(C) Microsoft Graph OAuth2 App Authentication using Azure AD

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

The Microsoft Graph supports two authentication providers:

• To authenticate users with personal Microsoft accounts, such as live.com or outlook.com accounts, use the Azure Active Directory (Azure AD) v2.0 endpoint.
• To authenticate users with enterprise (that is, work or school) accounts, use Azure AD.

This example uses the Azure AD endpoint (for enterprise accounts).

This example requires Chilkat v9.5.0.67 or greater.

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#include <C_CkOAuth2.h>
#include <C_CkJsonObject.h>
#include <C_CkFileAccess.h>

void ChilkatSample(void)
    {
    HCkOAuth2 oauth2;
    BOOL success;
    const char *url;
    int numMsWaited;
    HCkJsonObject json;
    HCkFileAccess fac;

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

    oauth2 = CkOAuth2_Create();

    // 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.
    CkOAuth2_putListenPort(oauth2,3017);

    CkOAuth2_putAuthorizationEndpoint(oauth2,"https://login.microsoftonline.com/common/oauth2/authorize");
    CkOAuth2_putTokenEndpoint(oauth2,"https://login.microsoftonline.com/common/oauth2/token");

    // -----------------------------------------------------------------------------
    // Important: Notice that the above endpoints are the "Azure AD" endpoints, not
    // the "Azure AD v2.0" endpoints.  The 2.0 endpoints are very similar. They are:
    // https://login.microsoftonline.com/common/oauth2/v2.0/authorize
    // and
    // https://login.microsoftonline.com/common/oauth2/v2.0/token
    // Pay close attention to the endpoints to make sure they match what you want.
    // -----------------------------------------------------------------------------

    // Replace these with actual values.
    CkOAuth2_putClientId(oauth2,"MY_AZURE_AD_APP_ID");
    // This is your app key/password/client secret:
    CkOAuth2_putClientSecret(oauth2,"MY_AZURE_AD_APP_KEY");

    CkOAuth2_putCodeChallenge(oauth2,FALSE);

    // -----------------------------------------------------------
    // Important difference between "Azure AD" and "Azure AD v2.0"
    // 
    // When using the Azure AD v2.0, endpoints (for personal accounts), the desired
    // scopes are selected by setting the OAuth2 Scope property here.
    // However, when using the "Azure AD" endpoints, we DO NOT set the Scope here,
    // but instead set the OAuth2 Resource property, as shown here:

    CkOAuth2_putResource(oauth2,"https://graph.microsoft.com/");

    // When using the "Azure AD" endpoint, the access token we receive will automatically
    // be for the scopes matching the permissions granted for the app during the app's registration.

    // Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
    url = CkOAuth2_startAuth(oauth2);
    if (CkOAuth2_getLastMethodSuccess(oauth2) != TRUE) {
        printf("%s\n",CkOAuth2_lastErrorText(oauth2));
        CkOAuth2_Dispose(oauth2);
        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...

    // Now wait for the authorization.
    // We'll wait for a max of 30 seconds.
    numMsWaited = 0;
    while ((numMsWaited < 30000) && (CkOAuth2_getAuthFlowState(oauth2) < 3)) {
        CkOAuth2_SleepMs(oauth2,100);
        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 (CkOAuth2_getAuthFlowState(oauth2) < 3) {
        CkOAuth2_Cancel(oauth2);
        printf("No response from the browser!\n");
        CkOAuth2_Dispose(oauth2);
        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 (CkOAuth2_getAuthFlowState(oauth2) == 5) {
        printf("OAuth2 failed to complete.\n");
        printf("%s\n",CkOAuth2_failureInfo(oauth2));
        CkOAuth2_Dispose(oauth2);
        return;
    }

    if (CkOAuth2_getAuthFlowState(oauth2) == 4) {
        printf("OAuth2 authorization was denied.\n");
        printf("%s\n",CkOAuth2_accessTokenResponse(oauth2));
        CkOAuth2_Dispose(oauth2);
        return;
    }

    if (CkOAuth2_getAuthFlowState(oauth2) != 3) {
        printf("Unexpected AuthFlowState:%d\n",CkOAuth2_getAuthFlowState(oauth2));
        CkOAuth2_Dispose(oauth2);
        return;
    }

    printf("OAuth2 authorization granted!\n");
    printf("Access Token = %s\n",CkOAuth2_accessToken(oauth2));

    // Get the full JSON response:
    json = CkJsonObject_Create();
    CkJsonObject_Load(json,CkOAuth2_accessTokenResponse(oauth2));
    CkJsonObject_putEmitCompact(json,FALSE);

    // The JSON response looks like this:
    // (Note: The scope property value should match the permissions granted for the app during the app's registration.)

    // {
    //     "token_type":"Bearer",
    //     "scope": "Calendar.ReadWrite Directory.Read.All Files.ReadWrite Group.ReadWrite.All Mail.ReadWrite Mail.Send User.ReadBasic.All",
    //     "expires_in":"3599",
    //     "ext_expires_in": "0",
    //     "expires_on":"1426551729",
    //     "not_before":"1426547829",
    //     "resource":"https://graph.microsoft.com/",
    //     "access_token":"eyJ0eXAiOiJKV1QiLCJhb...",
    //     "refresh_token":"AAABAAAAvPM1KaPlrEqd...",
    //     "id_token":"eyJ0eXAiOiJKV1QiLCJhbGci..."
    // }

    printf("%s\n",CkJsonObject_emit(json));

    // Save the JSON to a file for future requests.
    fac = CkFileAccess_Create();
    CkFileAccess_WriteEntireTextFile(fac,"qa_data/tokens/microsoftGraphAzureAD.json",CkJsonObject_emit(json),"utf-8",FALSE);


    CkOAuth2_Dispose(oauth2);
    CkJsonObject_Dispose(json);
    CkFileAccess_Dispose(fac);

    }