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.

C++

#include <CkRest.h>
#include <CkFileAccess.h>
#include <CkBinData.h>

void ChilkatSample(void)
    {
    bool success = false;

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

    CkRest rest;

    // Connect to the web server
    bool bTls = true;
    int port = 443;
    bool bAutoReconnect = true;
    success = rest.Connect("chilkatsoft.com",port,bTls,bAutoReconnect);
    if (success == false) {
        std::cout << rest.lastErrorText() << "\r\n";
        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 = rest.SendReqNoBody("GET","/hamlet.xml");
    if (success == false) {
        std::cout << rest.lastErrorText() << "\r\n";
        return;
    }

    // Get the response header.
    int statusCode = rest.ReadResponseHeader();
    if (statusCode < 0) {
        std::cout << rest.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "response status code = " << statusCode << "\r\n";

    const char *outputFile = "c:/temp/qa_output/hamlet.xml";

    CkFileAccess fac;
    success = fac.OpenForWrite(outputFile);
    if (statusCode < 0) {
        std::cout << fac.lastErrorText() << "\r\n";
        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.)
    CkBinData bd;
    int 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 = rest.ReadRespChunkBd(16000,bd);
        if (status >= 0) {
            std::cout << "Received chunk: " << bd.get_NumBytes() << " bytes" << "\r\n";
            fac.FileWriteBd(bd,0,0);
            bd.Clear();
        }

    }

    fac.FileClose();

    std::cout << "Success." << "\r\n";
    }