How do I communicate with an HTTPLISTENER that I have created?

**szlamany** · Dec 28th, 2011, 06:54 AM

I've got this code below that creates an HTTPLISTENER that is nicely waiting at listener.GetContext().

Code:

Imports System.Net
Imports System.Globalization

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim prefixes() As String = {"http://*:8080/HttpListener/"}

        ProcessRequests(prefixes)

    End Sub

    Private Sub ProcessRequests(ByVal prefixes() As String)
        If Not System.Net.HttpListener.IsSupported Then
            Console.WriteLine( _
                "Windows XP SP2, Server 2003, or higher is required to " & _
                "use the HttpListener class.")
            Exit Sub
        End If

        ' URI prefixes are required,
        If prefixes Is Nothing OrElse prefixes.Length = 0 Then
            Throw New ArgumentException("prefixes")
        End If

        ' Create a listener and add the prefixes.
        Dim listener As System.Net.HttpListener = _
            New System.Net.HttpListener()
        For Each s As String In prefixes
            listener.Prefixes.Add(s)
        Next

        Try
            ' Start the listener to begin listening for requests.
            listener.Start()
            Console.WriteLine("Listening...")

            ' Set the number of requests this application will handle.
            Dim numRequestsToBeHandled As Integer = 10

            For i As Integer = 0 To numRequestsToBeHandled
                Dim response As HttpListenerResponse = Nothing
                Try
                    ' Note: GetContext blocks while waiting for a request. 
                    Dim context As HttpListenerContext = listener.GetContext()

                    ' Create the response.
                    response = context.Response
                    Dim responseString As String = _
                        "<HTML><BODY>The time is currently " & _
                        DateTime.Now.ToString( _
                        DateTimeFormatInfo.CurrentInfo) & _
                        "</BODY></HTML>"
                    Dim buffer() As Byte = _
                        System.Text.Encoding.UTF8.GetBytes(responseString)
                    response.ContentLength64 = buffer.Length
                    Dim output As System.IO.Stream = response.OutputStream
                    output.Write(buffer, 0, buffer.Length)

                Catch ex As HttpListenerException
                    Console.WriteLine(ex.Message)
                Finally
                    If response IsNot Nothing Then
                        response.Close()
                    End If
                End Try
            Next
        Catch ex As HttpListenerException
            Console.WriteLine(ex.Message)
        Finally
            ' Stop listening for requests.
            listener.Close()
            Console.WriteLine("Done Listening...")
        End Try
    End Sub

End Class

How do I communicate with this from another VB app? I cannot seem to get WebRequest.Create to work with the URI that my HTTPLISTENER example is using.

This line of code from a second app is not working -

Code:

Dim prefixes() As String = {"http://*:8080/HttpListener/"}
Dim request As WebRequest = WebRequest.Create(prefixes(0))

**szlamany** · Dec 28th, 2011, 03:05 PM

I got it - had to change the */ to localhost/ - not sure what that is all about

What are the rules for URI naming and such???

At any rate - here is an attachment showing it running in VS and also FF

So cool - I can now talk to my running background services with a browser or another app!

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