VB .NET

How to access a WCF Service behind ISA Server 2006 Forms Based Authentication

Stacy Vicknair — Tue, 31 Jan 2012 22:25:35 GMT

I ran into this particular issue and didn’t find any answers to this specific question online. Here’s how I was able to accomplish this. A couple notes about my scenario:

I used slsvcutil.exe to generate my service. I could not get connected to a service through “Add Service Reference” when connecting from outside the ISA server protected connection.
This connection was tested and successfully retrieved data from a Windows Phone 7 device. I figured on the scale of success this was the platform that I had the most concern for.
This works for services behind ISA Server 2006’s cookie-based authentication.

Step 1: Get the details about the ISA Server POST

Using firebug or a similar tool, take a look at what information happens when you select “Log On” on the ISA Server FBA page. The important information to keep is the Request URL and any Form Data passed in the HTTP POST made when you click “Log On”. The request url should appear in the format https://mysite.com/CookieAuth.dll?Logon

Here’s the form data as reported in Chrome:

Step 2: Mimic the POST in your code with a provided CookieContainer

First we have to POST to the CookieAuth.dll?Logon in order to get our CookieContainer populated. _container is a private CookieContainer shared between all methods.

        1: Public Sub New()

       2:     InitializeComponent()

       3:  

       4:     Dim logonUrl = "https://mysite.com/CookieAuth.dll?Logon"

       5:     _container = New CookieContainer()

       6:  

       7:     Dim request = CType(WebRequest.Create(logonUrl), HttpWebRequest)

       8:     request.CookieContainer = _container

       9:     request.Method = "POST"

      10:  

      11:     request.ContentType = "application/x-www-form-urlencoded"

      12:  

      13:     request.BeginGetRequestStream(AddressOf RequestCallback, request)

      14: End Sub

      15:  

      16: Private Sub RequestCallback(ByVal ar As IAsyncResult)

      17:     Dim postData = String.Format("curl=Z2F&flags=0&forcedownlevel=0&formdir=3&trusted=4&username={0}&password={1}&SubmitCreds=Log On", "username", "password")

      18:  

      19:     Dim request = CType(ar.AsyncState, HttpWebRequest)

      20:  

      21:     Dim stream = request.EndGetRequestStream(ar)

      22:  

      23:     Using sw As New StreamWriter(stream)

      24:         sw.Write(postData)

      25:     End Using

      26:  

      27:     request.BeginGetResponse(AddressOf ResponseCallback, request)

      28: End Sub

Step 3: Pass the CookieContainer to your service

When using WCF basicHttpBinding make sure that the binding configuration specifies allowCookies=”true”. You can also set this by specifying the same in code against the binding.

       1: Private Sub ResponseCallback(ByVal ar As IAsyncResult)

       2:     Dim request = CType(ar.AsyncState, HttpWebRequest)

       3:     Dim response = request.EndGetResponse(ar)

       4:  

       5:     Dim service = New ListsSoapClient With {.CookieContainer = _container}

       6:  

       7:     AddHandler service.GetListCollectionCompleted, AddressOf GetListCollectionCompleted

       8:  

       9:     service.GetListCollectionAsync(service)

      10: End Sub

      11:  

      12: Private Sub GetListCollectionCompleted(ByVal sender As Object, ByVal e As GetListCollectionCompletedEventArgs)

      13:     Dim result = e.Result.Descendants().Select(Function(x) x.Attribute("Title").Value).ToList()

      14:     Deployment.Current.Dispatcher.BeginInvoke(Sub() ListBox1.ItemsSource = result)

      15: End Sub

Step 4: Profit!

Now you should be good to go get data from your service!

C# Example:

       1: public MainPage()

       2: {

       3:     InitializeComponent();

       4:  

       5:  

       6:     var logonUrl = "https://mysite.com/CookieAuth.dll?Logon";

       7:     _container = new CookieContainer();

       8:  

       9:     var request = (HttpWebRequest) WebRequest.Create(logonUrl);

    request.CookieContainer = _container;

    request.Method = "POST";

 

    request.ContentType = "application/x-www-form-urlencoded";

 

    request.BeginGetRequestStream(RequestCallback, request);

}

 

private void RequestCallback(IAsyncResult ar)

{

    var postData = string.Format("curl=Z2F&flags=0&forcedownlevel=0&formdir=3&trusted=4&username={0}&password={1}&SubmitCreds=Log On", @"username", "password");

    

    var request = (HttpWebRequest) ar.AsyncState;

 

    var stream = request.EndGetRequestStream(ar);

 

    using(var sw = new StreamWriter(stream))

