bionic (3) Mojolicious::Guides::Routing.3pm.gz
NAME
Mojolicious::Guides::Routing - Routing requests
OVERVIEW
This document contains a simple and fun introduction to the Mojolicious router and its underlying
concepts.
CONCEPTS
Essentials every Mojolicious developer should know.
Dispatcher
The foundation of every web framework is a tiny black box connecting incoming requests with code
generating the appropriate response.
GET /user/show/1 -> $c->render(text => 'Daniel');
This black box is usually called a dispatcher. There are many implementations using different strategies
to establish these connections, but pretty much all are based around mapping the path part of the request
URL to some kind of response generator.
/user/show/2 -> $c->render(text => 'Isabell');
/user/show/3 -> $c->render(text => 'Sara');
/user/show/4 -> $c->render(text => 'Stefan');
/user/show/5 -> $c->render(text => 'Fynn');
While it is very well possible to make all these connections static, it is also rather inefficient.
That's why regular expressions are commonly used to make the dispatch process more dynamic.
qr!/user/show/(\d+)! -> $c->render(text => $users{$1});
Modern dispatchers have pretty much everything HTTP has to offer at their disposal and can use many more
variables than just the request path, such as request method and headers like "Host", "User-Agent" and
"Accept".
GET /user/show/23 HTTP/1.1
Host: mojolicious.org
User-Agent: Mojolicious (Perl)
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Routes
While regular expressions are quite powerful they also tend to be unpleasant to look at and are generally
overkill for ordinary path matching.
qr!/user/show/(\d+)! -> $c->render(text => $users{$1});
This is where routes come into play, they have been designed from the ground up to represent paths with
placeholders.
/user/show/:id -> $c->render(text => $users{$id});
The only difference between a static path and the route above is the ":id" placeholder. One or more
placeholders can be anywhere in the route.
/user/:action/:id
A fundamental concept of the Mojolicious router is that extracted placeholder values are turned into a
hash.
/user/show/23 -> /user/:action/:id -> {action => 'show', id => 23}
This hash is basically the center of every Mojolicious application, you will learn more about this later
on. Internally, routes get compiled to regular expressions, so you can get the best of both worlds with a
little bit of experience.
/user/show/:id -> qr/(?-xism:^\/user\/show\/([^\/.]+))/
A trailing slash in the path is always optional.
/user/show/23/ -> /user/:action/:id -> {action => 'show', id => 23}
Reversibility
One more huge advantage routes have over regular expressions is that they are easily reversible,
extracted placeholders can be turned back into a path at any time.
/sebastian -> /:name -> {name => 'sebastian'}
{name => 'sebastian'} -> /:name -> /sebastian
Every placeholder has a name, even if it's just an empty string.
Standard placeholders
Standard placeholders are the simplest form of placeholders, they use a colon prefix and match all
characters except "/" and ".", similar to the regular expression "([^/.]+)".
/hello -> /:name/hello -> undef
/sebastian/23/hello -> /:name/hello -> undef
/sebastian.23/hello -> /:name/hello -> undef
/sebastian/hello -> /:name/hello -> {name => 'sebastian'}
/sebastian23/hello -> /:name/hello -> {name => 'sebastian23'}
/sebastian 23/hello -> /:name/hello -> {name => 'sebastian 23'}
All placeholders can be surrounded by parentheses to separate them from the surrounding text.
/hello -> /(:name)hello -> undef
/sebastian/23hello -> /(:name)hello -> undef
/sebastian.23hello -> /(:name)hello -> undef
/sebastianhello -> /(:name)hello -> {name => 'sebastian'}
/sebastian23hello -> /(:name)hello -> {name => 'sebastian23'}
/sebastian 23hello -> /(:name)hello -> {name => 'sebastian 23'}
The colon prefix is optional for standard placeholders that are surrounded by parentheses.
/i♥mojolicious -> /(one)♥(two) -> {one => 'i', two => 'mojolicious'}
Relaxed placeholders
Relaxed placeholders are just like standard placeholders, but use a hash prefix and match all characters
except "/", similar to the regular expression "([^/]+)".
