(C) OneDrive -- Streaming REST Download to File

Downloads the contents of a DriveItem directly to a file in the local filesystem using the Chilkat REST class.

Note: This example requires Chilkat v9.5.0.69 or greater.

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#include <C_CkRest.h>
#include <C_CkOAuth2.h>
#include <C_CkBinData.h>
#include <C_CkUrl.h>
#include <C_CkStringBuilder.h>
#include <C_CkJsonObject.h>
#include <C_CkStream.h>

void ChilkatSample(void)
    {
    HCkRest rest;
    BOOL success;
    HCkOAuth2 oauth2;
    const char *uriPath;
    int statusCode;
    HCkBinData discard;
    HCkUrl redirectUrl;
    HCkStringBuilder sbJson;
    HCkJsonObject jsonErr;
    const char *localPath;
    HCkStream stream;

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

    rest = CkRest_Create();

    // Use your previously obtained access token here:
    // See the following examples for getting an access token:
    //    Get Microsoft Graph OAuth2 Access Token (Azure AD v2.0 Endpoint).
    //    Get Microsoft Graph OAuth2 Access Token (Azure AD Endpoint).
    //    Refresh Access Token (Azure AD v2.0 Endpoint).
    //    Refresh Access Token (Azure AD Endpoint).

    // First connect to graph.microsoft.com.  If there's a connectivity problem, we'll find out here.
    success = CkRest_Connect(rest,"graph.microsoft.com",443,TRUE,TRUE);
    if (success != TRUE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkRest_Dispose(rest);
        return;
    }

    // (Make sure your token was obtained with the FilesRead or Files.ReadWrite scope.)
    oauth2 = CkOAuth2_Create();
    CkOAuth2_putAccessToken(oauth2,"MICROSOFT_GRAPH_ACCESS_TOKEN");
    CkRest_SetAuthOAuth2(rest,oauth2);

    // Send the GET request to download the file.
    uriPath = "/v1.0/me/drive/root:/Misc/wildlife/penguins.jpg:/content";
    success = CkRest_SendReqNoBody(rest,"GET",uriPath);
    if (CkRest_getLastMethodSuccess(rest) != TRUE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkRest_Dispose(rest);
        CkOAuth2_Dispose(oauth2);
        return;
    }

    // NOTE: This way of doing the HTTP GET (i.e. download) may be more cumbersome, but it 
    // allows for finer control of handling errors.  The connection establishment, the sending of the
    // request, the reading of the response header, and the reading of the response body (i.e. the file data)
    // are handled by separate method calls.  If the response header indicates an error, we can read
    // the response body and treat it differently than if reading the file data.

    // Read the response header.
    statusCode = CkRest_ReadResponseHeader(rest);
    printf("Response Status Code = %d\n",statusCode);
    if (statusCode == 302) {
        // This is a redirect.  Read the response body, if any, and then follow the redirect.
        // Usually the response body will be empty for a redirect, but we need to be sure to read
        // the response body just in case it exists.
        discard = CkBinData_Create();
        CkRest_ReadRespBd(rest,discard);
        CkRest_Disconnect(rest,10);

        // For OneDrive, the redirect URL does not need authorization because the only way
        // to have obtained the direct download URL is from an authenticated request.
        // In fact, if we leave the authentication present, the GET request to the redirect URL will fail.

        // Note: The ClearAuth method is introduced in v9.5.0.69.
        CkRest_ClearAuth(rest);

        // Follow the redirect URL...
        redirectUrl = CkRest_RedirectUrl(rest);
        printf("Redirect Host: %s\n",CkUrl_host(redirectUrl));
        printf("Redirect URI Path: %s\n",CkUrl_pathWithQueryParams(redirectUrl));

        success = CkRest_Connect(rest,CkUrl_host(redirectUrl),CkUrl_getPort(redirectUrl),CkUrl_getSsl(redirectUrl),TRUE);
        if (success != TRUE) {
            printf("%s\n",CkRest_lastErrorText(rest));
            CkRest_Dispose(rest);
            CkOAuth2_Dispose(oauth2);
            CkBinData_Dispose(discard);
            return;
        }

        // Send the request..
        success = CkRest_SendReqNoBody(rest,"GET",CkUrl_path(redirectUrl));
        CkUrl_Dispose(redirectUrl);
        if (CkRest_getLastMethodSuccess(rest) != TRUE) {
            printf("%s\n",CkRest_lastErrorText(rest));
            CkRest_Dispose(rest);
            CkOAuth2_Dispose(oauth2);
            CkBinData_Dispose(discard);
            return;
        }

        statusCode = CkRest_ReadResponseHeader(rest);
        printf("%s\n",CkRest_lastErrorText(rest));
        printf("Redirect Response Status Code = %d\n",statusCode);

    }

    if (statusCode >= 300) {

        // Read the error response body.
        sbJson = CkStringBuilder_Create();
        success = CkRest_ReadRespSb(rest,sbJson);
        if (success != TRUE) {
            printf("%s\n",CkRest_lastErrorText(rest));
            CkRest_Dispose(rest);
            CkOAuth2_Dispose(oauth2);
            CkBinData_Dispose(discard);
            CkStringBuilder_Dispose(sbJson);
            return;
        }

        jsonErr = CkJsonObject_Create();
        CkJsonObject_putEmitCompact(jsonErr,FALSE);
        CkJsonObject_LoadSb(jsonErr,sbJson);
        printf("%s\n",CkJsonObject_emit(jsonErr));

        CkRest_Dispose(rest);
        CkOAuth2_Dispose(oauth2);
        CkBinData_Dispose(discard);
        CkStringBuilder_Dispose(sbJson);
        CkJsonObject_Dispose(jsonErr);
        return;
    }

    // Stream the response body directly to a local file.
    localPath = "qa_output/penguins.jpg";

    stream = CkStream_Create();
    CkStream_putSinkFile(stream,localPath);

    success = CkRest_ReadRespBodyStream(rest,stream,TRUE);
    if (success != TRUE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkRest_Dispose(rest);
        CkOAuth2_Dispose(oauth2);
        CkBinData_Dispose(discard);
        CkStringBuilder_Dispose(sbJson);
        CkJsonObject_Dispose(jsonErr);
        CkStream_Dispose(stream);
        return;
    }

    printf("Successfully streamed a OneDrive file to the local filesystem.\n");


    CkRest_Dispose(rest);
    CkOAuth2_Dispose(oauth2);
    CkBinData_Dispose(discard);
    CkStringBuilder_Dispose(sbJson);
    CkJsonObject_Dispose(jsonErr);
    CkStream_Dispose(stream);

    }