFeather", "Stearns", "[email protected]", null, DateTime.Now, null));         return listPeople;     } }   TABLE CSS/HTML DESIGN Now, lets start with the implementation. First of all, lets create the table structure and the main CSS. 1. HTML Structure @{     Layout = null;     } <!DOCTYPE html> <html> <head>     <title>ASP.NET & jQuery</title>     <!-- referencing styles, scripts and writing custom js scripts will go here --> </head> <body>     <div>         <table class="tablesorter">             <thead>                 <tr>                     <th> value </th>                 </tr>             </thead>             <tbody>                 <tr>                     <td>value</td>                 </tr>             </tbody>             <tfoot>                 <tr>                     <th> value </th>                 </tr>             </tfoot>         </table>         <div id="pager">                      </div>     </div> </body> </html> So, this is the main structure you need to create for each of your tables where you want to apply the functionality we will create. Of course the scripts are referenced once ;). As you see, our table has class tablesorter and also we have a div with id pager. In the next steps we will use both these to create the needed functionalities. The complete Index.cshtml coded to get the data from controller and display in the page is: <body>     <div>         <table class="tablesorter">             <thead>                 <tr>                     <th>Name</th>                     <th>Surname</th>                     <th>Email</th>                     <th>Phone</th>                     <th>Date Added</th>                 </tr>             </thead>             <tbody>                 @{                     foreach (var p in ViewBag.People)                     {                                 <tr>                         <td>@p.Name</td>                         <td>@p.Surname</td>                         <td>@p.Email</td>                         <td>@p.Phone</td>                         <td>@p.DateAdded</td>                     </tr>                     }                 }             </tbody>             <tfoot>                 <tr>                     <th>Name</th>                     <th>Surname</th>                     <th>Email</th>                     <th>Phone</th>                     <th>Date Added</th>                 </tr>             </tfoot>         </table>         <div id="pager" style="position: none;">             <form>             <img src="@Url.Content("~/Content/images/first.png")" class="first" />             <img src="@Url.Content("~/Content/images/prev.png")" class="prev" />             <input type="text" class="pagedisplay" />             <img src="@Url.Content("~/Content/images/next.png")" class="next" />             <img src="@Url.Content("~/Content/images/last.png")" class="last" />             <select class="pagesize">                 <option selected="selected" value="5">5</option>                 <option value="10">10</option>                 <option value="20">20</option>                 <option value="30">30</option>                 <option value="40">40</option>             </select>             </form>         </div>     </div> </body> So, mainly the structure is the same. I have added @Razor code to create table with data retrieved from the ViewBag.People which has been filled with data in the home controller. 2. CSS Design The CSS code I’ve created is: /* DEMO TABLE */ body {     font-size: 75%;     font-family: Verdana, Tahoma, Arial, "Helvetica Neue", Helvetica, Sans-Serif;     color: #232323;     background-color: #fff; } table { border-spacing:0; border:1px solid gray;} table.tablesorter thead tr .header {     background-image: url(images/bg.png);     background-repeat: no-repeat;     background-position: center right;     cursor: pointer; } table.tablesorter tbody td {     color: #3D3D3D;     padding: 4px;     background-color: #FFF;     vertical-align: top; } table.tablesorter tbody tr.odd td {     background-color:#F0F0F6; } table.tablesorter thead tr .headerSortUp {     background-image: url(images/asc.png); } table.tablesorter thead tr .headerSortDown {     background-image: url(images/desc.png); } table th { width:150px;            border:1px outset gray;            background-color:#3C78B5;            color:White;            cursor:pointer; } table thead th:hover { background-color:Yellow; color:Black;} table td { width:150px; border:1px solid gray;} PAGINATION AND SORTING Now, when everything is ready and we have the data, lets make pagination and sorting functionalities 1. jQuery Scripts referencing <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.pager.js")" type="text/javascript"></script> 2. jQuery Sorting and Pagination script   <script type="text/javascript">     $(function () {         $("table.tablesorter").tablesorter({ widthFixed: true, sortList: [[0, 0]] })         .tablesorterPager({ container: $("#pager"), size: $(".pagesize option:selected").val() });     }); </script> So, with only two lines of code, I’m using both tablesorter and tablesorterPager plugins, giving some options to both these. Options added: tablesorter - widthFixed: true – gives fixed width of the columns tablesorter - sortList[[0,0]] – An array of instructions for per-column sorting and direction in the format: [[columnIndex, sortDirection], ... ] where columnIndex is a zero-based index for your columns left-to-right and sortDirection is 0 for Ascending and 1 for Descending. A valid argument that sorts ascending first by column 1 and then column 2 looks like: [[0,0],[1,0]] (source: http://tablesorter.com/docs/) tablesorterPager – container: $(“#pager”) – tells the pager container, the div with id pager in our case. tablesorterPager – size: the default size of each page, where I get the default value selected, so if you put selected to any other of the options in your select list, you will have this number of rows as default per page for the table too. END RESULTS 1. Table once the page is loaded (default results per page is 5 and is automatically sorted by 1st column as sortList is specified) 2. Sorted by Phone Descending 3. Changed pagination to 10 items per page 4. Sorted by Phone and Name (use SHIFT to sort on multiple columns) 5. Sorted by Date Added 6. Page 3, 5 items per page   ADDITIONAL ENHANCEMENTS We can do additional enhancements to the table. We can make search for each column. I will cover this in one of my next blogs. Stay tuned. DEMO PROJECT You can download demo project source code from HERE.CONCLUSION Once you finish with the demo, run your page and open the source code. You will be amazed of the purity of your code.Working with pagination in client side can be very useful. One of the benefits is performance, but if you have thousands of rows in your tables, you will get opposite result when talking about performance. Hence, sometimes it is nice idea to make pagination on back-end. So, the compromise between both approaches would be best to combine both of them. I use at most up to 500 rows on client-side and once the user reach the last page, we can trigger ajax postback which can get the next 500 rows using server-side pagination of the same data. I would like to recommend the following blog post http://weblogs.asp.net/gunnarpeipman/archive/2010/09/14/returning-paged-results-from-repositories-using-pagedresult-lt-t-gt.aspx, which will help you understand how to return page results from repository. I hope this was helpful post for you. Wait for my next posts ;). Please do let me know your feedback. Best Regards, Hajan

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• SQL Server 2012 - AlwaysOn

  - by Claus Jandausch

  Ich war nicht nur irritiert, ich war sogar regelrecht schockiert - und für einen kurzen Moment sprachlos (was nur selten der Fall ist). Gerade eben hatte mich jemand gefragt "Wann Oracle denn etwas Vergleichbares wie AlwaysOn bieten würde - und ob überhaupt?" War ich hier im falschen Film gelandet? Ich konnte nicht anders, als meinen Unmut kundzutun und zu erklären, dass die Fragestellung normalerweise anders herum läuft. Zugegeben - es mag vielleicht strittige Punkte geben im Vergleich zwischen Oracle und SQL Server - bei denen nicht unbedingt immer Oracle die Nase vorn haben muss - aber das Thema Clustering für Hochverfügbarkeit (HA), Disaster Recovery (DR) und Skalierbarkeit gehört mit Sicherheit nicht dazu. Dieses Erlebnis hakte ich am Nachgang als Einzelfall ab, der so nie wieder vorkommen würde. Bis ich kurz darauf eines Besseren belehrt wurde und genau die selbe Frage erneut zu hören bekam. Diesmal sogar im Exadata-Umfeld und einem Oracle Stretch Cluster. Einmal ist keinmal, doch zweimal ist einmal zu viel... Getreu diesem alten Motto war mir klar, dass man das so nicht länger stehen lassen konnte. Ich habe keine Ahnung, wie die Microsoft Marketing Abteilung es geschafft hat, unter dem AlwaysOn Brading eine innovative Technologie vermuten zu lassen - aber sie hat ihren Job scheinbar gut gemacht. Doch abgesehen von einem guten Marketing, stellt sich natürlich die Frage, was wirklich dahinter steckt und wie sich das Ganze mit Oracle vergleichen lässt - und ob überhaupt? Damit wären wir wieder bei der ursprünglichen Frage angelangt.  So viel zum Hintergrund dieses Blogbeitrags - von meiner Antwort handelt der restliche Blog. "Windows was the God ..." Um den wahren Unterschied zwischen Oracle und Microsoft verstehen zu können, muss man zunächst das bedeutendste Microsoft Dogma kennen. Es lässt sich schlicht und einfach auf den Punkt bringen: "Alles muss auf Windows basieren." Die Überschrift dieses Absatzes ist kein von mir erfundener Ausspruch, sondern ein Zitat. Konkret stammt es aus einem längeren Artikel von Kurt Eichenwald in der Vanity Fair aus dem August 2012. Er lautet Microsoft's Lost Decade und sei jedem ans Herz gelegt, der die "Microsoft-Maschinerie" unter Steve Ballmer und einige ihrer Kuriositäten besser verstehen möchte. "YOU TALKING TO ME?" Microsoft C.E.O. Steve Ballmer bei seiner Keynote auf der 2012 International Consumer Electronics Show in Las Vegas am 9. Januar   Manche Dinge in diesem Artikel mögen überspitzt dargestellt erscheinen - sind sie aber nicht. Vieles davon kannte ich bereits aus eigener Erfahrung und kann es nur bestätigen. Anderes hat sich mir erst so richtig erschlossen. Insbesondere die folgenden Passagen führten zum Aha-Erlebnis: “Windows was the god—everything had to work with Windows,” said Stone... “Every little thing you want to write has to build off of Windows (or other existing roducts),” one software engineer said. “It can be very confusing, …” Ich habe immer schon darauf hingewiesen, dass in einem SQL Server Failover Cluster die Microsoft Datenbank eigentlich nichts Nenneswertes zum Geschehen beiträgt, sondern sich voll und ganz auf das Windows Betriebssystem verlässt. Deshalb muss man auch die Windows Server Enterprise Edition installieren, soll ein Failover Cluster für den SQL Server eingerichtet werden. Denn hier werden die Cluster Services geliefert - nicht mit dem SQL Server. Er ist nur lediglich ein weiteres Server Produkt, für das Windows in Ausfallszenarien genutzt werden kann - so wie Microsoft Exchange beispielsweise, oder Microsoft SharePoint, oder irgendein anderes Server Produkt das auf Windows gehostet wird. Auch Oracle kann damit genutzt werden. Das Stichwort lautet hier: Oracle Failsafe. Nur - warum sollte man das tun, wenn gleichzeitig eine überlegene Technologie wie die Oracle Real Application Clusters (RAC) zur Verfügung steht, die dann auch keine Windows Enterprise Edition voraussetzen, da Oracle die eigene Clusterware liefert. Welche darüber hinaus für kürzere Failover-Zeiten sorgt, da diese Cluster-Technologie Datenbank-integriert ist und sich nicht auf "Dritte" verlässt. Wenn man sich also schon keine technischen Vorteile mit einem SQL Server Failover Cluster erkauft, sondern zusätzlich noch versteckte Lizenzkosten durch die Lizenzierung der Windows Server Enterprise Edition einhandelt, warum hat Microsoft dann in den vergangenen Jahren seit SQL Server 2000 nicht ebenfalls an einer neuen und innovativen Lösung gearbeitet, die mit Oracle RAC mithalten kann? Entwickler hat Microsoft genügend? Am Geld kann es auch nicht liegen? Lesen Sie einfach noch einmal die beiden obenstehenden Zitate und sie werden den Grund verstehen. Anders lässt es sich ja auch gar nicht mehr erklären, dass AlwaysOn aus zwei unterschiedlichen Technologien besteht, die beide jedoch wiederum auf dem Windows Server Failover Clustering (WSFC) basieren. Denn daraus ergeben sich klare Nachteile - aber dazu später mehr. Um AlwaysOn zu verstehen, sollte man sich zunächst kurz in Erinnerung rufen, was Microsoft bisher an HA/DR (High Availability/Desaster Recovery) Lösungen für SQL Server zur Verfügung gestellt hat. Replikation Basiert auf logischer Replikation und Pubisher/Subscriber Architektur Transactional Replication Merge Replication Snapshot Replication Microsoft's Replikation ist vergleichbar mit Oracle GoldenGate. Oracle GoldenGate stellt jedoch die umfassendere Technologie dar und bietet High Performance. Log Shipping Microsoft's Log Shipping stellt eine einfache Technologie dar, die vergleichbar ist mit Oracle Managed Recovery in Oracle Version 7. Das Log Shipping besitzt folgende Merkmale: Transaction Log Backups werden von Primary nach Secondary/ies geschickt Einarbeitung (z.B. Restore) auf jedem Secondary individuell Optionale dritte Server Instanz (Monitor Server) für Überwachung und Alarm Log Restore Unterbrechung möglich für Read-Only Modus (Secondary) Keine Unterstützung von Automatic Failover Database Mirroring Microsoft's Database Mirroring wurde verfügbar mit SQL Server 2005, sah aus wie Oracle Data Guard in Oracle 9i, war funktional jedoch nicht so umfassend. Für ein HA/DR Paar besteht eine 1:1 Beziehung, um die produktive Datenbank (Principle DB) abzusichern. Auf der Standby Datenbank (Mirrored DB) werden alle Insert-, Update- und Delete-Operationen nachgezogen. Modi Synchron (High-Safety Modus) Asynchron (High-Performance Modus) Automatic Failover Unterstützt im High-Safety Modus (synchron) Witness Server vorausgesetzt     Zur Frage der Kontinuität Es stellt sich die Frage, wie es um diesen Technologien nun im Zusammenhang mit SQL Server 2012 bestellt ist. Unter Fanfaren seinerzeit eingeführt, war Database Mirroring das erklärte Mittel der Wahl. Ich bin kein Produkt Manager bei Microsoft und kann hierzu nur meine Meinung äußern, aber zieht man den SQL AlwaysOn Team Blog heran, so sieht es nicht gut aus für das Database Mirroring - zumindest nicht langfristig. "Does AlwaysOn Availability Group replace Database Mirroring going forward?” “The short answer is we recommend that you migrate from the mirroring configuration or even mirroring and log shipping configuration to using Availability Group. Database Mirroring will still be available in the Denali release but will be phased out over subsequent releases. Log Shipping will continue to be available in future releases.” Damit wären wir endlich beim eigentlichen Thema angelangt. Was ist eine sogenannte Availability Group und was genau hat es mit der vielversprechend klingenden Bezeichnung AlwaysOn auf sich?   SQL Server 2012 - AlwaysOn Zwei HA-Features verstekcne sich hinter dem “AlwaysOn”-Branding. Einmal das AlwaysOn Failover Clustering aka SQL Server Failover Cluster Instances (FCI) - zum Anderen die AlwaysOn Availability Groups. Failover Cluster Instances (FCI) Entspricht ungefähr dem Stretch Cluster Konzept von Oracle Setzt auf Windows Server Failover Clustering (WSFC) auf Bietet HA auf Instanz-Ebene AlwaysOn Availability Groups (Verfügbarkeitsgruppen) Ähnlich der Idee von Consistency Groups, wie in Storage-Level Replikations-Software von z.B. EMC SRDF Abhängigkeiten zu Windows Server Failover Clustering (WSFC) Bietet HA auf Datenbank-Ebene   Hinweis: Verwechseln Sie nicht eine SQL Server Datenbank mit einer Oracle Datenbank. Und auch nicht eine Oracle Instanz mit einer SQL Server Instanz. Die gleichen Begriffe haben hier eine andere Bedeutung - nicht selten ein Grund, weshalb Oracle- und Microsoft DBAs schnell aneinander vorbei reden. Denken Sie bei einer SQL Server Datenbank eher an ein Oracle Schema, das kommt der Sache näher. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema. Wenn Sie die genauen Unterschiede kennen möchten, finden Sie eine detaillierte Beschreibung in meinem Buch "Oracle10g Release 2 für Windows und .NET", erhältich bei Lehmanns, Amazon, etc.   Windows Server Failover Clustering (WSFC) Wie man sieht, basieren beide AlwaysOn Technologien wiederum auf dem Windows Server Failover Clustering (WSFC), um einerseits Hochverfügbarkeit auf Ebene der Instanz zu gewährleisten und andererseits auf der Datenbank-Ebene. Deshalb nun eine kurze Beschreibung der WSFC. Die WSFC sind ein mit dem Windows Betriebssystem geliefertes Infrastruktur-Feature, um HA für Server Anwendungen, wie Microsoft Exchange, SharePoint, SQL Server, etc. zu bieten. So wie jeder andere Cluster, besteht ein WSFC Cluster aus einer Gruppe unabhängiger Server, die zusammenarbeiten, um die Verfügbarkeit einer Applikation oder eines Service zu erhöhen. Falls ein Cluster-Knoten oder -Service ausfällt, kann der auf diesem Knoten bisher gehostete Service automatisch oder manuell auf einen anderen im Cluster verfügbaren Knoten transferriert werden - was allgemein als Failover bekannt ist. Unter SQL Server 2012 verwenden sowohl die AlwaysOn Avalability Groups, als auch die AlwaysOn Failover Cluster Instances die WSFC als Plattformtechnologie, um Komponenten als WSFC Cluster-Ressourcen zu registrieren. Verwandte Ressourcen werden in eine Ressource Group zusammengefasst, die in Abhängigkeit zu anderen WSFC Cluster-Ressourcen gebracht werden kann. Der WSFC Cluster Service kann jetzt die Notwendigkeit zum Neustart der SQL Server Instanz erfassen oder einen automatischen Failover zu einem anderen Server-Knoten im WSFC Cluster auslösen.   Failover Cluster Instances (FCI) Eine SQL Server Failover Cluster Instanz (FCI) ist eine einzelne SQL Server Instanz, die in einem Failover Cluster betrieben wird, der aus mehreren Windows Server Failover Clustering (WSFC) Knoten besteht und so HA (High Availability) auf Ebene der Instanz bietet. Unter Verwendung von Multi-Subnet FCI kann auch Remote DR (Disaster Recovery) unterstützt werden. Eine weitere Option für Remote DR besteht darin, eine unter FCI gehostete Datenbank in einer Availability Group zu betreiben. Hierzu später mehr. FCI und WSFC Basis FCI, das für lokale Hochverfügbarkeit der Instanzen genutzt wird, ähnelt der veralteten Architektur eines kalten Cluster (Aktiv-Passiv). Unter SQL Server 2008 wurde diese Technologie SQL Server 2008 Failover Clustering genannt. Sie nutzte den Windows Server Failover Cluster. In SQL Server 2012 hat Microsoft diese Basistechnologie unter der Bezeichnung AlwaysOn zusammengefasst. Es handelt sich aber nach wie vor um die klassische Aktiv-Passiv-Konfiguration. Der Ablauf im Failover-Fall ist wie folgt: Solange kein Hardware-oder System-Fehler auftritt, werden alle Dirty Pages im Buffer Cache auf Platte geschrieben Alle entsprechenden SQL Server Services (Dienste) in der Ressource Gruppe werden auf dem aktiven Knoten gestoppt Die Ownership der Ressource Gruppe wird auf einen anderen Knoten der FCI transferriert Der neue Owner (Besitzer) der Ressource Gruppe startet seine SQL Server Services (Dienste) Die Connection-Anforderungen einer Client-Applikation werden automatisch auf den neuen aktiven Knoten mit dem selben Virtuellen Network Namen (VNN) umgeleitet Abhängig vom Zeitpunkt des letzten Checkpoints, kann die Anzahl der Dirty Pages im Buffer Cache, die noch auf Platte geschrieben werden müssen, zu unvorhersehbar langen Failover-Zeiten führen. Um diese Anzahl zu drosseln, besitzt der SQL Server 2012 eine neue Fähigkeit, die Indirect Checkpoints genannt wird. Indirect Checkpoints ähnelt dem Fast-Start MTTR Target Feature der Oracle Datenbank, das bereits mit Oracle9i verfügbar war.   SQL Server Multi-Subnet Clustering Ein SQL Server Multi-Subnet Failover Cluster entspricht vom Konzept her einem Oracle RAC Stretch Cluster. Doch dies ist nur auf den ersten Blick der Fall. Im Gegensatz zu RAC ist in einem lokalen SQL Server Failover Cluster jeweils nur ein Knoten aktiv für eine Datenbank. Für die Datenreplikation zwischen geografisch entfernten Sites verlässt sich Microsoft auf 3rd Party Lösungen für das Storage Mirroring.     Die Verbesserung dieses Szenario mit einer SQL Server 2012 Implementierung besteht schlicht darin, dass eine VLAN-Konfiguration (Virtual Local Area Network) nun nicht mehr benötigt wird, so wie dies bisher der Fall war. Das folgende Diagramm stellt dar, wie der Ablauf mit SQL Server 2012 gehandhabt wird. In Site A und Site B wird HA jeweils durch einen lokalen Aktiv-Passiv-Cluster sichergestellt.     Besondere Aufmerksamkeit muss hier der Konfiguration und dem Tuning geschenkt werden, da ansonsten völlig inakzeptable Failover-Zeiten resultieren. Dies liegt darin begründet, weil die Downtime auf Client-Seite nun nicht mehr nur von der reinen Failover-Zeit abhängt, sondern zusätzlich von der Dauer der DNS Replikation zwischen den DNS Servern. (Rufen Sie sich in Erinnerung, dass wir gerade von Multi-Subnet Clustering sprechen). Außerdem ist zu berücksichtigen, wie schnell die Clients die aktualisierten DNS Informationen abfragen. Spezielle Konfigurationen für Node Heartbeat, HostRecordTTL (Host Record Time-to-Live) und Intersite Replication Frequeny für Active Directory Sites und Services werden notwendig. Default TTL für Windows Server 2008 R2: 20 Minuten Empfohlene Einstellung: 1 Minute DNS Update Replication Frequency in Windows Umgebung: 180 Minuten Empfohlene Einstellung: 15 Minuten (minimaler Wert)   Betrachtet man diese Werte, muss man feststellen, dass selbst eine optimale Konfiguration die rigiden SLAs (Service Level Agreements) heutiger geschäftskritischer Anwendungen für HA und DR nicht erfüllen kann. Denn dies impliziert eine auf der Client-Seite erlebte Failover-Zeit von insgesamt 16 Minuten. Hierzu ein Auszug aus der SQL Server 2012 Online Dokumentation: Cons: If a cross-subnet failover occurs, the client recovery time could be 15 minutes or longer, depending on your HostRecordTTL setting and the setting of your cross-site DNS/AD replication schedule.    Wir sind hier an einem Punkt unserer Überlegungen angelangt, an dem sich erklärt, weshalb ich zuvor das "Windows was the God ..." Zitat verwendet habe. Die unbedingte Abhängigkeit zu Windows wird zunehmend zum Problem, da sie die Komplexität einer Microsoft-basierenden Lösung erhöht, anstelle sie zu reduzieren. Und Komplexität ist das Letzte, was sich CIOs heutzutage wünschen.  Zur Ehrenrettung des SQL Server 2012 und AlwaysOn muss man sagen, dass derart lange Failover-Zeiten kein unbedingtes "Muss" darstellen, sondern ein "Kann". Doch auch ein "Kann" kann im unpassenden Moment unvorhersehbare und kostspielige Folgen haben. Die Unabsehbarkeit ist wiederum Ursache vieler an der Implementierung beteiligten Komponenten und deren Abhängigkeiten, wie beispielsweise drei Cluster-Lösungen (zwei von Microsoft, eine 3rd Party Lösung). Wie man die Sache auch dreht und wendet, kommt man an diesem Fakt also nicht vorbei - ganz unabhängig von der Dauer einer Downtime oder Failover-Zeiten. Im Gegensatz zu AlwaysOn und der hier vorgestellten Version eines Stretch-Clusters, vermeidet eine entsprechende Oracle Implementierung eine derartige Komplexität, hervorgerufen duch multiple Abhängigkeiten. Den Unterschied machen Datenbank-integrierte Mechanismen, wie Fast Application Notification (FAN) und Fast Connection Failover (FCF). Für Oracle MAA Konfigurationen (Maximum Availability Architecture) sind Inter-Site Failover-Zeiten im Bereich von Sekunden keine Seltenheit. Wenn Sie dem Link zur Oracle MAA folgen, finden Sie außerdem eine Reihe an Customer Case Studies. Auch dies ist ein wichtiges Unterscheidungsmerkmal zu AlwaysOn, denn die Oracle Technologie hat sich bereits zigfach in höchst kritischen Umgebungen bewährt.   Availability Groups (Verfügbarkeitsgruppen) Die sogenannten Availability Groups (Verfügbarkeitsgruppen) sind - neben FCI - der weitere Baustein von AlwaysOn.   Hinweis: Bevor wir uns näher damit beschäftigen, sollten Sie sich noch einmal ins Gedächtnis rufen, dass eine SQL Server Datenbank nicht die gleiche Bedeutung besitzt, wie eine Oracle Datenbank, sondern eher einem Oracle Schema entspricht. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema.   Eine Verfügbarkeitsgruppe setzt sich zusammen aus einem Set mehrerer Benutzer-Datenbanken, die im Falle eines Failover gemeinsam als Gruppe behandelt werden. Eine Verfügbarkeitsgruppe unterstützt ein Set an primären Datenbanken (primäres Replikat) und einem bis vier Sets von entsprechenden sekundären Datenbanken (sekundäre Replikate).       Es können jedoch nicht alle SQL Server Datenbanken einer AlwaysOn Verfügbarkeitsgruppe zugeordnet werden. Der SQL Server Spezialist Michael Otey zählt in seinem SQL Server Pro Artikel folgende Anforderungen auf: Verfügbarkeitsgruppen müssen mit Benutzer-Datenbanken erstellt werden. System-Datenbanken können nicht verwendet werden Die Datenbanken müssen sich im Read-Write Modus befinden. Read-Only Datenbanken werden nicht unterstützt Die Datenbanken in einer Verfügbarkeitsgruppe müssen Multiuser Datenbanken sein Sie dürfen nicht das AUTO_CLOSE Feature verwenden Sie müssen das Full Recovery Modell nutzen und es muss ein vollständiges Backup vorhanden sein Eine gegebene Datenbank kann sich nur in einer einzigen Verfügbarkeitsgruppe befinden und diese Datenbank düerfen nicht für Database Mirroring konfiguriert sein Microsoft empfiehl außerdem, dass der Verzeichnispfad einer Datenbank auf dem primären und sekundären Server identisch sein sollte Wie man sieht, eignen sich Verfügbarkeitsgruppen nicht, um HA und DR vollständig abzubilden. Die Unterscheidung zwischen der Instanzen-Ebene (FCI) und Datenbank-Ebene (Availability Groups) ist von hoher Bedeutung. Vor kurzem wurde mir gesagt, dass man mit den Verfügbarkeitsgruppen auf Shared Storage verzichten könne und dadurch Kosten spart. So weit so gut ... Man kann natürlich eine Installation rein mit Verfügbarkeitsgruppen und ohne FCI durchführen - aber man sollte sich dann darüber bewusst sein, was man dadurch alles nicht abgesichert hat - und dies wiederum für Desaster Recovery (DR) und SLAs (Service Level Agreements) bedeutet. Kurzum, um die Kombination aus beiden AlwaysOn Produkten und der damit verbundene Komplexität kommt man wohl in der Praxis nicht herum.    Availability Groups und WSFC AlwaysOn hängt von Windows Server Failover Clustering (WSFC) ab, um die aktuellen Rollen der Verfügbarkeitsreplikate einer Verfügbarkeitsgruppe zu überwachen und zu verwalten, und darüber zu entscheiden, wie ein Failover-Ereignis die Verfügbarkeitsreplikate betrifft. Das folgende Diagramm zeigt de Beziehung zwischen Verfügbarkeitsgruppen und WSFC:   Der Verfügbarkeitsmodus ist eine Eigenschaft jedes Verfügbarkeitsreplikats. Synychron und Asynchron können also gemischt werden: Availability Modus (Verfügbarkeitsmodus) Asynchroner Commit-Modus Primäres replikat schließt Transaktionen ohne Warten auf Sekundäres Synchroner Commit-Modus Primäres Replikat wartet auf Commit von sekundärem Replikat Failover Typen Automatic Manual Forced (mit möglichem Datenverlust) Synchroner Commit-Modus Geplanter, manueller Failover ohne Datenverlust Automatischer Failover ohne Datenverlust Asynchroner Commit-Modus Nur Forced, manueller Failover mit möglichem Datenverlust   Der SQL Server kennt keinen separaten Switchover Begriff wie in Oracle Data Guard. Für SQL Server werden alle Role Transitions als Failover bezeichnet. Tatsächlich unterstützt der SQL Server keinen Switchover für asynchrone Verbindungen. Es gibt nur die Form des Forced Failover mit möglichem Datenverlust. Eine ähnliche Fähigkeit wie der Switchover unter Oracle Data Guard ist so nicht gegeben.   SQL Sever FCI mit Availability Groups (Verfügbarkeitsgruppen) Neben den Verfügbarkeitsgruppen kann eine zweite Failover-Ebene eingerichtet werden, indem SQL Server FCI (auf Shared Storage) mit WSFC implementiert wird. Ein Verfügbarkeitesreplikat kann dann auf einer Standalone Instanz gehostet werden, oder einer FCI Instanz. Zum Verständnis: Die Verfügbarkeitsgruppen selbst benötigen kein Shared Storage. Diese Kombination kann verwendet werden für lokale HA auf Ebene der Instanz und DR auf Datenbank-Ebene durch Verfügbarkeitsgruppen. Das folgende Diagramm zeigt dieses Szenario:   Achtung! Hier handelt es sich nicht um ein Pendant zu Oracle RAC plus Data Guard, auch wenn das Bild diesen Eindruck vielleicht vermitteln mag - denn alle sekundären Knoten im FCI sind rein passiv. Es existiert außerdem eine weitere und ernsthafte Einschränkung: SQL Server Failover Cluster Instanzen (FCI) unterstützen nicht das automatische AlwaysOn Failover für Verfügbarkeitsgruppen. Jedes unter FCI gehostete Verfügbarkeitsreplikat kann nur für manuelles Failover konfiguriert werden.   Lesbare Sekundäre Replikate Ein oder mehrere Verfügbarkeitsreplikate in einer Verfügbarkeitsgruppe können für den lesenden Zugriff konfiguriert werden, wenn sie als sekundäres Replikat laufen. Dies ähnelt Oracle Active Data Guard, jedoch gibt es Einschränkungen. Alle Abfragen gegen die sekundäre Datenbank werden automatisch auf das Snapshot Isolation Level abgebildet. Es handelt sich dabei um eine Versionierung der Rows. Microsoft versuchte hiermit die Oracle MVRC (Multi Version Read Consistency) nachzustellen. Tatsächlich muss man die SQL Server Snapshot Isolation eher mit Oracle Flashback vergleichen. Bei der Implementierung des Snapshot Isolation Levels handelt sich um ein nachträglich aufgesetztes Feature und nicht um einen inhärenten Teil des Datenbank-Kernels, wie im Falle Oracle. (Ich werde hierzu in Kürze einen weiteren Blogbeitrag verfassen, wenn ich mich mit der neuen SQL Server 2012 Core Lizenzierung beschäftige.) Für die Praxis entstehen aus der Abbildung auf das Snapshot Isolation Level ernsthafte Restriktionen, derer man sich für den Betrieb in der Praxis bereits vorab bewusst sein sollte: Sollte auf der primären Datenbank eine aktive Transaktion zu dem Zeitpunkt existieren, wenn ein lesbares sekundäres Replikat in die Verfügbarkeitsgruppe aufgenommen wird, werden die Row-Versionen auf der korrespondierenden sekundären Datenbank nicht sofort vollständig verfügbar sein. Eine aktive Transaktion auf dem primären Replikat muss zuerst abgeschlossen (Commit oder Rollback) und dieser Transaktions-Record auf dem sekundären Replikat verarbeitet werden. Bis dahin ist das Isolation Level Mapping auf der sekundären Datenbank unvollständig und Abfragen sind temporär geblockt. Microsoft sagt dazu: "This is needed to guarantee that row versions are available on the secondary replica before executing the query under snapshot isolation as all isolation levels are implicitly mapped to snapshot isolation." (SQL Storage Engine Blog: AlwaysOn: I just enabled Readable Secondary but my query is blocked?)  Grundlegend bedeutet dies, dass ein aktives lesbares Replikat nicht in die Verfügbarkeitsgruppe aufgenommen werden kann, ohne das primäre Replikat vorübergehend stillzulegen. Da Leseoperationen auf das Snapshot Isolation Transaction Level abgebildet werden, kann die Bereinigung von Ghost Records auf dem primären Replikat durch Transaktionen auf einem oder mehreren sekundären Replikaten geblockt werden - z.B. durch eine lang laufende Abfrage auf dem sekundären Replikat. Diese Bereinigung wird auch blockiert, wenn die Verbindung zum sekundären Replikat abbricht oder der Datenaustausch unterbrochen wird. Auch die Log Truncation wird in diesem Zustant verhindert. Wenn dieser Zustand längere Zeit anhält, empfiehlt Microsoft das sekundäre Replikat aus der Verfügbarkeitsgruppe herauszunehmen - was ein ernsthaftes Downtime-Problem darstellt. Die Read-Only Workload auf den sekundären Replikaten kann eingehende DDL Änderungen blockieren. Obwohl die Leseoperationen aufgrund der Row-Versionierung keine Shared Locks halten, führen diese Operatioen zu Sch-S Locks (Schemastabilitätssperren). DDL-Änderungen durch Redo-Operationen können dadurch blockiert werden. Falls DDL aufgrund konkurrierender Lese-Workload blockiert wird und der Schwellenwert für 'Recovery Interval' (eine SQL Server Konfigurationsoption) überschritten wird, generiert der SQL Server das Ereignis sqlserver.lock_redo_blocked, welches Microsoft zum Kill der blockierenden Leser empfiehlt. Auf die Verfügbarkeit der Anwendung wird hierbei keinerlei Rücksicht genommen.   Keine dieser Einschränkungen existiert mit Oracle Active Data Guard.   Backups auf sekundären Replikaten  Über die sekundären Replikate können Backups (BACKUP DATABASE via Transact-SQL) nur als copy-only Backups einer vollständigen Datenbank, Dateien und Dateigruppen erstellt werden. Das Erstellen inkrementeller Backups ist nicht unterstützt, was ein ernsthafter Rückstand ist gegenüber der Backup-Unterstützung physikalischer Standbys unter Oracle Data Guard. Hinweis: Ein möglicher Workaround via Snapshots, bleibt ein Workaround. Eine weitere Einschränkung dieses Features gegenüber Oracle Data Guard besteht darin, dass das Backup eines sekundären Replikats nicht ausgeführt werden kann, wenn es nicht mit dem primären Replikat kommunizieren kann. Darüber hinaus muss das sekundäre Replikat synchronisiert sein oder sich in der Synchronisation befinden, um das Beackup auf dem sekundären Replikat erstellen zu können.   Vergleich von Microsoft AlwaysOn mit der Oracle MAA Ich komme wieder zurück auf die Eingangs erwähnte, mehrfach an mich gestellte Frage "Wann denn - und ob überhaupt - Oracle etwas Vergleichbares wie AlwaysOn bieten würde?" und meine damit verbundene (kurze) Irritation. Wenn Sie diesen Blogbeitrag bis hierher gelesen haben, dann kennen Sie jetzt meine darauf gegebene Antwort. Der eine oder andere Punkt traf dabei nicht immer auf Jeden zu, was auch nicht der tiefere Sinn und Zweck meiner Antwort war. Wenn beispielsweise kein Multi-Subnet mit im Spiel ist, sind alle diesbezüglichen Kritikpunkte zunächst obsolet. Was aber nicht bedeutet, dass sie nicht bereits morgen schon wieder zum Thema werden könnten (Sag niemals "Nie"). In manch anderes Fettnäpfchen tritt man wiederum nicht unbedingt in einer Testumgebung, sondern erst im laufenden Betrieb. Erst recht nicht dann, wenn man sich potenzieller Probleme nicht bewusst ist und keine dedizierten Tests startet. Und wer AlwaysOn erfolgreich positionieren möchte, wird auch gar kein Interesse daran haben, auf mögliche Schwachstellen und den besagten Teufel im Detail aufmerksam zu machen. Das ist keine Unterstellung - es ist nur menschlich. Außerdem ist es verständlich, dass man sich in erster Linie darauf konzentriert "was geht" und "was gut läuft", anstelle auf das "was zu Problemen führen kann" oder "nicht funktioniert". Wer will schon der Miesepeter sein? Für mich selbst gesprochen, kann ich nur sagen, dass ich lieber vorab von allen möglichen Einschränkungen wissen möchte, anstelle sie dann nach einer kurzen Zeit der heilen Welt schmerzhaft am eigenen Leib erfahren zu müssen. Ich bin davon überzeugt, dass es Ihnen nicht anders geht. Nachfolgend deshalb eine Zusammenfassung all jener Punkte, die ich im Vergleich zur Oracle MAA (Maximum Availability Architecture) als unbedingt Erwähnenswert betrachte, falls man eine Evaluierung von Microsoft AlwaysOn in Betracht zieht. 1. AlwaysOn ist eine komplexe Technologie Der SQL Server AlwaysOn Stack ist zusammengesetzt aus drei verschiedenen Technlogien: Windows Server Failover Clustering (WSFC) SQL Server Failover Cluster Instances (FCI) SQL Server Availability Groups (Verfügbarkeitsgruppen) Man kann eine derartige Lösung nicht als nahtlos bezeichnen, wofür auch die vielen von Microsoft dargestellten Einschränkungen sprechen. Während sich frühere SQL Server Versionen in Richtung eigener HA/DR Technologien entwickelten (wie Database Mirroring), empfiehlt Microsoft nun die Migration. Doch weshalb dieser Schwenk? Er führt nicht zu einem konsisten und robusten Angebot an HA/DR Technologie für geschäftskritische Umgebungen.  Liegt die Antwort in meiner These begründet, nach der "Windows was the God ..." noch immer gilt und man die Nachteile der allzu engen Kopplung mit Windows nicht sehen möchte? Entscheiden Sie selbst ... 2. Failover Cluster Instanzen - Kein RAC-Pendant Die SQL Server und Windows Server Clustering Technologie basiert noch immer auf dem veralteten Aktiv-Passiv Modell und führt zu einer Verschwendung von Systemressourcen. In einer Betrachtung von lediglich zwei Knoten erschließt sich auf Anhieb noch nicht der volle Mehrwert eines Aktiv-Aktiv Clusters (wie den Real Application Clusters), wie er von Oracle bereits vor zehn Jahren entwickelt wurde. Doch kennt man die Vorzüge der Skalierbarkeit durch einfaches Hinzufügen weiterer Cluster-Knoten, die dann alle gemeinsam als ein einziges logisches System zusammenarbeiten, versteht man was hinter dem Motto "Pay-as-you-Grow" steckt. In einem Aktiv-Aktiv Cluster geht es zwar auch um Hochverfügbarkeit - und ein Failover erfolgt zudem schneller, als in einem Aktiv-Passiv Modell - aber es geht eben nicht nur darum. An dieser Stelle sei darauf hingewiesen, dass die Oracle 11g Standard Edition bereits die Nutzung von Oracle RAC bis zu vier Sockets kostenfrei beinhaltet. Möchten Sie dazu Windows nutzen, benötigen Sie keine Windows Server Enterprise Edition, da Oracle 11g die eigene Clusterware liefert. Sie kommen in den Genuss von Hochverfügbarkeit und Skalierbarkeit und können dazu die günstigere Windows Server Standard Edition nutzen. 3. SQL Server Multi-Subnet Clustering - Abhängigkeit zu 3rd Party Storage Mirroring  Die SQL Server Multi-Subnet Clustering Architektur unterstützt den Aufbau eines Stretch Clusters, basiert dabei aber auf dem Aktiv-Passiv Modell. Das eigentlich Problematische ist jedoch, dass man sich zur Absicherung der Datenbank auf 3rd Party Storage Mirroring Technologie verlässt, ohne Integration zwischen dem Windows Server Failover Clustering (WSFC) und der darunterliegenden Mirroring Technologie. Wenn nun im Cluster ein Failover auf Instanzen-Ebene erfolgt, existiert keine Koordination mit einem möglichen Failover auf Ebene des Storage-Array. 4. Availability Groups (Verfügbarkeitsgruppen) - Vier, oder doch nur Zwei? Ein primäres Replikat erlaubt bis zu vier sekundäre Replikate innerhalb einer Verfügbarkeitsgruppe, jedoch nur zwei im Synchronen Commit Modus. Während dies zwar einen Vorteil gegenüber dem stringenten 1:1 Modell unter Database Mirroring darstellt, fällt der SQL Server 2012 damit immer noch weiter zurück hinter Oracle Data Guard mit bis zu 30 direkten Stanbdy Zielen - und vielen weiteren durch kaskadierende Ziele möglichen. Damit eignet sich Oracle Active Data Guard auch für die Bereitstellung einer Reader-Farm Skalierbarkeit für Internet-basierende Unternehmen. Mit AwaysOn Verfügbarkeitsgruppen ist dies nicht möglich. 5. Availability Groups (Verfügbarkeitsgruppen) - kein asynchrones Switchover  Die Technologie der Verfügbarkeitsgruppen wird auch als geeignetes Mittel für administrative Aufgaben positioniert - wie Upgrades oder Wartungsarbeiten. Man muss sich jedoch einem gravierendem Defizit bewusst sein: Im asynchronen Verfügbarkeitsmodus besteht die einzige Möglichkeit für Role Transition im Forced Failover mit Datenverlust! Um den Verlust von Daten durch geplante Wartungsarbeiten zu vermeiden, muss man den synchronen Verfügbarkeitsmodus konfigurieren, was jedoch ernstzunehmende Auswirkungen auf WAN Deployments nach sich zieht. Spinnt man diesen Gedanken zu Ende, kommt man zu dem Schluss, dass die Technologie der Verfügbarkeitsgruppen für geplante Wartungsarbeiten in einem derartigen Umfeld nicht effektiv genutzt werden kann. 6. Automatisches Failover - Nicht immer möglich Sowohl die SQL Server FCI, als auch Verfügbarkeitsgruppen unterstützen automatisches Failover. Möchte man diese jedoch kombinieren, wird das Ergebnis kein automatisches Failover sein. Denn ihr Zusammentreffen im Failover-Fall führt zu Race Conditions (Wettlaufsituationen), weshalb diese Konfiguration nicht länger das automatische Failover zu einem Replikat in einer Verfügbarkeitsgruppe erlaubt. Auch hier bestätigt sich wieder die tiefere Problematik von AlwaysOn, mit einer Zusammensetzung aus unterschiedlichen Technologien und der Abhängigkeit zu Windows. 7. Problematische RTO (Recovery Time Objective) Microsoft postioniert die SQL Server Multi-Subnet Clustering Architektur als brauchbare HA/DR Architektur. Bedenkt man jedoch die Problematik im Zusammenhang mit DNS Replikation und den möglichen langen Wartezeiten auf Client-Seite von bis zu 16 Minuten, sind strenge RTO Anforderungen (Recovery Time Objectives) nicht erfüllbar. Im Gegensatz zu Oracle besitzt der SQL Server keine Datenbank-integrierten Technologien, wie Oracle Fast Application Notification (FAN) oder Oracle Fast Connection Failover (FCF). 8. Problematische RPO (Recovery Point Objective) SQL Server ermöglicht Forced Failover (erzwungenes Failover), bietet jedoch keine Möglichkeit zur automatischen Übertragung der letzten Datenbits von einem alten zu einem neuen primären Replikat, wenn der Verfügbarkeitsmodus asynchron war. Oracle Data Guard hingegen bietet diese Unterstützung durch das Flush Redo Feature. Dies sichert "Zero Data Loss" und beste RPO auch in erzwungenen Failover-Situationen. 9. Lesbare Sekundäre Replikate mit Einschränkungen Aufgrund des Snapshot Isolation Transaction Level für lesbare sekundäre Replikate, besitzen diese Einschränkungen mit Auswirkung auf die primäre Datenbank. Die Bereinigung von Ghost Records auf der primären Datenbank, wird beeinflusst von lang laufenden Abfragen auf der lesabaren sekundären Datenbank. Die lesbare sekundäre Datenbank kann nicht in die Verfügbarkeitsgruppe aufgenommen werden, wenn es aktive Transaktionen auf der primären Datenbank gibt. Zusätzlich können DLL Änderungen auf der primären Datenbank durch Abfragen auf der sekundären blockiert werden. Und imkrementelle Backups werden hier nicht unterstützt.   Keine dieser Restriktionen existiert unter Oracle Data Guard.

