(Java) OAuth2 using an HTTP Proxy (for a Desktop Application)

Demonstrates how to send OAuth2 communications through an HTTP proxy for a desktop application. The technique is the same for all OAuth2 applications. This one happens to demonstrate for Microsoft Graph.

Note: This example requires Chilkat v10.1.2 or greater.

Chilkat Java Downloads Java Libs for Windows, MacOS, Linux, Alpine Linux Java Libs for Android

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // To use an HTTP proxy with OAuth2, create a Chilkat socket object and specify the details.
    CkSocket socket = new CkSocket();
    // Use your HTTP proxy server domain or IP address.
    socket.put_HttpProxyHostname("myproxyserver.com");
    // Change this to the listening port of your HTTP proxy server (if necessary)
    socket.put_HttpProxyPort(808);
    // Specify login/password if needed.
    socket.put_HttpProxyUsername("myProxyLogin");
    socket.put_HttpProxyPassword("myProxyPassword");
    socket.put_HttpProxyForHttp(true);

    CkOAuth2 oauth2 = new CkOAuth2();

    // We don't need to connect the socket beforehand.
    // Just tell oauth2 to use the socket which has the HTTP proxy properties.
    boolean success = oauth2.UseConnection(socket);

    // 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);

    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("MICROSOFT-GRAPH-CLIENT-ID");
    // This is your app password:
    oauth2.put_ClientSecret("MICROSOFT-GRAPH-CLIENT-SECRET");

    oauth2.put_CodeChallenge(false);
    // 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, you have to ask for "offline_access" scope
    oauth2.put_Scope("openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite");

    // Begin the OAuth2 Authorization code flow.  This returns a URL that should be loaded in a browser.
    String url = oauth2.startAuth();
    if (oauth2.get_LastMethodSuccess() != true) {
        System.out.println(oauth2.lastErrorText());
        return;
        }

    System.out.println("url = " + url);

    // Launch the default browser on the system and navigate to the url.
    // The LaunchBrowser method was added in Chilkat v10.1.2.
    success = oauth2.LaunchBrowser(url);
    if (success == false) {
        System.out.println(oauth2.lastErrorText());
        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();
        System.out.println("No response from the browser!");
        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) {
        System.out.println("OAuth2 failed to complete.");
        System.out.println(oauth2.failureInfo());
        return;
        }

    if (oauth2.get_AuthFlowState() == 4) {
        System.out.println("OAuth2 authorization was denied.");
        System.out.println(oauth2.accessTokenResponse());
        return;
        }

    if (oauth2.get_AuthFlowState() != 3) {
        System.out.println("Unexpected AuthFlowState:" + oauth2.get_AuthFlowState());
        return;
        }

    System.out.println("OAuth2 authorization granted!");
    System.out.println("Access Token = " + oauth2.accessToken());

    // Get the full JSON response:
    CkJsonObject json = new CkJsonObject();
    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 = new CkDateTime();
        dtExpire.SetFromCurrentSystemTime();
        dtExpire.AddSeconds(json.IntOf("expires_in"));
        json.AppendString("expires_on",dtExpire.getAsUnixTimeStr(false));
        }

    System.out.println(json.emit());

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