# Middlewares

Middleware functions are functions that have access to the current request and can make changes that will be passed to the next request-response cycle.

Note: All express middlewares works on xpresser.

# Defining a middleware.

To create a middleware, use the xjs make:middleware command.

xjs make:middleware OnlyXhrRequests
=>  OnlyXhrRequestsMiddleware created successfully. 
=>  located @ backend/middlewares/OnlyXhrRequestsMiddleware.js

Notice the word Middleware is automatically added at the end of the specified name when creating the file for you.

This middleware will check if the request is a XmlHttpRequest, if true it will move to the next request cycle else it will return an error to the user.

* OnlyXhrRequestsMiddleware
module.exports = {

     * Handle Incoming request
     * @param {Xpresser.Http} http
     * @return any
    allow(http) {
        if (!http.req.xhr) {
            return http.status(401).send({
                error: "Only XmlHttpRequest requests allowed."

        return http.next()   


if http.req.xhr is false an error response is returned else the request proceeds to the next request-cycle when http.next() is called.

# Using middlewares

There are two ways your middleware can be used in your application

  • Router path middlewares
  • Controller action middlewares

# Route path Middlewares

When declaring routes using $.router.path() you can assign a middleware that will affect all requests that has the router path prefixed in it.

For example, we want to add the OnlyXhrRequest to requests prefixed with /api

$.router.path("/api", () => {

    $.router.get('users', 'Api@users');
    $.router.get('posts', 'Api@posts');


$.router.get('/api/comments', 'Api@comments');

/api/users and /api/posts will be guarded by the OnlyXhrRequest middleware.

Note: Routes prefixed /api/ outside and after the child routes function will also be guarded by the middleware. e.g /api/comments

# Controller action middlewares

Every controller has a middleware handler where you assign middlewares to actions.