ReThrottle

Request Throttling Middleware for ExpressJS

Limits a unique ip address to a certain number of requests per second.

###Version: 0.1.0

Uses Redis for volatile (LRU) cache. (http://redis.io/download)

###Config:

• redisPort: 6379 - Port of your redis instance.
• redisMaxMemoryInBytes: 2000 - Maximum amount of Memory Redis will use for cache. (Eviction: volatile-lru)
• intervalInSeconds: 1 - How much time in seconds an ip address has to reach limit.
• successCallback: fn(req, res, next) - Callback if the request was accepted.
• failureCallback: fn(req, res, next) - Callback if the request was rejected.
• maxRequestsPerInterval: 30 - How many requests are allowed in the given interval.

For example:

• 30req/sec = intervalInSeconds: 1, maxRequestsPerInterval:30. Will allow a maximum of 30 requests per second.

• 30req/sec = intervalInSeconds: 10, maxRequestsPerInterval: 300. Will allow at most 300 requests in a period of 10 seconds. e.x: Allows burst of 300 requests in the first second, and will reject all requests for the remaining 9 seconds. Over an interval of 10 seconds the average req/sec rate is 30.

###Examples: Simple Usage:

app.use(reThrottle.throttle);

Will use the following defaults:

• Request Limit of 10 req/sec.
• On Success: next()
• On Failure: res.status(503).send("Server is busy at the moment, try again.");
• Redis Port: 6379
• Redis MaxMemory: 100mb

** Example of configuration: **

(Allow 1 request every 10 seconds foreach unique ip, with custom success and fail callbacks)

    reThrottle.config({
        intervalInSeconds: 10,
        maxRequestsPerInterval: 1,
        successCallback: function(req, res, next){
            console.log("You passed this time...");
            next();
        },
        failureCallback: function(req, res, next){
            console.log("USER HAS REACHED REQUEST LIMIT.");
            res.status(503).send("Check back later...");
        }
    });

    app.use(reThrottle.throttle);