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• Why should you choose Oracle WebLogic 12c instead of JBoss EAP 6?

  - by Ricardo Ferreira

  In this post, I will cover some technical differences between Oracle WebLogic 12c and JBoss EAP 6, which was released a couple days ago from Red Hat. This article claims to help you in the evaluation of key points that you should consider when choosing for an Java EE application server. In the following sections, I will present to you some important aspects that most customers ask us when they are seriously evaluating for an middleware infrastructure, specially if you are considering JBoss for some reason. I would suggest that you keep the following question in mind while you are reading the points: "Why should I choose JBoss instead of WebLogic?" 1) Multi Datacenter Deployment and Clustering - D/R ("Disaster & Recovery") architecture support is embedded on the WebLogic Server 12c product. JBoss EAP 6 on the other hand has no direct D/R support included, Red Hat relies on third-part tools with higher prices. When you consider a middleware solution to host your business critical application, you should worry with every architectural aspect that are related with the solution. Fail-over support is one little aspect of a truly reliable solution. If you do not worry about D/R, your solution will not be reliable. Having said that, with Red Hat and JBoss EAP 6, you have this extra cost that will increase considerably the total cost of ownership of the solution. As we commonly hear from analysts, open-source are not so cheaper when you start seeing the big picture. - WebLogic Server 12c supports advanced LAN clustering, detection of death servers and have a common alert framework. JBoss EAP 6 on the other hand has limited LAN clustering support with no server death detection. They do not generate any alerts when servers goes down (only if you buy JBoss ON which is a separated technology, but until now does not support JBoss EAP 6) and manual intervention are required when servers goes down. In most cases, admin people must rely on "kill -9", "tail -f someFile.log" and "ps ax | grep java" commands to manage failures and clustering anomalies. - WebLogic Server 12c supports the concept of Node Manager, which is a separated process that runs on the physical | virtual servers that allows extend the administration of the cluster to WebLogic managed servers that are often distributed across multiple machines and geographic locations. JBoss EAP 6 on the other hand has no equivalent technology. Whole server instances must be managed individually. - WebLogic Server 12c Node Manager supports Coherence to boost performance when managing servers. JBoss EAP 6 on the other hand has no similar technology. There is no way to coordinate JBoss and infiniband instances provided by JBoss using high throughput and low latency protocols like InfiniBand. The Node Manager feature also allows another very important feature that JBoss EAP lacks: secure the administration. When using WebLogic Node Manager, all the administration tasks are sent to the managed servers in a secure tunel protected by a certificate, which means that the transport layer that separates the WebLogic administration console from the managed servers are secured by SSL. - WebLogic Server 12c are now integrated with OTD ("Oracle Traffic Director") which is a web server technology derived from the former Sun iPlanet Web Server. This software complements the web server support offered by OHS ("Oracle HTTP Server"). Using OTD, WebLogic instances are load-balanced by a high powerful software that knows how to handle SDP ("Socket Direct Protocol") over InfiniBand, which boost performance when used with engineered systems technologies like Oracle Exalogic Elastic Cloud. JBoss EAP 6 on the other hand only offers support to Apache Web Server with custom modules created to deal with JBoss clusters, but only across standard TCP/IP networks.  2) Application and Runtime Diagnostics - WebLogic Server 12c have diagnostics capabilities embedded on the server called WLDF ("WebLogic Diagnostic Framework") so there is no need to rely on third-part tools. JBoss EAP 6 on the other hand has no diagnostics capabilities. Their only diagnostics tool is the log generated by the application server. Admin people are encouraged to analyse thousands of log lines to find out what is going on. - WebLogic Server 12c complement WLDF with JRockit MC ("Mission Control"), which provides to administrators and developers a complete insight about the JVM performance, behavior and possible bottlenecks. WebLogic Server 12c also have an classloader analysis tool embedded, and even a log analyzer tool that enables administrators and developers to view logs of multiple servers at the same time. JBoss EAP 6 on the other hand relies on third-part tools to do something similar. Again, only log searching are offered to find out whats going on. - WebLogic Server 12c offers end-to-end traceability and monitoring available through Oracle EM ("Enterprise Manager"), including monitoring of business transactions that flows through web servers, ESBs, application servers and database servers, all of this with high deep JVM analysis and diagnostics. JBoss EAP 6 on the other hand, even using JBoss ON ("Operations Network"), which is a separated technology, does not support those features. Red Hat relies on third-part tools to provide direct Oracle database traceability across JVMs. One of those tools are Oracle EM for non-Oracle middleware that manage JBoss, Tomcat, Websphere and IIS transparently. - WebLogic Server 12c with their JRockit support offers a tool called JRockit Flight Recorder, which can give developers a complete visibility of a certain period of application production monitoring with zero extra overhead. This automatic recording allows you to deep analyse threads latency, memory leaks, thread contention, resource utilization, stack overflow damages and GC ("Garbage Collection") cycles, to observe in real time stop-the-world phenomenons, generational, reference count and parallel collects and mutator threads analysis. JBoss EAP 6 don't even dream to support something similar, even because they don't have their own JVM. 3) Application Server Administration - WebLogic Server 12c offers a complete administration console complemented with scripting and macro-like recording capabilities. A single WebLogic console can managed up to hundreds of WebLogic servers belonging to the same domain. JBoss EAP 6 on the other hand has a limited console and provides a XML centric administration. JBoss, after ten years, started the development of a rudimentary centralized administration that still leave a lot of administration tasks aside, so admin people and developers must touch scripts and XML configuration files for most advanced and even simple administration tasks. This lead applications to error prone and risky deployments. Even using JBoss ON, JBoss EAP are not able to offer decent administration features for admin people which must be high skilled in JBoss internal architecture and its managing capabilities. - Oracle EM is available to manage multiple domains, databases, application servers, operating systems and virtualization, with a complete end-to-end visibility. JBoss ON does not provide management capabilities across the complete architecture, only basic monitoring. Even deployment must be done aside JBoss ON which does no integrate well with others softwares than JBoss. Until now, JBoss ON does not supports JBoss EAP 6, so even their minimal support for JBoss are not available for JBoss EAP 6 leaving customers uncovered and subject to high skilled JBoss admin people. - WebLogic Server 12c has the same administration model whatever is the topology selected by the customer. JBoss EAP 6 on the other hand differentiates between two operational models: standalone-mode and domain-mode, that are not consistent with each other. Depending on the mode used, the administration skill is different. - WebLogic Server 12c has no point-of-failures processes, and it does not need to define any specialized server. Domain model in WebLogic is available for years (at least ten years or more) and is production proven. JBoss EAP 6 on the other hand needs special processes to garantee JBoss integrity, the PC ("Process-Controller") and the HC ("Host-Controller"). Different from WebLogic, the domain model in JBoss is quite new (one year at tops) of maturity, and need to mature considerably until start doing things like WebLogic domain model does. - WebLogic Server 12c supports parallel deployment model which enables some artifacts being deployed at the same time. JBoss EAP 6 on the other hand does not have any similar feature. Every deployment are done atomically in the containers. This means that if you have a huge EAR (an EAR of 120 MB of size for instance) and deploy onto JBoss EAP 6, this EAR will take some minutes in order to starting accept thread requests. The same EAR deployed onto WebLogic Server 12c will reduce the deployment time at least in 2X compared to JBoss. 4) Support and Upgrades - WebLogic Server 12c has patch management available. JBoss EAP 6 on the other hand has no patch management available, each JBoss EAP instance should be patched manually. To achieve such feature, you need to buy a separated technology called JBoss ON ("Operations Network") that manage this type of stuff. But until now, JBoss ON does not support JBoss EAP 6 so, in practice, JBoss EAP 6 does not have this feature. - WebLogic Server 12c supports previuous WebLogic domains without any reconfiguration since its kernel is robust and mature since its creation in 1995. JBoss EAP 6 on the other hand has a proven lack of supportability between JBoss AS 4, 5, 6 and 7. Different kernels and messaging engines were implemented in JBoss stack in the last five years reveling their incapacity to create a well architected and proven middleware technology. - WebLogic Server 12c has patch prescription based on customer configuration. JBoss EAP 6 on the other hand has no such capability. People need to create ticket supports and have their installations revised by Red Hat support guys to gain some patch prescription from them. - Oracle WebLogic Server independent of the version has 8 years of support of new patches and has lifetime release of existing patches beyond that. JBoss EAP 6 on the other hand provides patches for a specific application server version up to 5 years after the release date. JBoss EAP 4 and previous versions had only 4 years. A good question that Red Hat will argue to answer is: "what happens when you find issues after year 5"?  5) RAC ("Real Application Clusters") Support - WebLogic Server 12c ships with a specific JDBC driver to leverage Oracle RAC clustering capabilities (Fast-Application-Notification, Transaction Affinity, Fast-Connection-Failover, etc). Oracle JDBC thin driver are also available. JBoss EAP 6 on the other hand ships only the standard Oracle JDBC thin driver. Load balancing with Oracle RAC are not supported. Manual intervention in case of planned or unplanned RAC downtime are necessary. In JBoss EAP 6, situation does not reestablish automatically after downtime. - WebLogic Server 12c has a feature called Active GridLink for Oracle RAC which provides up to 3X performance on OLTP applications. This seamless integration between WebLogic and Oracle database enable more value added to critical business applications leveraging their investments in Oracle database technology and Oracle middleware. JBoss EAP 6 on the other hand has no performance gains at all, even when admin people implement some kind of connection-pooling tuning. - WebLogic Server 12c also supports transaction and web session affinity to the Oracle RAC, which provides aditional gains of performance. This is particularly interesting if you are creating a reliable solution that are distributed not only in an LAN cluster, but into a different data center. JBoss EAP 6 on the other hand has no such support. 6) Standards and Technology Support - WebLogic Server 12c is fully Java EE 6 compatible and production ready since december of 2011. JBoss EAP 6 on the other hand became fully compatible with Java EE 6 only in the community version after three months, and production ready only in a few days considering that this article was written in June of 2012. Red Hat says that they are the masters of innovation and technology proliferation, but compared with Oracle and even other proprietary vendors like IBM, they historically speaking are lazy to deliver the most newest technologies and standards adherence. - Oracle is the steward of Java, driving innovation into the platform from commercial and open-source vendors. Red Hat on the other hand does not have its own JVM and relies on third-part JVMs to complete their application server offer. 95% of Red Hat customers are using Oracle HotSpot as JVM, which means that without Oracle involvement, their support are limited exclusively to the application server layer and we all know that most problems are happens in the JVM layer. - WebLogic Server 12c supports natively JDK 7, which empower developers to explore the maximum of the Java platform productivity when writing code. This feature differentiate WebLogic from others application servers (except GlassFish that are also managed by Oracle) because the usage of JDK 7 introduce such remarkable productivity features like the "try-with-resources" enhancement, catching multiple exceptions with one try block, Strings in the switch statements, JVM improvements in terms of JDBC, I/O, networking, security, concurrency and of course, the most important feature of Java 7: native support for multiple non-Java languages. More features regarding JDK 7 can be found here. JBoss EAP 6 on the other hand does not support JDK 7 officially, they comment in their community version that "Java SE 7 can be used with JBoss 7" which does not gives you any guarantees of enterprise support for JDK 7. - Oracle WebLogic Server 12c supports integration with Spring framework allowing Spring applications to use WebLogic special transaction manager, exposing bean interfaces to WebLogic MBeans to take advantage of all WebLogic monitoring and administration advantages. JBoss EAP 6 on the other hand has no special integration with Spring. In fact, Red Hat offers a suspicious package called "JBoss Web Platform" that in theory supports Spring, but in practice this package does not offers any special integration. It is just a facility for Red Hat customers to have support from both JBoss and Spring technology using the same customer support. 7) Lightweight Development - Oracle WebLogic Server 12c and Oracle GlassFish are completely integrated and can share applications without any modifications. Starting with the 12c version, WebLogic now understands natively GlassFish deployment descriptors and specific configurations in order to offer you a truly and reliable migration path from a community Java EE application server to a enterprise middleware product like WebLogic. JBoss EAP 6 on the other hand has no support to natively reuse an existing (or still in development) application from JBoss AS community server. Users of JBoss suffer of critical issues during deployment time that includes: changing the libraries and dependencies of the application, patching the DTD or XSD deployment descriptors, refactoring of the application layers due classloading issues and anomalies, rebuilding of persistence, business and web layers due issues with "usage of the certified version of an certain dependency" or "frameworks that Red Hat potentially does not recommend" etc. If you have the culture or enterprise IT directive of developing Java EE applications using community middleware to in a certain future, transition to enterprise (supported by a vendor) middleware, Oracle WebLogic plus Oracle GlassFish offers you a more sustainable solution. - WebLogic Server 12c has a very light ZIP distribution (less than 165 MB). JBoss EAP 6 ZIP size is around 130 MB, together with JBoss ON you have more 100 MB resulting in a higher download footprint. This is particularly interesting if you plan to use automated setup of application server instances (for example, to rapidly setup a development or staging environment) using Maven or Hudson. - WebLogic Server 12c has a complete integration with Maven allowing developers to setup WebLogic domains with few commands. Tasks like downloading WebLogic, installation, domain creation, data sources deployment are completely integrated. JBoss EAP 6 on the other hand has a limited offer integration with those tools.  - WebLogic Server 12c has a startup mode called WLX that turns-off EJB, JMS and JCA containers leaving enabled only the web container with Java EE 6 web profile. JBoss EAP 6 on the other hand has no such feature, you need to disable manually the containers that you do not want to use. - WebLogic Server 12c supports fastswap, which enables you to change classes without redeployment. This is particularly interesting if you are developing patches for the application that is already deployed and you do not want to redeploy the entire application. This is the same behavior that most application servers offers to JSP pages, but with WebLogic Server 12c, you have the same feature for Java classes in general. JBoss EAP 6 on the other hand has no such support. Even JBoss EAP 5 does not support this until now. 8) JMS and Messaging - WebLogic Server 12c has a proven and high scalable JMS implementation since its initial release in 1995. JBoss EAP 6 on the other hand has a still immature technology called HornetQ, which was introduced in JBoss EAP 5 replacing everything that was implemented in the previous versions. Red Hat loves to introduce new technologies across JBoss versions, playing around with customers and their investments. And when they are asked about why they have changed the implementation and caused such a mess, their answer is always: "the previous implementation was inadequate and not aligned with the community strategy so we are creating a new a improved one". This Red Hat practice leads to uncomfortable investments that in a near future (sometimes less than a year) will be affected in someway. - WebLogic Server 12c has troubleshooting and monitoring features included on the WebLogic console and WLDF. JBoss EAP 6 on the other hand has no direct monitoring on the console, activity is reflected only on the logs, no debug logs available in case of JMS issues. - WebLogic Server 12c has extremely good performance and scalability. JBoss EAP 6 on the other hand has a JMS storage mechanism relying on Oracle database or MySQL. This means that if an issue in production happens and Red Hat affirms that an performance issue is happening due to database problems, they will not support you on the performance issue. They will orient you to call Oracle instead. - WebLogic Server 12c supports messaging enterprise features like SAF ("Store and Forward"), Distributed Queues/Topics and Foreign JMS providers support that leverage JMS implementations without compromise developer code making things completely transparent. JBoss EAP 6 on the other hand do not even dream to support such features. 9) Caching and Grid - Coherence, which is the leading and most mature data grid technology from Oracle, is available since early 2000 and was integrated with WebLogic in 2009. Coherence and WebLogic clusters can be both managed from WebLogic administrative console. Even Node Manager supports Coherence. JBoss on the other hand discontinued JBoss Cache, which was their caching implementation just like they did with the messaging implementation (JBossMQ) which was a issue for long term customers. JBoss EAP 6 ships InfiniSpan version 1.0 which is immature and lack a proven record of successful cases and reliability. - WebLogic Server 12c has a feature called ActiveCache which uses Coherence to, without any code changes, replicate HTTP sessions from both WebLogic and other application servers like JBoss, Tomcat, Websphere, GlassFish and even Microsoft IIS. JBoss EAP 6 on the other hand does have such support and even when they do in the future, they probably will support only their own application server. - Coherence can be used to manage both L1 and L2 cache levels, providing support to Oracle TopLink and others JPA compliant implementations, even Hibernate. JBoss EAP 6 and Infinispan on the other hand supports only Hibernate. And most important of all: Infinispan does not have any successful case of L1 or L2 caching level support using Hibernate, which lead us to reflect about its viability. 10) Performance - WebLogic Server 12c is certified with Oracle Exalogic Elastic Cloud and can run unchanged applications at this engineered system. This approach can benefit customers from Exalogic optimization's of both kernel and JVM layers to boost performance in terms of 10X for web, OLTP, JMS and grid applications. JBoss EAP 6 on the other hand has no investment on engineered systems: customers do not have the choice to deploy on a Java ultra fast system if their project becomes relevant and performance issues are detected. - WebLogic Server 12c maintains a performance gain across each new release: starting on WebLogic 5.1, the overall performance gain has been close to 4X, which close to a 20% gain release by release. JBoss on the other hand does not provide SPECJAppServer or SPECJEnterprise performance benchmarks. Their so called "performance gains" remains hidden in their customer environments, which lead us to think if it is true or not since we will never get access to those environments. - WebLogic Server 12c has industry performance benchmarks with submissions across platforms and configurations leading SPECJ. Oracle WebLogic leads SPECJAppServer performance in multiple categories, fitting all customer topologies like: dual-node, single-node, multi-node and multi-node with RAC. JBoss... again, does not provide any SPECJAppServer performance benchmarks. - WebLogic Server 12c has a feature called work manager which allows your application to embrace new performance levels based on critical resource utilization of the CPUs usage. Work managers prioritizes work and allocates threads based on an execution model that takes into account administrator-defined parameters and actual run-time performance and throughput. JBoss EAP 6 on the other hand has no compared feature and probably they never will. Not supporting such feature like work managers, JBoss EAP 6 forces admin people and specially developers to uncover performance gains in a intrusive way, rewriting the code and doing performance refactorings. 11) Professional Services Support - WebLogic Server 12c and any other technology sold by Oracle give customers the possibility of hire OCS ("Oracle Consulting Services") to manage critical scenarios, deployment assistance of new applications, high skilled consultancy of architecture, best practices and people allocation together with customer teams. All OCS services are available without any restrictions, having the customer bought software from Oracle or just starting their implementation before any acquisition. JBoss EAP 6 or Red Hat to be more specifically, only offers professional services if you buy subscriptions from them. If you are developing a new critical application for your business and need the help of Red Hat for a serious issue or architecture decision, they will probably say: "OK... I can help you but after you buy subscriptions from me". Red Hat also does not allows their professional services consultants to manage environments that uses community based software. They will probably force you to first buy a subscription, download their "enterprise" version and them, optionally hire their consultants. - Oracle provides you our university to educate your team into our technologies, including of course specialized trainings of WebLogic application server. At any time and location, you can hire Oracle to train your team so you get trustful knowledge according to your specific needs. Certifications for the products are also available if your technical people desire to differentiate themselves as professionals. Red Hat on the other hand have a limited pool of resources to train your team in their technologies. Basically they are selling training and certification for RHEL ("Red Hat Enterprise Linux") but if you demand more specialized training in JBoss middleware, they will probably connect you to some "certified" partner localized training since they are apparently discontinuing their education center, at least here in Brazil. They were not able to reproduce their success with RHEL education to their middleware division since they need first sell the subscriptions to after gives you specialized training. And again, they only offer you specialized training based on their enterprise version (EAP in the case of JBoss) which means that the courses will be a quite outdated. There are reports of developers that took official training's from Red Hat at this year (2012) and in a certain JBoss advanced course, Red Hat supposedly covered JBossMQ as the messaging subsystem, and even the printed material provided was based on JBossMQ since the training was created for JBoss EAP 4.3. 12) Encouraging Transparency without Ulterior Motives - WebLogic Server 12c like any other software from Oracle can be downloaded any time from anywhere, you should only possess an OTN ("Oracle Technology Network") credential and you can download any enterprise software how many times you want. And is not some kind of "trial" version. It is the official binaries that will be running for ever in your data center. Oracle does not encourages the usage of "specific versions" of our software. The binaries you buy from Oracle are the same binaries anyone in the world could download and use for testing and personal education. JBoss EAP 6 on the other hand are not available for download unless you buy a subscription and get access to the Red Hat enterprise repositories. If you need to test, learn or just start creating your application using Red Hat's middleware software, you should download it from the community website. You are not allowed to download the enterprise version that, according to Red Hat are more secure, reliable and robust. But no one of us want to start the development of a software with an unsecured, unreliable and not scalable middleware right? So what you do? You are "invited" by Red Hat to buy subscriptions from them to get access to the "cool" version of the software. - WebLogic Server 12c prices are publicly available in the Oracle website. If you want to know right now how much WebLogic will cost to your organization, just click here and get access to our price list. In the case of WebLogic, check out the "US Oracle Technology Commercial Price List". Oracle also encourages you to get in touch with a sales representative to discuss discounts that would make possible the investment into our technology. But you are not required to do this, only if you are interested in buying our technology or maybe you want to discuss some discount scenarios. JBoss EAP 6 on the other hand does not have its cost publicly available in Red Hat's website or in any other media, at least is not so easy to get such information. The only link you will possibly find in their website is a "Contact a Sales Representative" link. This is not a very good relationship between an customer and an vendor. This is not an example of transparency, mainly when the software are sold as open. In this situations, customers expects to see the software prices publicly available, so they can have the chance to decide, based on the existing features of the software, if the cost is fair or not. Conclusion Oracle WebLogic is the most mature, secure, reliable and scalable Java EE application server of the market, and have a proven record of success around the globe to prove it's majority. Don't lose the chance to discover today how WebLogic could fit your needs and sustain your global IT middleware strategy, no matter if your strategy are completely based on the Cloud or not.

