Develop Reference

Google Sign-in in Android with django-rest-auth

I've been trying to add Google Sign-In in Android but have a couple of doubts.
From the Android documentation Integrate google sign in android
In the server side authentication part Client Id is required which is OAuth 2.0 web application client ID for your backend server.
From android's documentation:
Get your backend server's OAuth 2.0 client ID
If your app authenticates with a backend server or accesses Google APIs from your backend server, you must get the OAuth 2.0 client ID that was created for your server. To find the OAuth 2.0 client ID
From my understanding the flow would be:
Android app will get the auth code from google which will be passed to the backend.
The backend will get the access token with the auth code from the android app and the client secret.
With the acess token we get the user's information and the access token is saved in the database.
My doubts are:
I read somewhere on StackOverflow that we need to create two OAuth client one for Android and one for Web Application. Is this True?
Django Rest Auth Login View need to have one redirect_url defined but I don't understand what would be the redirect_uri in case of Android device or we need to pass this URL while getting the auth code from Google.
On OAuth Playground I put my backend's client id and client secret and got the auth code and when I passed this auth code to my login view I was getting the redirect_uri_mismatch but If I put redirect_url = 'developer.google.com' It works, I guess the auth code contains host information from where it is generated that's why this should be the same as redirect_url in my rest-auth view but then for android what it should be?
Here is my Google Login View.
class GoogleLogin(SocialLoginView):
adapter_class = GoogleOAuth2Adapter
client_class = OAuth2Client
callback_url = 'localhost:8000' # What this should be?
Please ask for more information If I forgot to put any.
I am using this
django-rest-auth
Some helpful link -
https://github.com/Tivix/django-rest-auth/issues/262#issuecomment-256562095 # It says callback URL could be a fake one but I get redirect_uri_mismatch

So Finally, I figured it out, Answering my own question so someone might find this helpful.
Yes, you need two client id one for your Android device and one for your web application.
Just add http://localhost:8000/accounts/google/login/callback/ as callback_url in the GoogleLoginView and put the same in your Google developer console.
I don't know exactly if the auth code generated by the Android contains any host information or not but it seems as long as the callback URL you added in the login view class and in google developer console is the same it will work.
Your Google sign in view should look like this.
class GoogleLogin(SocialLoginView):
authentication_classes = (JSONWebTokenAuthentication,)
adapter_class = GoogleOAuth2Adapter
callback_url = 'http://localhost:8000/accounts/google/login/callback/'
client_class = OAuth2Client
Note: You only need callback_url and client_class in case where you are passing the auth code to this view but if in you are passing the access_token then callback_url and client_class is not necessary.

Android login via Google Sign-In with a Spring Boot backend

As the title says, I'm trying to use the Google Sign-In API with a Spring Boot backend server, as described here.
Just to describe the context, the Spring backend is basically a resource+authentication server, that is currently providing Oauth2 authentication to a second spring boot application containing the frontend website, via Google SSO or simple form login (similar to what's described here).
My original idea was to mimic the #EnableOauth2Sso annotation by simply providing an access token to the android app and attach it to every request as "Bearer ".
Using the user credentials for this was pretty straightforward: I simply make a request to the server at "/oauth/token", using those credentials inserted by the user as authentication and I correctly receive the access token.
Now, I have absolutely no idea on how to build a similar procedure with the Google API in Android. The tutorial page I linked before describes how to get a token ID and how the server should validate it, but after that I don't know what to do.
So far I've managed to add a filter to the security chain that simply checks the token like this:
private Authentication attemptOpenIDAuthentication(#NonNull String tokenString){
String clientId = authServices.getClientId();
GoogleIdTokenVerifier verifier = new GoogleIdTokenVerifier.Builder(transport, factory)
.setAudience(Arrays.asList(clientId, androidClient))
.build();
try {
GoogleIdToken token = verifier.verify(tokenString);
if (token != null) {
return authServices.loadAuthentication(token.getPayload());
} else {
throw new InvalidTokenException("ID token is null");
}
} catch (GeneralSecurityException | IOException e) {
throw new BadCredentialsException("Could not validate ID token");
}
}
This manages indeed to create an Authentication object, but how can I generate an access token after the authentication filtering?
To recap, so far I've got:
The Android app successfully retrieves the Google token ID and sends it to the server
The server sucessfully intercepts the request and validates the token
I'm basically missing the third point where I return a proper access token to the Android client.
Here you are a simple scheme to better understand the situation:
Is there any other way to validate the token and get an access token from the server, or should I completely change the authentication procedure on Android?

