The redis-ratelimit from isabella232

redis-ratelimit's Introduction

Rate limiting / throttling based using Redis

var ratelimit = require('redis-ratelimit')
var async = require('async')

var count = 0;
async.doWhilst(function(done) {
    ratelimit.check('counter', 10, 2, function(err, limited) {
        if(limited)
        {
            // Don't do anything, wait some amount of time
            // and check rate limit again
            setTimeout(done, 1000*5);
        }
        else
        {
            // Do work
            count++;
            done();
        }
    })
}, function() {
    return count < 10;
}, function(err) {
    // Done
    process.exit(0);
});

Installation

$ npm install redis-ratelimit

Features

Provides a distributed rate limit per key
Redis sorted sets used for high performance

Documentation

configure(port, host, options)

Optionally configures the underlying redis instance used by the rate limiter.

Arguments

port - Port redis is listening on
host - Host redis is on
options - Options hash passed through to underlying redis createClient() call

check(key, windowInSeconds, limit, callback)

Checks if the specified key over or under the rate limit. If over rate limit the call to check is not counted against the rate limit

Arguments

key - Unique key the rate limit is associated with
windowInSeconds - The length of the window during which the calls are rate limited. This is not a bucket but a sliding window
limit - Number of calls that are allowed before the rate limit kicks in
callback(err, limited) - A callback which indicates if the rate limit has kicked in or not. If an error occurred limited will be set to true. If limited returns true the call to check() does not count against the rate limit.

count(key, callback)

Returns the number of calls that are currently counting against the rate limit.

Arguments

key - Unique key the rate limit is associated with
callback(err, count) - A callback which returns the count of calls counting against the rate limit.