Easily cache pages of your app using Express and Redis. Could be used without Express too.
npm install express-redis-cache
express-redis-cache ships with a CLI utility you can invoke from the console. In order to use it, install express-redis-cache globally (might require super user privileges):
npm install -g express-redis-cache
Read this if you are upgrading from 0.0.8 to 0.1.x,
Just use it as a middleware in the stack of the route you want to cache.
var app = express();
var cache = require('express-redis-cache')();
// replace
app.get('/',
function (req, res) { ... });
// by
app.get('/',
cache.route(),
function (req, res) { ... });This will check if there is a cache entry for this route. If not. it will cache it and serve the cache next time route is called.
By default, redis-express-cache connects to Redis using localhost as host and nothing as port (using Redis default port 6379). To use different port or host, declare them when you require express-redis-cache. If your Redis server requires password, use the auth_pass option.
var cache = require('express-redis-cache')({
host: String, port: Number, auth_pass: REDIS_PASSWORD
});You can pass a Redis client as well:
require('express-redis-cache')({ client: require('redis').createClient() })You can have several clients if you want to serve from more than one Redis server:
var cache = require('express-redis-cache');
var client1 = cache({ host: "...", port: "..." });
var client2 = cache({ host: "...", port: "..." });
...Should the redis become unavailable, the express-redis-cache object will emit errors but will not crash the app. Express.js requests during this time will be bypass cache and will return fresh data.
Once the redis recovers, the caching will begin working again. See example code in the /example folder.
By default, the cache entry name will be default prefix:name where name's value defaults to req.originalUrl.
app.get('/',
cache.route(), // cache entry name is `cache.prefix + "/"`
function (req, res) { ... });You can specify a custom name like this:
app.get('/',
cache.route('home'), // cache entry name is now `cache.prefix + "home"`
function (req, res) { ... });You can also use the object syntax:
app.get('/',
cache.route({ name: 'home' }), // cache entry name is `cache.prefix + "home"`
function (req, res) { ... });Also, you can use res.express_redis_cache_name to specify the name of the entry such as:
app.get('/user/:userid',
// middleware to define cache name
function (req, res, next) {
// set cache name
res.express_redis_cache_name = 'user-' + req.params.userid;
next();
},
// cache middleware
cache.route(),
// content middleware
function (req, res) {
res.render('user');
}
);You can also use a previous middleware to set whether or not to use the cache by using res.use_express_redis_cache:
app.get('/user',
// middleware to decide if using cache
function (req, res, next) {
// Use only cache if user not signed in
res.use_express_redis_cache = ! req.signedCookies.user;
next();
}.
cache.route(), // this will be skipped if user is signed in
function (req, res) {
res.render('user');
}
);All entry names are prepended by a prefix. Prefix is set when calling the Constructor.
// Set default prefix to "test". All entry names will begin by "test:"
var cache = require('express-redis-cache')({ prefix: 'test' });To know the prefix:
console.log('prefix', cache.prefix);You can pass a custom prefix when calling route():
app.get('/index.html',
cache.route('index', { prefix: 'test' }), // force prefix to be "test", entry name will be "test:index"
function (req, res) { ... });You can also choose not to use prefixes:
app.get('/index.html',
cache.route({ prefix: false }), // no prefixing, entry name will be "/index.html"
function (req, res) { ... });Unless specified otherwise when calling the Constructor, cache entries don't expire. You can specify a default lifetime when calling the constructor:
// Set default lifetime to 60 seconds for all entries
var cache = require('express-redis-cache')({ expire: 60 });You can overwrite the default lifetime when calling route():
app.get('/index.html',
cache.route({ expire: 5000 }), // cache entry will live 5000 seconds
function (req, res) { ... });
// You can also use the number sugar syntax
cache.route(5000);
// Or
cache.route('index', 5000);
// Or
cache.route({ prefix: 'test' }, 5000);You can also provide a hash of status code / expiration values if you for example want to retry much sooner in failure cases (403/404/500/etc). Status ranges can be specified via 4xx/5xx. You must provide a default value (xxx). The most specific rule will be used. For example, if the status code is 200, and there are expirations set for 200, 2xx, and xxx, the expiration for 200 will be used.
app.get('/index.html',
cache.route({
expire: {
200: 5000,
4xx: 10,
403: 5000,
5xx: 10,
xxx: 1
}
}),
function (req, res) { ... });You can also specify
You can use express-redis-cache to cache HTML pages, CSS stylesheets, JSON objects, anything really. Content-types are saved along the cache body and are retrieved using res._headers['content-type']. If you want to overwrite that, you can pass a custom type.
app.get('/index.html',
cache.route({ type: 'text/plain' }), // force entry type to be "text/plain"
function (req, res) { ... });The module emits the following events:
You can catch errors by adding a listener:
cache.on('error', function (error) {
throw new Error('Cache error!');
});express-redis-cache logs some information at runtime. You can access it like this:
cache.on('message', function (message) {
// ...
