A simple request rate throttler for node and express applications.

The following command will install and set it up for your current project:

    npm install request-throttler-express

Currently you need to have a redis server running for using this module. More caching stores will be added soon.

Request throttler can be used just as any other standard express.js middleware.

    const requestThrottler = require('request-throttler-express');
    
    // Register as a middleware
    app.use(requestThrottler.redis());

By default, it will limit to 10 requests per minute. To take more control, check out the possible options you can pass to the middleware below.

For a general case though, you might want to pass some connection details to your redis server. The above middleware also accepts an optional object where you can pass connection details within a connection property as under:

    app.use(requestThrottler.redis({
        connection: {
            host: 'localhost',
            port: 6379,
        }
    }));

For more knowledge on what can be passed in the connection property, please go through the redis documentation here.

The middleware function accepts a variety of optional parameters.

• ttl
  The size of the time window in seconds(time to live). Default value is 60.

• maxHits
  The maximum number of requests that can be made from any particular IP in a given window. Default value is 10.

• ipGetter
  This parameter accepts a function with the request object as the argument. It expects the user to return the ip address as a string. The default implementation retrieves the standard express req.ip.

• throttleHandler
  This parameter accepts a function with the request object as the argument. The user can do logging and similar things based on their requirements here. By default, it's a no-op.

• errorHandler
  This parameter accepts a function with the err object as the argument. The user can handle caching store connection failures here. By default, it logs the error on the console.

The options can be used in any combination like following:

    app.use(requestThrottler.redis({
        ttl: 600,
        maxHits: 20,
    }));

This library is freely distributable under the terms of the MIT license. (MIT)