How to exchange data from database in Microservices - node.js

I am looking for advice on data sharing between microservices.
My app has 3 services but in this case, I need to share data between only 2 services:
-Main (Handling requests, store user data)
-Upload (Receive files and modify)
Before the user can send a file to the server, the server must verify if that the user exists and whether he has permission to send files.
My idea for it is to create a private API in the main service with an Nginx API gateway, so the upload service can make HTTP requests and fetch data about the user and permission. Does it make sense? or there is an easier solution for it? I use express and postgresql.

It is a good approach, but perhaps, the main service should be the auth server.
I mean, in order to ensure that a user has the proper permissions to do an action you have to use something to identify the user and something that cannot be altered, this normally is achieved using a signed token.
This token is created by the auth server when the users log into the application and when it is passed to a service, this service can check against the auth server if the token is valid and if the user identified by the token has the correct permissions to execute the action.
This process is very similar to the one you have explained before. In your case, the user service will be the auth server that is responsible for the authentication and authorization of users and the upload service is the one that is consumed

As you have two microservices(Customer, File upload).
The best way to communicate to other microservices is through the HTTP call(GET,POST,DELETE,PATCH) exposed by that MS.
In your case Customer microservices has few endpoints like GetCustomer,CreateCustomer,DeleteCustomer,PatchCustomer. Before uploading the file you can call the GetCustomer API for checking the customer's existence in the system. If it is present, then proceed with further processing of file data.
As mentioned by JArgente, Use the authorization token for authentication and authorization of microservice endpoint. Pass that token in HTTP_Header while calling the Microservice and validate that against your Authorization server. You can write the interceptor, which validates the token.

As long as your main server can authenticate the user, and verify the user is authenticated, you can implement a JWT token.
If your client is already sending a JWT token to your main server, the same token can be used to communicate with other microservice.
If not you can always generate a new JWT token to be sent to your micro services, without maintaining any centralize database
var token = jwt.sign({ user: 123 }, privateKey, { algorithm: 'RS256'});

Related

validate userId given by okta

I have an app which consists of frontend server and a backend server.
front end server connect to corporate OKTA mechanism so that user logins through their corporate ids into my app.
After this step, frontend server connects with some backend work at backkend server (node js). Their it passes in the request body the user id so that we can finally log that the below processing is happening due to user X.
Now suppose user A logs into the app . Now during the APi call to backend server, he can modify the arguments being passed to the api and somehow change the userID.
Is there some way by which backend server validate that userID is not compromised ?
Regards
If your front-end app uses OIDC to log a user in, then you should be able to get back an id_token, which has user identity in it. You can pass this token to your back end app for API calls. This approach is not ideal though, as your backend will still have issues with trust, as it does not know if the token presented by the front-end app is a legitimate one and not stolen.
Other way is to harness traditional authorization_code flow (again, assuming you can do OIDC with you company's identity provider). There your back-end would retrieve the tokens for you directly from authorization server and can get a user's identity from it. Based on that it can then create a session and embed user info into it. It's a bullet proof approach lacking trust issues from above.

Express backend with Firebase auth and my own database to persist users

I'm creating a system where the client in React will implement Firebase authentication, so Firebase will signIn users, but I have a backend server with Express and I need those users in my own DB (postgresql). I can use firebase-admin in the backend to verify the token sent from the client on each request, and from this token, extract user data, as well as its uid. So I could create a user in my own database with these information.
The problem is that since I'm not handling user signup in my own server, I would have to add a verification in the authentication middleware. Each time the user makes a request to the server, the backend verifies the token (with firebase-admin) and checks if the user already exists in my own database, because if it doensn't, then create this user.
I wanted to see if there is another way to handle this, since every request is not only going to verify a token but also query the database looking for the user.
Verifying the ID token in the backend code is pretty much how all Firebase backend services handle it too. They receive the ID token, request the public key from the project, decode the token, and then validate that the user is authorized for the action they're performing.
You seem to want to create a record for the user in some shared database however, which I'd typically recommend against as it affects scalability. The only thing most Firebase backend services cache is the project keys (as those require an expensive HTTP lookup) and recent encoded/decoded token pairs. But there are caches on each server separately, so it's quite different from having shared state in a database as you seem to want.

