B4X

HTTP POST and Stream Response to File

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Demonstrates how to send an HTTP POST and stream the response body directly to a file. B4X

Dim success As Boolean = False

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

Dim rest As ChilkatRest
rest.Initialize("rest")

Dim url As ChilkatUrl
url.Initialize
'  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
success = rest.Connect(url.Host, url.Port, url.Ssl, bAutoReconnect)
If success <> True Then
    Log(rest.LastErrorText)
    Return
End If


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

'   Send the HTTP POST.
success = rest.SendReqFormUrlEncoded("POST", url.Path)
If success <> True Then
    Log(rest.LastErrorText)
    Return
End If


'  Read the response header.
Dim responseStatusCode As Int = rest.ReadResponseHeader
If responseStatusCode < 0 Then
    Log(rest.LastErrorText)
    Return
End If


Log("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 ChilkatStream
    bodyStream.Initialize("bodyStream")

    '  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
        Log(rest.LastErrorText)
        Return
    End If


    Log("Successfully streamed the response to a file.")

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

End If