cached-request

Node.js module to perform HTTP requests with caching support.

Why?

At alltherooms we make lots of requests to external APIs, and caching is crucial to provide a good experience to our users. We also love streams! however, we had a hard time finding a good tool for caching HTTP responses and streaming them at the same time, so we wrote cached-request. We hope to help others, and feedback is always welcome. :)

How it works

This tool was made to work with the popular request module, which simplifies the HTTP requests in Node.js. Therefore, this must be considered a wrapper around request.

First, you instantiate a cachedRequest instance by passing a request function, which is going to act as the requester for the uncached requests - you still need to $npm install request independently. - Then, you can use cachedRequest to perform your HTTP requests.

The caching takes place in the filesystem, storing the responses as compressed gzipped files.

Please note this will cache everything, so don't use it for making things like POST or PUT requests that you don't want to be cached.

Installation

Install it using npm

$ npm install cached-request

Usage

First, you must set it up:

var request = require('request')
,   cachedRequest = require('cached-request')(request)
,   cacheDirectory = "/tmp/cache";

cachedRequest.setCacheDirectory(cacheDirectory);

Note: You have to ensure the user that launches the process has read+write permissions over cacheDirectory, otherwise the program will fail.

Then you can use cachedRequest just as you use request: passing a callback, or as a stream.

Passing a callback

cachedRequest(options, function (error, response, body) {
  if (error) {
    //Handle request error
  }
  //Do what you need with `response` and `body`
});

As a stream

cachedRequest(options).pipe(someWriteStream);

request options

When making a request, you must pass an options object as you can observe in the examples above. This object can contain any of the options supported by request with the addition of a required ttl option.

ttl: Number of milliseconds for the cached response to be considered stale.

  var options = {
    url: "https://www.google.com",
    ttl: 3000 //3 seconds
  };
  cachedRequest(options, callback);

You can also set a global ttl option for all requests:

cachedRequest.setValue('ttl', 1000);
cachedRequest({url: 'https://www.google.com'}, callback); // should benefit from the cache if previously cached

Can I use everything that comes with request?

No, there's some things you can't use. For example, the shortcut functions .get, .post, .put, etc. are not available in cached-request. If you'd like to have them, this is a great opportunity to contribute!

Running tests

Run the tests with npm

$ npm test

jhemmmm/cached-request