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 <C_CkRest.h>
#include <C_CkFileAccess.h>
#include <C_CkBinData.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkRest rest;
    BOOL bTls;
    int port;
    BOOL bAutoReconnect;
    int statusCode;
    const char *outputFile;
    HCkFileAccess fac;
    HCkBinData bd;
    int status;

    success = FALSE;

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

    rest = CkRest_Create();

    // Connect to the web server
    bTls = TRUE;
    port = 443;
    bAutoReconnect = TRUE;
    success = CkRest_Connect(rest,"chilkatsoft.com",port,bTls,bAutoReconnect);
    if (success == FALSE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkRest_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 = CkRest_SendReqNoBody(rest,"GET","/hamlet.xml");
    if (success == FALSE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkRest_Dispose(rest);
        return;
    }

    // Get the response header.
    statusCode = CkRest_ReadResponseHeader(rest);
    if (statusCode < 0) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkRest_Dispose(rest);
        return;
    }

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

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

    fac = CkFileAccess_Create();
    success = CkFileAccess_OpenForWrite(fac,outputFile);
    if (statusCode < 0) {
        printf("%s\n",CkFileAccess_lastErrorText(fac));
        CkRest_Dispose(rest);
        CkFileAccess_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 = CkBinData_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 = CkRest_ReadRespChunkBd(rest,16000,bd);
        if (status >= 0) {
            printf("Received chunk: %d bytes\n",CkBinData_getNumBytes(bd));
            CkFileAccess_FileWriteBd(fac,bd,0,0);
            CkBinData_Clear(bd);
        }

    }

    CkFileAccess_FileClose(fac);

    printf("Success.\n");


    CkRest_Dispose(rest);
    CkFileAccess_Dispose(fac);
    CkBinData_Dispose(bd);

    }