【发布时间】：2017-08-01 07:10:45
【问题描述】：
我们正在开发一个使用新的 firebase 云功能的应用程序。当前正在发生的事情是将事务放入队列节点中。然后该函数删除该节点并将其放入正确的节点中。由于能够离线工作，因此已经实施了这一点。
我们当前的问题是函数的速度。该函数本身大约需要 400 毫秒，所以没关系。但有时函数需要很长时间（大约 8 秒），而条目已经添加到队列中。
我们怀疑服务器启动需要时间，因为当我们在第一次之后再次执行该操作时。它需要更少的时间。
有没有办法解决这个问题？在这里，我添加了我们函数的代码。我们怀疑它没有任何问题，但我们添加了它以防万一。
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const database = admin.database();
exports.insertTransaction = functions.database
.ref('/userPlacePromotionTransactionsQueue/{userKey}/{placeKey}/{promotionKey}/{transactionKey}')
.onWrite(event => {
if (event.data.val() == null) return null;
// get keys
const userKey = event.params.userKey;
const placeKey = event.params.placeKey;
const promotionKey = event.params.promotionKey;
const transactionKey = event.params.transactionKey;
// init update object
const data = {};
// get the transaction
const transaction = event.data.val();
// transfer transaction
saveTransaction(data, transaction, userKey, placeKey, promotionKey, transactionKey);
// remove from queue
data[`/userPlacePromotionTransactionsQueue/${userKey}/${placeKey}/${promotionKey}/${transactionKey}`] = null;
// fetch promotion
database.ref(`promotions/${promotionKey}`).once('value', (snapshot) => {
// Check if the promotion exists.
if (!snapshot.exists()) {
return null;
}
const promotion = snapshot.val();
// fetch the current stamp count
database.ref(`userPromotionStampCount/${userKey}/${promotionKey}`).once('value', (snapshot) => {
let currentStampCount = 0;
if (snapshot.exists()) currentStampCount = parseInt(snapshot.val());
data[`userPromotionStampCount/${userKey}/${promotionKey}`] = currentStampCount + transaction.amount;
// determines if there are new full cards
const currentFullcards = Math.floor(currentStampCount > 0 ? currentStampCount / promotion.stamps : 0);
const newStamps = currentStampCount + transaction.amount;
const newFullcards = Math.floor(newStamps / promotion.stamps);
if (newFullcards > currentFullcards) {
for (let i = 0; i < (newFullcards - currentFullcards); i++) {
const cardTransaction = {
action: "pending",
promotion_id: promotionKey,
user_id: userKey,
amount: 0,
type: "stamp",
date: transaction.date,
is_reversed: false
};
saveTransaction(data, cardTransaction, userKey, placeKey, promotionKey);
const completedPromotion = {
promotion_id: promotionKey,
user_id: userKey,
has_used: false,
date: admin.database.ServerValue.TIMESTAMP
};
const promotionPushKey = database
.ref()
.child(`userPlaceCompletedPromotions/${userKey}/${placeKey}`)
.push()
.key;
data[`userPlaceCompletedPromotions/${userKey}/${placeKey}/${promotionPushKey}`] = completedPromotion;
data[`userCompletedPromotions/${userKey}/${promotionPushKey}`] = completedPromotion;
}
}
return database.ref().update(data);
}, (error) => {
// Log to the console if an error happened.
console.log('The read failed: ' + error.code);
return null;
});
}, (error) => {
// Log to the console if an error happened.
console.log('The read failed: ' + error.code);
return null;
});
});
function saveTransaction(data, transaction, userKey, placeKey, promotionKey, transactionKey) {
if (!transactionKey) {
transactionKey = database.ref('transactions').push().key;
}
data[`transactions/${transactionKey}`] = transaction;
data[`placeTransactions/${placeKey}/${transactionKey}`] = transaction;
data[`userPlacePromotionTransactions/${userKey}/${placeKey}/${promotionKey}/${transactionKey}`] = transaction;
}
【问题讨论】：
-
不返回上述 'once()' 调用的 Promise 是否安全？
标签： node.js firebase firebase-realtime-database google-cloud-functions