Visual FoxPro

REST Receive Response in Chunks

See more REST Examples

Demonstrates how to receive a REST HTTP response in chunks.

Note: This example requires Chilkat 10.1.0 or greater.

Visual FoxPro

LOCAL lnSuccess
LOCAL loRest
LOCAL lnBTls
LOCAL lnPort
LOCAL lnBAutoReconnect
LOCAL lnStatusCode
LOCAL lcOutputFile
LOCAL loFac
LOCAL loBd
LOCAL lnStatus

lnSuccess = 0

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

loRest = CreateObject('Chilkat.Rest')

* Connect to the web server
lnBTls = 1
lnPort = 443
lnBAutoReconnect = 1
lnSuccess = loRest.Connect("chilkatsoft.com",lnPort,lnBTls,lnBAutoReconnect)
IF (lnSuccess = 0) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    CANCEL
ENDIF

* Send the request.
* This can be *any* kind of request: POST, GET, PUT, etc. using *any* of the Chilkat REST methods that send requests.
* For this example, we'll just GET a simple XML document that is about 274K in size.

lnSuccess = loRest.SendReqNoBody("GET","/hamlet.xml")
IF (lnSuccess = 0) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    CANCEL
ENDIF

* Get the response header.
lnStatusCode = loRest.ReadResponseHeader()
IF (lnStatusCode < 0) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    CANCEL
ENDIF

? "response status code = " + STR(lnStatusCode)

lcOutputFile = "c:/temp/qa_output/hamlet.xml"

loFac = CreateObject('Chilkat.FileAccess')
lnSuccess = loFac.OpenForWrite(lcOutputFile)
IF (lnStatusCode < 0) THEN
    ? loFac.LastErrorText
    RELEASE loRest
    RELEASE loFac
    CANCEL
ENDIF

* Get the response in chunks.
* (Note: There are more efficient ways to simply download a file from a web server, such as by calling Chilkat's Http.Download method.
* The purpose of this method is to show how to receive a response chunk-by-chunk.)
loBd = CreateObject('Chilkat.BinData')
lnStatus = 1
DO WHILE lnStatus = 1
    * Read a minimum of 16000 bytes.
    * Note: Because of TLS message lengths, or the possibility of the response being either compressed (gzip/deflate) or in the HTTP chunked encoding,
    * the amount of data received in each call can be greater than the specified min size.
    * Chilkat will return from the call as soon as it has received an amount equal to or more than the specified size,
    * except for the very last chunk, which can be less that the min size or even 0 bytes.

    * The status will be one of three values:
    * -1 = error
    * 0 = received the last chunk of the response.
    * 1 = received a chunk, and more chunks are coming..

    * The received data is *appended* to the contents of the BinData object.
    lnStatus = loRest.ReadRespChunkBd(16000,loBd)
    IF (lnStatus >= 0) THEN
        ? "Received chunk: " + STR(loBd.NumBytes) + " bytes"
        loFac.FileWriteBd(loBd,0,0)
        loBd.Clear()
    ENDIF

ENDDO

loFac.FileClose()

? "Success."

RELEASE loRest
RELEASE loFac
RELEASE loBd