});Emitted when the client is connected (or re-connected) to Redis server
cache.on('connected', function () {
// ....
});Emitted when the client is disconnected from Redis server. When (and if) it reconnects, it will emit a 'connected' event again
cache.on('disconnected', function () {
// ....
});Note You can get the connexion status at any time by getting the property cache.connected which returns a boolean (true = connected, false = disconnected).
Warning emitted when stumbled upon a deprecated part of the code
cache.on('deprecated', function (deprecated) {
console.log('deprecated warning', {
type: deprecated.type,
name: deprecated.name,
substitute: deprecated.substitute,
file: deprecated.file,
line: deprecated.line
});
});This is the object synopsis we use to represent a cache entry:
var entry = {
body: String // the content of the cache
touched: Number // last time cache was set (created or updated) as a Unix timestamp
expire: Number // the seconds cache entry lives (-1 if does not expire)
type: String // the content-type
};The module exposes a function which instantiates a new instance of a class called ExpressRedisCache.
// This
var cache = require('express-redis-cache')({ /* ... */ });
// is the same than
var cache = new (require('express-redis-cache/lib/ExpressRedisCache'))({ /* ... */ });As stated above, call the function exposed by the module to create a new instance of ExpressRedisCache,
var cache = require('express-redis-cache')(/** Object | Undefined */ options);Where options is an object that has the following properties:
| Option | Type | Default | Description |
| ------------- |----------|-------|----------|--------|
| host | String | undefined | Redis server host
| port | Number | undefined | Redis server port
| prefix | String | require('express-redis-cache/package.json').config.prefix | Default prefix (This will be prepended to all entry names) |
| expire | Number | undefined | Default life time of entries in seconds |
| client | RedisClient | require('redis').createClient({ host: cache.host, port: cache.port }) | A Redis client |
The route method is designed to integrate easily with Express. You can also define your own caching logics using the other methos of the API shown below.
cache.get(/** Mixed (optional) */ query, /** Function( Error, [Entry] ) */ callback );To get all cache entries:
cache.get(function (error, entries) {
if ( error ) throw error;
entries.forEach(console.log.bind(console));
});To get a specific entry:
cache.get('home', function (error, entries) {});To get a specific entry for a given prefix:
cache.get({ name: 'home', prefix: 'test' }, function (error, entries) {});You can use wildcard:
cache.get('user*', function (error, entries) {});cache.add(/** String */ name, /** String */ body, /** Object (optional) **/ options, /** Function( Error, Entry ) */ callback )Where options is an object that can have the following properties:
- expire
Number(lifetime of entry in seconds) - type
String(the content-type)
Example:
cache.add('user:info', JSON.stringify({ id: 1, email: '[email protected]' }), { expire: 60 * 60 * 24, type: 'json' },
function (error, added) {});cache.del(/** String */ name, /** Function ( Error, Number deletions ) */ callback);You can use wildcard (*) in name.
cache.size(/** Function ( Error, Number bytes ) */);We ship with a CLI. You can invoke it like this: express-redis-cache
express-redis-cache lsexpress-redis-cache add $name $body $expire --type $type# Cache simple text
express-redis-cache add "test" "This is a test";
# Cache a file
express-redis-cache add "home" "$(cat index.html)";
# Cache a JSON object
express-redis-cache add "user1:location" '{ "lat": 4.7453, "lng": -31.332 }' --type json;
# Cache a text that will expire in one hour
express-redis-cache add "offer" "everything 25% off for the next hour" $(( 60 * 60 ));express-redis-cache get $name
# Example: express-redis-cache get user1:*
# Output:express-redis-cache del $name
# Example: express-redis-cache del user1:*
# Output:express-redis-cache size
# Output:Run the example to see how the caching behaves. You can kill the redis-server and the application will respond with non-cached information.
npm install
cd example
node example.js
We use Mocha and Should for the tests. You can invoke tests like this:
npm test
You can specify the following environments before running your tests:
export EX_RE_CA_HOST="";
export EX_RE_CA_PORT="";
export EX_RE_CA_PREFIX="";Enjoy!
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