I wanted to create website where I have separate Sign In and Sign Up form. I also want to have Google authentication with Firebase.
I've implemented it like this both on sign in and sign up page:
await FIREBASE_AUTH.signInWithPopup(googleAuthProvider);
But this code will always create new user.
What I would like to do is to block creating new user on sign in page, only log them in if user already exists (e.g. as I require terms of use consent on sign up page, but I don't want to require it on sign up page - it would be quite weird)
There is no way in Firebase Authentication to prevent users from signing up, while still allowing them to sign in if they're already created. The reason for this is that Firebase Authentication merely focuses on allowing users to authenticate themselves, so to prove who they are by providing credentials. What they can then do in your app is known as authorization, and is up to you to implement in your front-end application code, back-end application code, and server-side security rules.
For example, if you use one of Firebase's databases (Cloud Firestore or Realtime Database), you'll typically maintain a list of approved user's in that list (either their email or their UID). Then before granting the user access to specific screens in your app or data in your database, you check if the users exists in that list. If not, you don't grant access to the screen or data.
I don't see an issue here, when a user uses google auth when they already have an account it will create a new account with their in some cases new data he might have changed in his google account.
In case your users hold other data in your database I'm pretty sure there's a google auth API for that issue.
Related
I am trying to determine if the following scenario is possible with flutter and firebase:
we have users within the company who will be given access to the app, where on the homepage will be a signup another user button where they enter in that user's email and password, they get signed up, and then the original user specifies custom fields for the 2nd user, such as company name, role, position, etc.
Is this possible with flutter and firebase?
Have asked the flutter google group and was told about custom authentications, but from what I see that is just an external authentication system and doesn't show me how to let one user create another users profile with fields.
Any ideas?
The first thing to consider is whether those properties need to be in the user profile at all. The user profile is sent with every request, and should only contain information that is relevant for securing access. If you have additional information to store about the user, you should store it elsewhere (such as in one of Firebase's databases) using the UID of each user as its key.
Assuming that the information is about security (such as the role seems to be, there is no secure way to let one user set security properties (typically referred to as claims) from client-side code. As soon as this is allowed from client-side code, anyone could set such properties for anyone else. That's why setting custom claims for a user is only possible with Firebase's Admin SDKs, which are designed to run in a trusted environment - such as your development machine, a server you control, or Cloud Functions.
There are a few other options, but it's important to realize they're all implemented on top of the above approach.
There is an experimental extension that allows you to set auth claims by writing a document into Firestore, which something like this (JavaScript syntax, but the Flutter code will be similar):
db.collection("user_claims")
.doc("abc123")
.set({
role: "admin",
groups: ["example1", "example2"],
});
Now of course you'll want to make sure that you secure writing to the user_claims collection, as otherwise you'll end up with the same security risk I mentioned in the first paragraph, where everyone can claim any role they want.
Alternatively you can write your own server-side API (for example on Cloud Functions) that you expose to your application, and that then calls the Admin SDK. Here too, it is important to secure access to this API, to ensure only authorized users can call it.
I'm currently developing a web app using firebase authentication to make sure only authorized users can access the backend (e.g. firestore).
However, I don't really care about differentiating users but just want a single password based login/authentication. Meaning users come to the site, enter the password they know and then they get access to the protected data (e.g. from firestore). No need to create a own account.
However, I don't think firebase auth supports something like that.
What would likely work is just using .htaccess to protect the page and then provide users with anonymous accounts once they can access the app/page.
However, the browser popup caused by this is not nice enough for my purpose, I would prefer a nicely styled password form in the actual browser window.
What I could try is creating one account and sharing the password for that with all users (and set the email in the background). However, I'm not sure whether this works fine (e.g. multiple users being logged in at the same time on the same account).
Am I missing a simple option to implement such a single password based login shared between users?
Or is it e.g. possible to send a password to cloud functions, check it there and return an access token for an anonymous account from there to the user?
You can just create a single Firebase Auth email/password account and share the credentials with everyone. As long as you trust that each user will not share them with anyone else, and you trust that they will not maliciously overwrite each others' data, it should be fine.
CONTEXT:
In firebase settings, there's a permissions tab. This shows the users/emails that are associated with accounts that have admin access to the firebase project and console.
I could have sworn I once saw a document describing a method or some way of checking if a user account in firebase auth is also an administrator of the firebase project.
I seriously can't tell if it was in a dream (yes I dream code) or if I actually saw it. I often work late nights and fall asleep in front of my computer.
Question: Is there any way to tell if a user is also an administrator of the firebase app?
