Express Cheatsheet: GET (route params & query string) + POST (request body)

m2-express-cheatsheet-GET-POST.md

Intro

This cheatsheet covers the following topics:

1. URL: Route Params
2. URL: Query String
3. Request Body

URL: Route Params

• Example URL:

  • https://localhost:3000/artists/madonna

• How to use route params in Express:

  1. In the path, define a dynamic part with the syntax /:something
  2. Inside the route, read from req.params

• Example 1:

  app.get('/artists/:artistname/', (req, res) => {
      console.log(req.params); //req.params is an object
      const artist = req.params.artistName;
  });

• Example 2 (multiple route params):

  app.get('/artists/:artistname/albums/:albumName', (req, res) => {
      const artist = req.params.artistName;
      const album = req.params.albumName;
  });

---

URL: Query String

• Example URL:

  • https://localhost:3000/search?maxPrice=120

• How to read data from the query string: req.query

• Example 1:

  • If we receive a request GET https://localhost:3000/search?maxPrice=120

    app.get('/search', (req, res) => {
        console.log(req.query); // req.query is an object
        const price = req.query.maxPrice;
    });

• Example 2 (multiple query strings):

  • If we receive a request GET https://localhost:3000/search?maxPrice=120&location=berlin

    app.get('/search', (req, res) => {
        const price = req.query.maxPrice;
        const location = req.query.location;
    });

---

Request Body

• Data is sent in the 'body' of the http request (also called 'payload').

• How to read from the request body:

  • Step 1. Configure Express to be able to read incoming HTTP request that contain JSON data in the body.

    app.use(express.json());

  • Step 2. Read data from the request body: req.body

    app.post('/login', (req, res) => {
        console.log(req.body)
        if(req.body.email === 'bob@bob.com'){
            //...
        }
    })