I am currently writing an android app. In my app users can rate some objects. The data (the objects as well as the ratings) shall be stored in Google Firebase, especially Firestore.
I already linked my app to Firebase and implemented the com.google.android.gms.auth.api.signin to get the GoogleSignInAccount of the current user.
I want to save the data to the database like:
SomeObject: | objectId | name |
ObjectRating: | ratingId | objectId | userId | rating |
What I am not sure about is, what to save as userId. The documentation of GoogleSignInAccount.getId() says:
Important: Do not use this returned Google ID to communicate the currently signed in user to your backend server. Instead, send an ID token (requestIdToken(String)), which can be securely validated on the server; or send a server auth code (requestServerAuthCode(String)) which can be in turn exchanged for id token.
So I probably should not use this. But the recommended IdToken is signed, so I think it will be different everytime the method is called.
What most people do, is create a users directory in the database. But from the app I want to get the users rating as well as the overall mean rating of all users for the given object. So I think splitting the ratings in multiple user tables complicates the computation of the overall mean rating.
My question is: How can I link the ObjectRating to the user, without using the unsafe getId() while still be able to select all ObjectRatings by objectId to compute the mean rating?
To obtain the user's unique identifier you can use FirebaseAuth to get the FirebaseUser object:
FirebaseAuth.getInstance().getCurrentUser().getUid();
The getUid() method:
Returns a string used to uniquely identify your user in your Firebase
project's user database. Use it when storing information in Firebase
Database or Storage, or even in your own backend.
You'll need to ensure that you've used the GoogleSignInAccount to authenticate with Firebase before calling getCurrentUser(), otherwise it will return null.
Related
I want to link my game to a database that stores username and high scores, in order to create a leaderboard. A lot of tutorials I watched uses Firebase Authentication, but I want to store only the username without any email signup. Is it possible to only use Firebase Firestore to store user data? It would also be helpful if there is any guide I can use to do so.
A lot of tutorials I watched uses Firebase Authentication
The tutorials you have watched are using Firebase Authentication because it provides a really useful feature, which is securing the database using Cloud Firestore Security. These rules are enforced on the server, so can't be bypassed by malicious users.
Is it possible to only use Firebase Firestore to store user data?
Yes, it is. If you are not interested to secure your database, you can create a structure that looks like this:
Firestore-root
|
--- users (collection)
|
--- $username (document)
|
--- age: 20
|
--- gender: male
Having the username as the document ID will ensure that you will have no duplicates because in a collection you cannot have two documents with the same ID.
If you reconsider your approach to using Security Rules, please check the following article before:
How to fix Firestore Error: PERMISSION_DENIED: Missing or insufficient permissions
Yes you can do that. You need to implement also SharedPreference. SharedPreference will use as to check whether user already logged in or not.
Assume your json look like this:
-user
-userUid
-username = USERNAME
-psw = PSW
-otherData = ...
-userUid
-username = USERNAME2
-psw = PSW2
-otherData = ...
From here, you can do a loop and compare each of them if username and psw are correct. Once it is, exit the loop and make it as logged in.
I have a collection of "Users" in Cloud Firestore and I am using Firebase Auth to authenticate my app users as follows:
The user authenticates within the mobile app (for example with Google).
I verify that there is no document within the "Users" collection that corresponds to the UID of the authenticated user.
If the document does not exist in "Users" I use the user's UID to create a new document.
It is my question: Is there a security problem with this model or some other type?
I am confused by Google documentation because it says that the user's UID is unique to the Firebase project but should not be used to authenticate my user to the backend server. It also says that in that case, I should use FirebaseUser.getToken () but that token can change, so it will create a new user in my DB.
So, my second question is: When should you use that token? Give me an example, please.
Thanks for the help.
USER_ID
You can use the google generated user_id for future reference. That will never change for a given user email or authentication type as long as the user is already in the database.