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• Windows Azure: Import/Export Hard Drives, VM ACLs, Web Sockets, Remote Debugging, Continuous Delivery, New Relic, Billing Alerts and More

  - by ScottGu

  Two weeks ago we released a giant set of improvements to Windows Azure, as well as a significant update of the Windows Azure SDK. This morning we released another massive set of enhancements to Windows Azure.  Today’s new capabilities include: Storage: Import/Export Hard Disk Drives to your Storage Accounts HDInsight: General Availability of our Hadoop Service in the cloud Virtual Machines: New VM Gallery, ACL support for VIPs Web Sites: WebSocket and Remote Debugging Support Notification Hubs: Segmented customer push notification support with tag expressions TFS & GIT: Continuous Delivery Support for Web Sites + Cloud Services Developer Analytics: New Relic support for Web Sites + Mobile Services Service Bus: Support for partitioned queues and topics Billing: New Billing Alert Service that sends emails notifications when your bill hits a threshold you define All of these improvements are now available to use immediately (note that some features are still in preview).  Below are more details about them. Storage: Import/Export Hard Disk Drives to Windows Azure I am excited to announce the preview of our new Windows Azure Import/Export Service! The Windows Azure Import/Export Service enables you to move large amounts of on-premises data into and out of your Windows Azure Storage accounts. It does this by enabling you to securely ship hard disk drives directly to our Windows Azure data centers. Once we receive the drives we’ll automatically transfer the data to or from your Windows Azure Storage account.  This enables you to import or export massive amounts of data more quickly and cost effectively (and not be constrained by available network bandwidth). Encrypted Transport Our Import/Export service provides built-in support for BitLocker disk encryption – which enables you to securely encrypt data on the hard drives before you send it, and not have to worry about it being compromised even if the disk is lost/stolen in transit (since the content on the transported hard drives is completely encrypted and you are the only one who has the key to it).  The drive preparation tool we are shipping today makes setting up bitlocker encryption on these hard drives easy. How to Import/Export your first Hard Drive of Data You can read our Getting Started Guide to learn more about how to begin using the import/export service.  You can create import and export jobs via the Windows Azure Management Portal as well as programmatically using our Server Management APIs. It is really easy to create a new import or export job using the Windows Azure Management Portal.  Simply navigate to a Windows Azure storage account, and then click the new Import/Export tab now available within it (note: if you don’t have this tab make sure to sign-up for the Import/Export preview): Then click the “Create Import Job” or “Create Export Job” commands at the bottom of it.  This will launch a wizard that easily walks you through the steps required: For more comprehensive information about Import/Export, refer to Windows Azure Storage team blog.  You can also send questions and comments to the [email protected] email address. We think you’ll find this new service makes it much easier to move data into and out of Windows Azure, and it will dramatically cut down the network bandwidth required when working on large data migration projects.  We hope you like it. HDInsight: 100% Compatible Hadoop Service in the Cloud Last week we announced the general availability release of Windows Azure HDInsight. HDInsight is a 100% compatible Hadoop service that allows you to easily provision and manage Hadoop clusters for big data processing in Windows Azure.  This release is now live in production, backed by an enterprise SLA, supported 24x7 by Microsoft Support, and is ready to use for production scenarios. HDInsight allows you to use Apache Hadoop tools, such as Pig and Hive, to process large amounts of data in Windows Azure Blob Storage. Because data is stored in Windows Azure Blob Storage, you can choose to dynamically create Hadoop clusters only when you need them, and then shut them down when they are no longer required (since you pay only for the time the Hadoop cluster instances are running this provides a super cost effective way to use them).  You can create Hadoop clusters using either the Windows Azure Management Portal (see below) or using our PowerShell and Cross Platform Command line tools: The import/export hard drive support that came out today is a perfect companion service to use with HDInsight – the combination allows you to easily ingest, process and optionally export a limitless amount of data.  We’ve also integrated HDInsight with our Business Intelligence tools, so users can leverage familiar tools like Excel in order to analyze the output of jobs.  You can find out more about how to get started with HDInsight here. Virtual Machines: VM Gallery Enhancements Today’s update of Windows Azure brings with it a new Virtual Machine gallery that you can use to create new VMs in the cloud.  You can launch the gallery by doing New->Compute->Virtual Machine->From Gallery within the Windows Azure Management Portal: The new Virtual Machine Gallery includes some nice enhancements that make it even easier to use: Search: You can now easily search and filter images using the search box in the top-right of the dialog.  For example, simply type “SQL” and we’ll filter to show those images in the gallery that contain that substring. Category Tree-view: Each month we add more built-in VM images to the gallery.  You can continue to browse these using the “All” view within the VM Gallery – or now quickly filter them using the category tree-view on the left-hand side of the dialog.  For example, by selecting “Oracle” in the tree-view you can now quickly filter to see the official Oracle supplied images. MSDN and Supported checkboxes: With today’s update we are also introducing filters that makes it easy to filter out types of images that you may not be interested in. The first checkbox is MSDN: using this filter you can exclude any image that is not part of the Windows Azure benefits for MSDN subscribers (which have highly discounted pricing - you can learn more about the MSDN pricing here). The second checkbox is Supported: this filter will exclude any image that contains prerelease software, so you can feel confident that the software you choose to deploy is fully supported by Windows Azure and our partners. Sort options: We sort gallery images by what we think customers are most interested in, but sometimes you might want to sort using different views. So we’re providing some additional sort options, like “Newest,” to customize the image list for what suits you best. Pricing information: We now provide additional pricing information about images and options on how to cost effectively run them directly within the VM Gallery. The above improvements make it even easier to use the VM Gallery and quickly create launch and run Virtual Machines in the cloud. Virtual Machines: ACL Support for VIPs A few months ago we exposed the ability to configure Access Control Lists (ACLs) for Virtual Machines using Windows PowerShell cmdlets and our Service Management API. With today’s release, you can now configure VM ACLs using the Windows Azure Management Portal as well. You can now do this by clicking the new Manage ACL command in the Endpoints tab of a virtual machine instance: This will enable you to configure an ordered list of permit and deny rules to scope the traffic that can access your VM’s network endpoints. For example, if you were on a virtual network, you could limit RDP access to a Windows Azure virtual machine to only a few computers attached to your enterprise. Or if you weren’t on a virtual network you could alternatively limit traffic from public IPs that can access your workloads: Here is the default behaviors for ACLs in Windows Azure: By default (i.e. no rules specified), all traffic is permitted. When using only Permit rules, all other traffic is denied. When using only Deny rules, all other traffic is permitted. When there is a combination of Permit and Deny rules, all other traffic is denied. Lastly, remember that configuring endpoints does not automatically configure them within the VM if it also has firewall rules enabled at the OS level.  So if you create an endpoint using the Windows Azure Management Portal, Windows PowerShell, or REST API, be sure to also configure your guest VM firewall appropriately as well. Web Sites: Web Sockets Support With today’s release you can now use Web Sockets with Windows Azure Web Sites.  This feature enables you to easily integrate real-time communication scenarios within your web based applications, and is available at no extra charge (it even works with the free tier).  Higher level programming libraries like SignalR and socket.io are also now supported with it. You can enable Web Sockets support on a web site by navigating to the Configure tab of a Web Site, and by toggling Web Sockets support to “on”: Once Web Sockets is enabled you can start to integrate some really cool scenarios into your web applications.  Check out the new SignalR documentation hub on www.asp.net to learn more about some of the awesome scenarios you can do with it. Web Sites: Remote Debugging Support The Windows Azure SDK 2.2 we released two weeks ago introduced remote debugging support for Windows Azure Cloud Services. With today’s Windows Azure release we are extending this remote debugging support to also work with Windows Azure Web Sites. With live, remote debugging support inside of Visual Studio, you are able to have more visibility than ever before into how your code is operating live in Windows Azure. It is now super easy to attach the debugger and quickly see what is going on with your application in the cloud. Remote Debugging of a Windows Azure Web Site using VS 2013 Enabling the remote debugging of a Windows Azure Web Site using VS 2013 is really easy.  Start by opening up your web application’s project within Visual Studio. Then navigate to the “Server Explorer” tab within Visual Studio, and click on the deployed web-site you want to debug that is running within Windows Azure using the Windows Azure->Web Sites node in the Server Explorer.  Then right-click and choose the “Attach Debugger” option on it: When you do this Visual Studio will remotely attach the debugger to the Web Site running within Windows Azure.  The debugger will then stop the web site’s execution when it hits any break points that you have set within your web application’s project inside Visual Studio.  For example, below I set a breakpoint on the “ViewBag.Message” assignment statement within the HomeController of the standard ASP.NET MVC project template.  When I hit refresh on the “About” page of the web site within the browser, the breakpoint was triggered and I am now able to debug the app remotely using Visual Studio: Note above how we can debug variables (including autos/watchlist/etc), as well as use the Immediate and Command Windows. In the debug session above I used the Immediate Window to explore some of the request object state, as well as to dynamically change the ViewBag.Message property.  When we click the the “Continue” button (or press F5) the app will continue execution and the Web Site will render the content back to the browser.  This makes it super easy to debug web apps remotely. Tips for Better Debugging To get the best experience while debugging, we recommend publishing your site using the Debug configuration within Visual Studio’s Web Publish dialog. This will ensure that debug symbol information is uploaded to the Web Site which will enable a richer debug experience within Visual Studio.  You can find this option on the Web Publish dialog on the Settings tab: When you ultimately deploy/run the application in production we recommend using the “Release” configuration setting – the release configuration is memory optimized and will provide the best production performance.  To learn more about diagnosing and debugging Windows Azure Web Sites read our new Troubleshooting Windows Azure Web Sites in Visual Studio guide. Notification Hubs: Segmented Push Notification support with tag expressions In August we announced the General Availability of Windows Azure Notification Hubs - a powerful Mobile Push Notifications service that makes it easy to send high volume push notifications with low latency from any mobile app back-end.  Notification hubs can be used with any mobile app back-end (including ones built using our Mobile Services capability) and can also be used with back-ends that run in the cloud as well as on-premises. Beginning with the initial release, Notification Hubs allowed developers to send personalized push notifications to both individual users as well as groups of users by interest, by associating their devices with tags representing the logical target of the notification. For example, by registering all devices of customers interested in a favorite MLB team with a corresponding tag, it is possible to broadcast one message to millions of Boston Red Sox fans and another message to millions of St. Louis Cardinals fans with a single API call respectively. New support for using tag expressions to enable advanced customer segmentation With today’s release we are adding support for even more advanced customer targeting.  You can now identify customers that you want to send push notifications to by defining rich tag expressions. With tag expressions, you can now not only broadcast notifications to Boston Red Sox fans, but take that segmenting a step farther and reach more granular segments. This opens up a variety of scenarios, for example: Offers based on multiple preferences—e.g. send a game day vegetarian special to users tagged as both a Boston Red Sox fan AND a vegetarian Push content to multiple segments in a single message—e.g. rain delay information only to users who are tagged as either a Boston Red Sox fan OR a St. Louis Cardinal fan Avoid presenting subsets of a segment with irrelevant content—e.g. season ticket availability reminder to users who are tagged as a Boston Red Sox fan but NOT also a season ticket holder To illustrate with code, consider a restaurant chain app that sends an offer related to a Red Sox vs Cardinals game for users in Boston. Devices can be tagged by your app with location tags (e.g. “Loc:Boston”) and interest tags (e.g. “Follows:RedSox”, “Follows:Cardinals”), and then a notification can be sent by your back-end to “(Follows:RedSox || Follows:Cardinals) && Loc:Boston” in order to deliver an offer to all devices in Boston that follow either the RedSox or the Cardinals. This can be done directly in your server backend send logic using the code below: var notification = new WindowsNotification(messagePayload); hub.SendNotificationAsync(notification, "(Follows:RedSox || Follows:Cardinals) && Loc:Boston"); In your expressions you can use all Boolean operators: AND (&&), OR (||), and NOT (!).  Some other cool use cases for tag expressions that are now supported include: Social: To “all my group except me” - group:id && !user:id Events: Touchdown event is sent to everybody following either team or any of the players involved in the action: Followteam:A || Followteam:B || followplayer:1 || followplayer:2 … Hours: Send notifications at specific times. E.g. Tag devices with time zone and when it is 12pm in Seattle send to: GMT8 && follows:thaifood Versions and platforms: Send a reminder to people still using your first version for Android - version:1.0 && platform:Android For help on getting started with Notification Hubs, visit the Notification Hub documentation center.  Then download the latest NuGet package (or use the Notification Hubs REST APIs directly) to start sending push notifications using tag expressions.  They are really powerful and enable a bunch of great new scenarios. TFS & GIT: Continuous Delivery Support for Web Sites + Cloud Services With today’s Windows Azure release we are making it really easy to enable continuous delivery support with Windows Azure and Team Foundation Services.  Team Foundation Services is a cloud based offering from Microsoft that provides integrated source control (with both TFS and Git support), build server, test execution, collaboration tools, and agile planning support.  It makes it really easy to setup a team project (complete with automated builds and test runners) in the cloud, and it has really rich integration with Visual Studio. With today’s Windows Azure release it is now really easy to enable continuous delivery support with both TFS and Git based repositories hosted using Team Foundation Services.  This enables a workflow where when code is checked in, built successfully on an automated build server, and all tests pass on it – I can automatically have the app deployed on Windows Azure with zero manual intervention or work required. The below screen-shots demonstrate how to quickly setup a continuous delivery workflow to Windows Azure with a Git-based ASP.NET MVC project hosted using Team Foundation Services. Enabling Continuous Delivery to Windows Azure with Team Foundation Services The project I’m going to enable continuous delivery with is a simple ASP.NET MVC project whose source code I’m hosting using Team Foundation Services.  I did this by creating a “SimpleContinuousDeploymentTest” repository there using Git – and then used the new built-in Git tooling support within Visual Studio 2013 to push the source code to it.  Below is a screen-shot of the Git repository hosted within Team Foundation Services: I can access the repository within Visual Studio 2013 and easily make commits with it (as well as branch, merge and do other tasks).  Using VS 2013 I can also setup automated builds to take place in the cloud using Team Foundation Services every time someone checks in code to the repository: The cool thing about this is that I don’t have to buy or rent my own build server – Team Foundation Services automatically maintains its own build server farm and can automatically queue up a build for me (for free) every time someone checks in code using the above settings.  This build server (and automated testing) support now works with both TFS and Git based source control repositories. Connecting a Team Foundation Services project to Windows Azure Once I have a source repository hosted in Team Foundation Services with Automated Builds and Testing set up, I can then go even further and set it up so that it will be automatically deployed to Windows Azure when a source code commit is made to the repository (assuming the Build + Tests pass).  Enabling this is now really easy.  To set this up with a Windows Azure Web Site simply use the New->Compute->Web Site->Custom Create command inside the Windows Azure Management Portal.  This will create a dialog like below.  I gave the web site a name and then made sure the “Publish from source control” checkbox was selected: When we click next we’ll be prompted for the location of the source repository.  We’ll select “Team Foundation Services”: Once we do this we’ll be prompted for our Team Foundation Services account that our source repository is hosted under (in this case my TFS account is “scottguthrie”): When we click the “Authorize Now” button we’ll be prompted to give Windows Azure permissions to connect to the Team Foundation Services account.  Once we do this we’ll be prompted to pick the source repository we want to connect to.  Starting with today’s Windows Azure release you can now connect to both TFS and Git based source repositories.  This new support allows me to connect to the “SimpleContinuousDeploymentTest” respository we created earlier: Clicking the finish button will then create the Web Site with the continuous delivery hooks setup with Team Foundation Services.  Now every time someone pushes source control to the repository in Team Foundation Services, it will kick off an automated build, run all of the unit tests in the solution , and if they pass the app will be automatically deployed to our Web Site in Windows Azure.  You can monitor the history and status of these automated deployments using the Deployments tab within the Web Site: This enables a really slick continuous delivery workflow, and enables you to build and deploy apps in a really nice way. Developer Analytics: New Relic support for Web Sites + Mobile Services With today’s Windows Azure release we are making it really easy to enable Developer Analytics and Monitoring support with both Windows Azure Web Site and Windows Azure Mobile Services.  We are partnering with New Relic, who provide a great dev analytics and app performance monitoring offering, to enable this - and we have updated the Windows Azure Management Portal to make it really easy to configure. Enabling New Relic with a Windows Azure Web Site Enabling New Relic support with a Windows Azure Web Site is now really easy.  Simply navigate to the Configure tab of a Web Site and scroll down to the “developer analytics” section that is now within it: Clicking the “add-on” button will display some additional UI.  If you don’t already have a New Relic subscription, you can click the “view windows azure store” button to obtain a subscription (note: New Relic has a perpetually free tier so you can enable it even without paying anything): Clicking the “view windows azure store” button will launch the integrated Windows Azure Store experience we have within the Windows Azure Management Portal.  You can use this to browse from a variety of great add-on services – including New Relic: Select “New Relic” within the dialog above, then click the next button, and you’ll be able to choose which type of New Relic subscription you wish to purchase.  For this demo we’ll simply select the “Free Standard Version” – which does not cost anything and can be used forever:  Once we’ve signed-up for our New Relic subscription and added it to our Windows Azure account, we can go back to the Web Site’s configuration tab and choose to use the New Relic add-on with our Windows Azure Web Site.  We can do this by simply selecting it from the “add-on” dropdown (it is automatically populated within it once we have a New Relic subscription in our account): Clicking the “Save” button will then cause the Windows Azure Management Portal to automatically populate all of the needed New Relic configuration settings to our Web Site: Deploying the New Relic Agent as part of a Web Site The final step to enable developer analytics using New Relic is to add the New Relic runtime agent to our web app.  We can do this within Visual Studio by right-clicking on our web project and selecting the “Manage NuGet Packages” context menu: This will bring up the NuGet package manager.  You can search for “New Relic” within it to find the New Relic agent.  Note that there is both a 32-bit and 64-bit edition of it – make sure to install the version that matches how your Web Site is running within Windows Azure (note: you can configure your Web Site to run in either 32-bit or 64-bit mode using the Web Site’s “Configuration” tab within the Windows Azure Management Portal): Once we install the NuGet package we are all set to go.  We’ll simply re-publish the web site again to Windows Azure and New Relic will now automatically start monitoring the application Monitoring a Web Site using New Relic Now that the application has developer analytics support with New Relic enabled, we can launch the New Relic monitoring portal to start monitoring the health of it.  We can do this by clicking on the “Add Ons” tab in the left-hand side of the Windows Azure Management Portal.  Then select the New Relic add-on we signed-up for within it.  The Windows Azure Management Portal will provide some default information about the add-on when we do this.  Clicking the “Manage” button in the tray at the bottom will launch a new browser tab and single-sign us into the New Relic monitoring portal associated with our account: When we do this a new browser tab will launch with the New Relic admin tool loaded within it: We can now see insights into how our app is performing – without having to have written a single line of monitoring code.  The New Relic service provides a ton of great built-in monitoring features allowing us to quickly see: Performance times (including browser rendering speed) for the overall site and individual pages.  You can optionally set alert thresholds to trigger if the speed does not meet a threshold you specify. Information about where in the world your customers are hitting the site from (and how performance varies by region) Details on the latency performance of external services your web apps are using (for example: SQL, Storage, Twitter, etc) Error information including call stack details for exceptions that have occurred at runtime SQL Server profiling information – including which queries executed against your database and what their performance was And a whole bunch more… The cool thing about New Relic is that you don’t need to write monitoring code within your application to get all of the above reports (plus a lot more).  The New Relic agent automatically enables the CLR profiler within applications and automatically captures the information necessary to identify these.  This makes it super easy to get started and immediately have a rich developer analytics view for your solutions with very little effort. If you haven’t tried New Relic out yet with Windows Azure I recommend you do so – I think you’ll find it helps you build even better cloud applications.  Following the above steps will help you get started and deliver you a really good application monitoring solution in only minutes. Service Bus: Support for partitioned queues and topics With today’s release, we are enabling support within Service Bus for partitioned queues and topics. Enabling partitioning enables you to achieve a higher message throughput and better availability from your queues and topics. Higher message throughput is achieved by implementing multiple message brokers for each partitioned queue and topic.  The  multiple messaging stores will also provide higher availability. You can create a partitioned queue or topic by simply checking the Enable Partitioning option in the custom create wizard for a Queue or Topic: Read this article to learn more about partitioned queues and topics and how to take advantage of them today. Billing: New Billing Alert Service Today’s Windows Azure update enables a new Billing Alert Service Preview that enables you to get proactive email notifications when your Windows Azure bill goes above a certain monetary threshold that you configure.  This makes it easier to manage your bill and avoid potential surprises at the end of the month. With the Billing Alert Service Preview, you can now create email alerts to monitor and manage your monetary credits or your current bill total.  To set up an alert first sign-up for the free Billing Alert Service Preview.  Then visit the account management page, click on a subscription you have setup, and then navigate to the new Alerts tab that is available: The alerts tab allows you to setup email alerts that will be sent automatically once a certain threshold is hit.  For example, by clicking the “add alert” button above I can setup a rule to send myself email anytime my Windows Azure bill goes above $100 for the month: The Billing Alert Service will evolve to support additional aspects of your bill as well as support multiple forms of alerts such as SMS.  Try out the new Billing Alert Service Preview today and give us feedback. Summary Today’s Windows Azure release enables a ton of great new scenarios, and makes building applications hosted in the cloud even easier. If you don’t already have a Windows Azure account, you can sign-up for a free trial and start using all of the above features today.  Then visit the Windows Azure Developer Center to learn more about how to build apps with it. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• Converting a WPFToolkit DataGrid from 1D list to 2D matrix

