fastify/docs/Middlewares.md

Fast and low overhead web framework, for Node.js

<h1 align="center">Fastify</h1>

## Middlewares

Fastify provides out of the box an asynchronous [middleware engine](https://github.com/fastify/middie) compatible with Express and Restify middlewares.

This does not support the full syntax `middleware(err, req, res, next)`, because error handling is done inside Fastify.

If you are using Middlewares that bundles differets small middlewares, such as *helmet*, we recommend to use the single modules to get better performances.

```js
fastify.use(require('cors')())
fastify.use(require('dns-prefetch-control')())
fastify.use(require('frameguard')())
fastify.use(require('hide-powered-by')())
fastify.use(require('hsts')())
fastify.use(require('ienoopen')())
fastify.use(require('x-xss-protection')())
```
*If you need a visual feedback to understand when the middlewares are executed take a look to the [lifecycle](https://github.com/fastify/fastify/blob/master/docs/Lifecycle.md) page.*

<a name="restrict-usage"></a>
#### Restrict middleware execution to a certain path(s)
If you need to run a middleware only under certains path(s), just pass the path as first parameter to `use` and you are done!  
*Note that this does not support routes with parameters, (eg: `/user/:id/comments`)*
```js
// Single path
fastify.use('/public', staticFiles('/assets'))

// Multiple paths
fastify.use(['/public', '/dist'], staticFiles('/assets'))

```