    {

        sw.Write(postData);

    }

 

    request.BeginGetResponse(ResponseCallback, request);

 

}

       1: private void ResponseCallback(IAsyncResult ar)

       2: {

       3:     var request = (HttpWebRequest) ar.AsyncState;

       4:     var response = request.EndGetResponse(ar);

       5:  

       6:     var service = new ListsSoapClient { CookieContainer = _container};

       7:  

       8:     service.GetListCollectionCompleted += GetListCollectionCompleted;

       9:  

      10:     service.GetListCollectionAsync(service);

      11: }

      12:  

      13: private void GetListCollectionCompleted(object sender, GetListCollectionCompletedEventArgs e)

      14: {

      15:     var result = e.Result.Descendants().Select(x => x.Attribute("Title").Value).ToList();

      16:     Deployment.Current.Dispatcher.BeginInvoke(() => listBox1.ItemsSource = result);

      17: }

Test Data Builder pattern with object initializers in .NET

Stacy Vicknair — Sun, 09 Oct 2011 18:59:08 GMT

Test Data Builder Pattern

When unit testing we often need to fill any POCO objects with enough data to satisfy the needs of the test. Redoing this in every test can quickly become a burden and slow down the testing process. Test Data Builder is a pattern that’s meant to help in just that situation.

With test data builder you build a fluent interface that allows you to build out your POCO objects by only replacing the properties that you need specific values for. The other values are set to defaults specified by the builder.

Here’s a classic example of test data builder:

Our POCO Object

        1: Public Class Person

       2:     Public Property FirstName As String

       3:     Public Property LastName As String

       4:     Public Property DateOfBirth As DateTime

       5: End Class

Our Test Data Builder Class

       1: Public Class PersonBuilder

       2:     'Set the defaults

       3:     Private _firstName As String = "Default"

       4:     Private _lastName As String = "Default"

       5:     Private _dateOfBirth As DateTime = New DateTime(1999, 12, 31)

       6:  

       7:     Public Function WithFirstName(ByVal firstName As String) As PersonBuilder

       8:         _firstName = firstName

       9:         Return Me

    End Function

  

    Public Function WithLastName(ByVal lastName As String) As PersonBuilder

        _lastName = lastName

        Return Me

    End Function

  

    Public Function WithDateOfBirth(ByVal dateOfBirth As DateTime) As PersonBuilder

        _dateOfBirth = dateOfBirth

        Return Me

    End Function

  

    Public Function Build() As Person

        Return New Person() With

            {

                .FirstName = _firstName,

                .LastName = _lastName,

                .DateOfBirth = _dateOfBirth

            }

    End Function

End Class

Usage example

       1: Dim person = New PersonBuilder() _

       2:     .WithFirstName("Stacy") _

       3:     .WithDateOfBirth(New DateTime(1984, 12, 6)) _

       4:     .Build()

Still a lot of work

Depending on how many objects you need to create builders for and how many properties each object has you can still be in for a lot of upfront work following the test data builder pattern to create that fluent experience.

Creating the builder pattern with object initializers

In .NET we have object initializers that can take much of this extra work out by providing an expressive method of setting the object properties. If possible, simply subclassing off of the POCO will prevent us from even needing to write out all of the properties, then we can set default values in the constructor.

Our Subclassed Test Data Builder

       1: Public Class PersonBuilderWithObjectInitializers

       2:     Inherits Person

       3:  

       4:     Public Sub New()

       5:         FirstName = "Default"

       6:         LastName = "Default"

       7:         DateOfBirth = New DateTime(1999, 12, 31)

       8:     End Sub

       9:  

      10:     Public Function Build() As Person

      11:         Return New Person() With

      12:             {

      13:                 .FirstName = FirstName,

      14:                 .LastName = LastName,

      15:                 .DateOfBirth = DateOfBirth

      16:             }

      17:     End Function

      18: End Class

The new builder’s usage

       1: Dim person = New PersonBuilderWithObjectInitializers() With

       2:         {

       3:             .FirstName = "Stacy",

       4:             .DateOfBirth = New DateTime(1984, 12, 6)

       5:         }.Build()

Why still have a build method?

Some of you might be asking, “Why keep the build method when polymorphism should do the work?” Well, good point. The reason I keep the build method is that when working against Entity Framework against POCO objects it will attempt to figure out the true type of the object, not just the type the object is cast as. As a result, it will complain when trying to persist the object. The build method in this case just acts as added assurance that if any type discovery is called against the object you will be safe knowing that the correct type will be discovered.

