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[英]Node JS : Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[英]Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client in Node JS
我正在嘗試使用無法正常工作但出現上述錯誤的特定ID更新數據。
更新時,首先我在數據庫中搜索該特定ID,然后將數據保存到MongoDB
這是我的server.js
const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const mongoose = require('mongoose');
//importing MongoDB model schema
let ToDo = require('./todo.model');
const app = express();
const todoRoutes = express.Router();
const PORT = 4000;
//middlewares
app.use(bodyParser.json());
app.use(cors());
app.use('/todos', todoRoutes);
//connection to the MongoDB database
mongoose.connect('mongodb://127.0.0.1:27017/todos', {useNewUrlParser: true});
const connection = mongoose.connection;
connection.once('open', () =>{
console.log("Connected to the MongoDB through port: 27017");
});
app.listen(PORT, () => {
console.log(`Listening to port: ${PORT}`);
});
//get all data - removed to show only the code snippet I am getting errors
//get data by an ID - removed to show only the code snippet I am getting errors
//add items to database -removed to show only the code snippet I am getting errors
//update items
todoRoutes.route('/update/:id').post((req, res) => {
let id = req.params.id;
ToDo.findById(id, (err, todo) => {
if(err) throw err;
if(!todo) res.status(400).send("No data found");
todo.todo_description = req.body.todo_description;
todo.todo_responsible = req.body.todo_responsible;
todo.todo_priority = req.body.todo_priority;
todo.todo_completed = req.body.todo_completed;
res.end();
todo.save().then(todo => {
res.json(200).send("Data Updated! " + todo);
res.end();
}).catch(err => {
res.status(400).send("Error occured! " + err);
});
});
});
這是我得到的錯誤...
有人可以幫幫我嗎?
在'/update/:id'
路由中,您要發送一個res.end()
然后在三行之后再次執行。 如果刪除第一個res.end()
,它將正常工作。
如果todo
丟失,也應該return
:
todoRoutes.route('/update/:id').post((req, res) => {
let id = req.params.id;
ToDo.findById(id, (err, todo) => {
if(err) throw err;
if(!todo) return res.status(400).send("No data found");
todo.todo_description = req.body.todo_description;
todo.todo_responsible = req.body.todo_responsible;
todo.todo_priority = req.body.todo_priority;
todo.todo_completed = req.body.todo_completed;
todo.save().then(todo => {
res.status(200).send("Data Updated! " + todo);
}).catch(err => {
res.status(400).send("Error occured! " + err);
});
});
});
此錯誤通常表示您多次發送響應。
請注意,您發送了兩個響應,一個在另一個res.json()
和res.end()
如果出於某種原因想要結束響應,請使用res.end()
,否則請使用res.status(200).json({ result: 'Data updated' + todo })
如果兩者都發送,它將抱怨發送后(通過res.status().json()
)嘗試修改響應(通過res.end()
res.status().json()
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