net::ERR_CONNECTION_REFUSED 尝试在节点 js 中发出 post 请求时

Question

我正在尝试使用 fetch 发出 post 请求。通常当我使用 npm start 启动我的服务器时它工作得很好。但是使用 webpack dev server 它给了我这个错误：

这是我的服务器端代码：

require('dotenv').config();

const mockAPIResponse = require('./mockAPI.js')

const PORT = 8081

const apiKey = process.env.API_KEY
const baseUrl = 'https://api.meaningcloud.com/sentiment-2.1'

const express = require('express')
const cors = require('cors')
const bodyParser = require('body-parser')
const fetch = require('node-fetch')
var path = require('path')
const app = express();

app.use(cors())
app.use(bodyParser.json())
app.use(bodyParser.urlencoded({ extended: false }))
app.use(express.static('dist'))

app.get('/', function(req, res) {
    res.sendFile('dist/index.html')
        //res.sendFile(path.resolve('src/client/views/index.html'))
})
app.post('/api', async(req, res) => {
    console.log("you key is", apiKey)
    const enteredUrl = req.body.url;
    const apiUrl = baseUrl + '?key=' + apiKey + '&url=' + enteredUrl + '&lang=en'
    console.log(apiUrl)
    const response = await fetch(apiUrl)
    try {
        const fetchedData = await response.json()
        console.log(fetchedData)
        res.send(fetchedData)
    } catch (error) {
        console.log("error", error)
    }


})


app.get('/test', function(req, res) {
    res.send(mockAPIResponse)
})

// designates what port the app will listen to for incoming requests
app.listen(PORT, (error) => {
    if (error) throw new Error(error)
    console.log(`Server listening on port ${PORT}!`)
})

我的package.json:

{
    "name": "evaluate-news-nlp",
    "version": "0.0.1",
    "main": "index.js",
    "scripts": {
        "test": "jest",
        "start": "nodemon src/server/index.js",
        "build-prod": "webpack --config webpack.prod.js",
        "build-dev": "webpack-dev-server  --config webpack.dev.js --open"
    },
    "keywords": [],
    "author": "Alaa",
    "description": "",
    "dependencies": {
        "2": "^3.0.0",
        "@babel/runtime": "^7.16.7",
        "axios": "^0.21.1",
        "babel-polyfill": "^6.26.0",
        "body-parser": "^1.19.0",
        "cors": "^2.8.5",
        "dotenv": "^8.6.0",
        "express": "^4.17.1",
        "node-fetch": "^2.6.1",
        "sass": "^1.45.1",
        "webpack": "^4.44.2",
        "webpack-cli": "^3.3.5"
    },
    "devDependencies": {
        "@babel/core": "^7.5.4",
        "@babel/plugin-transform-runtime": "^7.16.7",
        "@babel/preset-env": "^7.5.4",
        "@types/jest": "^26.0.20",
        "babel-core": "^6.26.3",
        "babel-loader": "^8.0.6",
        "babel-plugin-transform-runtime": "^6.23.0",
        "babel-polyfill": "^6.26.0",
        "babel-preset-es2015": "^6.24.1",
        "babel-preset-stage-0": "^6.24.1",
        "clean-webpack-plugin": "^3.0.0",
        "css-loader": "^5.1.2",
        "file-loader": "^6.1.1",
        "html-webpack-plugin": "^3.2.0",
        "jest": "^26.5.3",
        "mini-css-extract-plugin": "^0.9.0",
        "nodemon": "^2.0.7",
        "optimize-css-assets-webpack-plugin": "^5.0.4",
        "prettier": "^2.2.1",
        "sass": "^1.45.2",
        "sass-loader": "^10.1.1",
        "style-loader": "^2.0.0",
        "supertest": "6.1.3",
        "terser-webpack-plugin": "^1.4.5",
        "webpack-dev-server": "^3.7.2",
        "workbox-webpack-plugin": "^6.1.1"
    }
}

Webpack 开发服务器工作正常，直到我尝试发出 post 请求。我尝试了不同版本的 webpacks、webpack dev server、node-fetch 但仍然出现相同的错误。我该如何解决这个错误？

编辑：我认为问题与以下事实有关：webpack dev 服务器在端口 8080 上运行，而我的 express 服务器在 8081 上运行。当我检查请求的网络选项卡时，显示如下：

错误后显示如下：

编辑：我能够通过运行 webpack 开发服务器解决问题，然后打开另一个终端和运行 npm start 来启动我的快递服务器。这是它应该如何正常工作吗？因为我遵循的教程仅适用于 webpack dev server

Answer 1

发生此错误是因为快递服务器不是运行。运行 npm start 启动快速服务器

net::ERR_CONNECTION_REFUSED 尝试在节点 js 中发出 post 请求时

net::ERR_CONNECTION_REFUSED when trying to make a post request in node js

javascript

fetch

node.js

webpack

webpack-dev-server