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Handler-agnostic URL router.

npm install boulevard

Usage

Takes a map of URLs (maybe with parameters) to functions and returns a function:

var route = require('boulevard');

route({
	'/': homeHandler,
	'/foo/:bar': barHandler
})

Handler arguments

Arguments are passed down from the returned function to the handler functions. This way, any shape of handler function can be used; the only requirement is that the request (or an object containing url) is the first argument. For example, you can use it directly with http.createServer:

http.createServer(route({
	'/': function(req, res) {
		res.end('home!');
	}
}));

Parameters

Parameters are, by default, passed as the last argument to the handler:

route({
	'/foo/:bar': function(req, res, params) {
		console.log('foo: ' + params.bar);
	}
});

Multiple matches

If there are multiple matching handlers, concrete matches are called before parameterised routes, and the first handler that doesn't return false wins:

route({
	'/foo/:bar': function(req, res, params) {
		console.log('foo: ' + params.bar);
	},
	'/foo/baz': function(req, res) {
		console.log('foobaz');
	}
});

Return values

Values returned from route handlers control what Boulevard does next. If you return false, control passes to the next matched handler (if any) or the 404 handler. If you return a non-false value or undefined, it considers your handling finished, and doesn't call any more handlers. The value is returned by the router.

Routes with the same path

If you need separate handlers at the same path (for example, a GET handler and a POST handler), you can pass in an array of maps or pairs instead of the the route map:

route([
	['/', function(req) {
		if(req.method === 'GET') {
			// ...
		} else return false;
	}],
	['/', function(req) {
		if(req.method === 'POST') {
			// ...
		} else return false;
	}],
	{'/': function(req) {
		if(req.method === 'PUT') {
			// ...
		} else return false;
	}}
])

404

If no routes match, a 404 handler is called. The default handler works with http.createServer; it sets the statusCode to 404 and sends an empty response.

Combining routers

concat

Returns a new router combining the routes.

var a = route({
	'/foo': function() {
		return 'foo';
	}
});

var b = route({
	'/bar': function() {
		return 'bar';
	}
});

var c = a.concat(b);
c({url: '/bar'}) //⇒ 'bar'
a({url: '/bar'}) //⇒ 404

use

Return a new router with the routes of the given router available as a subpath.

var a = route({
	'/foo': function() {
		return 'foo';
	}
});

var b = route({
	'/bar': function() {
		return 'bar';
	}
});

var c = a.use('quux', b);
c({url: '/quux/bar'}) //⇒ 'bar'
c({url: '/bar'}) //⇒ 404

Adding routes post-facto

The router function returned by Boulevard has an add method, which merges in a new map of routes:

var routes = route({
	'/': function() {
		return 'foo';
	}
});

routes({url: '/'}) //⇒ 'foo'
routes({url: '/bar'}) //⇒ 404

routes.add({
	'/bar': function() {
		return 'baz';
	}
});

routes({url: '/'}) //⇒ 'foo'
routes({url: '/bar'}) //⇒ 'baz'

Overriding default behaviour

As well as the default router, boulevard exports functions that allow you to override various parts of default behaviour. They each take functions to override and return a version of the router with the new behaviour.

Custom 404 handler (withFourOhFour)

Alias with404

Takes a handler of the same shape as your regular route handlers, which is called when none of the URLs match:

var myRoute = route.withFourOhFour(function(req, res) {
	res.statusCode = 404;
	res.end('Not found: ' + req.url);
});

Custom parameter munging (withAddParams)

Alias withParamHandler

Takes a function with arguments params (the parameters extracted from the URL) and args (the arguments passed to the original handler). Should return an array of arguments to pass to the matched handler.

var myRoute = route.withAddParams(function(params, args) {
	args[0].params = params;
	return args;
});

Custom URL gleaning (withGetUrl)

Gets passed the arguments from the router, should return the URL to match against. By default, parses the url to strip off any query string.

var myRoute = route.withGetUrl(function(req) {
	return req.url;
});

route_

route_ takes a hash of the above customisable functions as its first argument. Any not passed in is set to the default.

Licence

MIT.