  - by user61073

  Hello - I am wondering if anyone has attempted the following or has an idea as to how to do it. I have a WPFToolkit DataGrid which is bound to an ObservableCollection of items. As such, the DataGrid is shown with as many rows in the ObservableCollection, and as many columns as I have defined in for the DataGrid. That all is good. What I now need is to provide another view of the same data, only, instead, the DataGrid is shown with as many cells in the ObservableCollection. So let's say, my ObservableCollection has 100 items in it. The original scenario showed the DataGrid with 100 rows and 1 column. In the modified scenario, I need to show it with 10 rows and 10 columns, where each cell shows the value that was in the original representation. In other words, I need to transform my 1D ObservableCollection to a 2D ObservableCollection and display it in the DataGrid. I know how to do that programmatically in the code behind, but can it be done in XAML? Let me simplify the problem a little, in case anybody can have a crack at this. The XAML below does the following: * Defines an XmlDataProvider just for dummy data * Creates a DataGrid with 10 columns o each column is a DataGridTemplateColumn using the same CellTemplate * The CellTemplate is a simple TextBlock bound to an XML element If you run the XAML below, you will find that the DataGrid ends up with 5 rows, one for each book, and 10 columns that have identical content (all showing the book titles). However, what I am trying to accomplish, albeit with a different data set, is that in this case, I would end up with one row, with each book title appearing in a single cell in row 1, occupying cells 0-4, and nothing in cells 5-9. Then, if I added more data and had 12 books in my XML data source, I would get row 1 completely filled (cells covering the first 10 titles) and row 2 would get the first 2 cells filled. Can my scenario be accomplished primarily in XAML, or should I resign myself to working in the code behind? Any guidance would greatly be appreciated. Thanks so much! <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:custom="http://schemas.microsoft.com/wpf/2008/toolkit" mc:Ignorable="d" x:Name="UserControl" d:DesignWidth="600" d:DesignHeight="400" > <UserControl.Resources> <XmlDataProvider x:Key="InventoryData" XPath="Inventory/Books"> <x:XData> <Inventory xmlns=""> <Books> <Book ISBN="0-7356-0562-9" Stock="in" Number="9"> <Title>XML in Action</Title> <Summary>XML Web Technology</Summary> </Book> <Book ISBN="0-7356-1370-2" Stock="in" Number="8"> <Title>Programming Microsoft Windows With C#</Title> <Summary>C# Programming using the .NET Framework</Summary> </Book> <Book ISBN="0-7356-1288-9" Stock="out" Number="7"> <Title>Inside C#</Title> <Summary>C# Language Programming</Summary> </Book> <Book ISBN="0-7356-1377-X" Stock="in" Number="5"> <Title>Introducing Microsoft .NET</Title> <Summary>Overview of .NET Technology</Summary> </Book> <Book ISBN="0-7356-1448-2" Stock="out" Number="4"> <Title>Microsoft C# Language Specifications</Title> <Summary>The C# language definition</Summary> </Book> </Books> <CDs> <CD Stock="in" Number="3"> <Title>Classical Collection</Title> <Summary>Classical Music</Summary> </CD> <CD Stock="out" Number="9"> <Title>Jazz Collection</Title> <Summary>Jazz Music</Summary> </CD> </CDs> </Inventory> </x:XData> </XmlDataProvider> <DataTemplate x:Key="GridCellTemplate"> <TextBlock> <TextBlock.Text> <Binding XPath="Title"/> </TextBlock.Text> </TextBlock> </DataTemplate> </UserControl.Resources> <Grid x:Name="LayoutRoot"> <custom:DataGrid HorizontalAlignment="Stretch" VerticalAlignment="Stretch" IsSynchronizedWithCurrentItem="True" Background="{DynamicResource WindowBackgroundBrush}" HeadersVisibility="All" RowDetailsVisibilityMode="Collapsed" SelectionUnit="CellOrRowHeader" CanUserResizeRows="False" GridLinesVisibility="None" RowHeaderWidth="35" AutoGenerateColumns="False" CanUserReorderColumns="False" CanUserSortColumns="False"> <custom:DataGrid.Columns> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="01" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="02" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="03" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="04" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="05" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="06" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="07" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="08" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="09" /> <custom:DataGridTemplateColumn CellTemplate="{StaticResource GridCellTemplate}" Header="10" /> </custom:DataGrid.Columns> <custom:DataGrid.ItemsSource> <Binding Source="{StaticResource InventoryData}" XPath="Book"/> </custom:DataGrid.ItemsSource> </custom:DataGrid> </Grid>

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• Hosted bug tracking system with mercurial repositories (Summary of options & request for opinions)

  - by Mark Booth

  The Question What hosted mercurial repository/bug tracking system or systems have you used? Would you recommend it to others? Are there serious flaws, either in the repository hosting or the bug tracking features that would make it difficult to recommend it? Do you have any other experiences with it or opinions of it that you would like to share? If you have used other non mercurial hosted repository/bug tracking systems, how does it compare? (If I understand correctly, the best format for this type of community-wiki style question is one answer per option, if you have experienced if several) Background I have been looking into options for setting up a bug/issue tracking database and found some valuable advice in this thread and this. But then I got to thinking that a hosted solution might not only solve the problem of tracking bugs, but might also solve the problem we have accessing our mercurial source code repositories while at customer sites around the world. Since we currently have no way to serve mercurial repositories over ssl, when I am at a customer site I have to connect my laptop via VPN to my work network and access the mercurial repositories over a samba share (even if it is just to synce twice a day). This is excruciatingly slow on high latency networks and can be impossible with some customers' firewalls. Even if we could run a TRAC or Redmine server here (thanks turnkey), I'm not sure it would be much quicker as our internet connection is over-stretched as it is. What I would like is for developers to be able to be able to push/pull to/from a remote repository, servicing engineers to be able to pull from a remote repository and for customers (both internal and external) to be able to submit bug/issue reports. Initial options The two options I found were Assembla and Jira. Looking at Assembla I thought the 'group' price looked reasonable, but after enquiring, found that each workspace could only contain a single repository. Since each of our products might have up to a dozen repositories (mostly for libraries) which need to be managed seperately for each product, I could see it getting expensive really quickly. On the plus side, it appears that 'users' are just workspace members, so you can have as many client users (people who can only submit support tickets and track their own tickets) without using up your user allocation. Jira only charges based on the number of users, unfortunately client users also count towards this, if you want them to be able to track their tickets. If you only want clients to be able to submit untracked issues, you can let them submit anonymously, but that doesn't feel very professional to me. More options Looking through MercurialHosting page that @Paidhi suggested, I've added the options which appear to offer private repositories, along with another that I found with a web search. Prices are as per their website today (29th March 2010). Corrections welcome in the future. Anyway, here is my summary, according to the information given on their websites: Assembla, http://www.assembla.com/, looks to be a reasonable price, but suffers only one repository per workspace, so three projects with 6 repos each would use up most of the spaces associated with a $99/month professional account (20 spaces). Bug tracking is based on Trac. Mercurial+Trac support was announced in a blog entry in 2007, but they only list SVN and Git on their Features web page. Cost: $24, $49, $99 & $249/month for 40, 40, unlimited, unlimited users and 1, 10, 20, 100 workspaces. SSL based push/pull? Website https login. BitBucket, http://bitbucket.org/plans/, is primarily a mercurial hosting site for open source projects, with SSL support, but they have an integrated bug tracker and they are cheap for private repositories. It has it’s own issues tracker, but also integrates with Lighthouse & FogBugz. Cost: $0, $5, $12, $50 & $100/month for 1, 5, 15, 25 & 150 private repositories. SSL based push/pull. No https on website login, but supports OpenID, so you can chose an OpenID provider with https login. Codebase HQ, http://www.codebasehq.com/, supports Hg and is almost as cheap as BitBucket. Cost: £5, £13, £21 & £40/month for 3, 15, 30 & 60 active projects, unlimited repositories, unlimited users (except 10 users at £5/month) and 0.5, 2, 4 & 10GB. SSL based push/pull? Website https login? Firefly, http://www.activestate.com/firefly/, by ActiveState looks interesting, but the website is a little light on details, such as whether you can only have one repository per project or not. Cost: $9, $19, & £39/month for 1, 5 & 30 private projects, with a 0.5, 1.5 & 3 GB storage limit. SSL based push/pull? Website https login. Jira, http://www.atlassian.com/software/jira/, isn’t limited by the number of repositories you can have, but by ‘user’. It could work out quite expensive if we want client users to be able to track their issues, since they would need a full user account to be created for them. Also, while there is a Mercurial extension to support jira, there is no ‘Advanced integration’ for Mercurial from Atlassian Fisheye. Cost: $150, $300, $400, $500, $700/month for 10, 25, 50, 100, 100+ users. SSL based push/pull? Website https login. Kiln & FogBugz On Demand, http://fogcreek.com/Kiln/IntrotoOnDemand.html, integrates Kilns mercurial DVCS features with FogBugz, where the combined package is much cheaper than the component parts. Also, the Fogbugz integration is supposedly excellent. *8’) Cost: £30/developer/month ($5/d/m more than either on their own). SSL based push/pull? SourceRepo, http://sourcerepo.com/, also supports HG and is even cheaper than BitBucket & Codebase. Cost: $4, $7 & $13/month for 1, unlimited & unlimited repositories/trac/redmine instances and 500MB, 1GB & 3GB storage. SSL based push/pull. Website https login. Edit: 29th March 2010 & Bounty I split this question into sections, made the questions themselves more explicit, added other options from the research I have done since my first posting and made this community wiki, since I now understand what CW is for. *8') Also, I've added a bounty to encourage people to offer their opinions. At the end of the bounty period, I will award the bounty to whoever writes the best review (good or bad), irrespective of the number of up/down votes it gets. Given that it's probably more important to avoid bad providers than find the absolute best one, 'bad reviews' could be considered more important than good ones.

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• Generating moderately interesting images

  - by Williham Totland

  Abstract: Can you propose a mathematical-ish algorithm over a plane of pixels that will generate a moderately interesting image, preferably one that on the whole resembles something? The story thus far: Once upon a time I decided in an effort to reduce cycle waste on my (admittedly too) numerous computers, and set out to generate images in a moderately interesting fashion; using a PRNG and some clever math to create images that would, on the whole, resemble something. Or at least, that was the plan. As it turns out, clever math requires being a clever mathematician; this I am not. At some length I arrived at a method that preferred straight lines (as these are generally the components of which our world is made), perhaps too strongly. The result is mildly interesting; resembling, perhaps, city grids as such: Now for the question proper: Given the source code of this little program; can you improve upon it and propose a method that gives somewhat more interesting results? (e.g. not city grids, but perhaps faces, animals, geography, what have you) This is also meant as a sort of challenge; I suppose and as such I've set down some completely arbitrary and equally optional rules: The comments in the code says it all really. Suggestions and "solutions" should edit the algorithm itself, not the surrounding framework, except as for to fix errors that prevents the sample from compiling. The code should compile cleanly with a standard issue C compiler. (If the example provided doesn't, oops! Tell me, and I'll fix. :) The method should, though again, this is optional, not need to elicit help from your friendly neighborhood math library. Solutions should probably be deliverable by simply yanking out whatever is between the snip lines (the ones that say you should not edit above and below, respectively), with a statement to the effect of what you need to add to the preamble in particular. The code requires a C compiler and libpng to build; I'm not entirely confident that the MinGW compiler provides the necessities, but I would be surprised if it didn't. For Debian you'll want the libpng-dev package, and for Mac OS X you'll want the XCode tools.. The source code can be downloaded here. Warning: Massive code splurge incoming! // compile with gcc -o imggen -lpng imggen.c // optionally with -DITERATIONS=x, where x is an appropriate integer // If you're on a Mac or using MinGW, you may have to fiddle with the linker flags to find the library and includes. #include <stdio.h> #include <stdlib.h> #include <png.h> #ifdef ITERATIONS #define REPEAT #endif // ITERATIONS // YOU MAY CHANGE THE FOLLOWING DEFINES #define WIDTH 320 #define HEIGHT 240 // YOU MAY REPLACE THE FOLLOWING DEFINES AS APPROPRIATE #define INK 16384 void writePNG (png_bytepp imageBuffer, png_uint_32 width, png_uint_32 height, int iteration) { char *fname; asprintf(&fname, "out.%d.png", iteration); FILE *fp = fopen(fname, "wb"); if (!fp) return; png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); png_infop info_ptr = png_create_info_struct(png_ptr); png_init_io(png_ptr, fp); png_set_filter(png_ptr, PNG_FILTER_TYPE_DEFAULT, PNG_FILTER_NONE); png_set_compression_level(png_ptr, Z_BEST_COMPRESSION); png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT); png_set_rows(png_ptr, info_ptr, imageBuffer); png_set_invert_mono(png_ptr); /// YOU MAY COMMENT OUT THIS LINE png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL); png_destroy_write_struct(&png_ptr, &info_ptr); fclose(fp); free(fname); } int main (int argc, const char * argv[]) { png_uint_32 height = HEIGHT, width = WIDTH; int iteration = 1; #ifdef REPEAT for (iteration = 1; iteration <= ITERATIONS; iteration++) { #endif // REPEAT png_bytepp imageBuffer = malloc(sizeof(png_bytep) * height); for (png_uint_32 i = 0; i < height; i++) { imageBuffer[i] = malloc(sizeof(png_byte) * width); for (png_uint_32 j = 0; j < width; j++) { imageBuffer[i][j] = 0; } } /// CUT ACROSS THE DASHED LINES /// ------------------------------------------- /// NO EDITING ABOVE THIS LINE; EXCEPT AS NOTED int ink = INK; int x = rand() % width, y = rand() % height; int xdir = (rand() % 2)?1:-1; int ydir = (rand() % 2)?1:-1; while (ink) { imageBuffer[y][x] = 255; --ink; xdir += (rand() % 2)?(1):(-1); ydir += (rand() % 2)?(1):(-1); if (ydir > 0) { ++y; } else if (ydir < 0) { --y; } if (xdir > 0) { ++x; } else if (xdir < 0) { --x; } if (x == -1 || y == -1 || x == width || y == height || x == y && x == 0) { x = rand() % width; y = rand() % height; xdir = (rand() % 2)?1:-1; ydir = (rand() % 2)?1:-1; } } /// NO EDITING BELOW THIS LINE /// ------------------------------------------- writePNG(imageBuffer, width, height, iteration); for (png_uint_32 i = 0; i < height; i++) { free(imageBuffer[i]); } free(imageBuffer); #ifdef REPEAT } #endif // REPEAT return 0; } Note: While this question doesn't strictly speaking seem "answerable" as such; I still believe that it can give rise to some manner of "right" answer. Maybe. Happy hunting.

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• Records not being saved to core data sqlite file

  - by esd100

  I'm a complete newbie when it comes to iOS programming and much less Core Data. It's rather non-intuitive for me, as I really came into my own with programming with MATLAB, which I guess is more of a 'scripting' language. At any rate, my problem is that I had no idea what I had to do to create a database for my application. So I read a little bit and thought I had to create a SQL database of my stuff and then import it. Long story short, I created a SQLite db and I want to use the work I have already done to import stuff into my CoreData database. I tried exporting to comma-delimited files and xml files and reading those in, but I didn't like it and it seemed like an extra step that I shouldn't need to do. So, I imported the SQLite database into my resources and added the sqlite framework. I have my core data model setup and it is setting up the SQLite database for the model correctly in the background. When I run through my program to add objects to my entities, it seems to work and I can even fetch results afterward. However, when I inspect the Core Data Database SQLite file, no records have been saved. How is it possible for it to fetch results but not save them to the database? - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{ //load in the path for resources NSString *paths = [[NSBundle mainBundle] resourcePath]; NSString *databaseName = @"histology.sqlite"; NSString *databasePath = [paths stringByAppendingPathComponent:databaseName]; [self createDatabase:databasePath ]; NSError *error; if ([[self managedObjectContext] save:&error]) { NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]); } // Test listing all CELLS from the store NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entityMO = [NSEntityDescription entityForName:@"CELL" inManagedObjectContext:[self managedObjectContext]]; [fetchRequest setEntity:entityMO]; NSArray *fetchedObjects = [[self managedObjectContext] executeFetchRequest:fetchRequest error:&error]; for (CELL *cellName in fetchedObjects) { //NSLog(@"cellName: %@", cellName); } -(void) createDatabase:databasePath { NSLog(@"The createDatabase function was entered."); NSLog(@"The databasePath is %@ ",[databasePath description]); // Setup the database object sqlite3 *histoDatabase; // Open the database from filessytem if(sqlite3_open([databasePath UTF8String], &histoDatabase) == SQLITE_OK) { NSLog(@"The database was opened"); // Setup the SQL Statement and compile it for faster access const char *sqlStatement = "SELECT * FROM CELL"; sqlite3_stmt *compiledStatement; if(sqlite3_prepare_v2(histoDatabase, sqlStatement, -1, &compiledStatement, NULL) != SQLITE_OK) { NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(histoDatabase)); } if(sqlite3_prepare_v2(histoDatabase, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) { // Loop through the results and add them to cell MO array while(sqlite3_step(compiledStatement) == SQLITE_ROW) { CELL *cellMO = [NSEntityDescription insertNewObjectForEntityForName:@"CELL" inManagedObjectContext:[self managedObjectContext]]; if (sqlite3_column_type(compiledStatement, 0) != SQLITE_NULL) { cellMO.cellName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 0)]; } else { cellMO.cellName = @"undefined"; } if (sqlite3_column_type(compiledStatement, 1) != SQLITE_NULL) { cellMO.cellDescription = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)]; } else { cellMO.cellDescription = @"undefined"; } NSLog(@"The contents of NSString *cellName = %@",[cellMO.cellName description]); } } // Release the compiled statement from memory sqlite3_finalize(compiledStatement); } sqlite3_close(histoDatabase); } I have a feeling that it has something to do with the timing of opening/closing both of the databases? Attached I have some SQL debugging output to the terminal 2012-05-28 16:03:39.556 MedPix[34751:fb03] The createDatabase function was entered. 2012-05-28 16:03:39.557 MedPix[34751:fb03] The databasePath is /Users/jack/Library/Application Support/iPhone Simulator/5.1/Applications/A6B2A79D-BA93-4E24-9291-5B7948A3CDF4/MedPix.app/histology.sqlite 2012-05-28 16:03:39.559 MedPix[34751:fb03] The database was opened 2012-05-28 16:03:39.560 MedPix[34751:fb03] The database was prepared 2012-05-28 16:03:39.575 MedPix[34751:fb03] CoreData: annotation: Connecting to sqlite database file at "/Users/jack/Library/Application Support/iPhone Simulator/5.1/Applications/A6B2A79D-BA93-4E24-9291-5B7948A3CDF4/Documents/MedPix.sqlite" 2012-05-28 16:03:39.576 MedPix[34751:fb03] CoreData: annotation: creating schema. 2012-05-28 16:03:39.577 MedPix[34751:fb03] CoreData: sql: pragma page_size=4096 2012-05-28 16:03:39.578 MedPix[34751:fb03] CoreData: sql: pragma auto_vacuum=2 2012-05-28 16:03:39.630 MedPix[34751:fb03] CoreData: sql: BEGIN EXCLUSIVE 2012-05-28 16:03:39.631 MedPix[34751:fb03] CoreData: sql: SELECT TBL_NAME FROM SQLITE_MASTER WHERE TBL_NAME = 'Z_METADATA' 2012-05-28 16:03:39.632 MedPix[34751:fb03] CoreData: sql: CREATE TABLE ZCELL ( Z_PK INTEGER PRIMARY KEY, Z_ENT INTEGER, Z_OPT INTEGER, ZCELLDESCRIPTION VARCHAR, ZCELLNAME VARCHAR ) ... 2012-05-28 16:03:39.669 MedPix[34751:fb03] CoreData: annotation: Creating primary key table. 2012-05-28 16:03:39.671 MedPix[34751:fb03] CoreData: sql: CREATE TABLE Z_PRIMARYKEY (Z_ENT INTEGER PRIMARY KEY, Z_NAME VARCHAR, Z_SUPER INTEGER, Z_MAX INTEGER) 2012-05-28 16:03:39.672 MedPix[34751:fb03] CoreData: sql: INSERT INTO Z_PRIMARYKEY(Z_ENT, Z_NAME, Z_SUPER, Z_MAX) VALUES(1, 'CELL', 0, 0) ... 2012-05-28 16:03:39.701 MedPix[34751:fb03] CoreData: sql: CREATE TABLE Z_METADATA (Z_VERSION INTEGER PRIMARY KEY, Z_UUID VARCHAR(255), Z_PLIST BLOB) 2012-05-28 16:03:39.702 MedPix[34751:fb03] CoreData: sql: SELECT TBL_NAME FROM SQLITE_MASTER WHERE TBL_NAME = 'Z_METADATA' 2012-05-28 16:03:39.703 MedPix[34751:fb03] CoreData: sql: DELETE FROM Z_METADATA WHERE Z_VERSION = ? 2012-05-28 16:03:39.704 MedPix[34751:fb03] CoreData: sql: INSERT INTO Z_METADATA (Z_VERSION, Z_UUID, Z_PLIST) VALUES (?, ?, ?) 2012-05-28 16:03:39.705 MedPix[34751:fb03] CoreData: sql: COMMIT 2012-05-28 16:03:39.710 MedPix[34751:fb03] CoreData: sql: pragma cache_size=200 2012-05-28 16:03:39.711 MedPix[34751:fb03] CoreData: sql: SELECT Z_VERSION, Z_UUID, Z_PLIST FROM Z_METADATA 2012-05-28 16:03:39.712 MedPix[34751:fb03] The contents of NSString *cellName = Beta Cell 2012-05-28 16:03:39.712 MedPix[34751:fb03] The contents of NSString *cellName = Gastric Chief Cell ... 2012-05-28 16:03:39.714 MedPix[34751:fb03] The database was prepared 2012-05-28 16:03:39.764 MedPix[34751:fb03] The createDatabase function has finished. Now fetching. 2012-05-28 16:03:39.765 MedPix[34751:fb03] CoreData: sql: SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZCELLDESCRIPTION, t0.ZCELLNAME FROM ZCELL t0 2012-05-28 16:03:39.766 MedPix[34751:fb03] CoreData: annotation: sql connection fetch time: 0.0008s 2012-05-28 16:03:39.767 MedPix[34751:fb03] CoreData: annotation: total fetch execution time: 0.0016s for 0 rows. 2012-05-28 16:03:39.768 MedPix[34751:fb03] cellName: <CELL: 0x6bbc120> (entity: CELL; id: 0x6bbc160 <x-coredata:///CELL/t57D10DDD-74E2-474F-97EE-E3BD0FF684DA34> ; data: { cellDescription = "S cells are cells which release secretin, found in the jejunum and duodenum. They are stimulated by a drop in pH to 4 or below in the small intestine's lumen. The released secretin will increase the s"; cellName = "S Cell"; organs = ( ); specimens = ( ); systems = ( ); tissues = ( ); }) ... Sections were cut short to abbreviate. But note that the fetch results contain information, but it says that total fetch execution was for "0" rows? How can that be? Any help will be greatly appreciated, especially detailed explanations. :) Thanks.