/hello -> /#name/hello -> undef
/sebastian/23/hello -> /#name/hello -> undef
/sebastian.23/hello -> /#name/hello -> {name => 'sebastian.23'}
/sebastian/hello -> /#name/hello -> {name => 'sebastian'}
/sebastian23/hello -> /#name/hello -> {name => 'sebastian23'}
/sebastian 23/hello -> /#name/hello -> {name => 'sebastian 23'}
They can be especially useful for manually matching file names with extensions, rather than using format
detection.
/music/song.mp3 -> /music/#filename -> {filename => 'song.mp3'}
Wildcard placeholders
Wildcard placeholders are just like the two types of placeholders above, but use an asterisk prefix and
match absolutely everything, including "/" and ".", similar to the regular expression "(.+)".
/hello -> /*name/hello -> undef
/sebastian/23/hello -> /*name/hello -> {name => 'sebastian/23'}
/sebastian.23/hello -> /*name/hello -> {name => 'sebastian.23'}
/sebastian/hello -> /*name/hello -> {name => 'sebastian'}
/sebastian23/hello -> /*name/hello -> {name => 'sebastian23'}
/sebastian 23/hello -> /*name/hello -> {name => 'sebastian 23'}
BASICS
Most commonly used features every Mojolicious developer should know about.
Minimal route
The attribute "routes" in Mojolicious contains a router you can use to generate route structures.
# Application
package MyApp;
use Mojo::Base 'Mojolicious';
sub startup {
my $self = shift;
# Router
my $r = $self->routes;
# Route
$r->get('/welcome')->to(controller => 'foo', action => 'welcome');
}
1;
The minimal route above will load and instantiate the class "MyApp::Controller::Foo" and call its
"welcome" method. Routes are usually configured in the "startup" method of the application class, but the
router can be accessed from everywhere (even at runtime).
# Controller
package MyApp::Controller::Foo;
use Mojo::Base 'Mojolicious::Controller';
# Action
sub welcome {
my $self = shift;
# Render response
$self->render(text => 'Hello there.');
}
1;
All routes match in the same order in which they were defined, and matching stops as soon as a suitable
route has been found. So you can improve the routing performance by declaring your most frequently
accessed routes first. A routing cache will also be used automatically to handle sudden traffic spikes
more gracefully.
Routing destination
After you start a new route with methods like "get" in Mojolicious::Routes::Route, you can also give it a
destination in the form of a hash using the chained method "to" in Mojolicious::Routes::Route.
# /welcome -> {controller => 'foo', action => 'welcome'}
$r->get('/welcome')->to(controller => 'foo', action => 'welcome');
Now if the route matches an incoming request it will use the content of this hash to try and find
appropriate code to generate a response.
HTTP methods
There are already shortcuts for the most common HTTP request methods like "post" in
Mojolicious::Routes::Route, and for more control "any" in Mojolicious::Routes::Route accepts an optional
array reference with arbitrary request methods as first argument.
# PUT /hello -> undef
# GET /hello -> {controller => 'foo', action => 'hello'}
$r->get('/hello')->to(controller => 'foo', action => 'hello');
# PUT /hello -> {controller => 'foo', action => 'hello'}
$r->put('/hello')->to(controller => 'foo', action => 'hello');
# POST /hello -> {controller => 'foo', action => 'hello'}
$r->post('/hello')->to(controller => 'foo', action => 'hello');
# GET|POST /bye -> {controller => 'foo', action => 'bye'}
$r->any(['GET', 'POST'] => '/bye')->to(controller => 'foo', action => 'bye');
# * /whatever -> {controller => 'foo', action => 'whatever'}
$r->any('/whatever')->to(controller => 'foo', action => 'whatever');
There is one small exception, "HEAD" requests are considered equal to "GET", but content will not be sent
with the response even if it is present.
# GET /test -> {controller => 'bar', action => 'test'}
# HEAD /test -> {controller => 'bar', action => 'test'}
$r->get('/test')->to(controller => 'bar', action => 'test');
You can also use the "_method" query parameter to override the request method. This can be very useful
when submitting forms with browsers that only support "GET" and "POST".
# PUT /stuff -> {controller => 'baz', action => 'stuff'}
# POST /stuff?_method=PUT -> {controller => 'baz', action => 'stuff'}
$r->put('/stuff')->to(controller => 'baz', action => 'stuff');
IRIs
IRIs are handled transparently, that means paths are guaranteed to be unescaped and decoded from bytes to
characters.