C# examples

Our POCO Object

       1: public class Person

       2: {

       3:     public string FirstName { get; set; }

       4:     public string LastName { get; set; }

       5:     public DateTime DateOfBirth { get; set; }

       6: }

Our Test Data Builder Class

       1: public class PersonBuilder

       2: {

       3:     // Set our defaults

       4:     private string _firstName = "Default";

       5:     private string _lastName = "Default";

       6:     private DateTime _dateOfBirth = new DateTime(1999, 12, 31);

       7:  

       8:     public PersonBuilder WithFirstName(string firstName)

       9:     {

        _firstName = firstName;

        return this;

    }

  

    public PersonBuilder WithLastName(string lastName)

    {

        _lastName = lastName;

        return this;

    }

  

    public PersonBuilder WithDateOfBirth(DateTime dateOfBirth)

    {

        _dateOfBirth = dateOfBirth;

        return this;

    }

  

    public Person Build()

    {

        return new Person

                   {

                       FirstName = _firstName,

                       LastName = _lastName,

                       DateOfBirth = _dateOfBirth

                   };

    }

}

Usage example

       1: //arrange

       2: var person = new PersonBuilder()

       3:     .WithFirstName("Stacy")

       4:     .WithDateOfBirth(new DateTime(1984, 12, 6))

       5:     .Build();

Our Subclassed Test Data Builder

       1: public class PersonBuilderWithObjectInitializers : Person

       2: {

       3:     public PersonBuilderWithObjectInitializers()

       4:     {

       5:         // Set our defaults

       6:         FirstName = "Default";

       7:         LastName = "Default";

       8:         DateOfBirth = new DateTime(1999, 12, 31);

       9:     }

      10:  

      11:     public Person Build()

      12:     {

      13:         return new Person

      14:             {

      15:                 FirstName = FirstName,

      16:                 LastName = LastName,

      17:                 DateOfBirth = DateOfBirth

      18:             };

      19:     }

      20: }

The new builder’s usage

       1: var person = new PersonBuilderWithObjectInitializers

       2:                 {

       3:                     FirstName = "Stacy",

       4:                     DateOfBirth = new DateTime(1984, 12, 6)

       5:                 }.Build();

.NET XPath Returns No Results

Stacy Vicknair — Fri, 11 Mar 2011 02:57:00 GMT

When using XPath in .NET one of the gotchas to be aware of is that all namespaces must be named, otherwise you’ll end up with no results. Default namespaces that are specified with xmlns alone still need to be recognized in the XPath query!

Say I had a bit of XML like what is returned from the QueryService web service in Sharepoint:

        1: <?xml version="1.0" encoding="UTF-8"?>

       2: <ResponsePacket xmlns="urn:Microsoft.Search.Response">

       3:   <Response>

       4:     <Range>

       5:       ...

       6:       <Results>

       7:         <Document xmlns="urn:Microsoft.Search.Response.Document" relevance="849">

       8:             ...

When consuming and navigating this response with XPath it is necessary to name all namespaces. Then those named namespaces must be used in reference to the individual element being requested (i.e. doc:Document).

In VB:

       1: Dim xdoc = new XPathDocument(reader)

       2: Dim nav = xdoc.CreateNavigator()

       3: Dim nsMgr = new XmlNamespaceManager(nav.NameTable)

       4: nsMgr.AddNamespace("resp", "urn:Microsoft.Search.Response")

       5: nsMgr.AddNamespace("doc", "urn:Microsoft.Search.Response.Document")

       6:  

       7: Dim results = nav.Select("//doc:Document", nsMgr)

In C#:

       1: var xdoc = new XPathDocument(reader);

       2: var nav = xdoc.CreateNavigator();

       3: var nsMgr = new XmlNamespaceManager(nav.NameTable);

       4:  

       5: nsMgr.AddNamespace("resp", "urn:Microsoft.Search.Response");

       6: nsMgr.AddNamespace("doc", "urn:Microsoft.Search.Response.Document");

       7:  

       8: var results = nav.Select("//doc:Document", nsMgr);

Increase your Visual Studio 2010 keyboard kung-fu! Shortcut charts are available for VB.NET, C#, F# and C++

Stacy Vicknair — Sat, 17 Apr 2010 01:28:34 GMT

Get them now!

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Automating SQL Server 2000 based database generation with OSQL in .NET

Stacy Vicknair — Fri, 14 Aug 2009 23:55:14 GMT

This week I had a need for NUnit based unit testing against a class that depended on a provided SqlConnection. Up to this point I had been able to mock external objects and their behavior based on interfaces, but with a SqlConnection I could not mock. There are some options for mocking the SqlConnection such as TypeMock, but I needed a realistic connection to test against. This also proved as a good method for building the expected DB interface.

