B4X

Read the REST Response Body into a Stream

Demonstrates Rest.ReadRespBodyStream, which reads the response body into a Stream. The optional flag sets the stream character set from the response Content-Type charset for textual responses.

The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background. The staged request model separates sending from reading: a SendReq method transmits the request, ReadResponseHeader reads the status line and headers, and a ReadResp method reads the body. This gives fine control over large or streamed messages compared with the single-call full-request methods.

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Dim success As Boolean = False

Dim rest As ChilkatRest
rest.Initialize("rest")
Dim bTls As Boolean = True
Dim bAutoReconnect As Boolean = True
success = rest.Connect("example.com", 443, bTls, bAutoReconnect)
If success = False Then
    Log(rest.LastErrorText)
    Return
End If


'  The file paths are relative to the application's current working directory.  Absolute paths
'  may also be used.  Supply the paths appropriate to your own environment.

success = rest.SendReqNoBody("GET", "/api/images/1")
If success = False Then
    Log(rest.LastErrorText)
    Return
End If


Dim statusCode As Int = rest.ReadResponseHeader
If statusCode < 0 Then
    Log(rest.LastErrorText)
    Return
End If


'  Check for the expected success status code.  If the response is not 200, the body is likely
'  error text formatted as JSON, XML, or HTML rather than the expected binary content.  In that case
'  read the body as text, report it, and return.
If statusCode <> 200 Then
    Dim sbError As ChilkatStringBuilder
    sbError.Initialize
    success = rest.ReadRespSb(sbError)
    If success = False Then
        Log(rest.LastErrorText)
        Return
    End If

    Log("Request failed with status code " & statusCode)
    Log(sbError.GetAsString)
    Return
End If


'  The status code is 200.  Read the response body into a Stream.  Here the stream's sink is a local
'  file, which is appropriate for large or binary responses.
Dim respStream As ChilkatStream
respStream.Initialize("respStream")
respStream.SinkFile = "qa_output/image.png"

'  If the 2nd argument is True and the response is textual, the stream's character set is set from
'  the response Content-Type charset.  It has no effect for binary responses.
Dim bAutoSetCharset As Boolean = True
success = rest.ReadRespBodyStream(respStream, bAutoSetCharset)
If success = False Then
    Log(rest.LastErrorText)
    Return
End If

Log("Response body written to the stream sink.")