Read the REST Response Body in Chunks

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Demonstrates Rest.ReadRespChunkBd, which reads the response body one chunk at a time, appending each chunk to a BinData. A return value of 0 signals the body is complete, while -1 indicates a read failure.

IncludeFile "CkBinData.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkRest.pb"

Procedure ChilkatExample()

    success.i = 0

    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    bTls.i = 1
    bAutoReconnect.i = 1
    success = CkRest::ckConnect(rest,"example.com",443,bTls,bAutoReconnect)
    If success = 0
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    success = CkRest::ckSendReqNoBody(rest,"GET","/api/largefile")
    If success = 0
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    statusCode.i = CkRest::ckReadResponseHeader(rest)
    If statusCode < 0
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ;  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 content.  In that case read
    ;  the body as text, report it, and return.
    If statusCode <> 200
        sbError.i = CkStringBuilder::ckCreate()
        If sbError.i = 0
            Debug "Failed to create object."
            ProcedureReturn
        EndIf

        success = CkRest::ckReadRespSb(rest,sbError)
        If success = 0
            Debug CkRest::ckLastErrorText(rest)
            CkRest::ckDispose(rest)
            CkStringBuilder::ckDispose(sbError)
            ProcedureReturn
        EndIf

        Debug "Request failed with status code " + Str(statusCode)
        Debug CkStringBuilder::ckGetAsString(sbError)
        CkRest::ckDispose(rest)
        CkStringBuilder::ckDispose(sbError)
        ProcedureReturn
    EndIf

    ;  The status code is 200.  Read the response body in chunks, appending each chunk to the BinData.
    ;  Each call waits until at least the requested number of bytes is available, unless the response
    ;  ends first.  A return value of 0 means the final bytes were returned and the body is complete;
    ;  -1 indicates a read failure.
    bdBody.i = CkBinData::ckCreate()
    If bdBody.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    chunkResult.i = CkRest::ckReadRespChunkBd(rest,8192,bdBody)
    While chunkResult > 0
        chunkResult = CkRest::ckReadRespChunkBd(rest,8192,bdBody)
    Wend
    If chunkResult < 0
        Debug CkRest::ckLastErrorText(rest)
        CkRest::ckDispose(rest)
        CkStringBuilder::ckDispose(sbError)
        CkBinData::ckDispose(bdBody)
        ProcedureReturn
    EndIf

    Debug "Received " + Str(CkBinData::ckNumBytes(bdBody)) + " bytes."


    CkRest::ckDispose(rest)
    CkStringBuilder::ckDispose(sbError)
    CkBinData::ckDispose(bdBody)


    ProcedureReturn
EndProcedure