我正在尝试创建一个非常简单的Web应用程序，用户可以在其中创建要显示的Web日历上的事件。我正在使用的日历应用程序具有读取json文件以获取事件信息的功能。我已经使日历组件正常工作，并且将api设置为正确发送数据。即时消息遇到我的api的发布部分时，我在尝试处理数据时遇到问题。我将其范围缩小到了我的fs.writefile。我似乎在这里做错了。其余代码库工作正常，当我注释掉试图将要发送到/ createEvent的帖子数据的部分注释掉时，整个代码有效（减去写入json文件的预期目标）
这是我得到的错误：
(node:12756) [DEP0018] DeprecationWarning: Unhandled promise rejections are `deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.`
以下是我的API正在发送但未处理的示例帖子：
{ userInput: { title: 'Vinny', start: '2018-12-01', end: '2018-12-01' } }
这里是我的代码：
const express = require('express');
const routes = require('./routes/');
const app = express();
const port = 3000;
const router = express.Router();
const cors = require('cors');
const bodyParser = require('body-parser');
const helmet = require('helmet');
const fs = require('fs')
import ('./calendarevents.json');
routes(router);
app.use(cors()); // Allows for Cross origin requests
app.use(bodyParser.json()) // Turns all post requests to json
app.use(bodyParser.urlencoded({ extended: false }));
app.use(helmet()); // Helps secure apps with Http headers
app.use('/api',router);
app.get('/', (req, res) => res.send('Hello World!'))
app.use(bodyParser.json())
app.get('/api/createEvent'), (req, res) => {
res.render(req.body)
}
app.post('/api/createEvent', (req, res) => {
console.log(req.body);
//res.send("recieved your request!")
const UserInput = JSON.stringify(req.body);
fs.writeFile('./calendarevents.json', UserInput, (err) => {
if (err) throw err;
console.log("The file was saved!");
});
});
app.listen(port, () => console.log(`StoreUI Backend listening on ${port}!`))
答案 0 :(得分：1)
您抛出了一个错误，但没有处理。您也不会将对帖子的回复发送回客户端。
为什么不只发送500状态而不是抛出错误？
AB答案 1 :(得分：0)
您没有处理该错误，因此node发出了弃用警告。另外，您使用的是import ('./calendarevents.json');，这是无效的语法（除非您的API封装在webpack中，但是我也不确定为什么要将其导入）。并且...您的当前设置将在每次发送新事件时完全覆盖JSON文件。如果要附加它，请参阅选项2。
以下内容不是很干净，但是如果将fs调用包装在promises中，则可以清理干净。为了简单起见，我决定不这么做。
选项1：
app.post('/api/createEvent', (req, res) => {
const calanderEventPath = './calendarevents.json';
const newEvent = JSON.stringify(req.body);
try {
const pathExists = fs.existsSync(calandEventPath); // check if path exists
if (!pathExists) throw "The calandar JSON file has not been created yet.";
let error;
fs.writeFileSync(calanderEventPath, newEvent, 'utf-8' function(err) { // attempts to save newEvent to the calandar JSON path
if (err) error = 'Unable to save the new event to the calandar JSON file.';
});
if (error) throw error;
res.status(201).send("Successfully saved the event.");
} catch (err) {
res.status(500).send(err);
}
});
选项2：
app.post('/api/createEvent', async (req, res) => {
const newEvent = JSON.stringify(req.body);
const calanderEventPath = './calendarevents.json';
let savedEvents;
let error;
try {
const pathExists = fs.existsSync(calandEventPath); // check if path exists
if (!pathExists) throw "The calandar JSON file has not been created yet.";
fs.readFileSync(calanderEventPath, 'utf8', function(err, currentEvents) { // attempt to read file to extract current event data
if (err) error = "Unable to read the calandar JSON file.";
savedEvents = JSON.stringify(currentEvents.push({ newEvent })); // push "newEvent" data into the current event data and set it to "savedEvents"
}
if (error) throw error;
fs.writeFileSync(calanderEventPath, savedEvents, 'utf8', function(err) { // attempts to save "savedEvents" to the calandar JSON path
if (err) error = 'Unable to save the new event to the calandar JSON file.';
});
if (error) throw error;
res.status(201).send("Successfully added an event");
} catch (err) {
res.status(500).send(err)
}