(C++) Get OAuth2 Access Token for Azure Registered App

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This example requires Chilkat v10.1.2 or greater.

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#include <CkOAuth2.h>
#include <CkJsonObject.h>
#include <CkDateTime.h>
#include <CkFileAccess.h>

void ChilkatSample(void)
    {
    // To further clarify, see OAuth 2.0 Authorization Flow

    CkOAuth2 oauth2;

    // This should be the port in the localhost callback URL for your app.  
    // The callback URL would look like "http://localhost:3017/" if the port number is 3017.
    oauth2.put_ListenPort(3017);

    // ----------------------------------------------------------------------------------------------------------
    // The screenshot at the bottom of this page shows how we created the Azure App Registration for this example.
    // ----------------------------------------------------------------------------------------------------------

    // Note: The endpoint depends on the Azure App Registration.
    // See How to Choose the Correct Endpoints for your Azure App Registration
    oauth2.put_AuthorizationEndpoint("https://login.microsoftonline.com/common/oauth2/v2.0/authorize");
    oauth2.put_TokenEndpoint("https://login.microsoftonline.com/common/oauth2/v2.0/token");

    // Replace these with actual values.
    oauth2.put_ClientId("CLIENT_ID");

    // This is for Require Proof Key for Code Exchange (PKCE)
    // See OAuth2 PKCE Explained
    oauth2.put_CodeChallenge(true);
    oauth2.put_CodeChallengeMethod("S256");

    // Provide a SPACE separated list of scopes.
    // See https://developer.microsoft.com/en-us/graph/docs/authorization/permission_scopes 

    // Important: To get a refresh token in the final response, ask for "offline_access" scope
    oauth2.put_Scope("openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite");

    // Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
    const char *url = oauth2.startAuth();
    if (oauth2.get_LastMethodSuccess() != true) {
        std::cout << oauth2.lastErrorText() << "\r\n";
        return;
    }

    // Launch the default browser on the system and navigate to the url.
    // The LaunchBrowser method was added in Chilkat v10.1.2.
    bool success = oauth2.LaunchBrowser(url);
    if (success == false) {
        std::cout << oauth2.lastErrorText() << "\r\n";
        return;
    }

    // Wait for the user to approve or deny authorization in the browser.
    int numMsWaited = 0;
    while ((numMsWaited < 90000) && (oauth2.get_AuthFlowState() < 3)) {
        oauth2.SleepMs(100);
        numMsWaited = numMsWaited + 100;
    }

    // If the browser does not respond within the specified time, AuthFlowState will be:
    // 
    // 1: Waiting for Redirect – The OAuth2 background thread is waiting for the browser's redirect request.
    // 2: Waiting for Final Response – The thread is awaiting the final access token response.
    // In either case, cancel the background task initiated by StartAuth.

    if (oauth2.get_AuthFlowState() < 3) {
        oauth2.Cancel();
        std::cout << "No response from the browser!" << "\r\n";
        return;
    }

    // Check AuthFlowState to determine if authorization was granted, denied, or failed:
    // 
    // 3: Success – OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
    // 4: Access Denied – OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
    // 5: Failure – OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

    if (oauth2.get_AuthFlowState() == 5) {
        std::cout << "OAuth2 failed to complete." << "\r\n";
        std::cout << oauth2.failureInfo() << "\r\n";
        return;
    }

    if (oauth2.get_AuthFlowState() == 4) {
        std::cout << "OAuth2 authorization was denied." << "\r\n";
        std::cout << oauth2.accessTokenResponse() << "\r\n";
        return;
    }

    if (oauth2.get_AuthFlowState() != 3) {
        std::cout << "Unexpected AuthFlowState:" << oauth2.get_AuthFlowState() << "\r\n";
        return;
    }

    std::cout << "OAuth2 authorization granted!" << "\r\n";
    std::cout << "Access Token = " << oauth2.accessToken() << "\r\n";

    // When the token is near expiration, your app can refresh as shown here:
    // Refresh Expiring OAuth2 Access Token for Azure Registered App

    // Get the full JSON response:
    CkJsonObject json;
    json.Load(oauth2.accessTokenResponse());
    json.put_EmitCompact(false);

    // The JSON response looks like this:

    // {
    //   "token_type": "Bearer",
    //   "scope": "User.Read Mail.ReadWrite Mail.Send",
    //   "expires_in": 3600,
    //   "ext_expires_in": 0,
    //   "access_token": "EwBAA8l6B...",
    //   "refresh_token": "MCRMdbe...",
    //   "id_token": "eyJ0eXA..."
    // }

    // If an "expires_on" member does not exist, then add the JSON member by
    // getting the current system date/time and adding the "expires_in" seconds.
    // This way we'll know when the token expires.
    if (json.HasMember("expires_on") != true) {
        CkDateTime dtExpire;
        dtExpire.SetFromCurrentSystemTime();
        dtExpire.AddSeconds(json.IntOf("expires_in"));
        json.AppendString("expires_on",dtExpire.getAsUnixTimeStr(false));
    }

    std::cout << json.emit() << "\r\n";

    // Save the JSON to a file for future requests.
    CkFileAccess fac;
    fac.WriteEntireTextFile("qa_data/tokens/_myAzureApp.json",json.emit(),"utf-8",false);

    // This is a screenshot of how we created the Azure App for this example:
    // 
    }