# GET /☃ (Unicode snowman) -> {controller => 'foo', action => 'snowman'}
$r->get('/☃')->to(controller => 'foo', action => 'snowman');
Stash
The generated hash of a matching route is actually the center of the whole Mojolicious request cycle. We
call it the stash, and it persists until a response has been generated.
# /bye -> {controller => 'foo', action => 'bye', mymessage => 'Bye'}
$r->get('/bye')
->to(controller => 'foo', action => 'bye', mymessage => 'Bye');
There are a few stash values with special meaning, such as "controller" and "action", but you can
generally fill it with whatever data you need to generate a response. Once dispatched the whole stash
content can be changed at any time.
sub bye {
my $self = shift;
# Get message from stash
my $msg = $self->stash('mymessage');
# Change message in stash
$self->stash(mymessage => 'Welcome');
}
For a full list of reserved stash values see "stash" in Mojolicious::Controller.
Nested routes
It is also possible to build tree structures from routes to remove repetitive code. A route with children
can't match on its own though, only the actual endpoints of these nested routes can.
# /foo -> undef
# /foo/bar -> {controller => 'foo', action => 'bar'}
my $foo = $r->any('/foo')->to(controller => 'foo');
$foo->get('/bar')->to(action => 'bar');
The stash is simply inherited from route to route and newer values override old ones.
# /cats -> {controller => 'cats', action => 'index'}
# /cats/nyan -> {controller => 'cats', action => 'nyan'}
# /cats/lol -> {controller => 'cats', action => 'default'}
my $cats = $r->any('/cats')->to(controller => 'cats', action => 'default');
$cats->get('/')->to(action => 'index');
$cats->get('/nyan')->to(action => 'nyan');
$cats->get('/lol');
With a few common prefixes you can also greatly improve the routing performance of applications with many
routes, because children are only tried if the prefix matched first.
Special stash values
When the dispatcher sees "controller" and "action" values in the stash it will always try to turn them
into a class and method to dispatch to. The "controller" value gets converted from "snake_case" to
"CamelCase" using "camelize" in Mojo::Util and appended to one or more namespaces, defaulting to a
controller namespace based on the application class ("MyApp::Controller"), as well as the bare
application class ("MyApp"), and these namespaces are searched in that order. The action value is not
changed at all, so both values are case-sensitive.
# Application
package MyApp;
use Mojo::Base 'Mojolicious';
sub startup {
my $self = shift;
# /bye -> MyApp::Controller::Foo->bye
$self->routes->get('/bye')->to(controller => 'foo', action => 'bye');
}
1;
# Controller
package MyApp::Controller::Foo;
use Mojo::Base 'Mojolicious::Controller';
# Action
sub bye {
my $self = shift;
# Render response
$self->render(text => 'Good bye.');
}
1;
Controller classes are perfect for organizing code in larger projects. There are more dispatch
strategies, but because controllers are the most commonly used ones they also got a special shortcut in
the form of "controller#action".
# /bye -> {controller => 'foo', action => 'bye', mymessage => 'Bye'}
$r->get('/bye')->to('foo#bye', mymessage => 'Bye');
During camelization "-" characters get replaced with "::", this allows multi-level "controller"
hierarchies.
# / -> MyApp::Controller::Foo::Bar->hi
$r->get('/')->to('foo-bar#hi');
You can also just specify the "controller" in CamelCase form instead of snake_case.
# / -> MyApp::Controller::Foo::Bar->hi
$r->get('/')->to('Foo::Bar#hi');
For security reasons the dispatcher will always check if the "controller" is actually a subclass of
Mojolicious::Controller or Mojo before dispatching to it.
Namespaces
You can use the "namespace" stash value to change the namespace of a whole route with all its children.
# /bye -> MyApp::MyController::Foo::Bar->bye
$r->get('/bye')
->to(namespace => 'MyApp::MyController::Foo::Bar', action => 'bye');
The "controller" is always converted from "snake_case" to "CamelCase" with "camelize" in Mojo::Util, and
then appended to this "namespace".