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• WPF Data Binding won't work

  - by Tokk

  Hey, I have got an UserControll with a DependencyProperty called "Risikobewertung" whitch has the own Datatype "RisikoBewertung"(Datatype created by LINQ). So in my Controll I try to bind the Fields of RisikoBewertung to the TextBoxes on the Controll, but It won't work. I hope you can help me, and tell me why ;) Code: UserControl.xaml: <UserControl x:Class="Cis.Modules.RiskManagement.Views.Controls.RisikoBewertungEditor" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:gridtools="clr-namespace:TmgUnity.Common.Presentation.Controls.DataGridTools;assembly=TmgUnity.Common.Presentation" xmlns:converter="clr-namespace:Cis.Modules.RiskManagement.Views.Converter" xmlns:tmg="clr-namespace:TmgUnity.Common.Presentation.Controls.FilterDataGrid;assembly=TmgUnity.Common.Presentation" xmlns:validators="clr-namespace:TmgUnity.Common.Presentation.ValidationRules;assembly=TmgUnity.Common.Presentation" xmlns:toolkit="http://schemas.microsoft.com/wpf/2008/toolkit" xmlns:risikoControls="clr-namespace:Cis.Modules.RiskManagement.Views.Controls"> <UserControl.Resources> <converter:CountToArrowConverter x:Key="CountConverter" /> </UserControl.Resources> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Name="Veränderung"/> <ColumnDefinition Name="Volumen" /> <ColumnDefinition Name="Schadenshöhe" /> <ColumnDefinition Name="SchadensOrte" /> <ColumnDefinition Name="Wahrscheinlichkeit" /> <ColumnDefinition Name="Kategorie" /> <ColumnDefinition Name="Handlungsbedarf" /> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="20" /> <RowDefinition /> </Grid.RowDefinitions> <Image Source="{Binding Path=Entwicklung, Converter={StaticResource CountConverter}, UpdateSourceTrigger=PropertyChanged}" Grid.RowSpan="2" Grid.Row="0" Width="68" Height="68" Grid.Column="0" /> <TextBox Grid.Column="1" Grid.Row="0" Text="Volumen" /> <TextBox Grid.Column="1" Grid.Row="1"> <TextBox.Text> <Binding Path="Volumen" UpdateSourceTrigger="PropertyChanged" /> </TextBox.Text> </TextBox> <TextBox Grid.Column="2" Grid.Row="0" Text="Schadenshöhe" /> <TextBox Grid.Column="2" Grid.Row="1" Text="{Binding Path=Schadenshöhe, UpdateSourceTrigger=PropertyChanged}" /> <StackPanel Grid.Column="3" Grid.RowSpan="2" Grid.Row="0" Orientation="Horizontal"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="20" /> <RowDefinition /> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition /> <ColumnDefinition /> <ColumnDefinition /> </Grid.ColumnDefinitions> <TextBox Text ="Politik" Grid.Row="0" Grid.Column="0"/> <CheckBox Name="Politik" Grid.Row="1" Grid.Column="0" IsChecked="{Binding Path=Politik, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" HorizontalAlignment="Center" /> <TextBox Text ="Vermögen" Grid.Row="0" Grid.Column="1" /> <CheckBox Name="Vermögen" Grid.Row="1" Grid.Column="1" IsChecked="{Binding Path=Vermögen, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" HorizontalAlignment="Center" /> <TextBox Text ="Vertrauen" Grid.Row="0" Grid.Column="2" /> <CheckBox Name="Vertrauen" Grid.Row="1" Grid.Column="2" IsChecked="{Binding Path=Vertrauen, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" HorizontalAlignment="Center" /> </Grid> </StackPanel> <TextBox Grid.Column="4" Grid.Row="0" Text="Wahrscheinlichkeit" /> <TextBox Grid.Column="4" Grid.Row="1" Text="{Binding Path=Wahrscheinlichkeit, UpdateSourceTrigger=PropertyChanged}"/> <risikoControls:RiskTrafficLightControl Grid.Column="5" Grid.Row="0" Grid.RowSpan="2" RiskValue="{Binding Path=Kategorie, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" /> <StackPanel Grid.Column="6" Grid.RowSpan="2" Grid.Row="0" Orientation="Vertical"> <TextBox Text="Handlungsbedarf" /> <CheckBox VerticalAlignment="Center" HorizontalAlignment="Center" IsChecked="{Binding Path=Handlungsbedarf, UpdateSourceTrigger=PropertyChanged}" /> </StackPanel> </Grid> The CodeBehind: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using System.ComponentModel; using Cis.Modules.RiskManagement.Data; using Cis.Modules.RiskManagement.Views.Models; namespace Cis.Modules.RiskManagement.Views.Controls { /// <summary> /// Interaktionslogik für RisikoBewertungEditor.xaml /// </summary> public partial class RisikoBewertungEditor : UserControl, INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public static readonly DependencyProperty RisikoBewertungProperty = DependencyProperty.Register("RisikoBewertung", typeof(RisikoBewertung), typeof(RisikoBewertungEditor), new PropertyMetadata(null, new PropertyChangedCallback(RisikoBewertungChanged))); // public static readonly DependencyProperty Readonly = DependencyProperty.Register("EditorReadonly", typeof(Boolean), typeof(RisikoBewertungEditor), new PropertyMetadata(null, new PropertyChangedCallback(ReadonlyChanged))); private static void RisikoBewertungChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs arguments) { var bewertungEditor = dependencyObject as RisikoBewertungEditor; bewertungEditor.RisikoBewertung = arguments.NewValue as RisikoBewertung; } /* private static void ReadonlyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs arguments) { } */ public RisikoBewertung RisikoBewertung { get { return GetValue(RisikoBewertungProperty) as RisikoBewertung; } set { SetValue(RisikoBewertungProperty, value); if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs("RisikoBewertung")); } } } /* public Boolean EditorReadonly { get; set; } */ public void mebosho(object sender, RoutedEventArgs e) { MessageBox.Show(RisikoBewertung.LfdNr.ToString()); } public RisikoBewertungEditor() { InitializeComponent(); RisikoBewertung = new RisikoBewertung(); this.DataContext = (GetValue(RisikoBewertungProperty) as RisikoBewertung); } } } and a little example of it's usage: <tmg:FilterDataGrid Grid.Row="0" AutoGenerateColumns="False" ItemsSource="{Binding TodoListe}" IsReadOnly="False" x:Name="TodoListeDataGrid" CanUserAddRows="False" SelectionUnit="FullRow" SelectedValuePath="." SelectedValue="{Binding CurrentTodoItem}" gridtools:DataGridStyle.SelectAllButtonTemplate="{DynamicResource CisSelectAllButtonTemplate}" CanUserResizeColumns="True" MinHeight="80" SelectionChanged="SelectionChanged" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" diagnostics:PresentationTraceSources.TraceLevel="High" > <tmg:FilterDataGrid.RowDetailsTemplate> <DataTemplate> <risikoControls:RisikoBewertungEditor x:Name="BewertungEditor" RisikoBewertung="{Binding ElementName=TodoListeDataGrid, Path=SelectedValue}" diagnostics:PresentationTraceSources.TraceLevel="High"> </risikoControls:RisikoBewertungEditor> </DataTemplate> </tmg:FilterDataGrid.RowDetailsTemplate> <tmg:FilterDataGrid.Columns> <toolkit:DataGridTextColumn Binding="{Binding Path=LfdNr}" Header="LfdNr" /> </tmg:FilterDataGrid.Columns> </tmg:FilterDataGrid>

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• Implementing an async "read all currently available data from stream" operation

  - by Jon

  I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a console's standard output Stream. Console output streams are of type FileStream; the implementation can cast to that, if needed. There is also an associated StreamReader already present to leverage. There is only one thing I need to implement in this class to achieve my desired functionality: an async "read all the data available this moment" operation. Reading to the end of the stream is not viable because the stream will not end unless the process closes the console output handle, and it will not do that because it is interactive and expecting input before continuing. I will be using that hypothetical async operation to implement event-based notification, which will be more convenient for my callers. The public interface of the class is this: public class ConsoleAutomator { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Remember that the goal here is to read all of the chunk and call event subscribers exactly once for each chunk. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream. private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer (in which case we know that there was no more data to be read during the last read operation), all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Never more than one event for each time data is available to be read Is almost agnostic to the buffer size The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this. Update: I definitely did not communicate the scenario well in my initial writeup. I have since revised the writeup quite a bit, but to be extra sure: The question is about how to implement an async "read all the data available this moment" operation. My apologies to the people who took the time to read and answer without me making my intent clear enough.

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• iPhone SDK vs Windows Phone 7 Series SDK Challenge, Part 1: Hello World!

  In this series, I will be taking sample applications from the iPhone SDK and implementing them on Windows Phone 7 Series.  My goal is to do as much of an apples-to-apples comparison as I can.  This series will be written to not only compare and contrast how easy or difficult it is to complete tasks on either platform, how many lines of code, etc., but Id also like it to be a way for iPhone developers to either get started on Windows Phone 7 Series development, or for developers in general to learn the platform. Heres my methodology: Run the iPhone SDK app in the iPhone Simulator to get a feel for what it does and how it works, without looking at the implementation Implement the equivalent functionality on Windows Phone 7 Series using Silverlight. Compare the two implementations based on complexity, functionality, lines of code, number of files, etc. Add some functionality to the Windows Phone 7 Series app that shows off a way to make the scenario more interesting or leverages an aspect of the platform, or uses a better design pattern to implement the functionality. You can download Microsoft Visual Studio 2010 Express for Windows Phone CTP here, and the Expression Blend 4 Beta here. Hello World! Of course no first post would be allowed if it didnt focus on the hello world scenario.  The iPhone SDK follows that tradition with the Your First iPhone Application walkthrough.  I will say that the developer documentation for iPhone is pretty good.  There are plenty of walkthoughs and they break things down into nicely sized steps and do a good job of bringing the user along.  As expected, this application is quite simple.  It comprises of a text box, a label, and a button.  When you push the button, the label changes to Hello plus the  word you typed into the text box.  Makes perfect sense for a starter application.  Theres not much to this but it covers a few basic elements: Laying out basic UI Handling user input Hooking up events Formatting text     So, lets get started building a similar app for Windows Phone 7 Series! Implementing the UI: UI in Silverlight (and therefore Windows Phone 7) is defined in XAML, which is a declarative XML language also used by WPF on the desktop.  For anyone thats familiar with similar types of markup, its relatively straightforward to learn, but has a lot of power in it once you get it figured out.  Well talk more about that. This UI is very simple.  When I look at this, I note a couple of things: Elements are arranged vertically They are all centered So, lets create our Application and then start with the UI.  Once you have the the VS 2010 Express for Windows Phone tool running, create a new Windows Phone Project, and call it Hello World: Once created, youll see the designer on one side and your XAML on the other: Now, we can create our UI in one of three ways: Use the designer in Visual Studio to drag and drop the components Use the designer in Expression Blend 4 to drag and drop the components Enter the XAML by hand in either of the above Well start with (1), then kind of move to (3) just for instructional value. To develop this UI in the designer: First, delete all of the markup between inside of the Grid element (LayoutRoot).  You should be left with just this XAML for your MainPage.xaml (i shortened all the xmlns declarations below for brevity): 1: <phoneNavigation:PhoneApplicationPage 2: x:Class="HelloWorld.MainPage" 3: xmlns="...[snip]" 4: FontFamily="{StaticResource PhoneFontFamilyNormal}" 5: FontSize="{StaticResource PhoneFontSizeNormal}" 6: Foreground="{StaticResource PhoneForegroundBrush}"> 7:   8: <Grid x:Name="LayoutRoot" Background="{StaticResource PhoneBackgroundBrush}"> 9:   10: </Grid> 11:   12: </phoneNavigation:PhoneApplicationPage> .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; } .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; }   Well be adding XAML at line 9, so thats the important part. Now, Click on the center area of the phone surface Open the Toolbox and double click StackPanel Double click TextBox Double click TextBlock Double click Button That will create the necessary UI elements but they wont be arranged quite right.  Well fix it in a second.    Heres the XAML that we end up with: 1: <StackPanel Height="100" HorizontalAlignment="Left" Margin="10,10,0,0" Name="stackPanel1" VerticalAlignment="Top" Width="200"> 2: <TextBox Height="32" Name="textBox1" Text="TextBox" Width="100" /> 3: <TextBlock Height="23" Name="textBlock1" Text="TextBlock" /> 4: <Button Content="Button" Height="70" Name="button1" Width="160" /> 5: </StackPanel> .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; } .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; } The designer does its best at guessing what we want, but in this case we want things to be a bit simpler. So well just clean it up a bit.  We want the items to be centered and we want them to have a little bit of a margin on either side, so heres what we end up with.  Ive also made it match the values and style from the iPhone app: 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <TextBlock Name="textBlock1" HorizontalAlignment="Center" Margin="0,100,0,0" Text="Hello You!" /> 4: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello"/> 5: </StackPanel> .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; } .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; } .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; } Now lets take a look at what weve done there. Line 1: We removed all of the formatting from the StackPanel, except for Margin, as thats all we need.  Since our parent element is a Grid, by default the StackPanel will be sized to fit in that space.  The Margin says that we want to reserve 10 pixels on each side of the StackPanel. Line 2: Weve set the HorizontalAlignment of the TextBox to Stretch, which says that it should fill its parents size horizontally.  We want to do this so the TextBox is always full-width.  We also set TextAlignment to Center, to center the text. Line 3: In contrast to the TextBox above, we dont care how wide the TextBlock is, just so long as it is big enough for its text.  Thatll happen automatically, so we just set its Horizontal alignment to Center.  We also set a Margin above the TextBlock of 100 pixels to bump it down a bit, per the iPhone UI. Line 4: We do the same things here as in Line 3. Heres how the UI looks in the designer: Believe it or not, were almost done! Implementing the App Logic Now, we want the TextBlock to change its text when the Button is clicked.  In the designer, double click the Button to be taken to the Event Handler for the Buttons Click event.  In that event handler, we take the Text property from the TextBox, and format it into a string, then set it into the TextBlock.  Thats it! 1: private void button1_Click(object sender, RoutedEventArgs e) 2: { 3: string name = textBox1.Text; 4:   5: // if there isn't a name set, just use "World" 6: if (String.IsNullOrEmpty(name)) 7: { 8: name = "World"; 9: } 10:   11: // set the value into the TextBlock 12: textBlock1.Text = String.Format("Hello {0}!", name); 13:   14: } .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; } We use the String.Format() method to handle the formatting for us.    Now all thats left is to test the app in the Windows Phone Emulator and verify it does what we think it does! And it does! Comparing against the iPhone Looking at the iPhone example, there are basically three things that you have to touch as the developer: 1) The UI in the Nib file 2) The app delegate 3) The view controller Counting lines is a bit tricky here, but to try to keep this even, Im going to only count lines of code that I could not have (or would not have) generated with the tooling.  Meaning, Im not counting XAML and Im not counting operations that happen in the Nib file with the XCode designer tool.  So in the case of the above, even though I modified the XAML, I could have done all of those operations using the visual designer tool.  And normally I would have, but the XAML is more instructive (and less steps!).  Im interested in things that I, as the developer have to figure out in code.  Im also not counting lines that just have a curly brace on them, or lines that are generated for me (e.g. method names that are generated for me when I make a connection, etc.) So, by that count, heres what I get from the code listing for the iPhone app found here: HelloWorldAppDelegate.h: 6 HelloWorldAppDelegate.m: 12 MyViewController.h: 8 MyViewController.m: 18 Which gives me a grand total of about 44 lines of code on iPhone.  I really do recommend looking at the iPhone code for a comparison to the above. Now, for the Windows Phone 7 Series application, the only code I typed was in the event handler above Main.Xaml.cs: 4 So a total of 4 lines of code on Windows Phone 7.  And more importantly, the process is just A LOT simpler.  For example, I was surprised that the User Interface Designer in XCode doesnt automatically create instance variables for me and wire them up to the corresponding elements.  I assumed I wouldnt have to write this code myself (and risk getting it wrong!).  I dont need to worry about view controllers or anything.  I just write my code.  This blog post up to this point has covered almost every aspect of this apps development in a few pages.  The iPhone tutorial has 5 top level steps with 2-3 sub sections of each. Now, its worth pointing out that the iPhone development model uses the Model View Controller (MVC) pattern, which is a very flexible and powerful pattern that enforces proper separation of concerns.  But its fairly complex and difficult to understand when you first walk up to it.  Here at Microsoft weve dabbled in MVC a bit, with frameworks like MFC on Visual C++ and with the ASP.NET MVC framework now.  Both are very powerful frameworks.  But one of the reasons weve stayed away from MVC with client UI frameworks is that its difficult to tool.  We havent seen the type of value that beats double click, write code! for the broad set of scenarios. Another thing to think about is how many of those lines of code were focused on my apps functionality?.  Or, the converse of How many lines of code were boilerplate plumbing?  In both examples, the actual number of functional code lines is similar.  I count most of them in MyViewController.m, in the changeGreeting method.  Its about 7 lines of code that do the work of taking the value from the TextBox and putting it into the label.  Versus 4 on the Windows Phone 7 side.  But, unfortunately, on iPhone I still have to write that other 37 lines of code, just to get there. 10% of the code, 1 file instead of 4, its just much simpler. Making Some Tweaks It turns out, I can actually do this application with ZERO  lines of code, if Im willing to change the spec a bit. The data binding functionality in Silverlight is incredibly powerful.  And what I can do is databind the TextBoxs value directly to the TextBlock.  Take some time looking at this XAML below.  Youll see that I have added another nested StackPanel and two more TextBlocks.  Why?  Because thats how I build that string, and the nested StackPanel will lay things out Horizontally for me, as specified by the Orientation property. 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,100,0,0" > 4: <TextBlock Text="Hello " /> 5: <TextBlock Name="textBlock1" Text="{Binding ElementName=textBox1, Path=Text}" /> 6: <TextBlock Text="!" /> 7: </StackPanel> 8: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello" Click="button1_Click" /> 9: </StackPanel> .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; } Now, the real action is there in the bolded TextBlock.Text property: Text="{Binding ElementName=textBox1, Path=Text}" .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; } That does all the heavy lifting.  It sets up a databinding between the TextBox.Text property on textBox1 and the TextBlock.Text property on textBlock1. As I change the text of the TextBox, the label updates automatically. In fact, I dont even need the button any more, so I could get rid of that altogether.  And no button means no event handler.  No event handler means no C# code at all.  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.

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• help fixing pagination class

  - by michael

  here is my pagination class. the data in the construct is just an another class that does db queries and other stuff. the problem that i am having is that i cant seem to get the data output to match the pagination printing and i cant seem to get the mysql_fetch_assoc() to query the data and print it out. i get this error: Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in /phpdev/pagination/index.php on line 215 i know that can mean that the query isnt correct for it to fetch the data but i have entered it correctly. sorry for the script being a little long. i thank all in advance for any help. <?php include_once("class.db.php"); mysql_connect("host","login","password"); mysql_select_db("iadcart"); class Pagination { var $adjacents; var $limit; var $param; var $mPage; var $query; var $qData; var $printData; protected $db; function __construct() { $this->db = new MysqlDB; } function show() { $result = $this->db->query($this->query); $totalPages = $this->db->num_rows($result); $limit = $this->limit; /* ------------------------------------- Set Page ------------------------------------- */ if(isset($_GET['page'])) { $page = intval($_GET['page']); $start = ($page - 1) * $limit; } else { $start = 0; } /* ------------------------------------- Set Page Vars ------------------------------------- */ if($page == 0) { $page = 1; } $prev = $page - 1; $next = $page + 1; $lastPage = ceil($totalPages/$limit); $lpm1 = $lastPage - 1; $adjacents = $this->adjacents; $mPage = $this->mPage; //the magic $this->qData = $this->query . " LIMIT $start, $limit"; $this->printData = $this->db->query($this->qData); /* ------------------------------------- Draw Pagination Object ------------------------------------- */ $pagination = ""; if($lastPage > 1) { $pagination .= "<div class='pagination'>"; } /* ------------------------------------- Previous Link ------------------------------------- */ if($page > 1) { $pagination .= "<li><a href='$mPage?page=$prev'> previous </a></li>"; } else { $pagination .= "<li class='previous-off'> previous </li>"; } /* ------------------------------------- Page Numbers (not enough pages - just display active page) ------------------------------------- */ if($lastPage < 7 + ($adjacents * 2)) { for($counter = 1; $counter <= $lastPage; $counter++) { if($counter == $page) { $pagination .= "<li class='active'>$counter</li>"; } else { $pagination .= "<li><a href='$mPage?page=$counter'>$counter</a></li>"; } } } /* ------------------------------------- Page Numbers (enough pages to paginate) ------------------------------------- */ elseif($lastPage > 5 + ($adjacents * 2)) { //close to beginning; only hide later pages if($page < 1 + ($adjacents * 2)) { for ($counter = 1; $counter < 4 + ($adjacents * 2); $counter++) { if ($counter == $page) { $pagination.= "<li class='active'>$counter</li>"; } else { $pagination.= "<li><a href='$mPage?page=$counter'>$counter</a></li>"; } } $pagination.= "..."; $pagination.= "<li><a href='$mPage?page=$lpm1'>$lpm1</a></li>"; $pagination.= "<li><a href='$mPage?page=$lastPage'>$lastPage</a></li>"; } elseif($lastPage - ($adjacents * 2) > $page && $page > ($adjacents * 2)) { $pagination.= "<li><a href='$mPage?page=1'>1</a></li>"; $pagination.= "<li><a href='$mPage?page=2'>2</a></li>"; $pagination.= "..."; for ($counter = $page - $adjacents; $counter <= $page + $adjacents; $counter++) { if ($counter == $page) { $pagination.= "<li class='active'>$counter</li>"; } else { $pagination.= "<li><a href='$mPage?page=$counter'>$counter</a></li>"; } } $pagination.= "..."; $pagination.= "<li><a href='$mPage?page=$lpm1'>$lpm1</a></li>"; $pagination.= "<li><a href='$mPage?page=$lastPage'>$lastPage</a></li>"; } else { $pagination.= "<li><a href='$mPage?page=1'>1</a></li>"; $pagination.= "</li><a href='$mPage?page=2'>2</a></li>"; $pagination.= "..."; for ($counter = $lastPage - (2 + ($adjacents * 2)); $counter <= $lastPage; $counter++) { if ($counter == $page) { $pagination.= "<li class='active'>$counter</li>"; } else { $pagination.= "<li><a href='$mPage?page=$counter'>$counter</a></li>"; } } } } /* ------------------------------------- Next Link ------------------------------------- */ if ($page < $counter - 1) { $pagination.= "<li><a href='$mPage?page=$next'> Next </a></li>"; } else { $pagination.= "<li class='next-off'> Next </li>"; $pagination.= "</div>"; } print $pagination; } } ?> <html> <head> </head> <body> <table style="width:800px;"> <?php mysql_connect("localhost","root","games818"); mysql_select_db("iadcart"); $pagination = new pagination; $pagination->adjacents = 3; $pagination->limit = 10; $pagination->param = $_GET['page']; $pagination->mPage = "index.php"; $pagination->query = "select * from tbl_products where pVisible = 'yes'"; while($row = mysql_fetch_assoc($pagination->printData)) { print $row['pName']; } ?> </table> <br/><br/> <?php $pagination->show(); ?> </body> </html>

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• Building a better mouse-trap &ndash; Improving the creation of XML Message Requests using Reflection, XML &amp; XSLT

