CODEWITHSUNDEEP
node.jsfirebasefirebase-authentication
P.hunter
P.hunter

Reputation: 1365

Node.js: how to find a user in firebase Authentication by uid?

I'm fairly new to node and making a web-app in which I use passport to authenticate and then store the user using firebase authentication by a custom token.

and now i want to perform a lookup and check if the user is registered with my app.

So is there is a way to check for a specific user (like either by their uid or email)?

in the docs here it is given how to list all the users.

here is the code for it (i modified a bit for my purpose) -

function listAllUsers(id, nextPageToken) { // passing an id to check and page token is not passed as default
  // List batch of users, 1000 at a time.
  admin.auth().listUsers(1000, nextPageToken)
    .then(function(listUsersResult) {
      listUsersResult.users.forEach(function(userRecord) {
        if (userRecord.uid == id){
              return true // here i return from the function but it only return from one function. (do i have to make a flag to come out from all of them?)
            }
      });
      if (listUsersResult.pageToken) {
        // List next batch of users.
        listAllUsers(id, listUsersResult.pageToken)
      }
    })
    .catch(function(error) {
      console.log("Error listing users:", error);
    });
}
// Start listing users from the beginning, 1000 at a time.
let user = listAllUsers('some random id'); // i expect a Boolean here

but is there any way to do a lookup like listUsersResult.users.find(id) // which may return a boolean or whole user?

Upvotes: 1

Views: 2409

Answers (2)

wmash
wmash

Reputation: 4202

Looking at the docs you linked and having played around a little in firebase myself, there is no method that returns a found/not found boolean. However, you can do:

admin.auth().getUser(uid)
  .then(function(userRecord) {
       // See the UserRecord reference doc for the contents of userRecord.
       console.log("Successfully fetched user data:", userRecord.toJSON());
  })
  .catch(function(error) {
      console.log("Error fetching user data:", error);
  });

As quoted by their docs:

If the provided uid does not belong to an existing user or the user cannot be fetched for any other reason, the above method throws an error.

If you want a boolean simply set a boolean in the then...catch to whether the user was found or not.

For example:

let found = false;

admin.auth().getUser(uid)
  .then(function(userRecord) {
      found = true;
  })
  .catch(function(error) {
      found = false;
  });

EDIT

To return to your base function, the best way (in terms of Node) is to make the function asynchronous with a callback/Promise/Observable. As Promise's are newer I will create one here:

var user_check = new Promise(function(resolve, reject) {
    admin.auth().getUser(uid)
      .then(function(userRecord) {
          resolve(userRecord);
      })
      .catch(function(error) {
          reject(error);
      });
});
console.log(user_check); // if found, returns the user_record, else, returns an error

For more information regarding async code, refer to MSDN

Upvotes: 4

Doug Stevenson
Doug Stevenson

Reputation: 317487

See the documentation. You can call admin.auth.getUser(uid) for this (also see the API docs).

Upvotes: 1

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