CODEWITHSUNDEEP
firebasegoogle-cloud-firestorefirebase-securitytype-safety
EzPizza
EzPizza

Reputation: 1150

list type safety in firestore security rules

In my firestore security rules, I want to have a rule, that checks if all elements of a list are of type string.

My "user" documents have a field called "friends". It is an list of strings, that represent the documentIDs of other user documents. These are my current rules:

function userIsAuthenticated() {
  return request.auth != null;
}

match /users/{userID} {

  function resourceIsValidUser() {
    return displayNameIsValid();
  }

  function displayNameIsValid() {
    return request.resource.data.displayName is string &&
      request.resource.data.displayName.size() > 0 &&
      request.resource.data.displayName.size() < 17;
  }

  function photoUrlIsValid() {
    return request.resource.data.photoUrl is string;
  }

  function friendsIsValid() {
    return request.resource.data.friends is list;
  }

  function userIsUserOwner() {
    return request.auth.uid == userID;
  }

  allow read: if userIsAuthenticated();
  allow write: if
    userIsAuthenticated() &&
    resourceIsValidUser() &&
    userIsUserOwner();

}

Is there anything I could add to the friendsIsValid() function to ensure the friends-list only contains string-values?

Upvotes: 4

Views: 1684

Answers (1)

Doug Stevenson
Doug Stevenson

Reputation: 317392

There is currently no function that checks the types of all the elements of an array. Since there is also no way to iterate an array, the only thing you can do now is predict the size of the array and check each element individually, for example array[0] is string && array[1] is string and so on.

The Firebase team is aware that some rules might need to do this. It will help escalate the matter if you file a feature request with Firebase support.

Upvotes: 8

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