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.

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoRest
    Boolean iBTls
    Boolean iBAutoReconnect
    Integer iStatusCode
    Variant vSbError
    Handle hoSbError
    Variant vBdBody
    Handle hoBdBody
    Integer iChunkResult
    String sTemp1
    Integer iTemp1

    Move False To iSuccess

    Get Create (RefClass(cComChilkatRest)) To hoRest
    If (Not(IsComObjectCreated(hoRest))) Begin
        Send CreateComObject of hoRest
    End
    Move True To iBTls
    Move True To iBAutoReconnect
    Get ComConnect Of hoRest "example.com" 443 iBTls iBAutoReconnect To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComSendReqNoBody Of hoRest "GET" "/api/largefile" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComReadResponseHeader Of hoRest To iStatusCode
    If (iStatusCode < 0) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  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 (iStatusCode <> 200) Begin
        Get Create (RefClass(cComChilkatStringBuilder)) To hoSbError
        If (Not(IsComObjectCreated(hoSbError))) Begin
            Send CreateComObject of hoSbError
        End
        Get pvComObject of hoSbError to vSbError
        Get ComReadRespSb Of hoRest vSbError To iSuccess
        If (iSuccess = False) Begin
            Get ComLastErrorText Of hoRest To sTemp1
            Showln sTemp1
            Procedure_Return
        End

        Showln "Request failed with status code " iStatusCode
        Get ComGetAsString Of hoSbError To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  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.
    Get Create (RefClass(cComChilkatBinData)) To hoBdBody
    If (Not(IsComObjectCreated(hoBdBody))) Begin
        Send CreateComObject of hoBdBody
    End
    Get pvComObject of hoBdBody to vBdBody
    Get ComReadRespChunkBd Of hoRest 8192 vBdBody To iChunkResult
    While (iChunkResult > 0)
        Get pvComObject of hoBdBody to vBdBody
        Get ComReadRespChunkBd Of hoRest 8192 vBdBody To iChunkResult
    Loop

    If (iChunkResult < 0) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComNumBytes Of hoBdBody To iTemp1
    Showln "Received " iTemp1 " bytes."


End_Procedure