routes

Minimalist route matching for javascript

npm install routes
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Routes.js

routes lets you easily dispatch based on url-style strings. It comes with a default Router function that you can use to route http requests, but it also cleanly exposes the important functionality so you could also use it to perform more generic string pattern matching.

This might make it useful for things like:

  • URI routing
  • Cucumber-style pattern matching :)
  • Routing messages by channel name from an MQ
  • Dispatching hierarchical events by name

Router Example:

The full range of Path Formats is documented below.

var Router = require('routes');
var router = Router();
var noop = function(){};

router.addRoute("/articles/:title?", noop);
router.addRoute("/:controller/:action/:id.:format?", noop);

console.log(router.match("/articles"));
console.log(router.match("/articles/never-gonna-let-you-down"));
console.log(router.match("/posts/show/1.json"));

The output for router.match("/posts/show/1.json") would be:

{
  params: {
    controller: 'posts',
    action: 'show',
    id: '1',
    format: 'json'
  },
  splats: [],
  route: '/:controller/:action/:id.:format?',
  fn: [Function],
  next: [Function]
}

In the example above, fn would be the function that was passed into the router.

I return this object instead of calling your function for you because you will likely want to add additional parameters from the current context to the function invocation. Ex:

var route = router.match("/posts/show/1.json");
route.fn.apply(null, [req, res, route.params, route.splats]);

Match Continuation

The object returned by router.match includes a next function you can use to continue matching against subsequent routes. Routes are evaluated in the order they are added to the router, so generally, you would add your most specific routes first and most ambiguous routes last. Using the next function allows you evaluate more ambiguous routes first.

var Router = require('routes');
var router = new Router();

router.addRoute('/admin/*?', auth);
router.addRoute('/admin/users', adminUsers);

http.createServer(function (req, res) {
  var path = url.parse(req.url).pathname;
  var match = router.match(path);
  match.fn(req, res, match);
}).listen(1337)

// authenticate the user and pass them on to
// the next route, or respond with 403.
function auth(req, res, match) {
  if (checkUser(req)) {
    match = match.next();
    if (match) match.fn(req, res, match);
    return;
  }
  res.statusCode = 403;
  res.end()
}

// render the admin.users page
function adminUsers(req, res, match) {
  // send user list
  res.statusCode = 200;
  res.end();
}

Installation

npm install routes

Path Formats

Basic string:

"/articles" will only match routes that == "/articles".

Named parameters:

"/articles/:title" will only match routes like "/articles/hello", but *not* "/articles/".

Optional named parameters:

"/articles/:title?" will match "/articles/hello" AND "/articles/"

Periods before optional parameters are also optional:

"/:n.:f?" will match "/1" and "/1.json"

Splaaaat! :

"/assets/*" will match "/assets/blah/blah/blah.png" and "/assets/".

"/assets/*.*" will match "/assets/1/2/3.js" as splats: ["1/2/3", "js"]

Mix splat with named parameters:

"/account/:id/assets/*" will match "/account/2/assets/folder.png" as params: {id: 2}, splats:["folder.png"]

Named RegExp:

"/lang/:lang([a-z]{2})" will match "/lang/en" but not "/lang/12" or "/lang/eng"

Raw RegExp:

/^\/(\d{2,3}-\d{2,3}-\d{4})\.(\w*)$/ (note no quotes, this is a RegExp, not a string.) will match "/123-22-1234.json". Each match group will be an entry in splats: ["123-22-1234", "json"]

Router API

The Router() that routes exposes has two functions: addRoute and match.

addRoute: takes a path and a fn. Your path can match any of the formats in the "Path Formats" section.

match: takes a String or RegExp and returns an object that contains the named params, splats, route (string that was matched against), the fn handler you passed in with addRoute, and a next function which will run match against subsequent routes.

Library API

match: takes an array of Routes, and a String. It goes through Routes and returns an object for the first Route that matches the String, or undefined if none is found. The returned object contains params, splats, and route. params is an object containing the named matches, splats contains the unnamed globs ("*"), and route contains the original string that was matched against.

pathToRegExp: takes a path string and an empty keys array, returns a RegExp and populates keys with the names of the match groups that the RegExp will match. This is largely an internal function but is provided in case someone wants to make a nifty string -> [RegExp, keys] utility.

Test

Clone the repo, cd to it, and:

make test

Credits

This library is an extraction and re-factor of the connect router middleware. I found that connect-based routing worked reasonably well on the server side, but I wanted to do similar routing based on channel names when using Push-It and possibly for event names when using Evan. So, I extracted the relevant goodness out of the router middleware and presented it here. Big thanks to TJ Holowaychuk for writing the original router middleware.

License

This code is distributed under the MIT license, Copyright Aaron Blohowiak and TJ Holowaychuk 2011.

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