Allow write based on the value of a document fileld-CodePudding

I want all authenticated users to read the collection but only the user with the uid that is specified in the field named uid should be able to write.

service cloud.firestore {
    match /taken/{doc}{
      allow read: if request.auth.uid != null;
      allow read,write: if request.auth.uid == doc.id;
    }  
  }
}

However, the above code does not allow write access even if the query has the right uid.

CodePudding user response：

You can read data of the document being access using resource object as explained in the documentation.

service cloud.firestore {
    match /taken/{doc}{
      allow read: if request.auth != null;
      allow write: if request.auth.uid == resource.data.id;
    }  
  }
}

The above rules allow any authenticated users to read the documents in 'taken' collection but only user with that UID in the documentation to write it.

CodePudding user response：

Try this:

service cloud.firestore {
    match /taken/{doc}{
      allow read: if request.auth != null;
      allow create: if true;  // resource.data is not defined on create, hence the separate case
      allow update, delete: if request.auth.uid == resource.data.uid;
    }  
  }
}

And you can even force the uid field to be set on create, depending on your logic:

service cloud.firestore {
    match /taken/{doc}{
      allow read: if request.auth != null;
      allow create: if request.auth.uid == request.resource.data.uid;  // Forces uid to be set to the user's uid
      allow update, delete: if request.auth.uid == resource.data.uid;
    }  
  }
}