What is express-unless?
The express-unless package is a middleware for Express.js that allows you to conditionally skip other middleware based on certain criteria. This is useful for scenarios where you want to apply middleware to most routes but exclude certain ones based on conditions like the request path, HTTP method, or custom logic.
What are express-unless's main functionalities?
Path-based exclusion
This feature allows you to exclude certain paths from the middleware. In this example, the middleware is applied to all routes except '/public' and '/about'.
const express = require('express');
const unless = require('express-unless');
const app = express();
const myMiddleware = (req, res, next) => {
// Middleware logic
next();
};
myMiddleware.unless = unless;
app.use(myMiddleware.unless({ path: ['/public', '/about'] }));
app.get('/public', (req, res) => res.send('Public Page'));
app.get('/about', (req, res) => res.send('About Page'));
app.get('/private', (req, res) => res.send('Private Page'));
app.listen(3000, () => console.log('Server running on port 3000'));
Method-based exclusion
This feature allows you to exclude certain HTTP methods from the middleware. In this example, the middleware is applied to all routes except those using the GET and POST methods.
const express = require('express');
const unless = require('express-unless');
const app = express();
const myMiddleware = (req, res, next) => {
// Middleware logic
next();
};
myMiddleware.unless = unless;
app.use(myMiddleware.unless({ method: ['GET', 'POST'] }));
app.get('/test', (req, res) => res.send('GET request'));
app.post('/test', (req, res) => res.send('POST request'));
app.put('/test', (req, res) => res.send('PUT request'));
app.listen(3000, () => console.log('Server running on port 3000'));
Custom logic exclusion
This feature allows you to exclude middleware based on custom logic. In this example, the middleware is skipped if the request contains a header 'x-custom-header' with the value 'skip'.
const express = require('express');
const unless = require('express-unless');
const app = express();
const myMiddleware = (req, res, next) => {
// Middleware logic
next();
};
myMiddleware.unless = unless;
app.use(myMiddleware.unless((req) => {
return req.headers['x-custom-header'] === 'skip';
}));
app.get('/test', (req, res) => res.send('Test route'));
app.listen(3000, () => console.log('Server running on port 3000'));
Other packages similar to express-unless
express-conditional-middleware
The express-conditional-middleware package allows you to conditionally apply middleware based on custom conditions. It is similar to express-unless but focuses more on applying middleware conditionally rather than skipping it. This package is useful if you need more control over when middleware should be applied.
Conditionally skip a middleware when a condition is met.
Install
npm i express-unless --save
Usage
With existing middlewares:
var unless = require('express-unless');
var static = express.static(__dirname + '/public');
static.unless = unless;
app.use(static.unless({ method: 'OPTIONS' }));
If you are authoring a middleware you can support unless as follow:
module.exports = function (middlewareOptions) {
var mymid = function (req, res, next) {
};
mymid.unless = require('unless-express');
return mymid;
};
Current options
method
it could be an string or an array of strings. If the request method match the middleware will not run.path
it could be an string, a regexp or an array of any of those. If the request path match, the middleware will not run.ext
it could be an string or an array of strings. If the request path ends with one of these extensions the middleware will not run.custom
it must be a function that accepts req
and returns true
/ false
. If the function returns true for the given request, ithe middleware will not run.
Examples
Require authentication for every request unless the path is index.html.
app.use(requiresAuth.unless({ path: ['/index.html', '/'] }))
Avoid a fstat for request to routes doesnt end with a given extension.
app.use(static.unless(function (req) {
var ext = url.parse(req.originalUrl).pathname.substr(-4);
return !~['.jpg', '.html', '.css', '.js'].indexOf(ext);
}));
License
MIT 2014 - Jose Romaniello