Example:
If the user Signed In with google federated login with user1#example.com then the user record is maintained in the Firebase and USER_ID(Say ABFDe12cdaa2...) will be assigned(You can use this id in URLs to see the user profile etc it is kind of 32 chars long(I am not sure exactly here). Now, If a user tries to sign up again with the same email(user1#example.com) then it pulls the previous record ABFDe12cdaa2.... If you delete a user1#example.com from the firebase database(Firebase maintains its own database of the user for your project, With has a limited number of user properties). Then the user tries to sign in again then the new USER_ID is generated.
Now the TOKEN:
As you USER_ID is public, it can be seen by everyone. It is not used for authentication.
So you need to generate the token( This is longer the user id) to authenticate programmatically with the Firebase. It token is temporary and specific to the user. It will expire in some time ( you can define that time while creating the token). a refresh token is used to get a new token.
I don't have any code examples while writing this answer. I will update with code example,If, I find any.
Hope I clarified some of your questions.
my Android app requirement is to assign old (already exists UID) UID to new users while signing in with Google so that the new user can access the old user data directly. Note: old user data is stored with UID as the node but in various Firebase Realtime Database top-level nodes. Is it possible to change the UID.
There is no way to assign a UID to a user that is created with a client-side SDK, as that would be a major security risk. After all: what is keeping other users then also claiming the UID of any other user in your app.
The typical way is to deal with a scenario like this is to either track who has access to whose data in the database, or to perform a data migration when the new user is created and you've validated that they're indeed supposed to "inherit" another user account's data.
You can use link method from firebase SDK. see here
I am making an app, and in that app, users login and I am storing their information; however, I have noticed that I don't have a users' password information after they register. Is it a good idea to store users' password when they register through Firebase? And is there a point where I will need their passwords? I want to make sure before I proceed further. Thanks!
You do not do that.
Use the (awesome, amazing) Firebase authentication system.
Click right here:
on the left, to see all the users - click "Authentication".
You never see / you cannot see their passwords.
You don't handle or touch the passwords at all.
In the Android or iOS app, you get the userid - and that's it.
The answer by #PeterHaddad shows perfectly how to do that.
That's the first and most basic step in any Firebase ios/droid app.
In your data you'll have a "table" called probably "userData/" and that's where you keep all data about the user. (For example, you may store their address, real name, shoe size .. whatever is relevant in your app.)
Note - FBase is so amazing, your users can also connect with other methods (phone, etc). For your reference in the future, that is explained here
You don't need to store the password in the firebase database, after you authenticate the user using createUserWithEmailAndPassword the email and other info will be stored in the authentication console. So you do not need the password in the database, all you need is the userid to connect auth with database.
FirebaseUser user=FirebaseAuth.getInstance().getCurrentUser();
String useruid=user.getUid();
I have authenticated my user using phone authentication, and the user object that is returned has this long string when I call user.getUid() :
dn27dhJK..... (some long string).
If I authenticate this user on some other device (using my phone number etc), will user.getUid() always be the same ?
EDIT: From the documentation: https://firebase.google.com/docs/reference/android/com/google/firebase/auth/FirebaseUser
public abstract String getUid ()
Also: Google Play services Returns a string used to uniquely identify
your user in your Firebase project's user database. Use it when
storing information in Firebase Database or Storage, or even in your
own backend.
This identifier is opaque and does not correspond necessarily to the
user's email address or any other field.
It is unclear if this id remains constant or not.
When you first verify the phone number (or first sign in with a social provider, or call createUser), a user account is created - and thus a new unique UID id created. From that moment on, that user/phone number will remain associated with that account/UID. No matter if they re-verify on the same or a different device.
If you delete the account, a new account+UID will be generated when you use that same phone number next time.
If you're using Firebase Authentication in your project:
Remember
Firebase will generate a single unique key(i.e. UID) on registration of a/c whether using Email/Phone number.
This key remain associated to that a/c untill a/c is exist in firebase authentication list.
If your app is uninstalled on phone & then a/c is open in another then we can fetch that key from Firebase cloud auth. service.( UID remain safe).
This Uid is created when the user signs up and is linked to the phone number that you used. When you sign in you will get the same uid. But if you try to sign up again with the same phone number, it will basically give an error saying this phone number is already signed up.Hope that explains!