How does OAuth work? - algorithm

I do not mean how is it implemented, but rather what steps should user pass?
I'm working with Photobucket now and I found in its docs that I should generate a new token for every request, because the token can expire in a certain (but secret) period of time.
How does this generation work? Do I need a separate request for generating a token?

You can have a log in button, and when a user clicks on it you would make an ajax request to get a new oauth access token and then generate the oauth url based on that token.
Then after the user authenticates they will be redirected to a callback URL that you must specify from within your account settings.

Related

Does an API require a Logout endpoint?

I've read on various blog posts that a REST API does not require a logout endpoint.
Instead, the front end should just invalidate the token.
I'm using Laravel Sanctum, is this applicable to that?
Could someone explain why the session does not need invalidating on the server? If the token on the server is not invalidated, is there not a chance that a new user could be given the same token and access another user's details?
"is there not a chance that a new user could be given the same token and access another user's details?"
no mate, not a chance. because you must generating token with user information, in other words you are "attaching" a token to specified user. you can check this if you want.

How to invalidate mobile personal access token after backend deletion?

I am using Laravel as my backend together with Sanctum which generates personal access token for mobile users. For my mobile application I am using flutter.
To authenticate users they login with their username/password and get a personal access token in return. This works but requires a user to login every time they open the application again so I did what most tutorials suggest which is saving the token on the mobile device using shared preferences/secure storage.
Now comes the question how do you invalidate a user when you remove their token from the backend? On initial login it appears everything is still fine because like in most tutorial I check for the existence of a token. After that whenever I want to make a request which uses the token I obviously run into problems because it not longer exists on the backend.
Most tutorials/guide suggest saving the token and using that a reference to see if the user is logged in or not but this seems flawed because it gives the false impression you actually have a valid token.
My guess is this can be solved by always performing a heartbeat/ping action to check if the current token is valid and if not send them to the login screen instead of simply checking for the existence of the token.
Thoughts on this?
I can suggest a hack or trick here in every launch of the app you can send a request to an API to check if the user's token is valid or not and if it is valid then you can continue the app otherwise force the user to login and generate new token this way your app will be secure via server / API.
For this, you can store the user's secret token in the database and check it via HTTP API call and send a response from the API accordingly and check the response in app and do the next operation according to the response you get.
I don't know if this is a great way of doing this job but it is a kind of hack/trick to achieve what is needed.
Thanks

What to return after login via API?

I'm creating an API server which will be consumed by a mobile app that I will work on later. I have yet to see any reference of API best practices related to user flow and returned data even after searching for several hours.
My question is whether the login response of an API should return the a personal access token with the refresh token along with the user info? Or should I just return the token and make another API call for getting the user info.
I could just do what I have in mind but I'm trying to learn the best practices so that I don't have to adjust a lot of things later.
I need suggestions as well as good references related to my question.
Thank you.
It depends on what you are using for your authentication. If you are using libraries like Laravel Passport or JWT, you can have the token endpoint which returns the access token, refresh token, validity period and the token type (Bearer). You can then have an authenticated endpoint which will be used to get a user's profile based of the token passed in the request header.
However, if you go through the documentation for those libraries, in most there is an allowance to manually generate a token. You can use this in a custom endpoint that will return the token as well as the user profile Passport Manually Generate Token.
If you are using JWT, you can also embed a few user properties in the token itself. The client can the get the profile info from the JWT itself without having to make a round trip to the server. Passport ADD Profile to JWT
If you have a custom way in which you are handling authentication, you can pass the token as well as the user profile in the same response.
In the end, it's up to you to decide what suits you best.
Have you looked at OpenID Connect? It's another layer on top of OAuth 2.0 and provides user authentication (OAuth 2.0 does not cover authentication, it just assumes it happens) and ways to find information about the current user.
It has the concept of an ID_token, in addition to the OAuth access token, and also provides a /userinfo endpoint to retrieve information about the user.
You could put user information in your access token, but security best practice is to NOT allow your access token to be accessible from JavaScript (i.e. use HTTP_ONLY cookies to store your access token).

Can I know in which point we need to validate the JWT expiration?

I am quite new to JWT based authentication. And im quite confused about the refresh token mechanism. In my case, I have designed my application as,
1. User will login to the application, and when the login is successful then it will go to the authentication server and sign a jwt and will pass it to the client.
2. And then the client will store the refresh token and the short lived token in the local storage
3. Once the resource server is called the token will be sent through the header. and will get validated.
My question is, in which point should we request another token using the refresh token mechanism. Should we check whether the short lived token is invlaid before sending the request to the resource server. or should we get a new token once the validation fails in resource server? or is there any better way to handle this?
A Refresh Token is a special kind of token that can be used to obtain a renewed access token —that allows accessing a protected resource— at any time.
Although Access Tokens can be renewed at any time using Refresh Tokens, they should be renewed when old ones have expired, or when getting access to a new resource for the first time. Refresh Tokens never expire OR have very long expiration time.

Yammer Rest API > Authentication based on server side script (php) without user interaction

My project has the requirement to access the yammer data using the given REST API using server side script(mainly PHP) and not involve a client side login using yammer's OAuth dialog.
I have gone through this document:
https://developer.yammer.com/docs/oauth-2
but this says, we requires user interaction.
What I wanted was can I generate a client_id and client_Secret to further generate access token to make API call out, but in all these processes I only use the authenticated users username and password in my server-side script.
Can anyone suggest a solution or is a client-side interaction required by design?
Thanks in advance!!
You have to have a user authorize the application at least once. This is just the nature of the OAuth implementation and you can't work around it. Having users go through the OAuth flow is considered a best practice.
If you have an OAuth token for a verified admin of Yammer, you can use impersonation to get tokens for end users without them interacting with the OAuth flow.
The below from Microsoft blogs might help you & added source at the end of answer.
Obtain a Verified Admin token for your application in one of the following 2 ways
a. Create the app with a Verified Admin account and then in the app’s Basic Info page, click “Generate a developer token for this application.” Note that you’ll need to use this app’s info in the JS SDK and any subsequent calls.
b. Use the process outlined at https://developer.yammer.com/docs/test-token with a Verified Admin account to get an OAuth token for that VA account. Note that you must use the app info used to generate this token in all future steps.
Obtain the current user’s email address in the server-side script.
Using the VA token obtained in step 1 to authenticate, pass the user’s email address to our Get User by Email Address endpoint documented at https://developer.yammer.com/docs/usersby_emailjsonemailuserdomaincom, and then process the response
a. If the call to the API endpoint returns a 200 OK response, first check the “state” field to make sure the user is “active” and if so, store the “id” field that’s returned and go to step 4
b. If the call returns a 404 or a state other than “active,” direct the user to finish creating and activating their account however you like.
Once you have the user’s ID, you can pass it to our Impersonation endpoint to obtain a pre-authorized OAuth token for that user. This endpoint is documented at https://developer.yammer.com/docs/impersonation and must use the VA token obtained in step 1 to authorize the call, and the consumer_key of your JS SDK app.
You now have an OAuth token for the current user. When generating the code being passed to the browser, have the client side JS SDK code first call yam.platform.getLoginStatus and if there’s no active session and you have a token from step 4, pass that token to yam.platform.setAuthToken($tokenFromStep4, optional_callback_function_if_desired(response)). If you don’t have a valid token, direct the user to finish setting up their Yammer account.
Continue making JS SDK calls as you normally would, without needing the user to authenticate.
Source: https://blogs.technet.microsoft.com/askyammer/2016/11/04/preauthorizing-the-yammer-js-sdk/

Resources