  - by paulschapman

  Introduction The way I previously created messages to send to the GovTalk service I used the XMLDocument to create the request. While this worked it left a number of problems; not least that for every message a special function would need to created. This is OK for the short term but the biggest cost in any software project is maintenance and this would be a headache to maintain. So the following is a somewhat better way of achieving the same thing. For the purposes of this article I am going to be using the CompanyNumberSearch request of the GovTalk service – although this technique would work for any service that accepted XML. The C# functions which send and receive the messages remain the same. The magic sauce in this is the XSLT which defines the structure of the request, and the use of objects in conjunction with reflection to provide the content. It is a bit like Sweet Chilli Sauce added to Chicken on a bed of rice. So on to the Sweet Chilli Sauce The Sweet Chilli Sauce The request to search for a company based on it’s number is as follows; <GovTalkMessage xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" > <EnvelopeVersion>1.0</EnvelopeVersion> <Header> <MessageDetails> <Class>NumberSearch</Class> <Qualifier>request</Qualifier> <TransactionID>1</TransactionID> </MessageDetails> <SenderDetails> <IDAuthentication> <SenderID>????????????????????????????????</SenderID> <Authentication> <Method>CHMD5</Method> <Value>????????????????????????????????</Value> </Authentication> </IDAuthentication> </SenderDetails> </Header> <GovTalkDetails> <Keys/> </GovTalkDetails> <Body> <NumberSearchRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlgw.companieshouse.gov.uk/v1-0/schema/NumberSearch.xsd"> <PartialCompanyNumber>99999999</PartialCompanyNumber> <DataSet>LIVE</DataSet> <SearchRows>1</SearchRows> </NumberSearchRequest> </Body> </GovTalkMessage> This is the XML that we send to the GovTalk Service and we get back a list of companies that match the criteria passed A message is structured in two parts; The envelope which identifies the person sending the request, with the name of the request, and the body which gives the detail of the company we are looking for. The Chilli What makes it possible is the use of XSLT to define the message – and serialization to convert each request object into XML. To start we need to create an object which will represent the contents of the message we are sending. However there is a common properties in all the messages that we send to Companies House. These properties are as follows SenderId – the id of the person sending the message SenderPassword – the password associated with Id TransactionId – Unique identifier for the message AuthenticationValue – authenticates the request Because these properties are unique to the Companies House message, and because they are shared with all messages they are perfect candidates for a base class. The class is as follows; using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Security.Cryptography; using System.Text; using System.Text.RegularExpressions; using Microsoft.WindowsAzure.ServiceRuntime; namespace CompanyHub.Services { public class GovTalkRequest { public GovTalkRequest() { try { SenderID = RoleEnvironment.GetConfigurationSettingValue("SenderId"); SenderPassword = RoleEnvironment.GetConfigurationSettingValue("SenderPassword"); TransactionId = DateTime.Now.Ticks.ToString(); AuthenticationValue = EncodePassword(String.Format("{0}{1}{2}", SenderID, SenderPassword, TransactionId)); } catch (System.Exception ex) { throw ex; } } /// <summary> /// returns the Sender ID to be used when communicating with the GovTalk Service /// </summary> public String SenderID { get; set; } /// <summary> /// return the password to be used when communicating with the GovTalk Service /// </summary> public String SenderPassword { get; set; } // end SenderPassword /// <summary> /// Transaction Id - uses the Time and Date converted to Ticks /// </summary> public String TransactionId { get; set; } // end TransactionId /// <summary> /// calculate the authentication value that will be used when /// communicating with /// </summary> public String AuthenticationValue { get; set; } // end AuthenticationValue property /// <summary> /// encodes password(s) using MD5 /// </summary> /// <param name="clearPassword"></param> /// <returns></returns> public static String EncodePassword(String clearPassword) { MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider(); byte[] hashedBytes; UTF32Encoding encoder = new UTF32Encoding(); hashedBytes = md5Hasher.ComputeHash(ASCIIEncoding.Default.GetBytes(clearPassword)); String result = Regex.Replace(BitConverter.ToString(hashedBytes), "-", "").ToLower(); return result; } } } There is nothing particularly clever here, except for the EncodePassword method which hashes the value made up of the SenderId, Password and Transaction id. Each message inherits from this object. So for the Company Number Search in addition to the properties above we need a partial number, which dataset to search – for the purposes of the project we only need to search the LIVE set so this can be set in the constructor and the SearchRows. Again all are set as properties. With the SearchRows and DataSet initialized in the constructor. public class CompanyNumberSearchRequest : GovTalkRequest, IDisposable { /// <summary> /// /// </summary> public CompanyNumberSearchRequest() : base() { DataSet = "LIVE"; SearchRows = 1; } /// <summary> /// Company Number to search against /// </summary> public String PartialCompanyNumber { get; set; } /// <summary> /// What DataSet should be searched for the company /// </summary> public String DataSet { get; set; } /// <summary> /// How many rows should be returned /// </summary> public int SearchRows { get; set; } public void Dispose() { DataSet = String.Empty; PartialCompanyNumber = String.Empty; DataSet = "LIVE"; SearchRows = 1; } } As well as inheriting from our base class, I have also inherited from IDisposable – not just because it is just plain good practice to dispose of objects when coding, but it gives also gives us more versatility when using the object. There are four stages in making a request and this is reflected in the four methods we execute in making a call to the Companies House service; Create a request Send a request Check the status If OK then get the results of the request I’ve implemented each of these stages within a static class called Toolbox – which also means I don’t need to create an instance of the class to use it. When making a request there are three stages; Get the template for the message Serialize the object representing the message Transform the serialized object using a predefined XSLT file. Each of my templates I have defined as an embedded resource. When retrieving a resource of this kind we have to include the full namespace to the resource. In making the code re-usable as much as possible I defined the full ‘path’ within the GetRequest method. requestFile = String.Format("CompanyHub.Services.Schemas.{0}", RequestFile); So we now have the full path of the file within the assembly. Now all we need do is retrieve the assembly and get the resource. asm = Assembly.GetExecutingAssembly(); sr = asm.GetManifestResourceStream(requestFile); Once retrieved  So this can be returned to the calling function and we now have a stream of XSLT to define the message. Time now to serialize the request to create the other side of this message. // Serialize object containing Request, Load into XML Document t = Obj.GetType(); ms = new MemoryStream(); serializer = new XmlSerializer(t); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); serializer.Serialize(xmlTextWriter, Obj); ms = (MemoryStream)xmlTextWriter.BaseStream; GovTalkRequest = Toolbox.ConvertByteArrayToString(ms.ToArray()); First off we need the type of the object so we make a call to the GetType method of the object containing the Message properties. Next we need a MemoryStream, XmlSerializer and an XMLTextWriter so these can be initialized. The object is serialized by making the call to the Serialize method of the serializer object. The result of that is then converted into a MemoryStream. That MemoryStream is then converted into a string. ConvertByteArrayToString This is a fairly simple function which uses an ASCIIEncoding object found within the System.Text namespace to convert an array of bytes into a string. public static String ConvertByteArrayToString(byte[] bytes) { System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding(); return enc.GetString(bytes); } I only put it into a function because I will be using this in various places. The Sauce When adding support for other messages outside of creating a new object to store the properties of the message, the C# components do not need to change. It is in the XSLT file that the versatility of the technique lies. The XSLT file determines the format of the message. For the CompanyNumberSearch the XSLT file is as follows; <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="/"> <GovTalkMessage xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" > <EnvelopeVersion>1.0</EnvelopeVersion> <Header> <MessageDetails> <Class>NumberSearch</Class> <Qualifier>request</Qualifier> <TransactionID> <xsl:value-of select="CompanyNumberSearchRequest/TransactionId"/> </TransactionID> </MessageDetails> <SenderDetails> <IDAuthentication> <SenderID><xsl:value-of select="CompanyNumberSearchRequest/SenderID"/></SenderID> <Authentication> <Method>CHMD5</Method> <Value> <xsl:value-of select="CompanyNumberSearchRequest/AuthenticationValue"/> </Value> </Authentication> </IDAuthentication> </SenderDetails> </Header> <GovTalkDetails> <Keys/> </GovTalkDetails> <Body> <NumberSearchRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlgw.companieshouse.gov.uk/v1-0/schema/NumberSearch.xsd"> <PartialCompanyNumber> <xsl:value-of select="CompanyNumberSearchRequest/PartialCompanyNumber"/> </PartialCompanyNumber> <DataSet> <xsl:value-of select="CompanyNumberSearchRequest/DataSet"/> </DataSet> <SearchRows> <xsl:value-of select="CompanyNumberSearchRequest/SearchRows"/> </SearchRows> </NumberSearchRequest> </Body> </GovTalkMessage> </xsl:template> </xsl:stylesheet> The outer two tags define that this is a XSLT stylesheet and the root tag from which the nodes are searched for. The GovTalkMessage is the format of the message that will be sent to Companies House. We first set up the XslCompiledTransform object which will transform the XSLT template and the serialized object into the request to Companies House. xslt = new XslCompiledTransform(); resultStream = new MemoryStream(); writer = new XmlTextWriter(resultStream, Encoding.ASCII); doc = new XmlDocument(); The Serialize method require XmlTextWriter to write the XML (writer) and a stream to place the transferred object into (writer). The XML will be loaded into an XMLDocument object (doc) prior to the transformation. // create XSLT Template xslTemplate = Toolbox.GetRequest(Template); xslTemplate.Seek(0, SeekOrigin.Begin); templateReader = XmlReader.Create(xslTemplate); xslt.Load(templateReader); I have stored all the templates as a series of Embedded Resources and the GetRequestCall takes the name of the template and extracts the relevent XSLT file. /// <summary> /// Gets the framwork XML which makes the request /// </summary> /// <param name="RequestFile"></param> /// <returns></returns> public static Stream GetRequest(String RequestFile) { String requestFile = String.Empty; Stream sr = null; Assembly asm = null; try { requestFile = String.Format("CompanyHub.Services.Schemas.{0}", RequestFile); asm = Assembly.GetExecutingAssembly(); sr = asm.GetManifestResourceStream(requestFile); } catch (Exception) { throw; } finally { asm = null; } return sr; } // end private static stream GetRequest We first take the template name and expand it to include the full namespace to the Embedded Resource I like to keep all my schemas in the same directory and so the namespace reflects this. The rest is the default namespace for the project. Then we get the currently executing assembly (which will contain the resources with the call to GetExecutingAssembly() ) Finally we get a stream which contains the XSLT file. We use this stream and then load an XmlReader with the contents of the template, and that is in turn loaded into the XslCompiledTransform object. We convert the object containing the message properties into Xml by serializing it; calling the Serialize() method of the XmlSerializer object. To set up the object we do the following; t = Obj.GetType(); ms = new MemoryStream(); serializer = new XmlSerializer(t); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); We first determine the type of the object being transferred by calling GetType() We create an XmlSerializer object by passing the type of the object being serialized. The serializer writes to a memory stream and that is linked to an XmlTextWriter. Next job is to serialize the object and load it into an XmlDocument. serializer.Serialize(xmlTextWriter, Obj); ms = (MemoryStream)xmlTextWriter.BaseStream; xmlRequest = new XmlTextReader(ms); GovTalkRequest = Toolbox.ConvertByteArrayToString(ms.ToArray()); doc.LoadXml(GovTalkRequest); Time to transform the XML to construct the full request. xslt.Transform(doc, writer); resultStream.Seek(0, SeekOrigin.Begin); request = Toolbox.ConvertByteArrayToString(resultStream.ToArray()); So that creates the full request to be sent  to Companies House. Sending the request So far we have a string with a request for the Companies House service. Now we need to send the request to the Companies House Service. Configuration within an Azure project There are entire blog entries written about configuration within an Azure project – most of this is out of scope for this article but the following is a summary. Configuration is defined in two files within the parent project *.csdef which contains the definition of configuration setting. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="OnlineCompanyHub" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WebRole name="CompanyHub.Host"> <InputEndpoints> <InputEndpoint name="HttpIn" protocol="http" port="80" /> </InputEndpoints> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> <Setting name="DataConnectionString" /> </ConfigurationSettings> </WebRole> <WebRole name="CompanyHub.Services"> <InputEndpoints> <InputEndpoint name="HttpIn" protocol="http" port="8080" /> </InputEndpoints> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> <Setting name="SenderId"/> <Setting name="SenderPassword" /> <Setting name="GovTalkUrl"/> </ConfigurationSettings> </WebRole> <WorkerRole name="CompanyHub.Worker"> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> </ConfigurationSettings> </WorkerRole> </ServiceDefinition>   Above is the configuration definition from the project. What we are interested in however is the ConfigurationSettings tag of the CompanyHub.Services WebRole. There are four configuration settings here, but at the moment we are interested in the second to forth settings; SenderId, SenderPassword and GovTalkUrl The value of these settings are defined in the ServiceDefinition.cscfg file; <?xml version="1.0"?> <ServiceConfiguration serviceName="OnlineCompanyHub" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration"> <Role name="CompanyHub.Host"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="DataConnectionString" value="UseDevelopmentStorage=true" /> </ConfigurationSettings> </Role> <Role name="CompanyHub.Services"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="SenderId" value="UserID"/> <Setting name="SenderPassword" value="Password"/> <Setting name="GovTalkUrl" value="http://xmlgw.companieshouse.gov.uk/v1-0/xmlgw/Gateway"/> </ConfigurationSettings> </Role> <Role name="CompanyHub.Worker"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> </ConfigurationSettings> </Role> </ServiceConfiguration>   Look for the Role tag that contains our project name (CompanyHub.Services). Having configured the parameters we can now transmit the request. This is done by ‘POST’ing a stream of XML to the Companies House servers. govTalkUrl = RoleEnvironment.GetConfigurationSettingValue("GovTalkUrl"); request = WebRequest.Create(govTalkUrl); request.Method = "POST"; request.ContentType = "text/xml"; writer = new StreamWriter(request.GetRequestStream()); writer.WriteLine(RequestMessage); writer.Close(); We use the WebRequest object to send the object. Set the method of sending to ‘POST’ and the type of data as text/xml. Once set up all we do is write the request to the writer – this sends the request to Companies House. Did the Request Work Part I – Getting the response Having sent a request – we now need the result of that request. response = request.GetResponse(); reader = response.GetResponseStream(); result = Toolbox.ConvertByteArrayToString(Toolbox.ReadFully(reader));   The WebRequest object has a GetResponse() method which allows us to get the response sent back. Like many of these calls the results come in the form of a stream which we convert into a string. Did the Request Work Part II – Translating the Response Much like XSLT and XML were used to create the original request, so it can be used to extract the response and by deserializing the result we create an object that contains the response. Did it work? It would be really great if everything worked all the time. Of course if it did then I don’t suppose people would pay me and others the big bucks so that our programmes do not a) Collapse in a heap (this is an area of memory) b) Blow every fuse in the place in a shower of sparks (this will probably not happen this being real life and not a Hollywood movie, but it was possible to blow the sound system of a BBC Model B with a poorly coded setting) c) Go nuts and trap everyone outside the airlock (this was from a movie, and unless NASA get a manned moon/mars mission set up unlikely to happen) d) Go nuts and take over the world (this was also from a movie, but please note life has a habit of being of exceeding the wildest imaginations of Hollywood writers (note writers – Hollywood executives have no imagination and judging by recent output of that town have turned plagiarism into an art form). e) Freeze in total confusion because the cleaner pulled the plug to the internet router (this has happened) So anyway – we need to check to see if our request actually worked. Within the GovTalk response there is a section that details the status of the message and a description of what went wrong (if anything did). I have defined an XSLT template which will extract these into an XML document. <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ev="http://www.govtalk.gov.uk/CM/envelope" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <xsl:template match="/"> <GovTalkStatus xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Status> <xsl:value-of select="ev:GovTalkMessage/ev:Header/ev:MessageDetails/ev:Qualifier"/> </Status> <Text> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Text"/> </Text> <Location> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Location"/> </Location> <Number> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Number"/> </Number> <Type> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Type"/> </Type> </GovTalkStatus> </xsl:template> </xsl:stylesheet>   Only thing different about previous XSL files is the references to two namespaces ev & gt. These are defined in the GovTalk response at the top of the response; xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" If we do not put these references into the XSLT template then  the XslCompiledTransform object will not be able to find the relevant tags. Deserialization is a fairly simple activity. encoder = new ASCIIEncoding(); ms = new MemoryStream(encoder.GetBytes(statusXML)); serializer = new XmlSerializer(typeof(GovTalkStatus)); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); messageStatus = (GovTalkStatus)serializer.Deserialize(ms);   We set up a serialization object using the object type containing the error state and pass to it the results of a transformation between the XSLT above and the GovTalk response. Now we have an object containing any error state, and the error message. All we need to do is check the status. If there is an error then we can flag an error. If not then  we extract the results and pass that as an object back to the calling function. We go this by guess what – defining an XSLT template for the result and using that to create an Xml Stream which can be deserialized into a .Net object. In this instance the XSLT to create the result of a Company Number Search is; <?xml version="1.0" encoding="us-ascii"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ev="http://www.govtalk.gov.uk/CM/envelope" xmlns:sch="http://xmlgw.companieshouse.gov.uk/v1-0/schema" exclude-result-prefixes="ev"> <xsl:template match="/"> <CompanySearchResult xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <CompanyNumber> <xsl:value-of select="ev:GovTalkMessage/ev:Body/sch:NumberSearch/sch:CoSearchItem/sch:CompanyNumber"/> </CompanyNumber> <CompanyName> <xsl:value-of select="ev:GovTalkMessage/ev:Body/sch:NumberSearch/sch:CoSearchItem/sch:CompanyName"/> </CompanyName> </CompanySearchResult> </xsl:template> </xsl:stylesheet> and the object definition is; using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace CompanyHub.Services { public class CompanySearchResult { public CompanySearchResult() { CompanyNumber = String.Empty; CompanyName = String.Empty; } public String CompanyNumber { get; set; } public String CompanyName { get; set; } } } Our entire code to make calls to send a request, and interpret the results are; String request = String.Empty; String response = String.Empty; GovTalkStatus status = null; fault = null; try { using (CompanyNumberSearchRequest requestObj = new CompanyNumberSearchRequest()) { requestObj.PartialCompanyNumber = CompanyNumber; request = Toolbox.CreateRequest(requestObj, "CompanyNumberSearch.xsl"); response = Toolbox.SendGovTalkRequest(request); status = Toolbox.GetMessageStatus(response); if (status.Status.ToLower() == "error") { fault = new HubFault() { Message = status.Text }; } else { Object obj = Toolbox.GetGovTalkResponse(response, "CompanyNumberSearchResult.xsl", typeof(CompanySearchResult)); } } } catch (FaultException<ArgumentException> ex) { fault = new HubFault() { FaultType = ex.Detail.GetType().FullName, Message = ex.Detail.Message }; } catch (System.Exception ex) { fault = new HubFault() { FaultType = ex.GetType().FullName, Message = ex.Message }; } finally { } Wrap up So there we have it – a reusable set of functions to send and interpret XML results from an internet based service. The code is reusable with a little change with any service which uses XML as a transport mechanism – and as for the Companies House GovTalk service all I need to do is create various objects for the result and message sent and the relevent XSLT files. I might need minor changes for other services but something like 70-90% will be exactly the same.

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• Implementing a robust async stream reader

  - by Jon

  I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output, but that is a detail and does not play an important role. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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• Did I lose my RAID again?