IE the user email matches an email that’s listed in the IAM/access management section of firebase as an 'owner' role?
Im currently writing an admin panel for my app, so such a feature would be very useful.
If such a thing does not exist, can anyone suggest an alternative way to manage and authorise users that are capable of logging into the admin dashboard to have control over the app? I already understand custom claims so I will use them if no better solution is suggested.
Well, using only the FirebaseAuth through your app, I don't think you can (as far as my knowledge goes). But you can easily implement the Admin SDK to manage your Custom Claims. Basically, you can use the Admin SDK and find out which "role" you want to access.
Referencing Firebase
Custom claims can contain sensitive data, therefore they should only
be set from a privileged server environment by the Firebase Admin SDK.
and
Custom claims can only be retrieved through the user's ID token.
Access to these claims may be necessary to modify the client UI based
on the user's role or access level. However, backend access should
always be enforced through the ID token after validating it and
parsing its claims. Custom claims should not be sent directly to the
backend, as they can't be trusted outside of the token.
Once the latest claims have propagated to a user's ID token, you can
get them by retrieving the ID token.
Therefore, you'll only need the FirebaseAuth implemented on your app's (client), but will need an extra implementation using a server.
Please see the Firebase use cases, they'll probably fit your needs, and you can pick the one that is "easier" for you.
It turns out it can't do what I wanted in the first place because it's only available on certain triggers.
Here it is: context.authType
https://firebase.google.com/docs/reference/functions/functions.EventContext#.authType
The level of permissions for a user. Valid values are:
ADMIN Developer user or user authenticated via a service account. USER
Known user. UNAUTHENTICATED Unauthenticated action null For event
types that do not provide user information (all except Realtime
Database).
Although it would be great if we could get this information on callable functions and firebase triggers because it would help further secure hosted backend admin apps for customer service or developers, who have high-level access to admin functions. This variable seems to not be available on callable functions but is available on newUser trigger - which is strange, because how can user signup ever be authenticated anyway?
I am working on Firebase application ( Firebase version 4.1.3 )
My health care related application is made for dependent group of people such as children and seniors. However, most of my users are independent group of people age around 18-55. Most of my users use my application for their seniors/children. They need to create account for each of their family seniors/children member. Therefore, my users have to log in and out many times and they have to keep track of their family members' account. My first thought was I should make an account switching feature so that my user can switch their account back and forth between their family members to update information on my application.
After searches on Google, I found way to force switching account on Firebase authentication with Google provider, but those are not what I'm looking for.
My questions are:
Is it possible to store the multiple firebase auth objects (logged in object) in client side?
If it is possible, for how long will the token inside the firebase auth object last for?
If it doesn't last forever, is it possible to refresh update the token so that it can be use without authenticating with the social/phone login again?
The functionality you are asking for is not available out of the box. You have to build it on your own. I do think Firebase provides the pieces to allow you to build it (via Auth and Database).
Is it possible to store the multiple firebase auth objects (logged in object) in client side: You can have multiple Firebase app instances and each one have an auth instance with a current user. You would need to ask each user to authenticate though (you can't authenticate once and sign-in into all of the account). However, you can build your own user group login mechanism, where logging in with one "master" account can allow you to login with multiple accounts using custom Auth.
If it is possible, for how long will the token inside the firebase auth object last for. Firebase sessions are supposed to be indefinite. If a token expires (typically after one hour), it can be refreshed automatically if you are using real time database.
I do not think Firebase has that token capability. But what you could do is simply put the email address of the people in the device by Shared Preferences( for Android). When the user wants to log in with that user bring the email address just ask him to enter the password and then go through the log in process. If you do not want to use SharedPreferences you could simply store the users(also as you said family members) in Firebase Database and link them with the controller user so to speak. Whenever user wants the switch, go and bring the email addres of other family members from Firebase Database and ask in the client for the password and do the login by Firebase Authentication.Hope that helps!
If I create a new product, use simple auth, there is a "create user" API. How do I restrict it so that only invited emails (either by the email or via a one-time key) can sign up? Doesn't seem to fit easily into the rules, but I am probably missing something.
First, I should point out that the core Firebase API uses JSON Web Tokens for auth, which you can generate yourself, so you have full control over the creation of user accounts and can restrict it however you like:
https://www.firebase.com/docs/security/custom-login.html
I'm guessing you're referring to our Simple Login service.
Simple Login is a service that provides some common login options. It has no way to restrict creation of new accounts. However, you can restrict what those accounts can do with Firebase. For example, you could set your security rules up so that only user accounts in some authorized list (in Firebase) are actually able to read or write data.