Unicode C

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.

Unicode C

#include <C_CkRestW.h>
#include <C_CkFileAccessW.h>
#include <C_CkBinDataW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkRestW rest;
    BOOL bTls;
    int port;
    BOOL bAutoReconnect;
    int statusCode;
    const wchar_t *outputFile;
    HCkFileAccessW fac;
    HCkBinDataW bd;
    int status;

    success = FALSE;

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

    rest = CkRestW_Create();

    // Connect to the web server
    bTls = TRUE;
    port = 443;
    bAutoReconnect = TRUE;
    success = CkRestW_Connect(rest,L"chilkatsoft.com",port,bTls,bAutoReconnect);
    if (success == FALSE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkRestW_Dispose(rest);
        return;
    }

    // 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.

    success = CkRestW_SendReqNoBody(rest,L"GET",L"/hamlet.xml");
    if (success == FALSE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkRestW_Dispose(rest);
        return;
    }

    // Get the response header.
    statusCode = CkRestW_ReadResponseHeader(rest);
    if (statusCode < 0) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkRestW_Dispose(rest);
        return;
    }

    wprintf(L"response status code = %d\n",statusCode);

    outputFile = L"c:/temp/qa_output/hamlet.xml";

    fac = CkFileAccessW_Create();
    success = CkFileAccessW_OpenForWrite(fac,outputFile);
    if (statusCode < 0) {
        wprintf(L"%s\n",CkFileAccessW_lastErrorText(fac));
        CkRestW_Dispose(rest);
        CkFileAccessW_Dispose(fac);
        return;
    }

    // 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.)
    bd = CkBinDataW_Create();
    status = 1;
    while (status == 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.
        status = CkRestW_ReadRespChunkBd(rest,16000,bd);
        if (status >= 0) {
            wprintf(L"Received chunk: %d bytes\n",CkBinDataW_getNumBytes(bd));
            CkFileAccessW_FileWriteBd(fac,bd,0,0);
            CkBinDataW_Clear(bd);
        }

    }

    CkFileAccessW_FileClose(fac);

    wprintf(L"Success.\n");


    CkRestW_Dispose(rest);
    CkFileAccessW_Dispose(fac);
    CkBinDataW_Dispose(bd);

    }