# /bye -> MyApp::MyController::Foo::Bar->bye
$r->get('/bye')->to('foo-bar#bye', namespace => 'MyApp::MyController');
# /hey -> MyApp::MyController::Foo::Bar->hey
$r->get('/hey')->to('Foo::Bar#hey', namespace => 'MyApp::MyController');
You can also change the default namespaces for all routes in the application with the router attribute
"namespaces" in Mojolicious::Routes, which usually defaults to a namespace based on the application class
("MyApp::Controller"), as well as the bare application class ("MyApp").
$r->namespaces(['MyApp::MyController']);
Route to callback
The "cb" stash value, which won't be inherited by nested routes, can be used to bypass controllers and
execute a callback instead.
$r->get('/bye')->to(cb => sub {
my $c = shift;
$c->render(text => 'Good bye.');
});
But just like in Mojolicious::Lite you can also pass the callback directly, which usually looks much
better.
$r->get('/bye' => sub {
my $c = shift;
$c->render(text => 'Good bye.');
});
Named routes
Naming your routes will allow backreferencing in many methods and helpers throughout the whole framework,
most of which internally rely on "url_for" in Mojolicious::Controller for this.
# /foo/marcus -> {controller => 'foo', action => 'bar', user => 'marcus'}
$r->get('/foo/:user')->to('foo#bar')->name('baz');
# Generate URL "/foo/marcus" for route "baz"
my $url = $c->url_for('baz');
# Generate URL "/foo/jan" for route "baz"
my $url = $c->url_for('baz', user => 'jan');
# Generate URL "http://127.0.0.1:3000/foo/jan" for route "baz"
my $url = $c->url_for('baz', user => 'jan')->to_abs;
You can assign a name with "name" in Mojolicious::Routes::Route, or let the router generate one
automatically, which would be equal to the route itself without non-word characters, custom names have a
higher precedence though.
# /foo/bar ("foobar")
$r->get('/foo/bar')->to('test#stuff');
# Generate URL "/foo/bar"
my $url = $c->url_for('foobar');
To refer to the current route you can use the reserved name "current" or no name at all.
# Generate URL for current route
my $url = $c->url_for('current');
my $url = $c->url_for;
To check or get the name of the current route you can use the helper "current_route" in
Mojolicious::Plugin::DefaultHelpers.
# Name for current route
my $name = $c->current_route;
# Check route name in code shared by multiple routes
$c->stash(button => 'green') if $c->current_route('login');
Optional placeholders
Extracted placeholder values will simply redefine older stash values if they already exist.
# /bye -> {controller => 'foo', action => 'bar', mymessage => 'bye'}
# /hey -> {controller => 'foo', action => 'bar', mymessage => 'hey'}
$r->get('/:mymessage')->to('foo#bar', mymessage => 'hi');
One more interesting effect, a placeholder automatically becomes optional if there is already a stash
value of the same name present, this works similar to the regular expression "([^/.]+)?".
# / -> {controller => 'foo', action => 'bar', mymessage => 'hi'}
$r->get('/:mymessage')->to('foo#bar', mymessage => 'hi');
# /test/123 -> {controller => 'foo', action => 'bar', mymessage => 'hi'}
# /test/bye/123 -> {controller => 'foo', action => 'bar', mymessage => 'bye'}
$r->get('/test/:mymessage/123')->to('foo#bar', mymessage => 'hi');
And if two optional placeholders are only separated by a slash, that slash can become optional as well.
# / -> {controller => 'foo', action => 'bar'}
# /users -> {controller => 'users', action => 'bar'}
# /users/list -> {controller => 'users', action => 'list'}
$r->get('/:controller/:action')->to('foo#bar');
Special stash values like "controller" and "action" can also be placeholders, which is very convenient
especially during development, but should only be used very carefully, because every controller method
becomes a potential route. All uppercase methods as well as those starting with an underscore are
automatically hidden from the router and you can use "hide" in Mojolicious::Routes to add additional
ones.
# Hide "create" method in all controllers
$r->hide('create');
This has already been done for all attributes and methods from Mojolicious::Controller.
Restrictive placeholders
A very easy way to make placeholders more restrictive are alternatives, you just make a list of possible
values, which then work similar to the regular expression "(bender|leela)".
