Develop Reference

Authenticate my "app" to Google Cloud Endpoints not a "user"

What I'm trying to do is to authenticate my Android app to the Google Cloud Endpoint.
Basically the endpoints should only allow my Android app to access the methods and nothing else.
I have done these things -
Create a client id using my SHA1 value in Eclipse in the Google Cloud Console.
Create a web client id in the Google Cloud Console for my endpoint project.
Add both these client id's in the "#Api" mentioned on each endpoint.
Add an extra "user" parameter in the endpoint methods.
Regenerate and deploy the backend to the cloud.
But when I'm running this the "user" is always coming as "null". I'm at my wits end trying to find a proper working method for doing all this.
I've searched many forums but no proper answers anywhere.
Here's another similar post Restrict access to google cloud endpoints to Android app
This is the reference I'm using -
https://developers.google.com/appengine/docs/java/endpoints/auth
Has anyone here done this before? My main goal is to not allow unauthenticated apps and outside world to access the endpoints, for obvious security reasons. I don't want to use end-user based authentication since I want to keep my app very simple.

It sounds like it's working as intended. You control which client apps can call your endpoint methods via the client IDs as you have already done. The User parameter is coming in as null precisely because you aren't doing end-user authentication. The User parameter represents an actual real user (Google Account). So if you don't need end-user authenticated methods, you can just simply not define the User parameter, or else ignore the null value. You said your problem is that the User parameter is set null. What are you expecting it to be in this scenario?

You need to call authenticate on the client, then possibly the library you're using will 'inject' the user information.

Here's what worked for me :
Let's say you have the keys below :
static final String WEB_CLIENT_ID = "somekeyfor webclientid.apps.googleusercontent.com";
static final String ANDROID_CLIENT_ID = "somekeyfor androidclientid.apps.googleusercontent.com";
static final String ANDROID_AUDIENCE = WEB_CLIENT_ID;
Your Api anotation should look like this :
#Api(
name = "yourapiname",
clientIds = {CloudEndpoint.WEB_CLIENT_ID,CloudEndpoint.ANDROID_CLIENT_ID},
audiences = {CloudEndpoint.ANDROID_AUDIENCE},
version = "v1",
namespace = #ApiNamespace(
ownerDomain = "myapp.app.com",
ownerName = "myapp.app.com",
packagePath = ""
)
)
In the annotation below, notice how your audience is the variable --> ANDROID_AUDIENCE which is equal to WEB_CLIENT_ID.
Now in your app side, when you create the googleAccountCredential object, you should pass in the Web Client Id like this :
mAccountCredentials = GoogleAccountCredential.usingAudience(getApplicationContext(),"server:client_id:" + "yourwebclientID");
Note that even if this is properly done, your user object in the endpoint might still coming out as Null if the account name you pass in mAccountCredentials.setSelectedAccountName("accontname") does not exist in the device. Therefore make sure the account name you pass does exist in the Android device by going to --> (Settings/Accounts)

getting Google oauth authorization token from Android- return with invalid_scope/ Unknown error

I try to use Google oauth to authenticate users on my android app.
Then I would like to send it to my app server so it can connect at any time with Google calendar.
I tried to use
GoogleAuthUtil.getToken(getApplicationContext(), mAccountName, mScope);
Following this article:
https://developers.google.com/accounts/docs/CrossClientAuth
When I use it with scope
mScope = "oauth2:https://www.googleapis.com/auth/calendar https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile";
I get a token, which is valid for an hour
But when I try to get an authorization code (so I can get a refresh token that is valid for longer time, using
mScope2 ="oauth2:server:client_id:{CLIENT_ID}.apps.googleusercontent.com"+ ":api_scope:https://www.googleapis.com/auth/calendar https://www.googleapis.com/auth/userinfo.email https://www.googleapis.com/auth/userinfo.profile";
I receive either "invalid_scope" or "Unknown" exceptions.
What am I doing wrong?
EDIT:
OK, After creating a new app on google API console and adding plus.login to the scope I get a code, but for some reason my server can't resolve this token. When tying to resolve server gets an error about the redirection URL.
BTW, When I do the web flow with same parameters it works.

