nvdnkpr / connect-cache

Caching system for Connect framework

Connect-cache

Connect-cache is a middleware for Connect framework. It provides a easy way to cache GET requests on your application.

Usage

This middleware must be on the first called.

var connect_cache = require('connect-cache');
var connect = require('connect');
var server = connect.createServer(
  connect_cache({rules: [{regex: /.*/, ttl: 60000}]}),
  function(req, res) {
      res.writeHead(200, { 'Content-Type': 'text/plain' });
      res.end('Hello World');
  }
).listen(3000);

ConnectCache take only one parameter, a hash with following keys :

• rules : a set regular expression / ttl pairs, that should match on urls
• loopback (optional, default parse "Host" header in request) : host and port to call to get contents, ex : 'localhost:3000'
• storage (optional, default instance of BasicStorage) : the key-value storage system, see Storage paragraph for more informations
• sensitive (optional, default true) : caching datas are based on URL and sometimes URLs must be treated case insensitive. This option is here to avoid duplicate caches.

Rules must looks like :

{rules: [{regex: /path\/.*/, ttl: 60000},
         {regex: /other\/path\/.*/, ttl: 3600000},
         {regex: /specified.file/, ttl: 6000000}]}

Default TTL is in ms, default value is 3600000.

Storage

This package provide three bundled ways (a basic based file system, a basic memory and a wrapper for couchdb) to store your items, but you can define your own one. The storage class must implements 3 methods :

• get(key, callback) : get content for the given key.
• set(key, content, callback) : set content for the given key.
• remove(key, callback) : invalidate datas for the given key.
• writeStream(key, callback) : (optional) used to write cached content as stream
• readStream(key, callback) : (optional) used to read cached datas as stream

Look at examples/ folder for examples of bundled storage system.

Installation

$ npm install connect-cache

How it works

This module catch every request that match on a regular expression and call, if the result is not cached, himself with extra HTTP header : x-no-cache. The results is store and forward to final client.

Requirements

• node (>= 0.4.6)
• connect (>= 0.2.4)
• express & expresso - for tests
• markdown - for documentation generation
• cradle (= 0.1.0) - for CouchDB storage system