The solution that worked best for my environment (only SQL Server 2000, all machines have OSQL) was to execute an OSQL process from my TestFixtureSetUp that executed a .sql script I had already made for building the database. So my TestFixtureSetUp looked like this:

<TestFixtureSetUp()> _
Sub FixtureSetUp()
    Dim p As Process = Process.Start("OSQL.exe", "-E -S SERVER -i ""../SQL SCRIPTS/setup.sql""")
    p.WaitForExit()
End Sub

The script itself was quick and assumed that the database and procedures existed already. It deleted all entries from the table and then added some dummy values. However, this method could be used to create the entire DB if needed, but does have the strong assumption that the computer using it has OSQL installed.

I won’t go into much detail about OSQL. OSQL is a tool that comes with SQL Server Tools that allows execution of sql batch scripts from the command-line. Its usage is explained well in the MSDN.

Technorati Tags: OSQL,database generation,NUnit,unit testing,sql server 2000

List of influential VB’ers on Twitter

Stacy Vicknair — Thu, 02 Jul 2009 04:04:45 GMT

Antonio Chagoury, VB MVP, has constructed a list of Twitter accounts for VB MVPs, VB Team members, and others who are influential in the VB.NET community on his personal blog, CTO v2.0. This list has many great people who are not only talented in VB, but also who have great talents in many aspects of the .NET framework.

I’m listed as a VB MVP, but if you don’t want the full list you can still check me out at http://twitter.com/svickn. However, I’d recommend checking out the rest of these guys too, you might find someone you would never have thought to follow that you mesh with. Besides, it’s never a bad thing when .NET help is just a tweet away ;)

http://www.cto20.com/post/Tweeps-List-Microsoft-Visual-Basic-MVPe28099s-and-Influencers.aspx

Technorati Tags: VB.NET,Twitter,.NET

How To: Create a plugin architecture in VB.NET

Stacy Vicknair — Thu, 07 May 2009 01:19:35 GMT

Creating a plugin architecture in .NET can be achieved in a few steps using the .NET framework. All it takes is a little time, a common interface and reflection. In this blog we’re going to look at how to make a simple plugin that performs basic integer calculations. As a disclaimer, this method is not CLS compliant. If that is necessary for you, then stick around and I hope to have a new version that maintains compliance posted.

The code in this blog is mostly illustrative, and the full code is available on CodePlex at the following link:

http://wtfnext.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=27051

Setting up a common interface

Our main console application has to know just basic things about our plugin. It doesn’t need to know any more about it than that it complies to an expected interface. For this example, our plugins must:

Expose a class named Plugin
The class must implement our common interface: IPlugin.
The plugin must end in “Plugin.dll” and be present in the application directory.

If we get all of these done, we can connect to the plugin successfully. The first step is to define the IPlugin interface, which acts as the basic contract between any plugin and the console application. We’ll place this in its own project to compile into a separate DLL, so that we can easily reference it from our plugin projects.

Public Interface IPlugin
    ReadOnly Property Name() As String
    ReadOnly Property ActionName() As String
    Sub Calculate(ByVal value1 As Integer, ByVal value2 As Integer)
End Interface

Consuming the interface according to our rules

So our calculation plugins will expose the name, what their action is and a calculate function that operates on two values. We can create an example plugin that performs addition:

Public Class Plugin
    Implements IPlugin

    ReadOnly Public Property Name() As String Implements IPlugin.Name
        Get
            Return "Addition"
        End Get
    End Property

    ReadOnly Public Property ActionName() As String Implements IPlugin.ActionName
        Get
            Return "Add Values"
        End Get
    End Property

    Public Sub Calculate (ByVal value1 As Integer, ByVal value2 As Integer) Implements IPlugin.Calculate
        Dim result As Integer = value1 + value2
        MessageBox.Show ("The result is " + result.ToString)
    End Sub
End Class

See how we named the class that implements the plugin as just Plugin? This is because this is what the consol application expects. We can have other classes and whatnot in our plugin that do the meat of our work, but the application that consumes the plugin only cares that the possible plugin follow our rules stated earlier.

Checking and consuming the plugin

In our console application, all we’ve got to do is grab our possible plugins, then check their validity. Once we’re sure it is valid, we can consume it via the interface.

Dim asm As Assembly = Assembly.LoadFrom(possiblePlugin)
Dim myType As System.Type = asm.GetType(asm.GetName.Name + ".Plugin")
Dim implementsIPlugin As Boolean = GetType(IPlugin).IsAssignableFrom(myType)
If implementsIPlugin Then
    Console.WriteLine(asm.GetName.Name + " is a valid plugin!")

