What is the purpose of a route name in mojolicious?

I have been learning how to program apps using the Mojolicious framework and I am stumped as to why you use route names. For example a route could say

$r->route('/cities/new')
      ->via('get')
      ->to(controller => 'cities', action => 'new_form')
      ->name('cities_new_form');

But what is the purpose of the name parameter? I am new to web frameworks, so maybe this has a trivial answer to it.

Solution

Naming the route allows you to reference it later if you want to generate a URL dynamically. With your example, you could do this later in your code:

my $link = $self->url_for( 'cities_new_form' )

and $link would automatically be populated with a URL ending in /cities/new. You can get fancy if your route has dynamic parts. For example:

$r->route( '/cities/:cityname' )
    ->via( 'get' )
    ->to( controller => 'cities', action => 'new_form' )
    ->name( 'cities_new_form' );

Then you can generate a URL like

my $link = $self->url_for( 'cities_new_form', cityname => 'newyork' );

And $link would end up with /cities/newyork.

These are trivial examples, but you can build up fairly complex stuff once your routes get more involved.

If you don't name the route, it gets a default name which is just a concatenation of the alphanumeric characters in it. That can get tedious for long routes so you can use names to abbreviate them.

See also Named Routes in the Mojolicious documentation.