Heroku：当我尝试加载页面时出现应用程序错误 [Node.js + Express]

Question

index.js

// create an express app
const express = require("express");
const app = express();

// use the express-static middleware
app.use(express.static("public"));

// define the first route
app.get("/", function (req, res) {
  res.send("<h1>Hello World!</h1>");
});
  
// start the server listening for requests
app.listen(process.env.PORT || 3000, () => console.log("Server is running..."));

package.json

{
  "name": "SimpleApp",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "node index.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.17.1"
  },
  "engines": {
    "node": "10.x",
    "npm": "*"
  }
}

资料

web: echo "I don't want a web process"
service: npm start

我已经在 heroku 中部署了它。

日志显示如下

2021-06-22T13:16:11.346614+00:00 app[service.1]: ------------------------------------------------------------------
2021-06-22T13:16:11.371025+00:00 app[service.1]: Server is running...

但是当我尝试加载页面时出现应用程序错误。

在本地运行良好

Answer 1

您的网络测功机可能默认关闭。您需要将其打开才能运行您的 heroku 应用

Answer 2

在声明中间件时检查你设置的目录是否正确

app.use(express.static("public"));

如果不是，则使用 __dirname 连接正确的目录，如下所示

const public = path.join(__dirname, "../public")

然后

app.use(express.static(public));