在RealTime數據庫上刪除數據-Firebase

Question

我正在使用Firebase實時數據庫，並為數據庫設置了以下規則，

{
  "rules": {
    ".read": "auth !== null",
    ".write": "auth !== null"
  }
}

但是，當我嘗試刪除一個條目時，它給我一個錯誤，表明權限被拒絕，如下所示。

Database: Client doesn't have permission to access the desired data. (database/permission-denied).

我該怎么辦？ 我不明白為什么我可以使用當前規則進行所有讀寫操作，而不刪除。

誰能幫我這個？

注意：與Firebase Simulator相關的結果圖像

當檢查firebase.auth().currentUser ：

deleteUserAccount(userId) {
 let knownLocationRef = this.database.ref('lastKnown/' + userId);
 let promises = [];
 console.log('auth details', this.auth.currentUser);
 console.log('auth details null', this.auth.currentUser !== null); //returns true
         knownLocationRef.once('value').then( (data) => {
            console.log('data ', data.val());
            if (data.val() !== null) {
                let prevLat = data.val().lat;
                let prevLong = data.val().long;
                console.log('auth details', this.auth.currentUser);
                console.log('auth details null', this.auth.currentUser !== null); //returns false
                promises.push(knownLocationRef.remove());
            }
        });
         return Promise.all(promises);
 }

Answer 1

以下是代碼的一些問題以及如何處理promise：

function deleteUserAccount(userId) {
  let knownLocationRef = this.database.ref('lastKnown/' + userId);
  let promises = []; // good idea for collecting a list of distinct 
                     // promises, maybe not here

  // This is a promise, 'then' is a continuation from which you can return 
  // either a data result or another promise
  knownLocationRef.once('value').then((data) => {
    // if data is valid, return another promise
    if (data.val() !== null) {
      // ...

      // If you were looping and collecting promises, then this might help, 
      // but you don't want to collect inner promises.
      promises.push(knownLocationRef.remove());
    }
  });

  // This returns before everything in `.then` executes
  return Promise.all(promises);
}

這是固定版本：

function deleteUserAccount(userId) {
  let knownLocationRef = this.database.ref('lastKnown/' + userId);
  let promises = []; // For the sake of argument, I will use this to collect 
                     // outer promises.

  // normally I would return here, but as an example, I'll uses the 
  // promises array
  promises.push(knownLocationRef.once('value').then((data) => {
    // if data is valid, return another promise
    if (data.val() !== null) {
      // ...

      // Return a Promise from a promise
      return knownLocationRef.remove();
    }

    return null; // no data to process
  }));

  // wait on outer promises
  return Promise.all(promises)
    .catch(console.log); // log errors from any promise
}

這是一個沒有多余的promises數組的版本。

function deleteUserAccount(userId) {
  let knownLocationRef = this.database.ref('lastKnown/' + userId);

  return knownLocationRef.once('value')
    .then((data) => {
      // if data is valid, return another promise
      if (data.val() !== null) {

        // Return a Promise from a promise
        return knownLocationRef.remove();
      }

      return null; // no data to process
    })
    .catch(console.log);
}