# /fry -> undef
# /bender -> {controller => 'foo', action => 'bar', name => 'bender'}
# /leela -> {controller => 'foo', action => 'bar', name => 'leela'}
$r->get('/:name' => [name => ['bender', 'leela']])->to('foo#bar');
You can also adjust the regular expressions behind placeholders directly, just make sure not to use "^"
and "$" or capturing groups "(...)", because placeholders become part of a larger regular expression
internally, non-capturing groups "(?:...)" are fine though.
# /23 -> {controller => 'foo', action => 'bar', number => 23}
# /test -> undef
$r->get('/:number' => [number => qr/\d+/])->to('foo#bar');
# /23 -> undef
# /test -> {controller => 'foo', action => 'bar', name => 'test'}
$r->get('/:name' => [name => qr/[a-zA-Z]+/])->to('foo#bar');
This way you get easily readable routes and the raw power of regular expressions.
Introspection
The command Mojolicious::Command::routes can be used from the command line to list all available routes
together with names and underlying regular expressions.
$ ./myapp.pl routes -v
/foo/:name .... POST fooname ^/foo/([^/.]+)/?(?:\.([^/]+))?$
/bar ..U. * bar ^/bar
+/baz ...W GET baz ^/baz/?(?:\.([^/]+))?$
/yada .... * yada ^/yada/?(?:\.([^/]+))?$
Under
To share code with multiple nested routes you can use "under" in Mojolicious::Routes::Route, because
unlike normal nested routes, the routes generated with it have their own intermediate destination and
result in additional dispatch cycles when they match.
# /foo -> undef
# /foo/bar -> {controller => 'foo', action => 'baz'}
# {controller => 'foo', action => 'bar'}
my $foo = $r->under('/foo')->to('foo#baz');
$foo->get('/bar')->to('#bar');
The actual action code for this destination needs to return a true value or the dispatch chain will be
broken, this can be a very powerful tool for authentication.
# /blackjack -> {cb => sub {...}}
# {controller => 'hideout', action => 'blackjack'}
my $auth = $r->under('/' => sub {
my $c = shift;
# Authenticated
return 1 if $c->req->headers->header('X-Bender');
# Not authenticated
$c->render(text => "You're not Bender.", status => 401);
return undef;
});
$auth->get('/blackjack')->to('hideout#blackjack');
Broken dispatch chains can be continued by calling the method "continue" in Mojolicious::Controller, this
allows for example, non-blocking operations to finish before reaching the next dispatch cycle.
my $maybe = $r->under('/maybe' => sub {
my $c = shift;
# Wait 3 seconds and then give visitors a 50% chance to continue
Mojo::IOLoop->timer(3 => sub {
# Loser
return $c->render(text => 'No luck.') unless int rand 2;
# Winner
$c->continue;
});
return undef;
});
$maybe->get('/')->to('maybe#winner');
Every destination is just a snapshot of the stash at the time the route matched, and only the "format"
value is shared by all of them. For a little more power you can introspect the preceding and succeeding
destinations with "match" in Mojolicious::Controller.
# Action of the fourth dispatch cycle
my $action = $c->match->stack->[3]{action};
Formats
File extensions like ".html" and ".txt" at the end of a route are automatically detected and stored in
the stash value "format".
# /foo -> {controller => 'foo', action => 'bar'}
# /foo.html -> {controller => 'foo', action => 'bar', format => 'html'}
# /foo.txt -> {controller => 'foo', action => 'bar', format => 'txt'}
$r->get('/foo')->to('foo#bar');
This for example, allows multiple templates in different formats to share the same action code.
Restrictive placeholders can also be used to limit the allowed formats.
# /foo.txt -> undef
# /foo.rss -> {controller => 'foo', action => 'bar', format => 'rss'}
# /foo.xml -> {controller => 'foo', action => 'bar', format => 'xml'}
$r->get('/foo' => [format => ['rss', 'xml']])->to('foo#bar');
A "format" value can also be passed to "url_for" in Mojolicious::Controller.
# /foo/bar.txt -> {controller => 'foo', action => 'bar', format => 'txt'}
$r->get('/foo/:action')->to('foo#')->name('baz');
# Generate URL "/foo/bar.txt" for route "baz"
my $url = $c->url_for('baz', action => 'bar', format => 'txt');
Or you can just disable format detection with a special type of restrictive placeholder, which gets
inherited by nested routes, and then re-enable it on demand.
