Firebase fetches role-based documents-CodePudding

If I have a collection in firebase with several documents inside and each document has a field called for example "role", is it possible to show a user only the documents that belong to him when the whole collection is fetched?

CodePudding user response：

Yes. You can do this.

Let's assume the user has the role 'student', you can fetch all documents .where('role', isEqualTo: 'student').

NB: role could also be the userId (and you can fetch all documents where role is userId).

You can use the following firebase rules to prevent unauthorised access.

match /document/{docs=**} {
  allow write, read: if isAllowed();
}
function isAllowed() {
  // request.resource.data is the data being fetched.
  return request.resource.data.role == 'student';
}
function userRole() {
  // returns the user role. Use this if the user role is stored in a document.
  return get(/databases/$(database)/documents/users/$(userId)).data.role;
}

NB: your query must contain .where('role', isEqualTo: 'student') if not it will fail with insufficient permissions.