How to exchange facebook code for an access_token - java

I start oAuth2 with Facebook from client side and I get code after successful user login. Now I want exchange code for an access_token like here: https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow
How can I exchange code for token? I need do REST GET Request with WebClient or do simple redirect with Spring Controller? I want to do this without any external library.
My flow I think should look like:
User clicks Login with Facebook
Redirected with code to backend
Gets code and exchanges for a access_token
Call Graph QL for user data
Save user data, generate JWT and back to frontend.

From the question I understand you need to basically implement Authorization code flow of the OAuth2.0 protocol.
After you receive code, you have to exchange it for a token. For this you would have to send a POST request(through your spring controller) to access token endpoint of Facebook. With this you would have to send additional details like client_id, client_secret which you have received when you created a fakebook client application.
PS:I understand you might have constraints with using third party libaries to achive this, but have a look at this awsome open-source library.

Related

Authorization code flow - how to get Code parameter value

I've implemented an application that redirects to the wso2 identity server login page. If the login is successfull the user is redirected to a page where he can read his profile details.
Based on his role he can perform certain action, like create a new user.
I've implemented an API (http://localhost:8080/add-user) that calls this URL ( https://localhost:9443/t/carbon.super/oauth2/token) to generate the access token with the desired scope (for example internal_user_mgt_create) that I need in order to call
the wso2 SCIM2.0 API (https://is.docs.wso2.com/en/latest/apis/scim2-rest-apis/#/Users%20Endpoint/createUser).
Everything works if I use grant_type=password and I use the user credentials to generate the access token to call the wso2 SCIM2.0 API, but I want to use "authorization_code" as grant_type to avoid sending user credentials in my application.
How can I do that? And I know that one of the parameters that I need to use this flow is "code", where can I get its value?
You can configure authorization code grant in your application by selecting the Code from the Allowed Grant Types list OAuth/OpenID Connect Configuration in your application. [1]
When using the auth code grant your application needs to wso2 authorize endpoint to obtain the authorization code Using this authorization token and client secret you can obtain the access that is capable of calling the scim endpoint.
Refer to following documents for more information
[1]. https://is.docs.wso2.com/en/latest/guides/access-delegation/authorization-code/
[2]. https://medium.com/identity-beyond-borders/generating-access-tokens-using-wso2-identity-server-4d8c084a3bf5
It's harder to provide an exact answer to this question without knowing more details about the app and the flow you'd expect your users to go. However, it'd be much easier if you have a better understanding of the OAuth2 code grant type. The following is the basic flow.
The user accesses your application through a web browser.
Your application redirects the user to the identity server, with the following parameters in the request.
client_id=xxx
response_type=code
redirect_uri=yyy - Location in your application where you want to get the authz code. This needs to be registered with the IS service provider beforehand.
scopes
The IS prompts the user to log in.
The IS then redirects the user to the given redirect URI, with the authorization code.
Once the code is received by the client, it makes a back channel call to the token endpoint of the IS (https://localhost:9443/t/carbon.super/oauth2/token) with the following parameters.
grant_type=authorization_code
client_id=xxx
client_secret=zzz
code=ccc
IS validates the code and issues an access token.
Read more on OAuth2 here.
Now, if you're getting the "Inactive authorization code" error, your application might already be calling the token endpoint with the code received, before you call your add-user API.
Ideally, your add-user API shouldn't call the token endpoint at all. You should call the token endpoint from your application, get an access token and pass that to the add-user API if needed. Or you can directly call the SCIM API from your application itself.
I hope this helps!

Google Cloud OAuth 2.0 Request Token without user interaction - Java

I am working on a solution to read log files from the GCP for an internal process. However, i am having a difficult time trying to generate an Auth Token for the request to grab the logs needed. This is more of a flow\context question rather than a whats wrong with my code one
The key issues i am having is that i do not want to prompt for web-browser authentication. I want to be able to do this all through API request and have no user interaction. Everywhere i have looked and all implementations i have tried, i am prompt for user interaction in some way and that is just not feasible for this solution.
How can this be achieved?
We do not have IAM enabled, so i cannot generate a JWT token.
I am trying to do this through using a Service Account created using client id and client secret.
I have tried getting a "code" to pass into a request to generate an authorization token, but that has been prompting me for user authorization in the browser which will not work, even when I add the query parameter 'prompt' or 'approval_prompt' to none or force.
I feel like i am missing one crucial piece to be able to achieve this flow and any help/guidance will be greatly appreciated.
There are several ways to authenticate API calls. If you want to do it without user interaction, you will need to use a Service Account (more info here). The process would be the following:
You use the client ID and one private key to create a signed JWT and construct an access-token request in the appropriate format. Your application then sends the token request to the Google OAuth 2.0 Authorization Server, which returns an access token. The application uses the token to access a Google API. When the token expires, the application repeats the process.
For this, you can use Client Libraries or you can do it manually with HTTP requests directly. In the docs there is a guide to do so.

