Added subdomain matching capability.

[PhilLehmann]

If you'd like, feel free to pull this small change.

While the change is not backwards compatible due to newly introduced method parameters, adding them at the end of the parameter list didn't seem sensible 👿

Thanks!

-phil

[niahoo]

Hi,

I don't understand why you just simply work on a hostname level, why subdomains ?

I think there's too much changes to the API. Plus AltoRouter generates absolute paths, you can just prefix urls with your host of choice.

[koenpunt]

A backwards compatible solution could be adding additional methods for subdomain routing instead of modifying the existing ones.

[niahoo]

To me it's simple : If you don't want a route to be matched on a specific (sub)domain, you don't map it.

If the router doesn't even know a route it would discard anyway, it's even cheaper.

If you create a router and save it on APC cache, then you should create a router per subdomain. But if you have dynamic subdomains you first check wether the subdomain is someuser.host.com or simply host.com and pick the good router accordingly.

[koenpunt]

I see value in constraints on routes when they can be defined separate from them.

A format I like (and in someway use in my own implementation) is as follows:

$router->constraint(array('host' => 'example.com'), function($router) {
  $router->map('GET', '/', function() {
    echo "Root on example.com";
  });
});

Or even more flexible, with a generic function:

$router->constraint(function() {
  return $_SERVER['HTTP_HOST'] == 'example.com';
}, function($router) {
  $router->map('GET', '/', function() {
    echo "Root on example.com";
  });
});

And this can even be a function not in the library. Take for example:

function constraints($router, $constraint, $callback) {
  if($constraint()) {
    $callback($router);
  }
}

constraint($router, function() {
  return $_SERVER['HTTP_HOST'] == 'example.com';
}, function($router) {
  $router->map('GET', '/', function() {
    // Home on example.com
  });
  $router->map('GET', '/page/[i:id]', function() {
    // Page on example.com
  });
})

The concepts laid out here above can also be applied for namespace (#149) and route groups (#83).

Because this is a returning topic, I've opened an issue to discuss the requirements for such functionality: #156