# /foo -> {controller => 'foo', action => 'bar'}
# /foo.html -> undef
$r->get('/foo' => [format => 0])->to('foo#bar');
# /foo -> {controller => 'foo', action => 'bar'}
# /foo.html -> undef
# /baz -> undef
# /baz.txt -> {controller => 'baz', action => 'yada', format => 'txt'}
# /baz.html -> {controller => 'baz', action => 'yada', format => 'html'}
# /baz.xml -> undef
my $inactive = $r->under([format => 0]);
$inactive->get('/foo')->to('foo#bar');
$inactive->get('/baz' => [format => ['txt', 'html']])->to('baz#yada');
WebSockets
With the method "websocket" in Mojolicious::Routes::Route you can restrict access to WebSocket
handshakes, which are normal "GET" requests with some additional information.
# /echo (WebSocket handshake)
$r->websocket('/echo')->to('foo#echo');
# Controller
package MyApp::Controller::Foo;
use Mojo::Base 'Mojolicious::Controller';
# Action
sub echo {
my $self = shift;
$self->on(message => sub {
my ($self, $msg) = @_;
$self->send("echo: $msg");
});
}
1;
The connection gets established when you respond to the WebSocket handshake request with a 101 response
status, which happens automatically if you subscribe to an event with "on" in Mojolicious::Controller or
send a message with "send" in Mojolicious::Controller right away.
GET /echo HTTP/1.1
Host: mojolicious.org
User-Agent: Mojolicious (Perl)
Connection: Upgrade
Upgrade: websocket
Sec-WebSocket-Key: IDM3ODE4NDk2MjA1OTcxOQ==
Sec-WebSocket-Version: 13
HTTP/1.1 101 Switching Protocols
Server: Mojolicious (Perl)
Date: Tue, 03 Feb 2015 17:08:24 GMT
Connection: Upgrade
Upgrade: websocket
Sec-WebSocket-Accept: SWsp5N2iNxPbHlcOTIw8ERvyVPY=
Catch-all route
Since routes match in the order in which they were defined, you can catch all requests that did not match
in your last route with an optional wildcard placeholder.
# * /*
$r->any('/*whatever' => {whatever => ''} => sub {
my $c = shift;
my $whatever = $c->param('whatever');
$c->render(text => "/$whatever did not match.", status => 404);
});
Conditions
Conditions such as "headers", "agent" and "host" from Mojolicious::Plugin::HeaderCondition can be applied
to any route with the method "over" in Mojolicious::Routes::Route, and allow even more powerful route
constructs.
# / (Origin: http://perl.org)
$r->get('/')->over(headers => {Origin => qr/perl\.org/})->to('foo#bar');
# / (Firefox)
$r->get('/')->over(agent => qr/Firefox/)->to('browser-test#firefox');
# / (Internet Explorer)
$r->get('/')->over(agent => qr/Internet Explorer/)->to('browser-test#ie');
# http://mojolicious.org/perldoc
$r->get('/perldoc')->over(host => 'mojolicious.org')->to('perldoc#index');
Just be aware that conditions are too complex for the routing cache, which normally speeds up recurring
requests, and can therefore reduce performance.
Hooks
Hooks operate outside the routing system and allow you to extend the framework itself by sharing code
with all requests indiscriminately through "hook" in Mojolicious, which makes them a very powerful tool
especially for plugins.
# Application
package MyApp;
use Mojo::Base 'Mojolicious';
sub startup {
my $self = shift;
# Check all requests for a "/test" prefix
$self->hook(before_dispatch => sub {
my $c = shift;
$c->render(text => 'This request did not reach the router.')
if $c->req->url->path->contains('/test');
});
# These will not be reached if the hook above renders a response
my $r = $self->routes;
$r->get('/welcome')->to('foo#welcome');
$r->post('/bye')->to('foo#bye');
}
1;
Post-processing the response to add or remove headers is a very common use.
# Make sure static files are cached
$app->hook(after_static => sub {
my $c = shift;
$c->res->headers->cache_control('max-age=3600, must-revalidate');
});
# Remove a default header
$app->hook(after_dispatch => sub {
my $c = shift;
$c->res->headers->remove('Server');
});
Same for pre-processing the request.
