Twitter Trace Listener

Thanks to the Yedda Twitter C# Library I was able to port a subset of the code to create a TwitterTraceListener.

 

VB.NET Source Code:

 

Option Explicit On

Option Strict On

Option Infer On

 

Imports System.Net

 

Public Class TwitterTraceListener

    Inherits TraceListener

 

    Protected Overrides Function GetSupportedAttributes() As String()

        Return New String() {"username", "password"}

    End Function

 

    <Flags()> Private Enum ActionType

        friends = 1

        update = 2

    End Enum

 

    <Flags()> Private Enum ObjectType

        account = 1

        statuses = 2

        users = 4

    End Enum

 

    <Flags()> Private Enum FormatType

        atom = 1

        json = 2

        rss = 4

        xml = 8

    End Enum

 

    Private m_NetworkCredential As System.Net.NetworkCredential = Nothing

    Private ReadOnly Property NetworkCredential() As System.Net.NetworkCredential

        Get

            If IsNothing(m_NetworkCredential) Then

                m_NetworkCredential = New System.Net.NetworkCredential

                m_NetworkCredential.UserName = Me.Attributes("username")

                m_NetworkCredential.Password = Me.Attributes("password")

            End If

            Return m_NetworkCredential

        End Get

    End Property

 

    Private Shared Function TwitterURL(ByVal piObjectType As ObjectType, ByVal piActionType As ActionType, ByVal piFormatType As FormatType) As String

        Return String.Format("http://twitter.com/{0}/{1}.{2}", piObjectType, piActionType, piFormatType)

    End Function

 

    ' Eliminates the need for System.Web

    Private Shared Function UrlEncode(ByVal piValue As String) As String

        ' return System.Web.HttpUtility.UrlEncode(piValue)

        Dim lvResult As New System.Text.StringBuilder

        For Each lvChar In piValue

            If Char.IsLetterOrDigit(lvChar) Then

                lvResult.Append(lvChar)

            Else

                lvResult.AppendFormat("%{0:X02}", AscW(lvChar))

            End If

        Next

        Return lvResult.ToString

    End Function

 

    Private Shared Function TwitterStatus(ByVal piStatus As String) As String

        Return String.Format("status={0}", UrlEncode(piStatus))

    End Function

 

    Private Function ExecutePostCommand(ByVal piURL As String, ByVal piData As String) As String

#If DEBUG Then

        Dim lvResult = String.Format("piURL={0}, piData={1}", piURL, piData)

        MsgBox(lvResult)

        Return lvResult

#Else

        System.Net.ServicePointManager.Expect100Continue = False

        Dim lvRequest = WebRequest.Create(piURL)

        lvRequest.Credentials = NetworkCredential

        lvRequest.ContentType = "application/x-www-form-urlencoded"

        lvRequest.Method = "POST"

        Dim lvBytes = System.Text.Encoding.UTF8.GetBytes(piData)

        lvRequest.ContentLength = lvBytes.Length

        Using lvRequestStream = lvRequest.GetRequestStream

            lvRequestStream.Write(lvBytes, 0, lvBytes.Length)

            Using lvResponse = lvRequest.GetResponse

                Using lvResponseStream = lvResponse.GetResponseStream

                    Using lvReader As New System.IO.StreamReader(lvResponseStream)

                        Return lvReader.ReadToEnd

                    End Using

                End Using

            End Using

        End Using

#End If

    End Function

 

    Private Sub Update(ByVal piStatus As String)

        Dim lvURL = TwitterURL(ObjectType.statuses, ActionType.update, FormatType.xml)

        Dim lvData = TwitterStatus(piStatus)

        Dim lvResult = ExecutePostCommand(lvURL, lvData)

    End Sub

 

    Private m_Message As New System.Text.StringBuilder

    Public Overrides Sub Write(ByVal message As String)

        Me.m_Message.Append(message)

    End Sub

 

    Public Overrides Sub WriteLine(ByVal message As String)

        Me.m_Message.AppendLine(message)

    End Sub

 

    Public Overrides Sub Flush()

        Dim lvLength = Math.Min(160, Me.m_Message.Length)

        If (0 = lvLength) Then Return

        Dim lvStatus = Me.m_Message.ToString(0, lvLength)

        Me.m_Message.Length = 0

        Dim lvWorker = New System.ComponentModel.BackgroundWorker()

        AddHandler lvWorker.DoWork, AddressOf DoWorkHandler

        lvWorker.RunWorkerAsync(lvStatus)

    End Sub

 

    Private Sub DoWorkHandler(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs)

        Dim lvStatus = CStr(e.Argument)

        Update(lvStatus)

    End Sub

 

End Class

 

Sample app.config file:

 

 

<configuration>

  <system.diagnostics>

    <sources>

      <source name="DefaultSource" switchName="DefaultSwitch">

        <listeners>

          <add name="CriticalTwitterTraceListener"/>

        </listeners>

      </source>

    </sources>

    <switches>

      <add name="DefaultSwitch" value="All"/>

    </switches>

    <sharedListeners>

      <add name="CriticalTwitterTraceListener"

               type="YourNamespace.TwitterTraceListener, YourNamespace, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"

               username="username"

               password="password">

        <filter type="System.Diagnostics.EventTypeFilter" initializeData="Critical"/>

      </add>

    </sharedListeners>

  </system.diagnostics>

</configuration>