express-route-versioning

A Connect style middleware to re-direct the execution flow into multiple branches based on HTTP header values. Tested and used for REST API versioning with Express routes but other applications might be suiting.

Features

Customize the extraction of the version via version.use(options) for:

• any HTTP header using header, i.e. version.use({header: 'Accept-Version'})
• any HTTP header value using RegEx capture groups in grab, i.e. version.use({grab: /vnd.my.company.()})

Customize the HTTP status code for a failed re-routing using the error, i.e. version.use({error: 404})

Example

Re-route based on version in HTTP header Accept: vnd.mycompany.com+json; version=1.

var express = require('express');
    version = require('express-version-reroute');
version.use({
    'header': 'accept',
    'grab': /vnd.mycompany.com\+json; version=(\d+)(,|$)/,
    'error': 406,
});
var router = express.Router()
  .all('/ping',
       version.reroute({
         1: function(req, res, next) { res.json('pong'); },
         2: function(req, res, next) { res.status(200).end(); },
       })
   );
express().use(router).listen(5000, function() {});

cURL examples that give different behavior based on version.

➜  ~  curl -i -X GET 'http://127.0.0.1:5000/ping' -H 'Accept: vnd.mycompany.com+json; version=2'
HTTP/1.1 200 OK
X-Powered-By: Express
Date: Wed, 05 Nov 2014 10:09:50 GMT
Connection: keep-alive
Transfer-Encoding: chunked

➜  ~  curl -i -X GET 'http://127.0.0.1:5000/ping' -H 'Accept: vnd.mycompany.com+json; version=1'
HTTP/1.1 200 OK
X-Powered-By: Express
Content-Type: application/json; charset=utf-8
Content-Length: 6
ETag: W/"6-dca458aa"
Date: Wed, 05 Nov 2014 10:09:56 GMT
Connection: keep-alive

"pong"%
➜  ~  curl -i -X GET 'http://127.0.0.1:5000/ping' -H 'Accept: vnd.mycompany.com+json; version=0'
HTTP/1.1 406 Not Acceptable
X-Powered-By: Express
Date: Wed, 05 Nov 2014 10:09:58 GMT
Connection: keep-alive
Transfer-Encoding: chunked

Development

npm install
npm test