# Choose template variant based on request headers
$app->hook(before_dispatch => sub {
my $c = shift;
return unless my $agent = $c->req->headers->user_agent;
$c->stash(variant => 'ie') if $agent =~ /Internet Explorer/;
});
Or more advanced extensions to add monitoring to your application.
# Forward exceptions to a web service
$app->hook(after_dispatch => sub {
my $c = shift;
return unless my $e = $c->stash('exception');
$c->ua->post('https://example.com/bugs' => form => {exception => $e});
});
You can even extend much of the core functionality.
# Make controller object available to actions as $_
$app->hook(around_action => sub {
my ($next, $c, $action, $last) = @_;
local $_ = $c;
return $next->();
});
# Pass route name as argument to actions
$app->hook(around_action => sub {
my ($next, $c, $action, $last) = @_;
return $c->$action($c->current_route);
});
For a full list of available hooks see "HOOKS" in Mojolicious.
ADVANCED
Less commonly used and more powerful features.
Shortcuts
To make route generation more expressive, you can also add your own shortcuts with "add_shortcut" in
Mojolicious::Routes.
# Simple "resource" shortcut
$r->add_shortcut(resource => sub {
my ($r, $name) = @_;
# Prefix for resource
my $resource = $r->any("/$name")->to("$name#");
# Render a list of resources
$resource->get->to('#index')->name($name);
# Render a form to create a new resource (submitted to "store")
$resource->get('/create')->to('#create')->name("create_$name");
# Store newly created resource (submitted by "create")
$resource->post->to('#store')->name("store_$name");
# Render a specific resource
$resource->get('/:id')->to('#show')->name("show_$name");
# Render a form to edit a resource (submitted to "update")
$resource->get('/:id/edit')->to('#edit')->name("edit_$name");
# Store updated resource (submitted by "edit")
$resource->put('/:id')->to('#update')->name("update_$name");
# Remove a resource
$resource->delete('/:id')->to('#remove')->name("remove_$name");
return $resource;
});
# GET /users -> {controller => 'users', action => 'index'}
# GET /users/create -> {controller => 'users', action => 'create'}
# POST /users -> {controller => 'users', action => 'store'}
# GET /users/23 -> {controller => 'users', action => 'show', id => 23}
# GET /users/23/edit -> {controller => 'users', action => 'edit', id => 23}
# PUT /users/23 -> {controller => 'users', action => 'update', id => 23}
# DELETE /users/23 -> {controller => 'users', action => 'remove', id => 23}
$r->resource('users');
Rearranging routes
From application startup until the first request has arrived, all routes can still be moved around or
even removed with methods like "add_child" in Mojolicious::Routes::Route and "remove" in
Mojolicious::Routes::Route.
# GET /example/show -> {controller => 'example', action => 'show'}
my $show = $r->get('/show')->to('example#show');
$r->any('/example')->add_child($show);
# Nothing
$r->get('/secrets/show')->to('secrets#show')->name('show_secrets');
$r->find('show_secrets')->remove;
Especially for rearranging routes created by plugins this can be very useful, to find routes by their
name you can use "find" in Mojolicious::Routes::Route.
# GET /example/test -> {controller => 'example', action => 'test'}
$r->get('/something/else')->to('something#else')->name('test');
my $test = $r->find('test');
$test->pattern->parse('/example/test');
$test->pattern->defaults({controller => 'example', action => 'test'});
Even the route pattern and destination can still be changed with "parse" in Mojolicious::Routes::Pattern
and "defaults" in Mojolicious::Routes::Pattern.
Adding conditions
You can also add your own conditions with the method "add_condition" in Mojolicious::Routes. All
conditions are basically router plugins that run every time a new request arrives, and which need to
return a true value for the route to match.
# A condition that randomly allows a route to match
$r->add_condition(random => sub {
my ($route, $c, $captures, $num) = @_;
# Loser
return undef if int rand $num;
# Winner
return 1;
});
# /maybe (25% chance)
$r->get('/maybe')->over(random => 4)->to('foo#bar');
Use whatever request information you need.
