Question

我正在调用Firebase可调用函数，并返回Firebase指定的Promise，但出现此错误：

未处理的错误RangeError：超出最大调用堆栈大小

代码如下：

exports.getProductInfo = functions.https.onCall((data, context) => {
  // Message text passed from the client.
  const product = data.product;
  // Authentication / user information is automatically added to the request.
  // const uid = context.auth.uid;

  // Get the current Server Timestamp
  var ts = String(Date.now());
  var key, snap, node;

  // Get the price of the specified product
  return database.ref('/products/' + product)
                 .orderByKey()
                 .endAt(ts)
                 .limitToLast(1)
                 .once('value', function (snapshot) {
                   snap = snapshot.val();
                   console.log('snap: ' + JSON.stringify(snap));

                   key = Object.keys(snap)[0];
                   node = snap[key];
                   console.log('node: ' + JSON.stringify(node));

                   return(node);
                 });
});

这是我在功能日志中看到的输出：

快照：{“ 1538004276”：{“ description”：“这是基本产品”，“ price”：40}}

节点：{“ description”：“这是基本产品”，“ price”：40}

Unhandled error RangeError: Maximum call stack size exceeded
    at Object (native)
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:4905:24
    at baseForOwn (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:2996:24)
    at Function.mapValues (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13401:7)
    at encode (/user_code/node_modules/firebase-functions/lib/providers/https.js:242:18)
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13402:38
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:4911:15
    at baseForOwn (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:2996:24)
    at Function.mapValues (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13401:7)
    at encode (/user_code/node_modules/firebase-functions/lib/providers/https.js:242:18)
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13402:38
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:4911:15
    at baseForOwn (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:2996:24)
    at Function.mapValues (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13401:7)
    at encode (/user_code/node_modules/firebase-functions/lib/providers/https.js:242:18)
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13402:38
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:4911:15
    at baseForOwn (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:2996:24)
    at Function.mapValues (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13401:7)
    at encode (/user_code/node_modules/firebase-functions/lib/providers/https.js:242:18)
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13402:38
    at /user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:4911:15
    at baseForOwn (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:2996:24)
    at Function.mapValues (/user_code/node_modules/firebase-functions/node_modules/lodash/lodash.js:13401:7)

帮助！

Answer 1

问题类似于the one described here。您将返回由Firebase API生成的称为DocumentSnapshot的复杂对象。快照本身不是返回给客户端的原始JSON数据，它包含对其他对象的循环引用。 Cloud Functions卡在试图序列化所有这些对象的过程中。相反，只需在快照上调用val()即可在感兴趣的位置返回数据的原始JavaScript对象：

return database
    .ref('/products/' + product)
    .orderByKey()
    .endAt(ts)
    .limitToLast(1)
    .once('value')             // once() returns a promise containing a snapshost
    .then(snapshot => {
        return snapshot.val()  // this is the raw JS object
    })

您通常不会在同一调用中同时使用返回的诺言和回调。只使用诺言就更容易了。

Answer 2

对我来说，解决方案是将收益包装在Promise中：

exports.getIssue = functions.https.onCall(data => {
const issueKey = data.issueKey

return new Promise((resolve, reject) => {
    admin
        .database()
        .ref('issue')
        .child(issueKey)
        .once('value', snapIssue => {
            let issue = snapIssue.val()
            if (issue) {
                return resolve(issue)
            } else {
                reject('Issue not found')
            }
        })
        .catch(reject)
})

Answer 3

值得一提的是，这并未明确地写在Firebase doc中；您应该始终在HTTP请求之前对对象进行字符串化。另一方面，只需对其进行解析。删除JSON.stringify（）和JSON.parse（）将触发完全相同的错误。

客户端：

auth.signInWithEmailAndPassword(username, password).then(async (snapShot) => {
    const getToken = await functions.httpsCallable('getToken')(JSON.stringify(snapShot));
    ....
});

服务器端：

exports.getToken = functions.https.onCall(async (data, context) => {
    console.log(JSON.parse(data));
    ...
});

Firebase未处理的错误RangeError：超出最大调用堆栈大小

3 个答案: