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Routing is the process of determining what should happen when a URL is called, or also which parts of the application should handle a specific incoming request.
In the Hello World example we used this code
app.get('/', (req, res) => { /* */ })
This creates a route that maps accessing the root domain URL /
using the HTTP GET method to the response we want to provide.
Named parameters
What if we want to listen for custom requests, maybe we want to create a service that accepts a string, and returns that uppercase, and we don’t want the parameter to be sent as a query string, but part of the URL. We use named parameters:
app.get('/uppercase/:theValue', (req, res) => res.send(req.params.theValue.toUpperCase()))
If we send a request to /uppercase/test
, we’ll get TEST
in the body of the response.
You can use multiple named parameters in the same URL, and they will all be stored in req.params
.
Use a regular expression to match a path
You can use regular expressions to match multiple paths with one statement:
app.get(/post/, (req, res) => { /* */ })
will match /post
, /post/first
, /thepost
, /posting/something
, and so on.
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More express tutorials:
- Express, a popular Node.js Framework
- Retrieve the GET query string parameters using Express
- Validating input in Express using express-validator
- Express Templates
- Serving Static Assets with Express
- Send a JSON response using Express
- Express Sessions
- Send a response using Express
- Send files using Express
- Sanitizing input in Express using express-validator
- Routing in Express
- An Express HTTPS server with a self-signed certificate
- Express, Request Parameters
- Retrieve the POST query parameters using Express
- Handling redirects with Express
- Express Middleware
- Setup Let's Encrypt for Express
- Work with HTTP headers in Express
- Handling forms in Express
- Handling file uploads in forms using Express
- Handling CORS in Express
- Manage Cookies with Express