# A condition to check query parameters (useful for mock web services)
$r->add_condition(query => sub {
my ($route, $c, $captures, $hash) = @_;
for my $key (keys %$hash) {
my $param = $c->req->url->query->param($key);
return undef unless defined $param && $param eq $hash->{$key};
}
return 1;
});
# /hello?to=world&test=1
$r->get('/hello')->over(query => {test => 1, to => 'world'})->to('foo#bar');
Condition plugins
You can also package your conditions as reusable plugins.
# Plugin
package Mojolicious::Plugin::WerewolfCondition;
use Mojo::Base 'Mojolicious::Plugin';
use Astro::MoonPhase;
sub register {
my ($self, $app) = @_;
# Add "werewolf" condition
$app->routes->add_condition(werewolf => sub {
my ($route, $c, $captures, $days) = @_;
# Keep the werewolves out!
return undef if abs(14 - (phase(time))[2]) > ($days / 2);
# It's ok, no werewolf
return 1;
});
}
1;
Now just load the plugin and you are ready to use the condition in all your applications.
# Application
package MyApp;
use Mojo::Base 'Mojolicious';
sub startup {
my $self = shift;
# Plugin
$self->plugin('WerewolfCondition');
# /hideout (keep them out for 4 days after full moon)
$self->routes->get('/hideout')->over(werewolf => 4)
->to(controller => 'foo', action => 'bar');
}
1;
Mount applications
The easiest way to embed one application into another is Mojolicious::Plugin::Mount, which allows you to
mount whole self-contained applications under a domain and/or prefix.
use Mojolicious::Lite;
# Whole application mounted under "/prefix"
plugin Mount => {'/prefix' => '/home/sri/myapp.pl'};
# Mount application with subdomain
plugin Mount => {'test.example.com' => '/home/sri/myapp2.pl'};
# Normal route
get '/' => sub { shift->render(text => 'Hello World!') };
app->start;
Embed applications
For a little more power you can also embed applications by using them instead of a controller. This
allows for example, the use of the Mojolicious::Lite domain specific language in normal Mojolicious
controllers.
# Controller
package MyApp::Controller::Bar;
use Mojolicious::Lite;
# /hello
get '/hello' => sub {
my $c = shift;
my $name = $c->param('name');
$c->render(text => "Hello $name.");
};
1;
With the method "detour" in Mojolicious::Routes::Route which is very similar to "to" in
Mojolicious::Routes::Route, you can allow the route to partially match and use only the remaining path in
the embedded application, the base path will be passed along in the "path" stash value.
# /foo/*
$r->any('/foo')->detour('bar#', name => 'Mojo');
A minimal embeddable application is nothing more than a subclass of Mojo, containing a "handler" method
accepting Mojolicious::Controller objects.
package MyApp::Controller::Bar;
use Mojo::Base 'Mojo';
sub handler {
my ($self, $c) = @_;
$c->res->code(200);
my $name = $c->param('name');
$c->res->body("Hello $name.");
}
1;
The host application will only share very little information with the embedded application through the
stash. So you cannot currently use route placeholders in routes leading to embedded applications, since
that would cause problems with "url_for" in Mojolicious::Controller.
Application plugins
You can even package applications as self-contained reusable plugins.
# Plugin
package Mojolicious::Plugin::MyEmbeddedApp;
use Mojo::Base 'Mojolicious::Plugin';
sub register {
my ($self, $app) = @_;
# Automatically add route
$app->routes->any('/foo')->detour(app => EmbeddedApp::app());
}
package EmbeddedApp;
use Mojolicious::Lite;
get '/bar' => 'bar';
1;
__DATA__
@@ bar.html.ep
Hello World!
The "app" stash value, which won't be inherited by nested routes, can be used for already instantiated
applications. Now just load the plugin and you're done.
# Application
package MyApp;
use Mojo::Base 'Mojolicious';
sub startup {
my $self = shift;
# Plugin
$self->plugin('MyEmbeddedApp');
}
1;
MORE
You can continue with Mojolicious::Guides now or take a look at the Mojolicious wiki
<http://github.com/kraih/mojo/wiki>, which contains a lot more documentation and examples by many
different authors.
SUPPORT
If you have any questions the documentation might not yet answer, don't hesitate to ask on the mailing
list <http://groups.google.com/group/mojolicious> or the official IRC channel "#mojo" on "irc.perl.org"
(chat now! <https://chat.mibbit.com/?channel=%23mojo&server=irc.perl.org>).