(Unicode C++) Dropbox: OAuth2 Authorization to Obtain an Access Token

Demonstrates how to get a Dropbox OAuth2 access token from a desktop application or script.

This example runs the OAuth 2.0 authorization flow that lets the user sign in to Dropbox and authorize your app.

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#include <CkOAuth2W.h>
#include <CkJsonObjectW.h>

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

    // Note: This example requires Chilkat v9.5.0.66 or greater to work properly.

    CkOAuth2W oauth2;
    bool success;

    // The port should match the Authorized Redirect URL in your Dropbox app, 
    // which would look like "http://localhost:3017/"
    oauth2.put_ListenPort(3017);

    // IMPORTANT: One of the OAuth2 redirect URIs for your Dropbox app must be
    // exactly this string:  http://localhost:3017/

    oauth2.put_AuthorizationEndpoint(L"https://www.dropbox.com/oauth2/authorize");
    oauth2.put_TokenEndpoint(L"https://api.dropboxapi.com/oauth2/token");

    // Replace these with actual values.
    oauth2.put_ClientId(L"DROPBOX_APP_KEY");
    oauth2.put_ClientSecret(L"DROPBOX_APP_SECRET");
    oauth2.put_CodeChallenge(false);

    // Add token_access_type=offline to also get a refresh token in the response
    oauth2.AddAuthQueryParam(L"token_access_type",L"offline");

    // Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
    const wchar_t *url = oauth2.startAuth();
    if (oauth2.get_LastMethodSuccess() != true) {
        wprintf(L"%s\n",oauth2.lastErrorText());
        return;
    }

    // At this point, your application should load the URL in a browser.
    // For example, 
    // in C#: System.Diagnostics.Process.Start(url);
    // in Java: Desktop.getDesktop().browse(new URI(url));
    // in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
    //              wsh.Run url
    // in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
    // in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
    // The Microsoft account owner would interactively accept or deny the authorization request.

    // Add the code to load the url in a web browser here...
    // Add the code to load the url in a web browser here...
    // Add the code to load the url in a web browser here...

    // Now wait for the authorization.
    // We'll wait for a max of 30 seconds.
    int numMsWaited = 0;
    while ((numMsWaited < 30000) && (oauth2.get_AuthFlowState() < 3)) {
        oauth2.SleepMs(100);
        numMsWaited = numMsWaited + 100;
    }

    // If there was no response from the browser within 30 seconds, then 
    // the AuthFlowState will be equal to 1 or 2.
    // 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
    // 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
    // In that case, cancel the background task started in the call to StartAuth.
    if (oauth2.get_AuthFlowState() < 3) {
        oauth2.Cancel();
        wprintf(L"No response from the browser!\n");
        return;
    }

    // Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
    // The possible AuthFlowState values are:
    // 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
    // 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
    // 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
    if (oauth2.get_AuthFlowState() == 5) {
        wprintf(L"OAuth2 failed to complete.\n");
        wprintf(L"%s\n",oauth2.failureInfo());
        return;
    }

    if (oauth2.get_AuthFlowState() == 4) {
        wprintf(L"OAuth2 authorization was denied.\n");
        wprintf(L"%s\n",oauth2.accessTokenResponse());
        return;
    }

    if (oauth2.get_AuthFlowState() != 3) {
        wprintf(L"Unexpected AuthFlowState:%d\n",oauth2.get_AuthFlowState());
        return;
    }

    wprintf(L"OAuth2 authorization granted!\n");

    CkJsonObjectW json;
    json.Load(oauth2.accessTokenResponse());
    json.put_EmitCompact(false);

    wprintf(L"Access Token Response = %s\n",json.emit());

    // A sample access token response:

    // {
    //   "access_token": "...",
    //   "token_type": "bearer",
    //   "expires_in": 14399,
    //   "refresh_token": "...",
    //   "scope": "account_info.read",
    //   "uid": "562542581",
    //   "account_id": "dbid:AACQhDS0E3_Vb72Ynd0F-GxGWdTI2qcTHzA"
    // }

    wprintf(L"Access Token = %s\n",oauth2.accessToken());

    // Save the JSON access token response to a file for subsequent use..
    json.WriteFile(L"qa_data/tokens/dropbox.json");
    }