雙向使用Webclient進行二進制

Question

Webclient用於向服務器上傳指令文件（高達1兆字節），並將該操作指令集作爲響應（最高1兆字節）接收爲二進制數據。

我能夠上傳二進制文件並下載二進制文件，但我無法使用相同的請求/響應命令執行此操作。意思是，不同的web客戶端可以做到這一點。在這種情況下，它會丟失對服務器上設置的流的引用。

如何編寫和在一個單一序列讀取二進制數據？

。

服務器腳本

Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest 

      'Setup data reader 
      If cRead Is Nothing Then cRead = New ReadDataFromContext 
      cRead.Read(context) 'read data from 'context.Request.InputStream' 


      If cWrite Is Nothing Then cWrite = New WriteDataToContext 
      cWrite.Write(context) 'write data to 'context.Response.OutputStream' 


     End Sub 

。

Client類

Partial Public Class MainPage 
    Inherits UserControl 
    Private WithEvents WCUpload As WebClient 
    'Private WithEvents WCDownload As WebClient 
    Private Stream As IO.Stream 

    Dim U As New Uri("http://localhost:51001/communicator.ashx", UriKind.Absolute) 


    Public Sub New() 
     InitializeComponent() 
     WCUpload = New WebClient 
     'WCDownload = New WebClient 

    End Sub 

    Private Sub btnTest_Click(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles btnTest.Click 
     WCUpload.OpenWriteAsync(U) 
    End Sub 


    'This methode is never called if using WCUpload (on WCDownload it works but WCDownload has no more data) 
    'Private Sub WC_OpenReadCompleted(sender As Object, e As System.Net.OpenReadCompletedEventArgs) Handles WCDownload.OpenReadCompleted 
    ' Dim D(e.Result.Length - 1) As Byte 
    ' e.Result.Read(D, 0, D.Length) 
    ' Me.btnTest.Content = System.Text.Encoding.UTF8.GetString(D, 0, D.Length) 
    'End Sub 

    Private Sub WC_OpenWriteCompleted(sender As Object, e As System.Net.OpenWriteCompletedEventArgs) Handles WCUpload.OpenWriteCompleted 
     Me.Stream = e.Result 

     Dim D() As Byte = System.Text.Encoding.UTF8.GetBytes("Hallo Timo") 
     Me.Stream.Write(D, 0, D.Length) 
     Me.Stream.Close() 
    End Sub 

    Private Sub WC_WriteStreamClosed(sender As Object, e As System.Net.WriteStreamClosedEventArgs) Handles WCUpload.WriteStreamClosed 
     'WC.OpenReadAsync(U) 

     'WCDownload.OpenReadAsync(U) 

     Me.Stream.Position = 0 '<<--- ERROR, cannot access to disposed object 
     Dim D(Me.Stream.Length - 1) As Byte 
     Me.Stream.Read(D, 0, D.Length) 
     Me.btnTest.Content = System.Text.Encoding.UTF8.GetString(D, 0, D.Length) 

    End Sub 

    Public Sub PushData(ByVal StreamIn As IO.Stream, ByVal StreamOut As IO.Stream) 
     Dim Buffer(4096 - 1) As Byte 
     Dim BytesRead As Integer 
     On Error Resume Next 

     'RaiseEvent Progress(Me, 0) 

     Do 
      BytesRead = StreamIn.Read(Buffer, 0, Buffer.Length) 
      If BytesRead <= 0 Then Exit Do 
      StreamOut.Write(Buffer, 0, BytesRead) 
      'RaiseEvent Progress(Me, StreamOut.Length/StreamIn.Length * 99) 'max 99 to raise the event with 100% 
     Loop 

     'RaiseEvent Progress(Me, 100) 
    End Sub 
End Class 

Answer 1

這聽起來像你對我只是尋找UploadData方法，其中發送byte[]請求體到服務器，並返回一個byte[]響應體到客戶端。簡單：

byte[] req = ...; 
byte[] resp; 
using(var client = new WebClient()) { 
    resp = client.UploadData(address, req); 
} 

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最終，HTTP是一個請求/響應協議 - 你可以順序地執行多個請求，雖然。如果你需要更多的靈活性，我建議你看看網絡套接字，它可以讓兩端發送臨時的。

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有關Silverlight的異步使用，儘量的HttpClient的PCL版本 - 類似的API，但更全面執行比Silverlight提供開箱即用：http://blogs.msdn.com/b/bclteam/archive/2013/02/18/portable-httpclient-for-net-framework-and-windows-phone.aspx