net-a-porter / connect-cache-control-middleware

A Connect/Express middleware for consistently setting Cache-Control headers

Connect Cache Control Middleware

A Connect/Express middleware for consistently setting Cache-Control headers

Installing

npm i --save connect-cache-control-middleware

Usage

var cacheControlMiddleware = require('connect-cache-control-middleware');

// creates a middleware instance that prevents caching
var preventCaching = cacheControlMiddleware.create();

// creates a middleware instance that caches routes
var allowCaching = cacheControlMiddleware.create({
	maxAge: 600,
	staleWhileRevalidate: 86400
});

app.get('/dont-cache-me', [preventCaching], someHandlerFunction);
app.use(allowCaching);

API

cacheControlMiddleware.create([cacheControlConfig])

Returns a new instance of the middleware handler which can be passed to Connect.

If cacheControlConfig is omitted, then the middleware sets the following headers on each request:

• Cache-Control: 'no-cache, no-store, must-revalidate'
• User-Cache-Control: 'no-cache, no-store, must-revalidate'
• Pragma: 'no-cache'
• Expires: '0'

Otherwise, it will set Cache-Control and User-Cache-Control to:

• max-age=<cacheControlConfig.maxAge>
• stale-while-revalidate=<cacheControlConfig.staleWhileRevalidate>

cacheControlMiddleware.buildCacheControlHeader(cacheControlConfig)

A helper function, used internally, to consistently build Cache-Control headers. This is exposed publicly if one requires to set headers outside of the middleware chain e.g. express-remote-handlebars.

As with the create method, cacheControlConfig should be an object exposing respective maxAge and staleWhileRevalidate properties.

This method returns a String.

Unit tests

• npm i
• npm test

Releasing

• Bump version number in package.json (semver please!)
• git tag release-<version number>
• git push origin --tags