    Dim plugin As IPlugin = CType(Activator.CreateInstance(myType), IPlugin)
    Console.WriteLine("{0}: {1}", plugin.Name, plugin.ActionName)
    plugin.Calculate(5, 4)
End If

Wrapping things up

Well, this was a quick and dirty look at implementing your own plugin architecture into your application. Please leave feedback or questions. I’d be happy to hear both!

Technorati Tags: VB.NET,Plugin,architecture

.NET Tip: Using String Constructors

Stacy Vicknair — Mon, 04 May 2009 21:31:37 GMT

When we use string so often for its value-like behavior, it is easy to forget that the String class comes with its own constructors, and that there are some tasks you can achieve with the string constructor that you might have overlooked otherwise.

Repeating characters

One of the more useful overrides of the String constructor is the ability to easily repeat any character a number of times. Here’s a brief example:

Dim horizontalRule As New String("-"c, 100)
Console.WriteLine(horizontalRule)

Subsections of Char arrays

If you’ve got a Char array you can grab a subsection by specifying a start point and a length:

Dim catchyPhrase As Char() = CType("Catch for us the foxes.", Char())
Dim phrasePart As New String(catchyPhrase, 0, 12)

Console.WriteLine(phrasePart)

Other pointer based operations

There are a few more useful constructors if you are developing in C# or C++ that make use of arrays, but because Visual Basic doesn’t allow for the use of unsafe types I won’t go over them. You can check out the remaining constructors on the MSDN at the link below.

There are many useful features in .NET that can be easily overlooked, but in the long run you might find something that would have otherwise saved you time.

http://msdn.microsoft.com/en-us/library/system.string.string.aspx

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How NUnit and TDD helped me today

Stacy Vicknair — Thu, 12 Mar 2009 04:26:14 GMT

My work environment is usually an anything goes, wild west of development sort of place. There are no rules imposed, just a “get things done” attitude. Because of auditing, source control was a necessity that got added to the mix. We use SVN through VisualSVN Server and TortoiseSVN as a client.

Well, as a part of self improvement and to produce better more reliable code, I’ve taken up learning TDD for myself. Our current methodology of testing here is based mostly on WTFs per minute and copious prayer. This time around, I’m trying super scoffable alternative: automated testing and continuous integration. Tests better than no tests? pshaw.

So, when trying to read resources on TDD, getting started always seemed difficult. I even tried the book TDD By Example to see if that would help, but it seemed sluggish to read along and try these minute tests that don’t apply to my real world applications. I started trying to integrate TDD in a small project for work instead.

As a result, I can say I’m experiencing the benefits of TDD already. When I refactor or write new code, I’m confident that I’m doing it for a reason. If the tests fail, I know what exactly is failing and can isolate it.

Today, while writing tests, I somehow created a never-ending loop in code (must’ve been evil code fairies I swear.) This gave me my first problem with my TDD experience: How do I debug code for a partially constructed application, when all I’ve got to go on is that I know it doesn’t work?

Well, here’s what I was able to do.

Added a new console app project to the solution called Testing.Debug
Extracted my unit test and put it as the sole code in the console app.
Added a break point where I knew my problem was happening.

I knew the where, but I couldn’t discern the what. After running the small testing app I found it quickly and fixed the problem.

So my question to those of you who do TDD often, how would you handle the situation? How do you handle situations that might call for a debugger?

Technorati Tags: TDD,NUnit,SVN,debugging

Head First Design Patterns – VB.NET code examples on CodePlex

Stacy Vicknair — Fri, 30 Jan 2009 22:24:09 GMT

For those of you looking to get started with design patterns but reluctant because of language barriers, I started a project on CodePlex for the Head First Design Patterns book. The original code examples are in Java, and they have been made available in C# and C++ as well, which are all available on the book’s online page, http://www.headfirstlabs.com/books/hfdp/.

Currently the project is only Chapters 1-8, but pending the big game on Sunday I will be finished up sometime next week. This is one of my first CodePlex contributions, so any helpful hints or suggestions would be much appreciated. Otherwise, go ahead and get the source and start looking into design patterns. I definitely recommend getting the book and definitely check out the entire Head First series!

Get the VB.NET code examples here:
http://www.codeplex.com/HFDPinVB/

Get more info on all the Head First books:
http://www.headfirstlabs.com/

Technorati Tags: VB.NET,Head First Design Patterns,Code Examples