  - by BarsMonster

  Hi! A little history: 2 years ago I was really excited to find out that mdadm is so powerful that it even can reshape arrays, so you can start with a smaller array and then grow it as you need. I've bought 3x1Tb drives and made a RAID-5. It was fine for a year. Then I bought 2x more, and tried to reshape to RAID-6 out of 5 drives, and due to some mess with superblock versions, lost all content. Had to rebuild it from scratch, but 2Tb of data were gone. Yesterday I bought 2 more drives, and this time I had everything: properly built array, UPS. I've disabled write intent map, added 2 new drives as spares and run a command to grow array to 7-disks. It started working, but speed was ridiculously slow, ~100kb/sec. After processing first 37Mb at such an amazing speed, one of old HDDs fails. I properly shutdown the PC and disconnected the failed drive. After bootup it appeared that it recreated the intent map as it was still in mdadm config, so I removed it from config and rebooted again. Now all I see is that all mdadm processes deadlock, and don't do anything. PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1937 root 20 0 12992 608 444 D 0 0.1 0:00.00 mdadm 2283 root 20 0 12992 852 704 D 0 0.1 0:00.01 mdadm 2287 root 20 0 0 0 0 D 0 0.0 0:00.01 md0_reshape 2288 root 18 -2 12992 820 676 D 0 0.1 0:00.01 mdadm And all I see in mdstat is: $ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid6 sdb1[1] sdg1[4] sdf1[7] sde1[6] sdd1[0] sdc1[5] 2929683456 blocks super 1.2 level 6, 1024k chunk, algorithm 2 [7/6] [UU_UUUU] [>....................] reshape = 0.0% (37888/976561152) finish=567604147.2min speed=0K/sec I've already tried mdadm 2.6.7, 3.1.4 and 3.2 - nothing helps. Did I lose my data again? Any suggestions on how can I make this work? OS is Ubuntu Server 10.04.2. PS. Needless to say, the data is inaccessible - I cannot mount /dev/md0 to save the most valuable data. You can see my disappointment - the very specific thing I was excited about failed twice taking 5Tb of my data with it. Update: It appears there is some nice info in kern.log: 21:38:48 ...: [ 166.522055] raid5: reshape will continue 21:38:48 ...: [ 166.522085] raid5: device sdb1 operational as raid disk 1 21:38:48 ...: [ 166.522091] raid5: device sdg1 operational as raid disk 4 21:38:48 ...: [ 166.522097] raid5: device sdf1 operational as raid disk 5 21:38:48 ...: [ 166.522102] raid5: device sde1 operational as raid disk 6 21:38:48 ...: [ 166.522107] raid5: device sdd1 operational as raid disk 0 21:38:48 ...: [ 166.522111] raid5: device sdc1 operational as raid disk 3 21:38:48 ...: [ 166.523942] raid5: allocated 7438kB for md0 21:38:48 ...: [ 166.524041] 1: w=1 pa=2 pr=5 m=2 a=2 r=7 op1=0 op2=0 21:38:48 ...: [ 166.524050] 4: w=2 pa=2 pr=5 m=2 a=2 r=7 op1=0 op2=0 21:38:48 ...: [ 166.524056] 5: w=3 pa=2 pr=5 m=2 a=2 r=7 op1=0 op2=0 21:38:48 ...: [ 166.524062] 6: w=4 pa=2 pr=5 m=2 a=2 r=7 op1=0 op2=0 21:38:48 ...: [ 166.524068] 0: w=5 pa=2 pr=5 m=2 a=2 r=7 op1=0 op2=0 21:38:48 ...: [ 166.524073] 3: w=6 pa=2 pr=5 m=2 a=2 r=7 op1=0 op2=0 21:38:48 ...: [ 166.524079] raid5: raid level 6 set md0 active with 6 out of 7 devices, algorithm 2 21:38:48 ...: [ 166.524519] RAID5 conf printout: 21:38:48 ...: [ 166.524523] --- rd:7 wd:6 21:38:48 ...: [ 166.524528] disk 0, o:1, dev:sdd1 21:38:48 ...: [ 166.524532] disk 1, o:1, dev:sdb1 21:38:48 ...: [ 166.524537] disk 3, o:1, dev:sdc1 21:38:48 ...: [ 166.524541] disk 4, o:1, dev:sdg1 21:38:48 ...: [ 166.524545] disk 5, o:1, dev:sdf1 21:38:48 ...: [ 166.524550] disk 6, o:1, dev:sde1 21:38:48 ...: [ 166.524553] ...ok start reshape thread 21:38:48 ...: [ 166.524727] md0: detected capacity change from 0 to 2999995858944 21:38:48 ...: [ 166.524735] md: reshape of RAID array md0 21:38:48 ...: [ 166.524740] md: minimum _guaranteed_ speed: 1000 KB/sec/disk. 21:38:48 ...: [ 166.524745] md: using maximum available idle IO bandwidth (but not more than 200000 KB/sec) for reshape. 21:38:48 ...: [ 166.524756] md: using 128k window, over a total of 976561152 blocks. 21:39:05 ...: [ 166.525013] md0: 21:42:04 ...: [ 362.520063] INFO: task mdadm:1937 blocked for more than 120 seconds. 21:42:04 ...: [ 362.520068] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:42:04 ...: [ 362.520073] mdadm D 00000000ffffffff 0 1937 1 0x00000000 21:42:04 ...: [ 362.520083] ffff88002ef4f5d8 0000000000000082 0000000000015bc0 0000000000015bc0 21:42:04 ...: [ 362.520092] ffff88002eb5b198 ffff88002ef4ffd8 0000000000015bc0 ffff88002eb5ade0 21:42:04 ...: [ 362.520100] 0000000000015bc0 ffff88002ef4ffd8 0000000000015bc0 ffff88002eb5b198 21:42:04 ...: [ 362.520107] Call Trace: 21:42:04 ...: [ 362.520133] [<ffffffffa0224892>] get_active_stripe+0x312/0x3f0 [raid456] 21:42:04 ...: [ 362.520148] [<ffffffff81059ae0>] ? default_wake_function+0x0/0x20 21:42:04 ...: [ 362.520159] [<ffffffffa0228413>] make_request+0x243/0x4b0 [raid456] 21:42:04 ...: [ 362.520169] [<ffffffffa0221a90>] ? release_stripe+0x50/0x70 [raid456] 21:42:04 ...: [ 362.520179] [<ffffffff81084790>] ? autoremove_wake_function+0x0/0x40 21:42:04 ...: [ 362.520188] [<ffffffff81414df0>] md_make_request+0xc0/0x130 21:42:04 ...: [ 362.520194] [<ffffffff81414df0>] ? md_make_request+0xc0/0x130 21:42:04 ...: [ 362.520205] [<ffffffff8129f8c1>] generic_make_request+0x1b1/0x4f0 21:42:04 ...: [ 362.520214] [<ffffffff810f6515>] ? mempool_alloc_slab+0x15/0x20 21:42:04 ...: [ 362.520222] [<ffffffff8116c2ec>] ? alloc_buffer_head+0x1c/0x60 21:42:04 ...: [ 362.520230] [<ffffffff8129fc80>] submit_bio+0x80/0x110 21:42:04 ...: [ 362.520236] [<ffffffff8116c849>] submit_bh+0xf9/0x140 21:42:04 ...: [ 362.520244] [<ffffffff8116f124>] block_read_full_page+0x274/0x3b0 21:42:04 ...: [ 362.520251] [<ffffffff81172c90>] ? blkdev_get_block+0x0/0x70 21:42:04 ...: [ 362.520258] [<ffffffff8110d875>] ? __inc_zone_page_state+0x35/0x40 21:42:04 ...: [ 362.520265] [<ffffffff810f46d8>] ? add_to_page_cache_locked+0xe8/0x160 21:42:04 ...: [ 362.520272] [<ffffffff81173d78>] blkdev_readpage+0x18/0x20 21:42:04 ...: [ 362.520279] [<ffffffff810f484b>] __read_cache_page+0x7b/0xe0 21:42:04 ...: [ 362.520285] [<ffffffff81173d60>] ? blkdev_readpage+0x0/0x20 21:42:04 ...: [ 362.520290] [<ffffffff81173d60>] ? blkdev_readpage+0x0/0x20 21:42:04 ...: [ 362.520297] [<ffffffff810f57dc>] do_read_cache_page+0x3c/0x120 21:42:04 ...: [ 362.520304] [<ffffffff810f5909>] read_cache_page_async+0x19/0x20 21:42:04 ...: [ 362.520310] [<ffffffff810f591e>] read_cache_page+0xe/0x20 21:42:04 ...: [ 362.520317] [<ffffffff811a6cb0>] read_dev_sector+0x30/0xa0 21:42:04 ...: [ 362.520324] [<ffffffff811a7fcd>] amiga_partition+0x6d/0x460 21:42:04 ...: [ 362.520331] [<ffffffff811a7938>] check_partition+0x138/0x190 21:42:04 ...: [ 362.520338] [<ffffffff811a7a7a>] rescan_partitions+0xea/0x2f0 21:42:04 ...: [ 362.520344] [<ffffffff811744c7>] __blkdev_get+0x267/0x3d0 21:42:04 ...: [ 362.520350] [<ffffffff81174650>] ? blkdev_open+0x0/0xc0 21:42:04 ...: [ 362.520356] [<ffffffff81174640>] blkdev_get+0x10/0x20 21:42:04 ...: [ 362.520362] [<ffffffff811746c1>] blkdev_open+0x71/0xc0 21:42:04 ...: [ 362.520369] [<ffffffff811419f3>] __dentry_open+0x113/0x370 21:42:04 ...: [ 362.520377] [<ffffffff81253f8f>] ? security_inode_permission+0x1f/0x30 21:42:04 ...: [ 362.520385] [<ffffffff8114de3f>] ? inode_permission+0xaf/0xd0 21:42:04 ...: [ 362.520391] [<ffffffff81141d67>] nameidata_to_filp+0x57/0x70 21:42:04 ...: [ 362.520398] [<ffffffff8115207a>] do_filp_open+0x2da/0xba0 21:42:04 ...: [ 362.520406] [<ffffffff811134a8>] ? unmap_vmas+0x178/0x310 21:42:04 ...: [ 362.520414] [<ffffffff8115dbfa>] ? alloc_fd+0x10a/0x150 21:42:04 ...: [ 362.520421] [<ffffffff81141769>] do_sys_open+0x69/0x170 21:42:04 ...: [ 362.520428] [<ffffffff811418b0>] sys_open+0x20/0x30 21:42:04 ...: [ 362.520437] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b 21:42:04 ...: [ 362.520446] INFO: task mdadm:2283 blocked for more than 120 seconds. 21:42:04 ...: [ 362.520450] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:42:04 ...: [ 362.520454] mdadm D 0000000000000000 0 2283 2212 0x00000000 21:42:04 ...: [ 362.520462] ffff88002cca7d98 0000000000000086 0000000000015bc0 0000000000015bc0 21:42:04 ...: [ 362.520470] ffff88002ededf78 ffff88002cca7fd8 0000000000015bc0 ffff88002ededbc0 21:42:04 ...: [ 362.520478] 0000000000015bc0 ffff88002cca7fd8 0000000000015bc0 ffff88002ededf78 21:42:04 ...: [ 362.520485] Call Trace: 21:42:04 ...: [ 362.520495] [<ffffffff81543a97>] __mutex_lock_slowpath+0xf7/0x180 21:42:04 ...: [ 362.520502] [<ffffffff8154397b>] mutex_lock+0x2b/0x50 21:42:04 ...: [ 362.520508] [<ffffffff8117404d>] __blkdev_put+0x3d/0x190 21:42:04 ...: [ 362.520514] [<ffffffff811741b0>] blkdev_put+0x10/0x20 21:42:04 ...: [ 362.520520] [<ffffffff811741f3>] blkdev_close+0x33/0x60 21:42:04 ...: [ 362.520527] [<ffffffff81145375>] __fput+0xf5/0x210 21:42:04 ...: [ 362.520534] [<ffffffff811454b5>] fput+0x25/0x30 21:42:04 ...: [ 362.520540] [<ffffffff811415ad>] filp_close+0x5d/0x90 21:42:04 ...: [ 362.520546] [<ffffffff81141697>] sys_close+0xb7/0x120 21:42:04 ...: [ 362.520553] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b 21:42:04 ...: [ 362.520559] INFO: task md0_reshape:2287 blocked for more than 120 seconds. 21:42:04 ...: [ 362.520563] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:42:04 ...: [ 362.520567] md0_reshape D ffff88003aee96f0 0 2287 2 0x00000000 21:42:04 ...: [ 362.520575] ffff88003cf05a70 0000000000000046 0000000000015bc0 0000000000015bc0 21:42:04 ...: [ 362.520582] ffff88003aee9aa8 ffff88003cf05fd8 0000000000015bc0 ffff88003aee96f0 21:42:04 ...: [ 362.520590] 0000000000015bc0 ffff88003cf05fd8 0000000000015bc0 ffff88003aee9aa8 21:42:04 ...: [ 362.520597] Call Trace: 21:42:04 ...: [ 362.520608] [<ffffffffa0224892>] get_active_stripe+0x312/0x3f0 [raid456] 21:42:04 ...: [ 362.520616] [<ffffffff81059ae0>] ? default_wake_function+0x0/0x20 21:42:04 ...: [ 362.520626] [<ffffffffa0226f80>] reshape_request+0x4c0/0x9a0 [raid456] 21:42:04 ...: [ 362.520634] [<ffffffff81084790>] ? autoremove_wake_function+0x0/0x40 21:42:04 ...: [ 362.520644] [<ffffffffa022777a>] sync_request+0x31a/0x3a0 [raid456] 21:42:04 ...: [ 362.520651] [<ffffffff81052713>] ? __wake_up+0x53/0x70 21:42:04 ...: [ 362.520658] [<ffffffff814156b1>] md_do_sync+0x621/0xbb0 21:42:04 ...: [ 362.520668] [<ffffffff810387b9>] ? default_spin_lock_flags+0x9/0x10 21:42:04 ...: [ 362.520675] [<ffffffff8141640c>] md_thread+0x5c/0x130 21:42:04 ...: [ 362.520681] [<ffffffff81084790>] ? autoremove_wake_function+0x0/0x40 21:42:04 ...: [ 362.520688] [<ffffffff814163b0>] ? md_thread+0x0/0x130 21:42:04 ...: [ 362.520694] [<ffffffff81084416>] kthread+0x96/0xa0 21:42:04 ...: [ 362.520701] [<ffffffff810131ea>] child_rip+0xa/0x20 21:42:04 ...: [ 362.520707] [<ffffffff81084380>] ? kthread+0x0/0xa0 21:42:04 ...: [ 362.520713] [<ffffffff810131e0>] ? child_rip+0x0/0x20 21:42:04 ...: [ 362.520718] INFO: task mdadm:2288 blocked for more than 120 seconds. 21:42:04 ...: [ 362.520721] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:42:04 ...: [ 362.520725] mdadm D 0000000000000000 0 2288 1 0x00000000 21:42:04 ...: [ 362.520733] ffff88002cca9c18 0000000000000086 0000000000015bc0 0000000000015bc0 21:42:04 ...: [ 362.520741] ffff88003aee83b8 ffff88002cca9fd8 0000000000015bc0 ffff88003aee8000 21:42:04 ...: [ 362.520748] 0000000000015bc0 ffff88002cca9fd8 0000000000015bc0 ffff88003aee83b8 21:42:04 ...: [ 362.520755] Call Trace: 21:42:04 ...: [ 362.520763] [<ffffffff81543a97>] __mutex_lock_slowpath+0xf7/0x180 21:42:04 ...: [ 362.520771] [<ffffffff812a6d50>] ? exact_match+0x0/0x10 21:42:04 ...: [ 362.520777] [<ffffffff8154397b>] mutex_lock+0x2b/0x50 21:42:04 ...: [ 362.520783] [<ffffffff811742c8>] __blkdev_get+0x68/0x3d0 21:42:04 ...: [ 362.520790] [<ffffffff81174650>] ? blkdev_open+0x0/0xc0 21:42:04 ...: [ 362.520795] [<ffffffff81174640>] blkdev_get+0x10/0x20 21:42:04 ...: [ 362.520801] [<ffffffff811746c1>] blkdev_open+0x71/0xc0 21:42:04 ...: [ 362.520808] [<ffffffff811419f3>] __dentry_open+0x113/0x370 21:42:04 ...: [ 362.520815] [<ffffffff81253f8f>] ? security_inode_permission+0x1f/0x30 21:42:04 ...: [ 362.520821] [<ffffffff8114de3f>] ? inode_permission+0xaf/0xd0 21:42:04 ...: [ 362.520828] [<ffffffff81141d67>] nameidata_to_filp+0x57/0x70 21:42:04 ...: [ 362.520834] [<ffffffff8115207a>] do_filp_open+0x2da/0xba0 21:42:04 ...: [ 362.520841] [<ffffffff810ff0e1>] ? lru_cache_add_lru+0x21/0x40 21:42:04 ...: [ 362.520848] [<ffffffff8111109c>] ? do_anonymous_page+0x11c/0x330 21:42:04 ...: [ 362.520855] [<ffffffff81115d5f>] ? handle_mm_fault+0x31f/0x3c0 21:42:04 ...: [ 362.520862] [<ffffffff8115dbfa>] ? alloc_fd+0x10a/0x150 21:42:04 ...: [ 362.520868] [<ffffffff81141769>] do_sys_open+0x69/0x170 21:42:04 ...: [ 362.520874] [<ffffffff811418b0>] sys_open+0x20/0x30 21:42:04 ...: [ 362.520882] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b 21:44:04 ...: [ 482.520065] INFO: task mdadm:1937 blocked for more than 120 seconds. 21:44:04 ...: [ 482.520071] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:44:04 ...: [ 482.520077] mdadm D 00000000ffffffff 0 1937 1 0x00000000 21:44:04 ...: [ 482.520087] ffff88002ef4f5d8 0000000000000082 0000000000015bc0 0000000000015bc0 21:44:04 ...: [ 482.520096] ffff88002eb5b198 ffff88002ef4ffd8 0000000000015bc0 ffff88002eb5ade0 21:44:04 ...: [ 482.520104] 0000000000015bc0 ffff88002ef4ffd8 0000000000015bc0 ffff88002eb5b198 21:44:04 ...: [ 482.520112] Call Trace: 21:44:04 ...: [ 482.520139] [<ffffffffa0224892>] get_active_stripe+0x312/0x3f0 [raid456] 21:44:04 ...: [ 482.520154] [<ffffffff81059ae0>] ? default_wake_function+0x0/0x20 21:44:04 ...: [ 482.520165] [<ffffffffa0228413>] make_request+0x243/0x4b0 [raid456] 21:44:04 ...: [ 482.520175] [<ffffffffa0221a90>] ? release_stripe+0x50/0x70 [raid456] 21:44:04 ...: [ 482.520185] [<ffffffff81084790>] ? autoremove_wake_function+0x0/0x40 21:44:04 ...: [ 482.520194] [<ffffffff81414df0>] md_make_request+0xc0/0x130 21:44:04 ...: [ 482.520201] [<ffffffff81414df0>] ? md_make_request+0xc0/0x130 21:44:04 ...: [ 482.520212] [<ffffffff8129f8c1>] generic_make_request+0x1b1/0x4f0 21:44:04 ...: [ 482.520221] [<ffffffff810f6515>] ? mempool_alloc_slab+0x15/0x20 21:44:04 ...: [ 482.520229] [<ffffffff8116c2ec>] ? alloc_buffer_head+0x1c/0x60 21:44:04 ...: [ 482.520237] [<ffffffff8129fc80>] submit_bio+0x80/0x110 21:44:04 ...: [ 482.520244] [<ffffffff8116c849>] submit_bh+0xf9/0x140 21:44:04 ...: [ 482.520252] [<ffffffff8116f124>] block_read_full_page+0x274/0x3b0 21:44:04 ...: [ 482.520258] [<ffffffff81172c90>] ? blkdev_get_block+0x0/0x70 21:44:04 ...: [ 482.520266] [<ffffffff8110d875>] ? __inc_zone_page_state+0x35/0x40 21:44:04 ...: [ 482.520273] [<ffffffff810f46d8>] ? add_to_page_cache_locked+0xe8/0x160 21:44:04 ...: [ 482.520280] [<ffffffff81173d78>] blkdev_readpage+0x18/0x20 21:44:04 ...: [ 482.520286] [<ffffffff810f484b>] __read_cache_page+0x7b/0xe0 21:44:04 ...: [ 482.520293] [<ffffffff81173d60>] ? blkdev_readpage+0x0/0x20 21:44:04 ...: [ 482.520299] [<ffffffff81173d60>] ? blkdev_readpage+0x0/0x20 21:44:04 ...: [ 482.520306] [<ffffffff810f57dc>] do_read_cache_page+0x3c/0x120 21:44:04 ...: [ 482.520313] [<ffffffff810f5909>] read_cache_page_async+0x19/0x20 21:44:04 ...: [ 482.520319] [<ffffffff810f591e>] read_cache_page+0xe/0x20 21:44:04 ...: [ 482.520327] [<ffffffff811a6cb0>] read_dev_sector+0x30/0xa0 21:44:04 ...: [ 482.520334] [<ffffffff811a7fcd>] amiga_partition+0x6d/0x460 21:44:04 ...: [ 482.520341] [<ffffffff811a7938>] check_partition+0x138/0x190 21:44:04 ...: [ 482.520348] [<ffffffff811a7a7a>] rescan_partitions+0xea/0x2f0 21:44:04 ...: [ 482.520355] [<ffffffff811744c7>] __blkdev_get+0x267/0x3d0 21:44:04 ...: [ 482.520361] [<ffffffff81174650>] ? blkdev_open+0x0/0xc0 21:44:04 ...: [ 482.520367] [<ffffffff81174640>] blkdev_get+0x10/0x20 21:44:04 ...: [ 482.520373] [<ffffffff811746c1>] blkdev_open+0x71/0xc0 21:44:04 ...: [ 482.520380] [<ffffffff811419f3>] __dentry_open+0x113/0x370 21:44:04 ...: [ 482.520388] [<ffffffff81253f8f>] ? security_inode_permission+0x1f/0x30 21:44:04 ...: [ 482.520396] [<ffffffff8114de3f>] ? inode_permission+0xaf/0xd0 21:44:04 ...: [ 482.520403] [<ffffffff81141d67>] nameidata_to_filp+0x57/0x70 21:44:04 ...: [ 482.520410] [<ffffffff8115207a>] do_filp_open+0x2da/0xba0 21:44:04 ...: [ 482.520417] [<ffffffff811134a8>] ? unmap_vmas+0x178/0x310 21:44:04 ...: [ 482.520426] [<ffffffff8115dbfa>] ? alloc_fd+0x10a/0x150 21:44:04 ...: [ 482.520432] [<ffffffff81141769>] do_sys_open+0x69/0x170 21:44:04 ...: [ 482.520438] [<ffffffff811418b0>] sys_open+0x20/0x30 21:44:04 ...: [ 482.520447] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b 21:44:04 ...: [ 482.520458] INFO: task mdadm:2283 blocked for more than 120 seconds. 21:44:04 ...: [ 482.520462] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:44:04 ...: [ 482.520467] mdadm D 0000000000000000 0 2283 2212 0x00000000 21:44:04 ...: [ 482.520475] ffff88002cca7d98 0000000000000086 0000000000015bc0 0000000000015bc0 21:44:04 ...: [ 482.520483] ffff88002ededf78 ffff88002cca7fd8 0000000000015bc0 ffff88002ededbc0 21:44:04 ...: [ 482.520490] 0000000000015bc0 ffff88002cca7fd8 0000000000015bc0 ffff88002ededf78 21:44:04 ...: [ 482.520498] Call Trace: 21:44:04 ...: [ 482.520508] [<ffffffff81543a97>] __mutex_lock_slowpath+0xf7/0x180 21:44:04 ...: [ 482.520515] [<ffffffff8154397b>] mutex_lock+0x2b/0x50 21:44:04 ...: [ 482.520521] [<ffffffff8117404d>] __blkdev_put+0x3d/0x190 21:44:04 ...: [ 482.520527] [<ffffffff811741b0>] blkdev_put+0x10/0x20 21:44:04 ...: [ 482.520533] [<ffffffff811741f3>] blkdev_close+0x33/0x60 21:44:04 ...: [ 482.520541] [<ffffffff81145375>] __fput+0xf5/0x210 21:44:04 ...: [ 482.520547] [<ffffffff811454b5>] fput+0x25/0x30 21:44:04 ...: [ 482.520554] [<ffffffff811415ad>] filp_close+0x5d/0x90 21:44:04 ...: [ 482.520560] [<ffffffff81141697>] sys_close+0xb7/0x120 21:44:04 ...: [ 482.520568] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b 21:44:04 ...: [ 482.520574] INFO: task md0_reshape:2287 blocked for more than 120 seconds. 21:44:04 ...: [ 482.520578] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:44:04 ...: [ 482.520582] md0_reshape D ffff88003aee96f0 0 2287 2 0x00000000 21:44:04 ...: [ 482.520590] ffff88003cf05a70 0000000000000046 0000000000015bc0 0000000000015bc0 21:44:04 ...: [ 482.520597] ffff88003aee9aa8 ffff88003cf05fd8 0000000000015bc0 ffff88003aee96f0 21:44:04 ...: [ 482.520605] 0000000000015bc0 ffff88003cf05fd8 0000000000015bc0 ffff88003aee9aa8 21:44:04 ...: [ 482.520612] Call Trace: 21:44:04 ...: [ 482.520623] [<ffffffffa0224892>] get_active_stripe+0x312/0x3f0 [raid456] 21:44:04 ...: [ 482.520633] [<ffffffff81059ae0>] ? default_wake_function+0x0/0x20 21:44:04 ...: [ 482.520643] [<ffffffffa0226f80>] reshape_request+0x4c0/0x9a0 [raid456] 21:44:04 ...: [ 482.520651] [<ffffffff81084790>] ? autoremove_wake_function+0x0/0x40 21:44:04 ...: [ 482.520661] [<ffffffffa022777a>] sync_request+0x31a/0x3a0 [raid456] 21:44:04 ...: [ 482.520668] [<ffffffff81052713>] ? __wake_up+0x53/0x70 21:44:04 ...: [ 482.520675] [<ffffffff814156b1>] md_do_sync+0x621/0xbb0 21:44:04 ...: [ 482.520685] [<ffffffff810387b9>] ? default_spin_lock_flags+0x9/0x10 21:44:04 ...: [ 482.520692] [<ffffffff8141640c>] md_thread+0x5c/0x130 21:44:04 ...: [ 482.520699] [<ffffffff81084790>] ? autoremove_wake_function+0x0/0x40 21:44:04 ...: [ 482.520705] [<ffffffff814163b0>] ? md_thread+0x0/0x130 21:44:04 ...: [ 482.520711] [<ffffffff81084416>] kthread+0x96/0xa0 21:44:04 ...: [ 482.520718] [<ffffffff810131ea>] child_rip+0xa/0x20 21:44:04 ...: [ 482.520725] [<ffffffff81084380>] ? kthread+0x0/0xa0 21:44:04 ...: [ 482.520730] [<ffffffff810131e0>] ? child_rip+0x0/0x20 21:44:04 ...: [ 482.520735] INFO: task mdadm:2288 blocked for more than 120 seconds. 21:44:04 ...: [ 482.520739] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:44:04 ...: [ 482.520743] mdadm D 0000000000000000 0 2288 1 0x00000000 21:44:04 ...: [ 482.520751] ffff88002cca9c18 0000000000000086 0000000000015bc0 0000000000015bc0 21:44:04 ...: [ 482.520759] ffff88003aee83b8 ffff88002cca9fd8 0000000000015bc0 ffff88003aee8000 21:44:04 ...: [ 482.520767] 0000000000015bc0 ffff88002cca9fd8 0000000000015bc0 ffff88003aee83b8 21:44:04 ...: [ 482.520774] Call Trace: 21:44:04 ...: [ 482.520782] [<ffffffff81543a97>] __mutex_lock_slowpath+0xf7/0x180 21:44:04 ...: [ 482.520790] [<ffffffff812a6d50>] ? exact_match+0x0/0x10 21:44:04 ...: [ 482.520797] [<ffffffff8154397b>] mutex_lock+0x2b/0x50 21:44:04 ...: [ 482.520804] [<ffffffff811742c8>] __blkdev_get+0x68/0x3d0 21:44:04 ...: [ 482.520810] [<ffffffff81174650>] ? blkdev_open+0x0/0xc0 21:44:04 ...: [ 482.520816] [<ffffffff81174640>] blkdev_get+0x10/0x20 21:44:04 ...: [ 482.520822] [<ffffffff811746c1>] blkdev_open+0x71/0xc0 21:44:04 ...: [ 482.520829] [<ffffffff811419f3>] __dentry_open+0x113/0x370 21:44:04 ...: [ 482.520837] [<ffffffff81253f8f>] ? security_inode_permission+0x1f/0x30 21:44:04 ...: [ 482.520843] [<ffffffff8114de3f>] ? inode_permission+0xaf/0xd0 21:44:04 ...: [ 482.520850] [<ffffffff81141d67>] nameidata_to_filp+0x57/0x70 21:44:04 ...: [ 482.520857] [<ffffffff8115207a>] do_filp_open+0x2da/0xba0 21:44:04 ...: [ 482.520864] [<ffffffff810ff0e1>] ? lru_cache_add_lru+0x21/0x40 21:44:04 ...: [ 482.520871] [<ffffffff8111109c>] ? do_anonymous_page+0x11c/0x330 21:44:04 ...: [ 482.520878] [<ffffffff81115d5f>] ? handle_mm_fault+0x31f/0x3c0 21:44:04 ...: [ 482.520885] [<ffffffff8115dbfa>] ? alloc_fd+0x10a/0x150 21:44:04 ...: [ 482.520891] [<ffffffff81141769>] do_sys_open+0x69/0x170 21:44:04 ...: [ 482.520897] [<ffffffff811418b0>] sys_open+0x20/0x30 21:44:04 ...: [ 482.520905] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b 21:46:04 ...: [ 602.520053] INFO: task mdadm:1937 blocked for more than 120 seconds. 21:46:04 ...: [ 602.520059] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:46:04 ...: [ 602.520065] mdadm D 00000000ffffffff 0 1937 1 0x00000000 21:46:04 ...: [ 602.520075] ffff88002ef4f5d8 0000000000000082 0000000000015bc0 0000000000015bc0 21:46:04 ...: [ 602.520084] ffff88002eb5b198 ffff88002ef4ffd8 0000000000015bc0 ffff88002eb5ade0 21:46:04 ...: [ 602.520091] 0000000000015bc0 ffff88002ef4ffd8 0000000000015bc0 ffff88002eb5b198 21:46:04 ...: [ 602.520099] Call Trace: 21:46:04 ...: [ 602.520127] [<ffffffffa0224892>] get_active_stripe+0x312/0x3f0 [raid456] 21:46:04 ...: [ 602.520142] [<ffffffff81059ae0>] ? default_wake_function+0x0/0x20 21:46:04 ...: [ 602.520153] [<ffffffffa0228413>] make_request+0x243/0x4b0 [raid456] 21:46:04 ...: [ 602.520162] [<ffffffffa0221a90>] ? release_stripe+0x50/0x70 [raid456] 21:46:04 ...: [ 602.520171] [<ffffffff81084790>] ? autoremove_wake_function+0x0/0x40 21:46:04 ...: [ 602.520180] [<ffffffff81414df0>] md_make_request+0xc0/0x130 21:46:04 ...: [ 602.520187] [<ffffffff81414df0>] ? md_make_request+0xc0/0x130 21:46:04 ...: [ 602.520197] [<ffffffff8129f8c1>] generic_make_request+0x1b1/0x4f0 21:46:04 ...: [ 602.520206] [<ffffffff810f6515>] ? mempool_alloc_slab+0x15/0x20 21:46:04 ...: [ 602.520215] [<ffffffff8116c2ec>] ? alloc_buffer_head+0x1c/0x60 21:46:04 ...: [ 602.520222] [<ffffffff8129fc80>] submit_bio+0x80/0x110 21:46:04 ...: [ 602.520229] [<ffffffff8116c849>] submit_bh+0xf9/0x140 21:46:04 ...: [ 602.520237] [<ffffffff8116f124>] block_read_full_page+0x274/0x3b0 21:46:04 ...: [ 602.520244] [<ffffffff81172c90>] ? blkdev_get_block+0x0/0x70 21:46:04 ...: [ 602.520252] [<ffffffff8110d875>] ? __inc_zone_page_state+0x35/0x40 21:46:04 ...: [ 602.520259] [<ffffffff810f46d8>] ? add_to_page_cache_locked+0xe8/0x160 21:46:04 ...: [ 602.520266] [<ffffffff81173d78>] blkdev_readpage+0x18/0x20 21:46:04 ...: [ 602.520273] [<ffffffff810f484b>] __read_cache_page+0x7b/0xe0 21:46:04 ...: [ 602.520279] [<ffffffff81173d60>] ? blkdev_readpage+0x0/0x20 21:46:04 ...: [ 602.520285] [<ffffffff81173d60>] ? blkdev_readpage+0x0/0x20 21:46:04 ...: [ 602.520292] [<ffffffff810f57dc>] do_read_cache_page+0x3c/0x120 21:46:04 ...: [ 602.520300] [<ffffffff810f5909>] read_cache_page_async+0x19/0x20 21:46:04 ...: [ 602.520306] [<ffffffff810f591e>] read_cache_page+0xe/0x20 21:46:04 ...: [ 602.520314] [<ffffffff811a6cb0>] read_dev_sector+0x30/0xa0 21:46:04 ...: [ 602.520321] [<ffffffff811a7fcd>] amiga_partition+0x6d/0x460 21:46:04 ...: [ 602.520328] [<ffffffff811a7938>] check_partition+0x138/0x190 21:46:04 ...: [ 602.520335] [<ffffffff811a7a7a>] rescan_partitions+0xea/0x2f0 21:46:04 ...: [ 602.520342] [<ffffffff811744c7>] __blkdev_get+0x267/0x3d0 21:46:04 ...: [ 602.520348] [<ffffffff81174650>] ? blkdev_open+0x0/0xc0 21:46:04 ...: [ 602.520354] [<ffffffff81174640>] blkdev_get+0x10/0x20 21:46:04 ...: [ 602.520359] [<ffffffff811746c1>] blkdev_open+0x71/0xc0 21:46:04 ...: [ 602.520367] [<ffffffff811419f3>] __dentry_open+0x113/0x370 21:46:04 ...: [ 602.520375] [<ffffffff81253f8f>] ? security_inode_permission+0x1f/0x30 21:46:04 ...: [ 602.520383] [<ffffffff8114de3f>] ? inode_permission+0xaf/0xd0 21:46:04 ...: [ 602.520390] [<ffffffff81141d67>] nameidata_to_filp+0x57/0x70 21:46:04 ...: [ 602.520397] [<ffffffff8115207a>] do_filp_open+0x2da/0xba0 21:46:04 ...: [ 602.520404] [<ffffffff811134a8>] ? unmap_vmas+0x178/0x310 21:46:04 ...: [ 602.520413] [<ffffffff8115dbfa>] ? alloc_fd+0x10a/0x150 21:46:04 ...: [ 602.520419] [<ffffffff81141769>] do_sys_open+0x69/0x170 21:46:04 ...: [ 602.520425] [<ffffffff811418b0>] sys_open+0x20/0x30 21:46:04 ...: [ 602.520434] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b 21:46:04 ...: [ 602.520443] INFO: task mdadm:2283 blocked for more than 120 seconds. 21:46:04 ...: [ 602.520447] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. 21:46:04 ...: [ 602.520451] mdadm D 0000000000000000 0 2283 2212 0x00000000 21:46:04 ...: [ 602.520460] ffff88002cca7d98 0000000000000086 0000000000015bc0 0000000000015bc0 21:46:04 ...: [ 602.520468] ffff88002ededf78 ffff88002cca7fd8 0000000000015bc0 ffff88002ededbc0 21:46:04 ...: [ 602.520475] 0000000000015bc0 ffff88002cca7fd8 0000000000015bc0 ffff88002ededf78 21:46:04 ...: [ 602.520483] Call Trace: 21:46:04 ...: [ 602.520492] [<ffffffff81543a97>] __mutex_lock_slowpath+0xf7/0x180 21:46:04 ...: [ 602.520500] [<ffffffff8154397b>] mutex_lock+0x2b/0x50 21:46:04 ...: [ 602.520506] [<ffffffff8117404d>] __blkdev_put+0x3d/0x190 21:46:04 ...: [ 602.520512] [<ffffffff811741b0>] blkdev_put+0x10/0x20 21:46:04 ...: [ 602.520518] [<ffffffff811741f3>] blkdev_close+0x33/0x60 21:46:04 ...: [ 602.520526] [<ffffffff81145375>] __fput+0xf5/0x210 21:46:04 ...: [ 602.520533] [<ffffffff811454b5>] fput+0x25/0x30 21:46:04 ...: [ 602.520539] [<ffffffff811415ad>] filp_close+0x5d/0x90 21:46:04 ...: [ 602.520545] [<ffffffff81141697>] sys_close+0xb7/0x120 21:46:04 ...: [ 602.520552] [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b

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• Authoritative sources about Database vs. Flatfile decision

  - by FastAl

  <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

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• JPA : Add and remove operations on lazily initialized collection behaviour ?

