如何获取 Firebase 集合中的所有文档（包括不存在的祖先文档）？

Question

I am trying to pull all the documents in the collection 'users', but it only pulls 'fred' and 'lisa', and ignores all the italicized documents:

For this data:

Trying to get all documents:

Will yield:

info: length 2
info: fred  =>  { gender: 'male', contacts: [ '' ] }
      lisa  =>  { contacts: [ '' ] }

According to the Firebase documentation ( Firebase: Add and Manage Data ):

Warning: Even though non-existent ancestor documents appear in the console, they do not appear in queries and snapshots. You must create the document to include it in query results.

Note: The non-existent ancestor users seem to be auto-created when the user hits the sign-up button that triggers a firebase.auth() function ( fred and lisa were created manually).

How would I print the contacts of each user if some of the users do not show up in my queries? Would I need to periodically run a script that manually re-adds all the users or is there a more elegant solution?

Answer 1

As you have mentioned, these "documents" are displayed with an italic font in the Firebase console: this is because these documents are only present (in the console) as "container" of one or more sub-collection but they are not "genuine" documents.

As matter of fact, if you create a document directly under a col1 collection with the full path doc1/subCol1/subDoc1 , no intermediate documents will be created (ie no doc1 document).

The Firebase console shows this kind of "container" (or "placeholder") in italics in order to "materialize" the hierarchy and allow you to navigate to the subDoc1 document but doc1 document doesn't exist in the Firestore database.

Let's take an example: Imagine a doc1 document under the col1 collection

col1/doc1/

and another one subDoc1 under the subCol1 (sub-)collection

col1/doc1/subCol1/subDoc1

Actually, from a technical perspective, they are not at all relating to each other. They just share a part of their path but nothing else. One side effect of this is that if you delete a document, its sub-collection(s) still exist .

So, if you want to be able to query for these parent documents, you will have to create them yourself, as jackz314 mentioned in the comments.

Answer 2

If you're trying to list all your registered users from Firebase auth, you can use the Firebase SDK function:

    function listAllUsers(nextPageToken) {
      admin.auth().listUsers(1000, nextPageToken)
        .then(function(listUsersResult){
          listUsersResult.users.forEach(function(userRecord) {
            console.log('user', userRecord.toJSON());
          })
          if (listUsersResult.pageToken) {
            // list next batch of users
          }
        })
        .catch(function(err) {
          console.log('Error listing users: ', error)
        });
    }

    listAllUsers();

via http://firebase.google.com/docs/auth/admin/manage-users#list_all_users