根据firebase中的用户类型防止写入文档?

是的,这是完全可能的,在Firebase上的文档中有很好的介绍 role based access control 。当您在Firestore文档中定义角色时,以下是示例规则:

service cloud.firestore {
  match /databases/{database}/documents {
    // For attribute-based access control, Check a boolean `admin` attribute
    allow write: if get(/databases/$(database)/documents/users/$(request.auth.uid)).data.admin == true;
    allow read: true;

    // Alterntatively, for role-based access, assign specific roles to users
    match /some_collection/{document} {
     allow read: if get(/databases/$(database)/documents/users/$(request.auth.uid)).data.role == "Reader"
     allow write: if get(/databases/$(database)/documents/users/$(request.auth.uid)).data.role == "Writer"
   }
  }
}

在自定义属性中定义角色时的以下规则:

service cloud.firestore {
  match /databases/{database}/documents {
    // For attribute-based access control, check for an admin claim
    allow write: if request.auth.token.admin == true;
    allow read: true;

    // Alterntatively, for role-based access, assign specific roles to users
    match /some_collection/{document} {
     allow read: if request.auth.token.reader == "true";
     allow write: if request.auth.token.writer == "true";
   }
  }
}

我还建议您从Firebase专家那里查看以下视频: Implementing Authorization Models