OK, found the solution, I expected Google to have a lot better documentation about working with Google Oauth and Android. A few things you have to know to work with Android and offline token
When you create google Client ID Don't create a service application before you create a web application
Must include https://www.googleapis.com/auth/plus.login in your scope
The weirdest, to resolve the one time authorization code on my server, I had to use the redirection URL from the Android client ID details (which doesn't even look like a url) and not from the Web client details on Google API console.

That scope string is only documented to work when passed to GoogleAuthUtil(), see http://developer.android.com/reference/com/google/android/gms/auth/GoogleAuthUtil.html, on Android. But it would be cool if it worked on iOS too; our infrastructure there is a little behind where we’re at on Android.

I have had the same issue then i realised that my app is not published and is in debug mode, so i had to add test users to the Google project -> Consent Screen, then i was able to fetch the token for the added test user.

You just need to follow the correct steps/format for specifying the scopes. Find them here https://developers.google.com/android/guides/http-auth#SpecifyingScopes

What is the proper way to validate google granted OAuth tokens in a node.js server?

I'm trying to authenticate a mobile application for the Android platform to a custom node.js server api. I would like to use Google OAuth2 tokens for this rather than roll my own authentication, since Android devices with Google Play installed make this available to app developers. I'm using the GoogleAuthUtil.getToken call from the Google Play Services library, documented here. I'm trying to follow the advice outlinedin this android developers blogpost
The getToken method is returning in my case a long 857 byte string. If I try to pass this token to Google's TokenInfo endpoint, it returns:
{'error': 'invalid_token', 'error_description': 'Invalid Value'}
What am I doing wrong here? In the 'scope' of the getToken call, I am sending:
audience:server:client_id:**i_put_my_clientid_here**. I have a clientid generated for "installed applications". Using this client id, the call to getToken doesn't work at all. When I generated a client id for a "service account", the call succeeds, but I get an 857 byte token that fails when passed to the TokenInfo endpoint as described above.
EDIT:
I also created a client id for "web applications", as it appears that is the right client id to use when calling getToken. But the behavior is the same, I get back an 857 byte token that doesn't validate when calling Google's endpoint.
How can I properly get a valid auth token using Google Play services on Android? Once I have the right token, what is the right node.js library to validate it server side? Can I use passport-google-oauth ?

Hm, this is really a comment rather than an answer, but I can’t put newlines in those:
it has to be the web-side Clent ID that goes in the put_my_clientid_here spot
if GoogleAuthUtil.getToken() gives you a String withou throwing an Exception, it really ought to be valid. When you hit tokeninfo, did you use ...tokeninfo?id_token=<857-byte-value-here>
if you’re a rubyist, grab the google-id-token gem and see if it can validate your 857-byte token.

If you just want to read the contents of the data returned by GoogleAuthUtil.getToken then the process is very simple. The returned data is simply a JWT. So all you'd have to do is split the data by the . character, and then base64 (url) decode each piece.
It gets slightly more complicated if you want you want to verify the message's authenticity. Simply use your favorite crypto library to do the verification. The 3rd component of the JWT is the signature of the data and the Google certs are publicly available; that's all you need to verify the message.

For a week I have been looking into how to validate GoogleAuthUtil tokens received in Android Client application at Node.js server using passport.js
Finally I came across passport-google-token passport strategy which perfectly performs the task.
https://www.npmjs.com/package/passport-google-token
More details are present in the above link.

