C

REST Stream Response to File (Streaming Download) (Amazon S3)

See more Amazon S3 (new) Examples

Demonstrates how to stream the response body directly to a file. (The example shows how to stream a JPG from the Amazon S3 service.) C

#include <C_CkRest.h>
#include <C_CkAuthAws.h>
#include <C_CkStream.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkRest rest;
    BOOL bTls;
    int port;
    BOOL bAutoReconnect;
    HCkAuthAws authAws;
    int responseStatusCode;
    HCkStream bodyStream;
    const char *errResponse;

    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 Amazon AWS REST server.
    bTls = TRUE;
    port = 443;
    bAutoReconnect = TRUE;
    success = CkRest_Connect(rest,"s3.amazonaws.com",port,bTls,bAutoReconnect);

    // ----------------------------------------------------------------------------
    // Important: For buckets created in regions outside us-east-1,
    // there are three important changes that need to be made.
    // See Working with S3 Buckets in Non-us-east-1 Regions for the details.
    // ----------------------------------------------------------------------------

    // Provide AWS credentials for the REST call.
    authAws = CkAuthAws_Create();
    CkAuthAws_putAccessKey(authAws,"AWS_ACCESS_KEY");
    CkAuthAws_putSecretKey(authAws,"AWS_SECRET_KEY");
    CkAuthAws_putServiceName(authAws,"s3");
    success = CkRest_SetAuthAws(rest,authAws);

    // Set the bucket name via the HOST header.
    // In this case, the bucket name is "chilkat100".
    CkRest_putHost(rest,"chilkat100.s3.amazonaws.com");

    // Send the request to download the JPG.
    success = CkRest_SendReqNoBody(rest,"GET","/starfish.jpg");
    if (success != TRUE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkRest_Dispose(rest);
        CkAuthAws_Dispose(authAws);
        return;
    }

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

    printf("Response status code = %d\n",responseStatusCode);

    // We expect a 200 response status if the JPG data is coming.
    // Otherwise, we'll get a string response body with an error message(or no response body).
    if (responseStatusCode == 200) {

        bodyStream = CkStream_Create();

        // The stream's sink will be a file.
        CkStream_putSinkFile(bodyStream,"qa_output/starfish.jpg");

        // Read the response body to the stream.  Given that we've
        // set the stream's sink to a file, it will stream directly
        // to the file.
        success = CkRest_ReadRespBodyStream(rest,bodyStream,TRUE);
        if (success != TRUE) {
            printf("%s\n",CkRest_lastErrorText(rest));
            CkRest_Dispose(rest);
            CkAuthAws_Dispose(authAws);
            CkStream_Dispose(bodyStream);
            return;
        }

        printf("Successfully received the JPG file.\n");

    }
    else {
        errResponse = CkRest_readRespBodyString(rest);
        if (CkRest_getLastMethodSuccess(rest) != TRUE) {
            printf("%s\n",CkRest_lastErrorText(rest));
        }
        else {
            printf("%s\n",errResponse);
        }

    }



    CkRest_Dispose(rest);
    CkAuthAws_Dispose(authAws);
    CkStream_Dispose(bodyStream);

    }