Cloud Functions for Firebase：尝试从实时数据库读取时出现标头错误

Question

我在尝试从云功能访问 firebase 实时数据库时遇到了这个奇怪的错误，我想不出更多关于如何修复它的想法。这是我的代码：

const functions = require('firebase-functions');
const admin = require('firebase-admin');

admin.initializeApp(functions.config().firebase);

exports.createNewGame = functions.https.onRequest((request, response) => {

        return admin.database().ref().once('value').then(function (data) {
                console.log("BLA");
                response.end();
        });
});

还有错误：

info: User function triggered, starting execution
info: Execution took 60010 ms, finished with status: 'timeout'
info: Execution took 60046 ms, finished with status: 'crash'
error: Something went wrong with the function!
error:  Error: Can't set headers after they are sent.
    at validateHeader (_http_outgoing.js:504:11)
    at ServerResponse.setHeader (_http_outgoing.js:511:3)
    at ServerResponse.header (C:\Users\Thugm\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\express\lib\response.js:730:10)
    at ServerResponse.send (C:\Users\Thugm\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\express\lib\response.js:170:12)
    at ServerResponse.json (C:\Users\Thugm\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\express\lib\response.js:256:15)
    at ProxyServer.Supervisor._proxy.on (C:\Users\Thugm\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\@google-cloud\functions-emulator\src\supervisor\supervisor.js:104:14)
    at ProxyServer.emit (C:\Users\Thugm\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\eventemitter3\index.js:144:27)
    at ClientRequest.proxyError (C:\Users\Thugm\AppData\Roaming\npm\node_modules\firebase-tools\node_modules\http-proxy\lib\http-proxy\passes\web-incoming.js:156:18)
    at emitOne (events.js:115:13)
    at ClientRequest.emit (events.js:210:7)

如果有人能指出我找到解决方案的正确方向，我们将不胜感激。干杯！

Answer 1

使用 HTTP 函数，您不会像使用其他类型的函数那样返回承诺。当您向客户端完全发送响应时，HTTP 函数将终止。

在读取数据后尝试使用response.send("") 之类的方法以空响应完成您的函数：

exports.createNewGame = functions.https.onRequest((request, response) => {
    admin.database().ref().once('value').then(function (data) {
        console.log("BLA");
        response.send("");
    });
});