OAuth 2.0 access_token renewable - ios

I have an iOS application which connects to different APIs such as the Instagram, Facebook and Twitter API's.
I thing you need to do when authenticating via OAuth 2.0 is to get a access_token, which I have.
I just have one question, when do I renew it? I have read online that it will last a long time but still needs renewing..... Well.... how long is the time period for renewing?
Or do I renew it on every API call I make, for example when I want to GET the JSON feed of a Instagram or Twitter user, do I need to review the access_token first?
And how about when I want to do a POST to a service such as Twitter. Do I need to renew the access_token before I can do a POST??
Thanks for your time, Dan.

Renewing your Oauth token on every API request is time-expensive and too many frequent token requests could result in your application's token becoming revoked. Reference
Instead of trying to avoid sending a request with an invalid token, you should consider implementing a callback or interceptor which would check if the response contains an error code and then appropriately handle the error (display an error message or automatically redirect to request for authentication). The callback/interceptor pattern allows this error checking to be triggered automatically when each request has completed.

Related

Getting "invalid_grant" error when exchanging a refresh token for an access token

I've seen this issue in a lot of questions, but so far, none seem to apply to my situation.
The problem we are having is we are getting an "invalid_grant" error when we attempt to get an access token. This only happens to some accounts, but when it does happen, in every case I looked at, the refresh token worked before, and now has stopped working. This is happening far to frequently for it to be customers revoking access (seems to be nearly 20% of the channels we manage in the last couple weeks have been invalidated).
As a note, we have a backend process that uploads the videos to our customer's YouTube channels.
We use OAuth2 to get a refresh token, here are the parameters we send...
scope = "https://www.googleapis.com/auth/youtube",
client_id = "",
response_type = "code",
access_type = "offline",
approval_prompt = "force",
redirect_uri = "http://www.us.com/OAuth/YouTube"
NOTE: for client_id we use the email address that is in the Google API manager (or was, I just looked and it is no longer there). We used to use the client ID from this page, but that caused us problems as well. Did this change? Should we be using the client ID from this page now?
We exchange the code that is returned for a refresh and access token and store the refresh token in our database.
The backend process exchanges the refresh token for an access token and this is where we seem to be getting the "invalid_grant" error.
Guaranteed only a single access token for the channel is in use at any time (25 limit doesn't apply). We don't store the access token, we get a fresh one every time we process a channel.
Any ideas what might be happening? Something to look for? See note above about client ID. This might have something to do with it, but I'm hesitant to try it since using the "Client ID" from the API manager caused problems before.
Guaranteed only a single access token for the channel is in use at any time (25 limit doesn't apply). We don't store the access token, we get a fresh one every time we process a channel.
This statement is incorrect: Access tokens can be used as many times as you need while they are still good (for an hour).
Answer:
"invalid_grant" basically means that your refresh token no longer works. The only solution to the problem is to request access again and get a new one. The question should be why is it expiring in the first place.
Assuming that the user did not revoke access, and that the refresh token has been used to request a new access token within the last six months. This is probably an issue with it being over written.
When a user authenticates your application you are given a refresh token. This refresh token is associated to the client id of your application and the user who has just authenticated. If said user then authenticates your application again you will get another refresh token. Again this refresh token is associated to the user and your projects client id. Both of these refresh tokens will work. Your user can keep doing this up to 25 (Note I think the changed it recently to 50 but I haven't tested it with all APIs yet) once they have hit this magic number the first refresh token will expired and if you try and use it you will get an invalid grant.
The only solution is then to just request authentication again. It is important to always save the most recent refresh token that your user has granted your application. In the event (like me) you have an application that is stored on a number of servers all requiring authentication. Your going to have to tell them not to refresh it to many times or they will have to go back and reauthenticate the first one that they expired.
If this is happening with ALL of your requests. You can also check that you server is sync with (NTP) and that you are sending the payload of your request in the post field. Not attached to the authentication end point like a HTTP GET (been there done that).
Here are the possible reasons why a token stops working and becomes invalid:
The user has revoked access.
The token has not been used for six months.
The user changed passwords and the token contains Gmail scopes.
The user account has exceeded a certain number of token requests.
As you can see, it's not recommended that you request a fresh one every time you process a channel. As also mentioned in Token expiration:
If you need to authorize multiple programs, machines, or devices, one workaround is to limit the number of clients that you authorize per user account to 15 or 20. If you are a Google Apps admin, you can create additional admin users and use them to authorize some of the clients.
With regards to the use of client_ID, it is usually needed to call the sign-in API as mentioned in Creating a Google API Console project and client ID.
And lastly, this Google Groups discussion - OAuth 2.0 400 - error:invalid_grant and ideas? might also help.

Seamlessly deal with authorization token expiration in client app

Say I'm developing an Evernote or YouTube client, and after the user logs in, the app gets an authorization token from the API server.
Then I use this token to interact with the server until, sometime later, the token expires.
The key is, I don't know if this token is expired until the server returns an error with a message like 'token expired'. Then I have to fetch a new token. Maybe it occurs while the user is posting a message.
So what is an elegant way to deal with this scenario? I want to combine fetching a new token with continuing the last request, so that the user just feels it works as usual.
It depends on which flow you're using. But in general, if you are able to refresh the auth token (via refresh token) without redirecting the user for credentials again, you should do it seamlessly.
Also, you should know exactly when a token is going to expire. If you're coding against an OAuth 2 implementation, the auth token response should give you an 'expires_in' field as a time span telling you exactly how long the token will expire after it was issued to you.

What is the Youtube OAuth 2.0 user token validity period?

I read the documentation in the Youtube developers website it does not talk about any validity.
Does the OAuth 2.0 standards define any validity period or is the authorization token valid till the user revokes it manually ?
The OAuth spec defines that the token should expire shortly after its granted, so will it expire after I get the
access and refresh tokens ?
And can I use this access token for all future API requests or do I need to get a new token periodically ?
I'm assuming you are talking about the authorization code, you're mixing the terms a bit here.
From the OAuth 2.0 draft:
The authorization code MUST expire shortly after it is issued to mitigate the risk of leaks. A maximum authorization code lifetime of 10 minutes is RECOMMENDED. The client MUST NOT use the authorization code more than once. If an authorization code is used more than once, the authorization server MUST deny the request and SHOULD revoke (when possible) all tokens previously issued based on that authorization code.
After using it once for getting the access token, you can not use it again. You also don't need to retrieve an authorization code periodically. You do this only when you have no access token for a user, but want to request his data.
Your access token some time expires. You know when by either looking at the expires_in value that got send with it, or by doing a request to the API and getting an access token expired error back. Then you can use the refresh token to get a new access token without the user being involved.
Very useful step-by-step guide about how to get access and fresh tokens and save them for future use using YouTube OAuth API v3.
PHP server-side YouTube V3 OAuth API video upload guide.
The good thing is, you do not need to worry about the expiry of the tokens, as the script in this guide checks, saves, and updates the token in a txt file for future access.
{"access_token":"XXXXXXXXX","token_type":"Bearer", "expires_in":3600, "refresh_token":"XXXXXXX", "created":000000}
We use at http://presentationtube.com and it works fine with thousands of users.

Oauth flow for google

I am trying to impliment Oauth for my webapplication for google.I am worked upon a POC and it working fine but i have a confusion and not sure how best it can be achieved.
I am using scribe java API for Oauth.
here are the steps i am performing.
Getting request token from Google.
Redirecting user to Google to authenticate them self and authorize my serivice to access his/her few details.
get Access Toekn from google by providing request token and verification code given by google.
Accessing user info once google provide Access token.
now my main confusion is at step no 3, since i am working on a web-application so it will be a 2 step process.
Redirecting user to google
Handling back google redirect.
In order to get an Access token i need to provide same request token which i got at step1 else my request being rejected by the user.
The request token contains 2 things
Toekn -->which is based on the registered application so not an issue
Secret-->This is always being a random string so it should be same when asking for access token
that means i need to store this secret either in my session or some where so that i can access this secret when user is being redirected back to my application.
My confusion is,since in order to save it in session i have to create a unique key and some way to access it in the other action class which will handle Google Redirect back how can i achieve this since at a given time so many user can ask to login using google.
any help in this regard will be much appriciated.
Thanks in advance
When you receive the request token + token secret, use the request token as the unique key of your session to store the token information. After the authorization process, in the callback url, you have access to the request token (it's one of the parameters passed to the callback url). Using this parameter as the session key, you can restore the token information from session, including the token secret, and use it to sign your request for changing the request token for access token. After receiving the access token, a new token secret is returned to you and you can delete the old one from session.
how can i achieve this since at a given time so many user can ask to
login using google
This is not of any problem because for every single user on your site, you are given a different request token.

Appcelerator. Twitter auth in webview

I am trying to do a Twitter connection using a webview in the excellent Appcelerator Titanium. I know there is a great library from David R out, but I do not want to use a popup and I feel that I need more control over the flow.
My question is: During the authentication flow I need to get an oauth_token which (in my knowledge) is a combination of the consumer key and other values. How can I do this? How can I generate this token so that I can continue the process?
I am of course using Javascript.
Thankful for all input!
It is a multi-step process based on the OAuth 1.0 specs, you can find the details at <http://oauth.net/core/1.0/>
Before doing anything, you will need to register an application with Twitter and they will provide you with a Twitter API Key and a Consumer Token (Key and Secret).
For the next steps, I highly recommend you use OAuthConsumer or some other library, but the steps include generating a proper request to get a "Request Token" from <https://api.twitter.com/oauth/request_token>
then using this Request Token, you need to request the user to authorize your application using <https://api.twitter.com/oauth/authorize?oauth_token=REQUESTTOKENKEY>.
This last step provided you with a Request Verifier allowing your application to make the final request for a permanent Access Token from <https://api.twitter.com/oauth/access_token>.
When you receive the Access Token, you should store a copy somewhere so the user does not have to re-authenticate your application every time (unless that's what you desire). This Access Token does not expire until the user specifically removes the access rights of your application from his Twitter profile. Make sure to store the entire Access Token, meaning storing both the Key and the Secret.
Good luck!

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