Looking for JWT Auth microservice example

I am wanting to build a authentication/authorization service using NodeJS, Mongo, and JWT. This service would be a micro-service that handles requests not only from my API Gateway before allowing requests, but from other services that might want to check auth and roles. I am assuming that all other services will use this Auth Service to validate the JWT as well as roles, etc.
Hopefully this diagram better explains what I am looking for.
Can anyone point me to a resource that might help me learn how to do this with NodeJS?
If you have a single client application then you can do following steps
Make one microservice for authentication that generates jwt token.
The jwt contains all essential user information in its payload, ie Role, UserId etc.
The jwt token will be sent in Authorization header for every authorised request.
Before processing any request you can validate and decode the jwt token using middlewares. Now you can set the user's info in req object easliy and can easily access users role and its id in your controller.
if the token is not valid then you can throw error in middlewares and it will provide json response of unauthorised.
You can call the authentication api to validate and decode your token or you can write 3 to 4 line of code in every microservice in middleware.
Here are some links for sample implementation of jwt, you should customize these sample code according to above steps.
5-steps-to-authenticating-node-js
authenticate a nodejs api with json web tokens
If you have multiple client applications
You should use openid connect standard that provides single sign on solution to authenticate multiple application with same username and password.
here is a openid connect playground to understand the authorization flow.

Microservices authentication architecture with passport.js

I'm writting a toy application for practicing microservices and authentication on nodejs (expressjs).
I have a react client, an authentication service and other services (they just respond "Hi" so far).
The client will be hosted in a CDN.
The auth service listens on port 5000 (for example)
The rest of the services listen on port 6000-6100.
I have a redis db to store session information (oauth token provided by twitter).
A mongodb where the application information is stored (not relevant for this question).
The idea is that an unauthenticated client goes to the auth service by clicking the Twitter button (SSO). Then the auth service obtains the generated twitter oath token and it sets this token in the redis store. Then the token is accessible to the rest of the services so they know if a request is authenticated or not by checking if the it already exists in the redis store (if the user removes its account, it will also be deleted from the redis store).
I send the twitter token back and forth from client to server once authenticated.
I find this approach pretty simple (others use an nginx proxy for authentication but I see no reason for that, except if the services are hosted in different domains, but I don't understand it very well) so I'm worried I'm missing something about security for example.
Questions:
Is this approach correct?
Is it safe to share the twitter token (I think so)?
Is there any security issue I'm not noticing here?
Using this approach you will have to validate the token in all your services, if you are okay with this then you are probably fine.
The twitter access token may have an expire time that will make it necessary to use a refresh token to get a new access token from the auth service:
When the access token expires you would return a 401 to the client, from the Service X that you are trying to talk to.
The client would have to call the Auth service providing a refresh token, getting a new access token
Finaly the client would be hitting the Service X again with this new access token, have it validated and get the expected response from Service X.
In my recent assignment I wrote a micro-service that proxied all the tokens, using this approach my proxy handled everything from auth to roles and sending 401's for expired tokens and revoking refresh tokens etc. I think this gave me a greater separation of concerns.
Important Note: In the refresh token scenario above my proxy only would experience load for an invalid/expired accesstoken, whilst in your scenario any service could be reached with invalid tokens...
Another approach would be to let Service-A and Service-B call the auth service to validate the tokens, but this would infer a lot of more traffic between the services since each HTTP request with a token has to be validated. In this scenario as well a invalid token request would reach your Service X and hence infer some load on it...

nodejs authentication using api

I am building an application which needs to authenticate from another application (via api)which provides response status(success, failure) and an access-token.I need simple authentication where when user supplies correct credentials, I hit the api and save the authentication user name and access-token in session and have a persistent session.I have tried looking passport http and other strategies.But I don't think they serve this use case?Kindly let me know if I am wrong and what is the easy and effective way to achieve this.
You don't need store access-token in session.
The easiest way is use JWT (JSON Web Token) - http://jwt.io. When user sends username\password credentials to your API, you check if these credentials is correct. After that you are signing JWT and respond to the client.
When client sends to you signed access-token, you can check it with passport-jwt module - https://www.npmjs.com/package/passport-jwt.

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