  - by Albert Kam

  Hello, im currently trying out JPA 2 and using Hibernate 3.6.x as the engine. I have an entity of ReceivingGood that contains a List of ReceivingGoodDetail, and has a bidirectional relation. Some related codes for each entity follows : ReceivingGood.java @OneToMany(mappedBy="receivingGood", targetEntity=ReceivingGoodDetail.class, fetch=FetchType.LAZY, cascade = CascadeType.ALL) private List<ReceivingGoodDetail> details = new ArrayList<ReceivingGoodDetail>(); public void addReceivingGoodDetail(ReceivingGoodDetail receivingGoodDetail) { receivingGoodDetail.setReceivingGood(this); } void internalAddReceivingGoodDetail(ReceivingGoodDetail receivingGoodDetail) { this.details.add(receivingGoodDetail); } public void removeReceivingGoodDetail(ReceivingGoodDetail receivingGoodDetail) { receivingGoodDetail.setReceivingGood(null); } void internalRemoveReceivingGoodDetail(ReceivingGoodDetail receivingGoodDetail) { this.details.remove(receivingGoodDetail); } @ManyToOne @JoinColumn(name = "receivinggood_id") private ReceivingGood receivingGood; ReceivingGoodDetail.java : public void setReceivingGood(ReceivingGood receivingGood) { if (this.receivingGood != null) { this.receivingGood.internalRemoveReceivingGoodDetail(this); } this.receivingGood = receivingGood; if (receivingGood != null) { receivingGood.internalAddReceivingGoodDetail(this); } } In my experiements with both of these entities, both adding the detail to the receivingGood's collection, and even removing the detail from the receivingGood's collection, will trigger a query to fill the collection before doing the add or remove. This assumption is based on my experiments that i will paste below. My concern is that : is it ok to do changes on only a little bit of records on the collection, and the engine has to query all of the details belonging to the collection ? What if the collection would have to be filled with 1000 records when i just want to edit a single record ? Here are my experiments with the output as the comment above each method : /* Hibernate: select receivingg0_.id as id9_14_, receivingg0_.creationDate as creation2_9_14_, ... too long Hibernate: select receivingg0_.id as id10_20_, receivingg0_.creationDate as creation2_10_20_, ... too long removing existing detail from lazy collection Hibernate: select details0_.receivinggood_id as receivi13_9_8_, details0_.id as id8_, details0_.id as id10_7_, details0_.creationDate as creation2_10_7_, details0_.modificationDate as modifica3_10_7_, details0_.usercreate_id as usercreate10_10_7_, details0_.usermodify_id as usermodify11_10_7_, details0_.version as version10_7_, details0_.buyQuantity as buyQuant5_10_7_, details0_.buyUnit as buyUnit10_7_, details0_.internalQuantity as internal7_10_7_, details0_.internalUnit as internal8_10_7_, details0_.product_id as product12_10_7_, details0_.receivinggood_id as receivi13_10_7_, details0_.supplierLotNumber as supplier9_10_7_, user1_.id as id2_0_, user1_.creationDate as creation2_2_0_, user1_.modificationDate as modifica3_2_0_, user1_.usercreate_id as usercreate6_2_0_, user1_.usermodify_id as usermodify7_2_0_, user1_.version as version2_0_, user1_.name as name2_0_, user2_.id as id2_1_, user2_.creationDate as creation2_2_1_, user2_.modificationDate as modifica3_2_1_, user2_.usercreate_id as usercreate6_2_1_, user2_.usermodify_id as usermodify7_2_1_, user2_.version as version2_1_, user2_.name as name2_1_, user3_.id as id2_2_, user3_.creationDate as creation2_2_2_, user3_.modificationDate as modifica3_2_2_, user3_.usercreate_id as usercreate6_2_2_, user3_.usermodify_id as usermodify7_2_2_, user3_.version as version2_2_, user3_.name as name2_2_, user4_.id as id2_3_, user4_.creationDate as creation2_2_3_, user4_.modificationDate as modifica3_2_3_, user4_.usercreate_id as usercreate6_2_3_, user4_.usermodify_id as usermodify7_2_3_, user4_.version as version2_3_, user4_.name as name2_3_, product5_.id as id0_4_, product5_.creationDate as creation2_0_4_, product5_.modificationDate as modifica3_0_4_, product5_.usercreate_id as usercreate7_0_4_, product5_.usermodify_id as usermodify8_0_4_, product5_.version as version0_4_, product5_.code as code0_4_, product5_.name as name0_4_, user6_.id as id2_5_, user6_.creationDate as creation2_2_5_, user6_.modificationDate as modifica3_2_5_, user6_.usercreate_id as usercreate6_2_5_, user6_.usermodify_id as usermodify7_2_5_, user6_.version as version2_5_, user6_.name as name2_5_, user7_.id as id2_6_, user7_.creationDate as creation2_2_6_, user7_.modificationDate as modifica3_2_6_, user7_.usercreate_id as usercreate6_2_6_, user7_.usermodify_id as usermodify7_2_6_, user7_.version as version2_6_, user7_.name as name2_6_ from ReceivingGoodDetail details0_ left outer join COMMON_USER user1_ on details0_.usercreate_id=user1_.id left outer join COMMON_USER user2_ on user1_.usercreate_id=user2_.id left outer join COMMON_USER user3_ on user2_.usermodify_id=user3_.id left outer join COMMON_USER user4_ on details0_.usermodify_id=user4_.id left outer join Product product5_ on details0_.product_id=product5_.id left outer join COMMON_USER user6_ on product5_.usercreate_id=user6_.id left outer join COMMON_USER user7_ on product5_.usermodify_id=user7_.id where details0_.receivinggood_id=? after removing try selecting the size : 4 after removing, now flushing Hibernate: update ReceivingGood set creationDate=?, modificationDate=?, usercreate_id=?, usermodify_id=?, version=?, purchaseorder_id=?, supplier_id=?, transactionDate=?, transactionNumber=?, transactionType=?, transactionYearMonth=?, warehouse_id=? where id=? and version=? Hibernate: update ReceivingGoodDetail set creationDate=?, modificationDate=?, usercreate_id=?, usermodify_id=?, version=?, buyQuantity=?, buyUnit=?, internalQuantity=?, internalUnit=?, product_id=?, receivinggood_id=?, supplierLotNumber=? where id=? and version=? detail size : 4 */ public void removeFromLazyCollection() { String headerId = "3b373f6a-9cd1-4c9c-9d46-240de37f6b0f"; ReceivingGood receivingGood = em.find(ReceivingGood.class, headerId); // get existing detail ReceivingGoodDetail detail = em.find(ReceivingGoodDetail.class, "323fb0e7-9bb2-48dc-bc07-5ff32f30e131"); detail.setInternalUnit("MCB"); System.out.println("removing existing detail from lazy collection"); receivingGood.removeReceivingGoodDetail(detail); System.out.println("after removing try selecting the size : " + receivingGood.getDetails().size()); System.out.println("after removing, now flushing"); em.flush(); System.out.println("detail size : " + receivingGood.getDetails().size()); } /* Hibernate: select receivingg0_.id as id9_14_, receivingg0_.creationDate as creation2_9_14_, ... too long Hibernate: select receivingg0_.id as id10_20_, receivingg0_.creationDate as creation2_10_20_, ... too long adding existing detail into lazy collection Hibernate: select details0_.receivinggood_id as receivi13_9_8_, details0_.id as id8_, details0_.id as id10_7_, details0_.creationDate as creation2_10_7_, details0_.modificationDate as modifica3_10_7_, details0_.usercreate_id as usercreate10_10_7_, details0_.usermodify_id as usermodify11_10_7_, details0_.version as version10_7_, details0_.buyQuantity as buyQuant5_10_7_, details0_.buyUnit as buyUnit10_7_, details0_.internalQuantity as internal7_10_7_, details0_.internalUnit as internal8_10_7_, details0_.product_id as product12_10_7_, details0_.receivinggood_id as receivi13_10_7_, details0_.supplierLotNumber as supplier9_10_7_, user1_.id as id2_0_, user1_.creationDate as creation2_2_0_, user1_.modificationDate as modifica3_2_0_, user1_.usercreate_id as usercreate6_2_0_, user1_.usermodify_id as usermodify7_2_0_, user1_.version as version2_0_, user1_.name as name2_0_, user2_.id as id2_1_, user2_.creationDate as creation2_2_1_, user2_.modificationDate as modifica3_2_1_, user2_.usercreate_id as usercreate6_2_1_, user2_.usermodify_id as usermodify7_2_1_, user2_.version as version2_1_, user2_.name as name2_1_, user3_.id as id2_2_, user3_.creationDate as creation2_2_2_, user3_.modificationDate as modifica3_2_2_, user3_.usercreate_id as usercreate6_2_2_, user3_.usermodify_id as usermodify7_2_2_, user3_.version as version2_2_, user3_.name as name2_2_, user4_.id as id2_3_, user4_.creationDate as creation2_2_3_, user4_.modificationDate as modifica3_2_3_, user4_.usercreate_id as usercreate6_2_3_, user4_.usermodify_id as usermodify7_2_3_, user4_.version as version2_3_, user4_.name as name2_3_, product5_.id as id0_4_, product5_.creationDate as creation2_0_4_, product5_.modificationDate as modifica3_0_4_, product5_.usercreate_id as usercreate7_0_4_, product5_.usermodify_id as usermodify8_0_4_, product5_.version as version0_4_, product5_.code as code0_4_, product5_.name as name0_4_, user6_.id as id2_5_, user6_.creationDate as creation2_2_5_, user6_.modificationDate as modifica3_2_5_, user6_.usercreate_id as usercreate6_2_5_, user6_.usermodify_id as usermodify7_2_5_, user6_.version as version2_5_, user6_.name as name2_5_, user7_.id as id2_6_, user7_.creationDate as creation2_2_6_, user7_.modificationDate as modifica3_2_6_, user7_.usercreate_id as usercreate6_2_6_, user7_.usermodify_id as usermodify7_2_6_, user7_.version as version2_6_, user7_.name as name2_6_ from ReceivingGoodDetail details0_ left outer join COMMON_USER user1_ on details0_.usercreate_id=user1_.id left outer join COMMON_USER user2_ on user1_.usercreate_id=user2_.id left outer join COMMON_USER user3_ on user2_.usermodify_id=user3_.id left outer join COMMON_USER user4_ on details0_.usermodify_id=user4_.id left outer join Product product5_ on details0_.product_id=product5_.id left outer join COMMON_USER user6_ on product5_.usercreate_id=user6_.id left outer join COMMON_USER user7_ on product5_.usermodify_id=user7_.id where details0_.receivinggood_id=? after adding try selecting the size : 5 after adding, now flushing Hibernate: update ReceivingGood set creationDate=?, modificationDate=?, usercreate_id=?, usermodify_id=?, version=?, purchaseorder_id=?, supplier_id=?, transactionDate=?, transactionNumber=?, transactionType=?, transactionYearMonth=?, warehouse_id=? where id=? and version=? detail size : 5 */ public void editLazyCollection() { String headerId = "3b373f6a-9cd1-4c9c-9d46-240de37f6b0f"; ReceivingGood receivingGood = em.find(ReceivingGood.class, headerId); // get existing detail ReceivingGoodDetail detail = em.find(ReceivingGoodDetail.class, "323fb0e7-9bb2-48dc-bc07-5ff32f30e131"); detail.setInternalUnit("MCB"); System.out.println("adding existing detail into lazy collection"); receivingGood.addReceivingGoodDetail(detail); System.out.println("after adding try selecting the size : " + receivingGood.getDetails().size()); System.out.println("after adding, now flushing"); em.flush(); System.out.println("detail size : " + receivingGood.getDetails().size()); } Please share your experience on this matter ! Thank you !

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• How do I prove I should put a table of values in source code instead of a database table?

  - by FastAl

  <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

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• C++ 2d Array Class Function Call Help

  - by johnny-conrad

  I hope this question takes a simple fix, and I am just missing something very small. I am in my second semester of C++ in college, and we are just getting into OOP. This is my first OOP program, and it is causing me a little problem. Here are the errors I am getting: Member function must be called or its address taken in function displayGrid(int,Cell ( *)[20]) Member function must be called or its address taken in function Turn(int,int,Cell ( *)[20]) Member function must be called or its address taken in function Turn(int,int,Cell ( *)[20]) Warning: Parameter 'grid' is never used in function displayGrid(int,Cell ( *)[20]) Here is all of my code. I am aware It is much more code than necessary, sorry if it makes it more difficult. I was worried that I might accidentally delete something. const int MAX=20; //Struct Cell holds player and their symbol. class Cell { private: int Player; char Symbol; public: Cell(void); void setPlayer(int); void setSymbol(char); int getPlayer(void); char getSymbol(void); }; Cell::Cell(void) { Symbol ='-'; } void Cell::setPlayer(int player_num) { Player = player_num; } void Cell::setSymbol(char rps) { Symbol = rps; } int Cell::getPlayer(void) { return Player; } char Cell::getSymbol(void) { return Symbol; } void Turn(int, int, Cell[MAX][MAX]); void displayGrid(int, Cell[MAX][MAX]); void main(void) { int size; cout << "How big would you like the grid to be: "; cin >> size; //Checks to see valid grid size while(size>MAX || size<3) { cout << "Grid size must between 20 and 3." << endl; cout << "Please re-enter the grid size: "; cin >> size; } int cnt=1; int full; Cell grid[MAX][MAX]; //I use full to detect when the game is over by squaring size. full = size*size; cout << "Starting a new game." << endl; //Exits loop when cnt reaches full. while(cnt<full+1) { displayGrid(size, grid); //calls function to display grid if(cnt%2==0) //if cnt is even then it's 2nd players turn cout << "Player 2's turn." << endl; else cout << "Player 1's turn" << endl; Turn(size, cnt, grid); //calls Turn do each players turn cnt++; } cout << endl; cout << "Board is full... Game Over" << endl; } void displayGrid(int size, Cell grid[MAX][MAX]) { cout << endl; cout << " "; for(int x=1; x<size+1; x++) // prints first row cout << setw(3) << x; // of numbers. cout << endl; //Nested-For prints the grid. for(int i=1; i<size+1; i++) { cout << setw(2) << i; for(int c=1; c<size+1; c++) { cout << setw(3) << grid[i][c].getSymbol; } cout << endl; } cout << endl; } void Turn(int size, int cnt, Cell grid[MAX][MAX]) { char temp; char choice; int row=0; int column=0; cout << "Enter the Row: "; cin >> row; cout << "Enter the Column: "; cin >> column; //puts what is in the current cell in "temp" temp = grid[row][column].getSymbol; //Checks to see if temp is occupied or not while(temp!='-') { cout << "Cell space is Occupied..." << endl; cout << "Enter the Row: "; cin >> row; cout << "Enter the Column: "; cin >> column; temp = grid[row][column].getSymbol; //exits loop when finally correct } if(cnt%2==0) //if cnt is even then its player 2's turn { cout << "Enter your Symbol R, P, or S (Capitals): "; cin >> choice; grid[row][column].setPlayer(1); in >> choice; } //officially sets choice to grid cell grid[row][column].setSymbol(choice); } else //if cnt is odd then its player 1's turn { cout << "Enter your Symbol r, p, or s (Lower-Case): "; cin >> choice; grid[row][column].setPlayer(2); //checks for valid input by user1 while(choice!= 'r' && choice!='p' && choice!='s') { cout << "Invalid Symbol... Please Re-Enter: "; cin >> choice; } //officially sets choice to grid cell. grid[row][column].setSymbol(choice); } cout << endl; } Thanks alot for your help!

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• Implementing a robust async stream reader for a console

  - by Jon

  I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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• C# Persistent WebClient

  - by Nullstr1ng

  I have a class written in C# (Windows Forms) It's a WebClient class which I intent to use in some website and for Logging In and navigation. Here's the complete class pastebin.com (the class has 197 lines so I just use pastebin. Sorry if I made a little bit harder for you to read the class, also below this post) The problem is, am not sure why it's not persistent .. I was able to log in, but when I navigate to other page (without leaving the domain), I was thrown back to log in page. Can you help me solving this problem? one issue though is, the site I was trying to connect is "HTTPS" protocol. I have not yet tested this on just a regular HTTP. Thank you in advance. /* * Web Client v1.2 * --------------- * Date: 12/17/2010 * author: Jayson Ragasa */ using System; using System.Collections; using System.Collections.Specialized; using System.Collections.Generic; using System.Text; using System.IO; using System.Net; using System.Web; namespace Nullstring.Modules.WebClient { public class WebClientLibrary { #region vars string _method = string.Empty; ArrayList _params; CookieContainer cookieko; HttpWebRequest req = null; HttpWebResponse resp = null; Uri uri = null; #endregion #region properties public string Method { set { _method = value; } } #endregion #region constructor public WebClientLibrary() { _method = "GET"; _params = new ArrayList(); cookieko = new CookieContainer(); } #endregion #region methods public void ClearParameter() { _params.Clear(); } public void AddParameter(string key, string value) { _params.Add(string.Format("{0}={1}", WebTools.URLEncodeString(key), WebTools.URLEncodeString(value))); } public string GetResponse(string URL) { StringBuilder response = new StringBuilder(); #region create web request { uri = new Uri(URL); req = (HttpWebRequest)WebRequest.Create(URL); req.Method = "GET"; req.GetLifetimeService(); } #endregion #region get web response { resp = (HttpWebResponse)req.GetResponse(); Stream resStream = resp.GetResponseStream(); int bytesReceived = 0; string tempString = null; int count = 0; byte[] buf = new byte[8192]; do { count = resStream.Read(buf, 0, buf.Length); if (count != 0) { bytesReceived += count; tempString = Encoding.UTF8.GetString(buf, 0, count); response.Append(tempString); } } while (count > 0); } #endregion return response.ToString(); } public string GetResponse(string URL, bool HasParams) { StringBuilder response = new StringBuilder(); #region create web request { uri = new Uri(URL); req = (HttpWebRequest)WebRequest.Create(URL); req.MaximumAutomaticRedirections = 20; req.AllowAutoRedirect = true; req.Method = this._method; req.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"; req.KeepAlive = true; req.CookieContainer = this.cookieko; req.UserAgent = "Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_8; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.224 Safari/534.10"; } #endregion #region build post data { if (HasParams) { if (this._method.ToUpper() == "POST") { string Parameters = String.Join("&", (String[])this._params.ToArray(typeof(string))); UTF8Encoding encoding = new UTF8Encoding(); byte[] loginDataBytes = encoding.GetBytes(Parameters); req.ContentType = "application/x-www-form-urlencoded"; req.ContentLength = loginDataBytes.Length; Stream stream = req.GetRequestStream(); stream.Write(loginDataBytes, 0, loginDataBytes.Length); stream.Close(); } } } #endregion #region get web response { resp = (HttpWebResponse)req.GetResponse(); Stream resStream = resp.GetResponseStream(); int bytesReceived = 0; string tempString = null; int count = 0; byte[] buf = new byte[8192]; do { count = resStream.Read(buf, 0, buf.Length); if (count != 0) { bytesReceived += count; tempString = Encoding.UTF8.GetString(buf, 0, count); response.Append(tempString); } } while (count > 0); } #endregion return response.ToString(); } #endregion } public class WebTools { public static string EncodeString(string str) { return HttpUtility.HtmlEncode(str); } public static string DecodeString(string str) { return HttpUtility.HtmlDecode(str); } public static string URLEncodeString(string str) { return HttpUtility.UrlEncode(str); } public static string URLDecodeString(string str) { return HttpUtility.UrlDecode(str); } } } UPDATE Dec 22GetResponse overload public string GetResponse(string URL) { StringBuilder response = new StringBuilder(); #region create web request { //uri = new Uri(URL); req = (HttpWebRequest)WebRequest.Create(URL); req.Method = "GET"; req.CookieContainer = this.cookieko; } #endregion #region get web response { resp = (HttpWebResponse)req.GetResponse(); Stream resStream = resp.GetResponseStream(); int bytesReceived = 0; string tempString = null; int count = 0; byte[] buf = new byte[8192]; do { count = resStream.Read(buf, 0, buf.Length); if (count != 0) { bytesReceived += count; tempString = Encoding.UTF8.GetString(buf, 0, count); response.Append(tempString); } } while (count 0); } #endregion return response.ToString(); } But still I got thrown back to login page. UPDATE: Dec 23 I tried listing the cookie and here's what I get at first, I have to login to a webform and this I have this Cookie JSESSIONID=368C0AC47305282CBCE7A566567D2942 then I navigated to another page (but on the same domain) I got a different Cooke? JSESSIONID=9FA2D64DA7669155B9120790B40A592C What went wrong? I use the code updated last Dec 22

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• F# - Facebook Hacker Cup - Double Squares

  - by Jacob

  I'm working on strengthening my F#-fu and decided to tackle the Facebook Hacker Cup Double Squares problem. I'm having some problems with the run-time and was wondering if anyone could help me figure out why it is so much slower than my C# equivalent. There's a good description from another post; Source: Facebook Hacker Cup Qualification Round 2011 A double-square number is an integer X which can be expressed as the sum of two perfect squares. For example, 10 is a double-square because 10 = 3^2 + 1^2. Given X, how can we determine the number of ways in which it can be written as the sum of two squares? For example, 10 can only be written as 3^2 + 1^2 (we don't count 1^2 + 3^2 as being different). On the other hand, 25 can be written as 5^2 + 0^2 or as 4^2 + 3^2. You need to solve this problem for 0 = X = 2,147,483,647. Examples: 10 = 1 25 = 2 3 = 0 0 = 1 1 = 1 My basic strategy (which I'm open to critique on) is to; Create a dictionary (for memoize) of the input numbers initialzed to 0 Get the largest number (LN) and pass it to count/memo function Get the LN square root as int Calculate squares for all numbers 0 to LN and store in dict Sum squares for non repeat combinations of numbers from 0 to LN If sum is in memo dict, add 1 to memo Finally, output the counts of the original numbers. Here is the F# code (See code changes at bottom) I've written that I believe corresponds to this strategy (Runtime: ~8:10); open System open System.Collections.Generic open System.IO /// Get a sequence of values let rec range min max = seq { for num in [min .. max] do yield num } /// Get a sequence starting from 0 and going to max let rec zeroRange max = range 0 max /// Find the maximum number in a list with a starting accumulator (acc) let rec maxNum acc = function | [] -> acc | p::tail when p > acc -> maxNum p tail | p::tail -> maxNum acc tail /// A helper for finding max that sets the accumulator to 0 let rec findMax nums = maxNum 0 nums /// Build a collection of combinations; ie [1,2,3] = (1,1), (1,2), (1,3), (2,2), (2,3), (3,3) let rec combos range = seq { let count = ref 0 for inner in range do for outer in Seq.skip !count range do yield (inner, outer) count := !count + 1 } let rec squares nums = let dict = new Dictionary<int, int>() for s in nums do dict.[s] <- (s * s) dict /// Counts the number of possible double squares for a given number and keeps track of other counts that are provided in the memo dict. let rec countDoubleSquares (num: int) (memo: Dictionary<int, int>) = // The highest relevent square is the square root because it squared plus 0 squared is the top most possibility let maxSquare = System.Math.Sqrt((float)num) // Our relevant squares are 0 to the highest possible square; note the cast to int which shouldn't hurt. let relSquares = range 0 ((int)maxSquare) // calculate the squares up front; let calcSquares = squares relSquares // Build up our square combinations; ie [1,2,3] = (1,1), (1,2), (1,3), (2,2), (2,3), (3,3) for (sq1, sq2) in combos relSquares do let v = calcSquares.[sq1] + calcSquares.[sq2] // Memoize our relevant results if memo.ContainsKey(v) then memo.[v] <- memo.[v] + 1 // return our count for the num passed in memo.[num] // Read our numbers from file. //let lines = File.ReadAllLines("test2.txt") //let nums = [ for line in Seq.skip 1 lines -> Int32.Parse(line) ] // Optionally, read them from straight array let nums = [1740798996; 1257431873; 2147483643; 602519112; 858320077; 1048039120; 415485223; 874566596; 1022907856; 65; 421330820; 1041493518; 5; 1328649093; 1941554117; 4225; 2082925; 0; 1; 3] // Initialize our memoize dictionary let memo = new Dictionary<int, int>() for num in nums do memo.[num] <- 0 // Get the largest number in our set, all other numbers will be memoized along the way let maxN = findMax nums // Do the memoize let maxCount = countDoubleSquares maxN memo // Output our results. for num in nums do printfn "%i" memo.[num] // Have a little pause for when we debug let line = Console.Read() And here is my version in C# (Runtime: ~1:40: using System; using System.Collections.Generic; using System.Diagnostics; using System.IO; using System.Linq; using System.Text; namespace FBHack_DoubleSquares { public class TestInput { public int NumCases { get; set; } public List<int> Nums { get; set; } public TestInput() { Nums = new List<int>(); } public int MaxNum() { return Nums.Max(); } } class Program { static void Main(string[] args) { // Read input from file. //TestInput input = ReadTestInput("live.txt"); // As example, load straight. TestInput input = new TestInput { NumCases = 20, Nums = new List<int> { 1740798996, 1257431873, 2147483643, 602519112, 858320077, 1048039120, 415485223, 874566596, 1022907856, 65, 421330820, 1041493518, 5, 1328649093, 1941554117, 4225, 2082925, 0, 1, 3, } }; var maxNum = input.MaxNum(); Dictionary<int, int> memo = new Dictionary<int, int>(); foreach (var num in input.Nums) { if (!memo.ContainsKey(num)) memo.Add(num, 0); } DoMemoize(maxNum, memo); StringBuilder sb = new StringBuilder(); foreach (var num in input.Nums) { //Console.WriteLine(memo[num]); sb.AppendLine(memo[num].ToString()); } Console.Write(sb.ToString()); var blah = Console.Read(); //File.WriteAllText("out.txt", sb.ToString()); } private static int DoMemoize(int num, Dictionary<int, int> memo) { var highSquare = (int)Math.Floor(Math.Sqrt(num)); var squares = CreateSquareLookup(highSquare); var relSquares = squares.Keys.ToList(); Debug.WriteLine("Starting - " + num.ToString()); Debug.WriteLine("RelSquares.Count = {0}", relSquares.Count); int sum = 0; var index = 0; foreach (var square in relSquares) { foreach (var inner in relSquares.Skip(index)) { sum = squares[square] + squares[inner]; if (memo.ContainsKey(sum)) memo[sum]++; } index++; } if (memo.ContainsKey(num)) return memo[num]; return 0; } private static TestInput ReadTestInput(string fileName) { var lines = File.ReadAllLines(fileName); var input = new TestInput(); input.NumCases = int.Parse(lines[0]); foreach (var lin in lines.Skip(1)) { input.Nums.Add(int.Parse(lin)); } return input; } public static Dictionary<int, int> CreateSquareLookup(int maxNum) { var dict = new Dictionary<int, int>(); int square; foreach (var num in Enumerable.Range(0, maxNum)) { square = num * num; dict[num] = square; } return dict; } } } Thanks for taking a look. UPDATE Changing the combos function slightly will result in a pretty big performance boost (from 8 min to 3:45): /// Old and Busted... let rec combosOld range = seq { let rangeCache = Seq.cache range let count = ref 0 for inner in rangeCache do for outer in Seq.skip !count rangeCache do yield (inner, outer) count := !count + 1 } /// The New Hotness... let rec combos maxNum = seq { for i in 0..maxNum do for j in i..maxNum do yield i,j }

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• I need help on my C++ assignment using Microsoft Visual C++

  - by krayzwytie

  Ok, so I don't want you to do my homework for me, but I'm a little lost with this final assignment and need all the help I can get. Learning about programming is tough enough, but doing it online is next to impossible for me... Now, to get to the program, I am going to paste what I have so far. This includes mostly //comments and what I have written so far. If you can help me figure out where all the errors are and how to complete the assignment, I will really appreciate it. Like I said, I don't want you to do my homework for me (it's my final), but any constructive criticism is welcome. This is my final assignment for this class and it is due tomorrow (Sunday before midnight, Arizona time). This is the assignment: Examine the following situation: Your company, Datamax, Inc., is in the process of automating its payroll systems. Your manager has asked you to create a program that calculates overtime pay for all employees. Your program must take into account the employee’s salary, total hours worked, and hours worked more than 40 in a week, and then provide an output that is useful and easily understood by company management. Compile your program utilizing the following background information and the code outline in Appendix D (included in the code section). Submit your project as an attachment including the code and the output. Company Background: Three employees: Mark, John, and Mary The end user needs to be prompted for three specific pieces of input—name, hours worked, and hourly wage. Calculate overtime if input is greater than 40 hours per week. Provide six test plans to verify the logic within the program. Plan 1 must display the proper information for employee #1 with overtime pay. Plan 2 must display the proper information for employee #1 with no overtime pay. Plans 3-6 are duplicates of plan 1 and 2 but for the other employees. Program Requirements: Define a base class to use for the entire program. The class holds the function calls and the variables related to the overtime pay calculations. Define one object per employee. Note there will be three employees. Your program must take the objects created and implement calculations based on total salaries, total hours, and the total number of overtime hours. See the Employee Summary Data section of the sample output. Logic Steps to Complete Your Program: Define your base class. Define your objects from your base class. Prompt for user input, updating your object classes for all three users. Implement your overtime pay calculations. Display overtime or regular time pay calculations. See the sample output below. Implement object calculations by summarizing your employee objects and display the summary information in the example below. And this is the code: // Final_Project.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <iostream> #include <string> #include <iomanip> using namespace std; // //CLASS DECLARATION SECTION // class CEmployee { public: void ImplementCalculations(string EmployeeName, double hours, double wage); void DisplayEmployInformation(void); void Addsomethingup (CEmployee, CEmployee, CEmployee); string EmployeeName ; int hours ; int overtime_hours ; int iTotal_hours ; int iTotal_OvertimeHours ; float wage ; float basepay ; float overtime_pay ; float overtime_extra ; float iTotal_salaries ; float iIndividualSalary ; }; int main() { system("cls"); cout << "Welcome to the Employee Pay Center"; /* Use this section to define your objects. You will have one object per employee. You have only three employees. The format is your class name and your object name. */ std::cout << "Please enter Employee's Name: "; std::cin >> EmployeeName; std::cout << "Please enter Total Hours for (EmployeeName): "; std::cin >> hours; std::cout << "Please enter Base Pay for(EmployeeName): "; std::cin >> basepay; /* Here you will prompt for the first employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Example of Prompts Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will prompt for the second employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will prompt for the third employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will implement a function call to implement the employ calcuations for each object defined above. You will do this for each of the three employees or objects. The format for this step is the following: [(object name.function name(objectname.name, objectname.hours, objectname.wage)] ; */ /* This section you will send all three objects to a function that will add up the the following information: - Total Employee Salaries - Total Employee Hours - Total Overtime Hours The format for this function is the following: - Define a new object. - Implement function call [objectname.functionname(object name 1, object name 2, object name 3)] /* } //End of Main Function void CEmployee::ImplementCalculations (string EmployeeName, double hours, double wage){ //Initialize overtime variables overtime_hours=0; overtime_pay=0; overtime_extra=0; if (hours > 40) { /* This section is for the basic calculations for calculating overtime pay. - base pay = 40 hours times the hourly wage - overtime hours = hours worked – 40 - overtime pay = hourly wage * 1.5 - overtime extra pay over 40 = overtime hours * overtime pay - salary = overtime money over 40 hours + your base pay */ /* Implement function call to output the employee information. Function is defined below. */ } // if (hours > 40) else { /* Here you are going to calculate the hours less than 40 hours. - Your base pay is = your hours worked times your wage - Salary = your base pay */ /* Implement function call to output the employee information. Function is defined below. */ } // End of the else } //End of Primary Function void CEmployee::DisplayEmployInformation(); { // This function displays all the employee output information. /* This is your cout statements to display the employee information: Employee Name ............. = Base Pay .................. = Hours in Overtime ......... = Overtime Pay Amount........ = Total Pay ................. = */ } // END OF Display Employee Information void CEmployee::Addsomethingup (CEmployee Employ1, CEmployee Employ2) { // Adds two objects of class Employee passed as // function arguments and saves them as the calling object's data member values. /* Add the total hours for objects 1, 2, and 3. Add the salaries for each object. Add the total overtime hours. */ /* Then display the information below. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% EMPLOYEE SUMMARY DATA%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% Total Employee Salaries ..... = 576.43 %%%% Total Employee Hours ........ = 108 %%%% Total Overtime Hours......... = 5 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% */ } // End of function

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