As far as I can tell: Yes, you need an access token from the server. If I understand this correctly, a webapp is already authenticated via Oauth on your backend, so the procedure is similar here: Load the user with the google-ID and generate a token. In my application I used a JWT which is valid for 30 days. If the token expires, the Google authentication in the app is usually still valid, so the token can be renewed using the Google ID. With Oauth you can also send a refresh-token directly.
It is important that the app always checks the Google authentication first and only in a second step that of the backend.
For the Authentication process on the backend u may need to manually implement a dedicated securityConfiguration for this. Have a look at the jhipster project, they implemented a custom jwt-authentication which may give you an idea how it works.

Foursquare Redirect uri mismatch on native Android OAuth login

I am trying to implement Foursquare Native OAuth on my Android app. I have followed the foursquare-oauth-library sample and have succesfully generated an access_token for the user.
However, following Foursquare's recommendation of my App's Secret not being stored anywhere in the app and instead performing a server side auth code/access_token exchange I am doing the call on my server but get a redirect_uri_mismatch error everytime I do it this way.
I am getting the auth code as specified in the sample app:
AuthCodeResponse codeResponse = FoursquareOAuth.getAuthCodeFromResult(resultCode, data);
Afterwards, I send that auth code from my Android app to my rails server. I assume the access_token should be obtained following Step 3 of https://developer.foursquare.com/overview/auth#code but I get the redirect_uri_mismatch response.
I am using Nestful on my rails server to send Foursquare my request for the access_token:
response = Nestful.post 'https://foursquare.com/oauth2/access_token',
client_id: ENV_CONFIG['foursquare_client_id'],
client_secret: ENV_CONFIG['foursquare_client_secret'],
grant_type: 'authorization_code',
redirect_uri: ENV_CONFIG['redirect_uri'],
code: params[:code]
#token = response['access_token']
The response is:
{"error":"redirect_uri_mismatch"}
I have already double checked the app's configuration on Foursquare, where I have also set my generated Android Hash Key, and even tried providing that as a redirect_uri parameter to generate the acess token, but to no avail.
Any idea of what I could be doing wrong?

It turns out that the given code checks upon the redirect_uri provided originally. Since one wasn't specified in the first place, no redirect_uri param should be passed to the code/access_token exchange call.

Android subscription and Google API

I'm trying to use the new Android subscription system from Google Play into my application (I already had in-app billing working fine). I have successfully done the subscription billing, but I now want to retrieve informations about this subscription by using the google apis as indicated in the android documentation (http://developer.android.com/guide/market/billing/billing_subscriptions.html).
I want my service to be able to do the API call to retrieve these informations, but I have problems with authentication (with oauth2). So far, this is what I do (in my php service) :
require_once 'google-api-php-client/src/apiClient.php'
const SERVICE_ACCOUNT_NAME = 'email from services account access';
$key = 'content of my private key retrieved from services account access';
$client = new apiClient();
$cred = new apiAssertionCredentials(SERVICE_ACCOUNT_NAME, array('https://www.googleapis.com/auth/androidpublisher'), $key);
$assertion = $cred->generateAssertion(); // This generate my encrypted JWT
I then try to retrieve the access token with this JWT object. The problem is that when I use the access token given I got the error that the developer account does not own the application, which is not true.
(I know this is not the way to do it, but I just wanted to retrieve the access_token using the JWT to understand why it is not working, if I do it as indicated in the google apis documentation it is not working too).
I need to do this API call from a server, so no end-user has to be involved (no manual consent).

I had the same issue, and ultimately discovered that as of right now service accounts can not access the Play API.
I'm not sure when Google is planning on fixing this but you can get around this by creating a web app client ID and setting up a basic login page to first generate a code using the new web app Client data and going to $client->createAuthUrl():
$client = new apiClient();
$key = file_get_contents(KEY_FILE);
$client->setClientId(CLIENT_ID);
$client->setClientSecret(CLIENT_SECRET);
$client->setRedirectUri(MY_WEBAPP_URL);
$client->setDeveloperKey($key);
$client->setScopes(array('https://www.googleapis.com/auth/androidpublisher'));
$authUrl = $client->createAuthUrl();
print "<a class='login' href='$authUrl'>Connect Me!</a>";
This should take you to a Google login page where you should log in with the developer account. When you authorize the app, it will take you back to your web app URL as defined when you set up the client ID with a CODE as a get parameter. You can use to generate a token (and more importantly, a refresh token) like so:
$url = 'https://accounts.google.com/o/oauth2/token';
$fields = array(
'grant_type'=>'authorization_code',
'code'=>$code,
'client_id'=>CLIENT_ID,
'client_secret'=>CLIENT_SECRET,
'redirect_uri'=>MY_WEBAPP_URL
);
// cURL call to OAuth URL with $fields sent as POST
This should return you JSON data with a refresh token. Save this token and use it to make another call whenever you need to generate an access token. You will essentially run the same code you did to get the refresh token, but with different fields:
$fields = array(
'grant_type'=>'refresh_token',
'refresh_token'=>$refresh_token,
'client_id'=>CLIENT_ID,
'client_secret'=>CLIENT_SECRET,
);
This will give you an access token you can use to get purchase data from the following URL:
https://www.googleapis.com/androidpublisher/v1/applications/[PACKAGE]/subscriptions/[SKU]/purchases/[PURCHASE_TOKEN]?access_token=[ACCESS_TOKEN]
The trick is getting the refresh token, once you have that the rest should be pretty straightforward.

I`ve got the same problem. It occurs because you authorize user in Google API who does not own the application and try to get data which belows to your app.
In this topic it is well described. http://support.google.com/googleplay/android-developer/bin/answer.py?hl=en&answer=2528691&topic=16285&ctx=topic
You should authorize by OAuth2 the owner of application, and then use Google API with obtained token.

Facebook auth token exchange

Is it possible to authenticate the user on server side using auth token retrieved by Android applicaton from Facebook?
In other words Android application uses SSO and obtain auth token. Then sends this token to backend application deployed on Google App Engine. Then backend application verifies the user against Facebook using the token.
I guess it's not feasible because retrieved token can be used only by Android application, but who knows? Maybe it may be reused somehow?

The Token you get from Android API can be sent to your server, who can check the validity of the token by querying the graph ( using /me?auth_token=.... for example).
The problem is that the same token can be used by any third party - it's not client specific - and so if you base server identification based on that, you have a problem (since a third app could use its user token and get authenticated by you). I am trying to find a way to solve this issue, but I don't have good ideas yet...

Facebook actually has an Android SDK that lets you do this. Information can be found here.

Yes you can. A valid access token is a valid access token. The Graph API does from where the token came, but only that the token has the appropriate permissions to access that portion of the graph api. Keep in mind, though, that the token is only valid for 24 hours from the time of its issuance. (is that really a word?) From the time it is issued?

When using facebook android sdk with SingleSignOn (SSO), the access token format actually changed.
Instead of getting traditional auth token which contains userid & session key as a part of authToken
now we get a different format of authToken
As Facebook Devs are still in process to support there rest apis with newly formated access token
meanwhile we can disable the SSO on android facebook sdk by changing DEFAULT_AUTH_ACTIVITY_CODE to -1 from 32665 (in Facebook.java)
This will invoke Traditional dialouge for granting acess token and in return you'll get access token which will contain session key in it.
Those who are looking for generating secure session key you need to add your own method in Facebook.java like
public String getSessionSecret(String accessToken) throws MalformedURLException, IOException
{
Bundle b = new Bundle();
b.putString("method", "auth.promoteSession");
b.putString("access_token", accessToken);
b.putString("session_key_only", "true");
String response = request(b);
return response;
}