How should I create a new Federated Identity Provider for Firebase Authentication

I would like to integrate PayPal signin into an android app so to authenticate the client to the Firebase Database. I've managed to create a custom funtion on the node.js server that creates tokens from the provided uid, in order to use "signin withcustomtoken" function in the client application. Should I send the uid to the nodejs server through https in order to get the token? Is there a better way?
Don't create an HTTP endpoint that accepts a uid and returns a custom token. This is a huge security vulnerability as any attacker would be able to impersonate any user knowing their uid.
What you need to do is the following:
Implement a paypal OAuth code flow. You can use third party libraries for that.
When you get the paypal OAuth authorization code, you send it to your backend, you use the paypal client ID and secret to exchange for a paypal refresh token and access token. You can then get the user info associated with that paypal user including their paypal uid. You would then mint a Firebase custom token using the Firebase Admin SDKs and return it to the client.
On the client you would signInWithCustomToken to complete sign in with that custom token.
In this case you are exposing an HTTP endpoint that takes an authorization code and returns a Firebase custom token.
This is the basic idea (details excluded). Of course you still have to ensure the flow starts and ends on the same device by passing some state and then check that you get it back in the end. You also have to ensure the auth code is returned to the correct app using something like app links, etc. Firebase Dynamic Links can be helpful there.

How to achieve login in java consuming a web service?

I have a project in java which utilize j_security_check and ldap for authentication. Now my employer want to change it to an authentication using a webservice provided . What they gave me is actually a link as shown below
"http://11.111.111.111/ADManager/ADlogin.asmx"
I am a total newbie to java and webservice.All I know is if we provide some data to a webservice it will give a response. my doubts are
Is it possible to create a login consuming that link they provided?
Should I ask them for more info?
Is it posible to replace the j_security_check and ldap already configured in my java project?
P.S : The one who assigned me this task doesn't seems to have much knowledge either.
The short answer is you can.
You need to do the following:
Each web resource is protected by a (servlet) filter. This filter checks each incoming request and validates the token which needs to be on the http header. If the token is valid then the request is served. If the token is invalid the filter is going to send back http 401 unauthorized. Then redirect to the loin page.
Login with rest service:
1) Create a custom login page with username/password field.
2) Create a rest web service, receives username/password. It will check the credentials against an external access management infrastructure like OpenAM.
3) First, call auth(username, password) rest api to get the auth token. If the given credentials are okay then just send back the auth cookie to the client with HTTP 200 response code.
4) Then, you can call protected rest apis. You need to send auth cookie with your request each time.
5) Servlet filter (or something similar) checks each incoming request and validates the token. If the token is valid then the request goes forward to the rest method, if not you need to generate an http 401/403 response.
I suggest you not to write your own authentication layer, please use an existing one, for example OpenAM.
This forum topic explain everything you.

Authenticating a user using Google

I'm having a hard time wrapping my head around how to authenticate a user in my REST service. I plan to use Google Sign-in (on Android, namely). I can't quite figure out how to authenticate users on my server. I do not want to have any authorizations (other than validating the identity of the user), all I want to do is when I receive a request, validate that the user is who he (or she) says he is.
My understanding is that the user will login, get some sort of token from Google, then send that token along his request to my server which I will use to validate his identity. However, from what I read, the user will encode their requests in a JWT (json web token), which I will then use to validate their identity without ever talking to the Google server directly. Did I understand properly?
On Google's documentation, it says
If you do not require offline access, you can retrieve the access token and send it to your server over a secure connection. You can obtain the access token directly using GoogleAuthUtil.getToken() by specifying the scopes without your server's OAuth 2.0 client ID.
But it does not say what the server should do with the token.
You have an android app which enables user to log in via Google+ Sign-In, and then this Android app will call your REST API. What you want is how your service authenticates this request. This Android client will send request to your service with token, and you need to validate this token for authentication. Is my understanding right?
If so, you need to validate the token sent to your service. The reference you mentioned is for Google API calls, in your case; it's your own service API call. For the Android side, just follow the reference, in your service side you can use TokenInfo validation to authenticate users.

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