Header Based Routing

header-router is a Node.js express module for routing requests based on predefined header matching patterns.

Installation

$ npm install header-router --save

Basic Usage

Header Router is designed to be used with express, however it may be suited to any other routing based framework.

The below example configures a single rule to match content-type headers that have a value of image/*.

var router = require('express').Router();
var headerRouter = require('header-router');

headerRouter.newRule('content-type')
    .addPredicate({ pattern : /image\/(\w+)/ })
    .routeTo(function(req, res, next) {
        // process req.body image payload
        res.json({ success : true, type : 'image' });
    });

router.use(headerRouter.route());

The headerRouter.route() method can also be used as a request handler directly, instead of middleware:

router.put('/save', headerRouter.route());

The advantage of using the route() as middleware, is that you can define a default handler if no request matches the pre-defined rules.

var router = require('express').Router();
var headerRouter = require('header-router');

headerRouter.newRule('content-type')
    .addPredicate({ value :'application/json' })
    .routeTo(function(req, res, next) {
        //process json payload
        res.json({ success : true, type : 'json' });
    });

router.use(headerRouter.route());

router.save('/save', function(req, res, next) {
    // If not request doesn't have content-type: application/json, fallback to this handler
    res.json({ success : true, type : 'none' });
});