node.js - 使用 Node.js 和 Express for Action on Google 进行同步调用？

Question

我正在使用 Express 运行 Node.js 服务器来与 Actions on Google 交互。为了满足请求，我需要访问外部服务器，因此我使用 Fetch 库。我似乎无法让 Node 服务器等待 Web 服务调用给出适当的响应。我尝试过使用 Promises 和 Await/Async 但我没有正确实现它..有人可以帮助完成这项工作吗？谢谢!

let fetch = require('node-fetch');
let express = require('express');
let bodyParser = require('body-parser');
let { dialogflow, Image } = require('actions-on-google');
let app = dialogflow();
let json;

function middleware(req,res,next) {
    json = req.body;
    next();
}

app.intent('StartIntent', conv => async function() {
    const response = await communicate(json);
    console.log(response);
    // Not running synchronously
    conv.ask('Need the response from above');
});

function communicate( message ) {
    let response;
    try {
        response = fetch('https://stackoverflow.com', {
            method: 'POST',
            body:   JSON.stringify(message),
            headers: {
                'Content-Type': 'application/json'
            },
        });
        return response;
    } catch(e) {
        console.log(e);
        return null;
    }
}

express().use(bodyParser.json(), middleware, app).listen(3000);

@Prisoner 是正确的 - 仅当返回 communications() 结果中的 json 数据后才应调用 conv.ask()。然而，此时 Promise 对象中唯一返回的东西。数据被正确检索为 json 对象。

let fetch = require('node-fetch');
let express = require('express');
let bodyParser = require('body-parser');
let { dialogflow, Image } = require('actions-on-google');
let app = dialogflow();
let json;

function middleware(req,res,next) {
    json = req.body;
    next();
}

app.intent('StartIntent', conv => {
    const response = communicate(json);
    console.log("StartIntent Response:");
    console.log(response); // output: Promise { <pending> }
    // Not running synchronously :(
    console.log(response.text);
    conv.ask('Need the response from above');
});

function communicate( message ) {
    let response;
    try {
        response = fetch('https://google.com', {
            method: 'POST',
            body:   JSON.stringify(message),
            headers: {
                'Content-Type': 'application/json'
            },
        }).then(function(body) {
            return body.json();
        }).then(function(json) {
            // The data is returning successfully
            // For example: {"BTCUSD":10000}
            return json;
        }).catch(function() {
            // error handling
        });
        return response; // This is returning a pending Promise
    } catch(e) {
        console.log(e);
        return null;
    }
}

express().use(bodyParser.json(), middleware, app).listen(3006);

Answer 1

fetch() 返回一个 Promise。您可以为 communicate() 链接 then() 调用，并在正文中使用 conv.ask() 的响应。

下面是一个简单的示例代码片段，使用 node-fetch 进行 API 调用并使用该调用的响应。 (请注意，此示例正在对 JSON 数据执行 GET 请求。)

'use strict';

const { dialogflow } = require('actions-on-google');
const functions = require('firebase-functions');
const fetch = require('node-fetch');

const app = dialogflow({debug: true});

// Default Welcome Intent
app.intent('Default Welcome Intent', (conv) => {
  return apiCall().then((response) => {
    conv.ask(`Response from above ${JSON.stringify(response)}`);
  });
});

// Makes an API call to a URL to retrieve JSON data.
function apiCall() {
  const URL = 'https://example.com/data.json';
  return fetch(URL).then((response) => response.json());
}

exports.endpoint = functions.https.onRequest(app);