The official node SDK lets you do that now.
Here's the link: https://github.com/google/google-auth-library-nodejs/blob/master/lib/auth/oauth2client.js#L384

I'm not too familiar with the details of how Android works with respect to handing a token from the device to the server. My general impression, however, is that you don't go through the typical web-based OAuth dance. Instead, you directly call the "user info" endpoint, which will return the info corresponding to the user who holds the token, or reject the request if the token is invalid. There's some discussion on this related question:
validating Android's authToken on third party server
In effect, the token becomes a secret that is shared between both the device and your server, so its important to protect it.
There are a couple strategies for Facebook and Twitter that were developed to do similar things using tokens from iOS devices:
https://github.com/drudge/passport-twitter-token
https://github.com/drudge/passport-facebook-token
You can take some inspiration from them and tweak it to talk to Google's endpoints. Let me know how this turns out. I'd love to see a similar "passport-google-token" strategy, so if you implement one, let me know and I'll link to it!

How to refresh Token in GoogleCredential

I have implement function retrieve credentials from saved token in SharedPreferences.
mCredential = new GoogleCredential.Builder()
.setClientSecrets(CLIENT_ID, CLIENT_SECRET)
.setJsonFactory(mJsonFactory)
.setTransport(mHttpTransport).build();
mCredential.setRefreshToken(accessRefreshTokenSave);
mCredential.setAccessToken(accessTokenSave);
Long expires = mCredential.getExpiresInSeconds();
boolean result = mCredential.refreshToken();
When the token is expired. We should call mCredential.refreshToken() to refresh the token, is it right ?
When i call refreshToken i got exception.
com.google.api.client.auth.oauth2.TokenResponseException: 400 Bad Request
{
"error" : "invalid_grant"
}
What should i need to do to refresh the token ? I found some document in Using OAuth 2.0 say about refresh token. But i don't know how to implement it in Android code? Is there any sample code do this ?

Generally (in my experience, since I haven't found any documentation) 'invalid grant' means there is some problem with your stored refresh token. This includes (I think):-
The user has revoked it
Your testing has caused multiple refresh tokens to be generated. Only 25 may be extant
The scopes associated with the stored token have changed
To recover the situation, delete the stored refresh token and start the process again. The good news, is that apart from the user revocation scenario (1) this is a testing environment issue and doesn't necessarily mean you have a bug.

Have a look on https://developers.google.com/+/mobile/android/sign-in that's the OAUTH for Android, and you can check what is wrong, or maybe use the example code in your Project. To give you more details, you have to post the entire project (linking it to GitHub for example) or post the interested Class ;-)

Android Google Calendar Authorization Problem

I'm trying to make an app that accesses a user's Google Calendar using OAuth. I have the code in place that gets all of the proper tokens and they are saved into some preferences. I used the tutorial here to do this all, by the way. I have successfully changed the scope and request URL's so that I'm getting the needed tokens. The problem comes when I actually try to USE the token. Instead of calendar info, I get back some HTML that says "Unknown authorization header Error 401". The request URL I am using is:
https://www.google.com/calendar/feeds/default/allcalendars/full
and the scope is:
http://www.google.com/calendar/feeds/
I have tried replacing 'default' with my email address (which is also the one that I used for the OAuth) to no avail. Am I using the wrong URL? if not, what else could cause this error? I have been looking for a few days now to find someone who has accessed the Calendar using OAuth, but everything I have found is people giving up because it's too difficult or doesn't work.
EDIT:
I believe my header is correct, here is an example of it:
OAuth oauth_token="************-********-**********-****",
oauth_consumer_key="anonymous",
oauth_version="1.0",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="1303161387",
oauth_nonce="*******************",
oauth_signature="*******************"
That is pulled directly from my app, and from what I could find it looks right to me, but I'm still getting the error above (Unknown Authorization Header Error 401).

The Authorization header needs to be "Authorization: OAuth oauth_nonce="deadbeefdeadbeef" oauth_version="1.0" ....
See http://code.google.com/apis/accounts/docs/OAuth_ref.html#RequestToken. You can, supposedly, also but the authorization parameters in the querystring or in the body of a POST, but I have not attempted that.
As noted in the comments below, Google is now, at least with the Calendar feed, appending a 'gsessionid=' querystring and redirecting; and so a redirect handler must create a new nonce and timestamp, and make a new signature making sure to add the gsessionid to the base signature string in the correct lexicographical order (preceding any of the oauth_ variables).