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.

llSuccess = .F.

loRest = createobject("CkRest")
llBTls = .T.
llBAutoReconnect = .T.
llSuccess = loRest.Connect("example.com",443,llBTls,llBAutoReconnect)
if (llSuccess = .F.) then
    ? loRest.LastErrorText
    release loRest
    return
endif

llSuccess = loRest.SendReqNoBody("GET","/api/largefile")
if (llSuccess = .F.) then
    ? loRest.LastErrorText
    release loRest
    return
endif

lnStatusCode = loRest.ReadResponseHeader()
if (lnStatusCode < 0) then
    ? loRest.LastErrorText
    release loRest
    return
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 (lnStatusCode <> 200) then
    loSbError = createobject("CkStringBuilder")
    llSuccess = loRest.ReadRespSb(loSbError)
    if (llSuccess = .F.) then
        ? loRest.LastErrorText
        release loRest
        release loSbError
        return
    endif

    ? "Request failed with status code " + str(lnStatusCode)
    ? loSbError.GetAsString()
    release loRest
    release loSbError
    return
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.
loBdBody = createobject("CkBinData")
lnChunkResult = loRest.ReadRespChunkBd(8192,loBdBody)
do while lnChunkResult > 0
    lnChunkResult = loRest.ReadRespChunkBd(8192,loBdBody)
enddo
if (lnChunkResult < 0) then
    ? loRest.LastErrorText
    release loRest
    release loSbError
    release loBdBody
    return
endif

? "Received " + str(loBdBody.NumBytes) + " bytes."


release loRest
release loSbError
release loBdBody