Branch behavior by request path
Route-aware middleware
Express.js · Pipe
req.path
req.path is a string containing the path portion of an Express request URL. It excludes the query string, and mounted middleware sees the path without its mount point.
How it works
req.path is a string property on the request object that reports the path portion of the incoming URL. It excludes the query string, and middleware mounted at a path sees the path after that mount point rather than the mount point itself.
Syntax
req.pathReturns
String containing the path part of the request URL.
Key points
req.pathexposes the URL's path portion as a string.- For a URL such as
example.com/users?sort=desc, the path portion is/users. - The property can be inspected directly with
console.dir(req.path).
Common mistakes
- Mounted middleware receives a path with its mount point removed, so
req.pathmay differ from the original URL path.
Example: Read the request path
const express = require('express');
const app = express();
app.get('/users', (req, res) => {
res.json({ path: req.path });
});
app.listen(3000);Run the app and request /users?sort=desc; the response contains /users, without the query string.
When to use it
Record the URL path without query data
Request logging
Group requests by path component
Path-based metrics
Interview questions
QWhat does req.path contain?
It is a string containing the path part of the request URL. For /users?sort=desc, its value is /users.
Follow-up: How would you obtain the query string values? Use the request's query-related API, such as req.query, rather than req.path.
QDoes req.path include query parameters?
The query string is not part of req.path; only the URL path is represented. Therefore /users?sort=desc produces /users.
Follow-up: What happens in mounted middleware? The mount point is omitted from the value visible there.
QWhat caveat applies when reading req.path in middleware?
It is affected by middleware mounting: the mount point is not included when the property is read from that middleware. This reflects the path remaining after the middleware's mount location.
Follow-up: Why should middleware account for this? Path checks inside mounted middleware must use the shortened path rather than the application's original full path.
Related
req.urlreq.originalUrlreq.baseUrlreq.queryreq.params