(VB.NET) HTTP POST and Stream Response to File

Demonstrates how to send an HTTP POST and stream the response body directly to a file.

Chilkat .NET Downloads Chilkat .NET Framework Chilkat for .NET Core

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim rest As New Chilkat.Rest

Dim url As New Chilkat.Url
' This URL will emit a response that echos the query params (name and age)
url.ParseUrl("https://www.chilkatsoft.com/readPost.asp")

' Connect to the web server
Dim bAutoReconnect As Boolean = True
Dim success As Boolean = rest.Connect(url.Host,url.Port,url.Ssl,bAutoReconnect)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


rest.AddQueryParam("name","John")
rest.AddQueryParam("age","33")

'  Send the HTTP POST.
success = rest.SendReqFormUrlEncoded("POST",url.Path)
If (success <> True) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


' Read the response header.
Dim responseStatusCode As Integer = rest.ReadResponseHeader()
If (responseStatusCode < 0) Then
    Debug.WriteLine(rest.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Response status code = " & responseStatusCode)

' We expect a 200 response status if the file data is coming.
' Otherwise, we'll get a string response body with an error message(or no response body).
If (responseStatusCode = 200) Then

    Dim bodyStream As New Chilkat.Stream

    ' The stream's sink will be a file.
    bodyStream.SinkFile = "qa_output/out.txt"

    ' Read the response body to the stream.  Given that we've
    ' set the stream's sink to a file, it will stream directly
    ' to the file.
    success = rest.ReadRespBodyStream(bodyStream,True)
    If (success <> True) Then
        Debug.WriteLine(rest.LastErrorText)
        Exit Sub
    End If


    Debug.WriteLine("Successfully streamed the response to a file.")

Else
    Dim errResponse As String = rest.ReadRespBodyString()
    If (rest.LastMethodSuccess <> True) Then
        Debug.WriteLine(rest.LastErrorText)
    Else
        Debug.WriteLine(errResponse)
    End If

End If