(Unicode C) REST Download Bandwidth Throttle

Demonstrates how to use download bandwidth throttling with the REST API. This example will download a file from Drobox using a file stream, with a limit on the bandwidth that can be used for the transfer.

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#include <C_CkSocketW.h>
#include <C_CkRestW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkStreamW.h>
#include <C_CkDateTimeW.h>
#include <C_CkDtObjW.h>

void ChilkatSample(void)
    {
    HCkSocketW socket;
    int maxWaitMs;
    BOOL success;
    HCkRestW rest;
    HCkJsonObjectW json;
    HCkStreamW fileStream;
    int expectedStatus;
    const wchar_t *responseStr;
    const wchar_t *apiResult;
    HCkJsonObjectW jsonResult;
    int size;
    const wchar_t *rev;
    const wchar_t *clientModified;
    HCkDateTimeW ckdt;
    BOOL bLocalTime;
    HCkDtObjW dt;

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

    // A Dropbox access token should have been previously obtained.
    // Dropbox access tokens do not expire.
    // See Dropbox Access Token.

    // To use bandwidth throttling, the connection should be made using the socket API.
    // This provides numerous properties to customize the connection, such as
    // BandwidthThrottleDown, BandwidthThrottleUp, ClientIpAddress, ClintPort, Http Proxy,
    // KeepAlive, PreferIpv6, RequireSslCertVerify, SoRcvBuf, SoSndBuf, SoReuseAddr,
    // SOCKS proxy, TcpNoSDelay, TlsPinSet, TlsCipherSuite, SslAllowedCiphers, etc.

    socket = CkSocketW_Create();
    maxWaitMs = 5000;
    success = CkSocketW_Connect(socket,L"content.dropboxapi.com",443,TRUE,maxWaitMs);
    if (success != TRUE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(socket));
        wprintf(L"Connect Fail Reason: %d\n",CkSocketW_getConnectFailReason(socket));
        CkSocketW_Dispose(socket);
        return;
    }

    // Set the download bandwidth throttle rate to 50000 bytes per second.
    CkSocketW_putBandwidthThrottleDown(socket,50000);

    rest = CkRestW_Create();

    // Tell the REST object to use the connected socket.
    CkRestW_UseConnection(rest,socket,TRUE);

    // The remainder of this example is identical to the example at:
    // Dropbox Download File.

    // Add request headers.
    CkRestW_AddHeader(rest,L"Authorization",L"Bearer DROPBOX_ACCESS_TOKEN");

    // The download "parameters" are contained in JSON passed in an HTTP request header.
    // This is the JSON indicating the file to be downloaded:
    // { 
    //    "path": "/Homework/lit/hamlet.xml",
    // }

    json = CkJsonObjectW_Create();
    CkJsonObjectW_AppendString(json,L"path",L"/Homework/lit/hamlet.xml");
    CkRestW_AddHeader(rest,L"Dropbox-API-Arg",CkJsonObjectW_emit(json));

    // Setup a file stream for the download
    fileStream = CkStreamW_Create();
    CkStreamW_putSinkFile(fileStream,L"qa_output/hamletFromDropbox.xml");

    // Indicate that the call to FullRequestNoBody should send the response body
    // to fileStream if the response status code is 200.
    // If a non-success response status code is received, then nothing
    // is streamed to the output file and the error response is returned by FullRequestNoBody.
    expectedStatus = 200;
    CkRestW_SetResponseBodyStream(rest,expectedStatus,TRUE,fileStream);

    responseStr = CkRestW_fullRequestNoBody(rest,L"POST",L"/2/files/download");
    if (CkRestW_getLastMethodSuccess(rest) != TRUE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkSocketW_Dispose(socket);
        CkRestW_Dispose(rest);
        CkJsonObjectW_Dispose(json);
        CkStreamW_Dispose(fileStream);
        return;
    }

    // When successful, Dropbox responds with a 200 response code.
    if (CkRestW_getResponseStatusCode(rest) != 200) {
        // Examine the request/response to see what happened.
        wprintf(L"response status code = %d\n",CkRestW_getResponseStatusCode(rest));
        wprintf(L"response status text = %s\n",CkRestW_responseStatusText(rest));
        wprintf(L"response header: %s\n",CkRestW_responseHeader(rest));
        wprintf(L"response body (if any): %s\n",responseStr);
        wprintf(L"---\n");
        wprintf(L"LastRequestStartLine: %s\n",CkRestW_lastRequestStartLine(rest));
        wprintf(L"LastRequestHeader: %s\n",CkRestW_lastRequestHeader(rest));
        CkSocketW_Dispose(socket);
        CkRestW_Dispose(rest);
        CkJsonObjectW_Dispose(json);
        CkStreamW_Dispose(fileStream);
        return;
    }

    // Information about the downloaded file is also available as JSON in a response header.
    // The "dropbox-api-result" response header contains the information.  For example:
    apiResult = CkRestW_responseHdrByName(rest,L"dropbox-api-result");
    wprintf(L"%s\n",apiResult);

    // In this case, the pretty-formatted dropbox-api-result JSON looks like this:
    // { 
    //   "name": "hamlet.xml",
    //   "path_lower": "/homework/lit/hamlet.xml",
    //   "path_display": "/Homework/lit/hamlet.xml",
    //   "id": "id:74FkdeNuyKAAAAAAAAAAAQ",
    //   "client_modified": "2016-06-02T23:19:00Z",
    //   "server_modified": "2016-06-02T23:19:00Z",
    //   "rev": "9482db15f",
    //   "size": 279658
    // }

    // Load the JSON, pretty-print it, and demonstrate how to get some values...
    jsonResult = CkJsonObjectW_Create();
    CkJsonObjectW_putEmitCompact(jsonResult,FALSE);
    CkJsonObjectW_Load(jsonResult,apiResult);
    // Show the JSON pretty-printed...
    wprintf(L"%s\n",CkJsonObjectW_emit(jsonResult));

    // Sample code to get data from the JSON response:
    size = CkJsonObjectW_IntOf(jsonResult,L"size");
    wprintf(L"size = %d\n",size);

    rev = CkJsonObjectW_stringOf(jsonResult,L"rev");
    wprintf(L"rev = %s\n",rev);

    clientModified = CkJsonObjectW_stringOf(jsonResult,L"client_modified");
    ckdt = CkDateTimeW_Create();
    CkDateTimeW_SetFromTimestamp(ckdt,clientModified);
    bLocalTime = TRUE;
    dt = CkDateTimeW_GetDtObj(ckdt,bLocalTime);
    wprintf(L"%d/%d/%d %d:%d\n",CkDtObjW_getDay(dt),CkDtObjW_getMonth(dt),CkDtObjW_getYear(dt),CkDtObjW_getHour(dt),CkDtObjW_getMinute(dt));
    CkDtObjW_Dispose(dt);


    CkSocketW_Dispose(socket);
    CkRestW_Dispose(rest);
    CkJsonObjectW_Dispose(json);
    CkStreamW_Dispose(fileStream);
    CkJsonObjectW_Dispose(jsonResult);
    CkDateTimeW_Dispose(ckdt);

    }