Custom middleware

• matching routes = http method + url path
  • GET /, POST /submit, etc
• Essentially, middleware functions (like the one you wrote) run before the route handlers, and they can either:
  • End the request (with res.send, res.json, etc.).
  • Pass control to the next matching route or middleware with next().
• next()
  • passes control to the next matching route or middleware
  • if u dont use it, request never moves past the middleware & it will hang forever
• this is why the order of middleware is important

import express from "express";
import { dirname } from "path";
import { fileURLToPath } from "url";
 
const app = express();
const port = 3000;
const __dirname = dirname(fileURLToPath(import.meta.url));
 
app.use((req, res, next) => {
  console.log("Request url: ", req.url);
  console.log("Request method: ", req.method);
  next(); // proceeds to next step of handling that rewuest
});
 
app.get("/", (req, res) => {
  console.log("page shown!");
  res.sendFile(__dirname + "/public/index.html");
});
 
app.post("/submit", (req, res) => {
  res.send("Form succesfully submitted!");
  console.log("Submitted!");
});
 
app.listen(port, () => {
  console.log(`Listening on port ${port}`);
});
 

or a defined function

// app.use(logger);
function logger(req, res, next) {
  console.log("Request url: ", req.url);
  console.log("Request method: ", req.method);
  next();
}
 
app.use(logger);