Most commonly used features every Mojolicious developer should know about.
Minimalroute
The attribute "routes" in Mojolicious contains a router you can use to generate route structures.
# Application
package MyApp;
use Mojo::Base 'Mojolicious', -signatures;
sub startup ($self) {
# Router
my $r = $self->routes;
# Route
$r->get('/welcome')->to(controller => 'foo', action => 'welcome');
}
1;
The minimal route above will load and instantiate the class "MyApp::Controller::Foo" and call its
"welcome" method. Routes are usually configured in the "startup" method of the application class, but
the router can be accessed from everywhere (even at runtime).
# Controller
package MyApp::Controller::Foo;
use Mojo::Base 'Mojolicious::Controller', -signatures;
# Action
sub welcome ($self) {
# 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.
Routingdestination
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.
HTTPmethods
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'}
$r->get('/bye')->to(controller => 'foo', action => 'bye', mymessage => 'Bye');
There are a few stash values with special meaning, such as "controller" and "action", but you can
generally fill it with whatever data you need to generate a response. Once dispatched the whole stash
content can be changed at any time.
sub bye ($self) {
# Get message from stash
my $msg = $self->stash('mymessage');
# Change message in stash
$self->stash(mymessage => 'Welcome');
}
You can use "defaults" in Mojolicious to set default stash values that will be available everywhere in
the application.
$app->defaults(mymessage => 'Howdy');
For a full list of reserved stash values see "stash" in Mojolicious::Controller.
Nestedroutes
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');
$cats->get('/lol');
With a few common prefixes you can also greatly improve the routing performance of applications with many
routes, because children are only tried if the prefix matched first.
Specialstashvalues
When the dispatcher sees "controller" and "action" values in the stash it will always try to turn them
into a class and method to dispatch to. The "controller" value gets converted from "snake_case" to
"CamelCase" using "camelize" in Mojo::Util and appended to one or more namespaces, defaulting to a
controller namespace based on the application class ("MyApp::Controller"), as well as the bare
application class ("MyApp"), and these namespaces are searched in that order. The action value is not
changed at all, so both values are case-sensitive.
# Application
package MyApp;
use Mojo::Base 'Mojolicious', -signatures;
sub startup ($self) {
# /bye -> MyApp::Controller::Foo->bye
$self->routes->get('/bye')->to(controller => 'foo', action => 'bye');
}
1;
# Controller
package MyApp::Controller::Foo;
use Mojo::Base 'Mojolicious::Controller', -signatures;
# Action
sub bye ($self) {
# 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', controller => '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']);
Routetocallback
The "cb" stash value, which won't be inherited by nested routes, can be used to bypass controllers and
execute a callback instead.
$r->get('/bye')->to(cb => sub ($c) {
$c->render(text => 'Good bye.');
});
But just like in Mojolicious::Lite you can also pass the callback directly, which usually looks much
better.
$r->get('/bye' => sub ($c) {
$c->render(text => 'Good bye.');
});
Namedroutes
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" (in previous request context)
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');
Optionalplaceholders
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.
Restrictiveplaceholders
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.
Placeholdertypes
And if you have multiple routes using restrictive placeholders you can also turn them into placeholder
types with "add_type" in Mojolicious::Routes.
# A type with alternatives
$r->add_type(futurama_name => ['bender', 'leela']);
# /fry -> undef
# /bender -> {controller => 'foo', action => 'bar', name => 'bender'}
# /leela -> {controller => 'foo', action => 'bar', name => 'leela'}
$r->get('/<name:futurama_name>')->to('foo#bar');
Placeholder types work just like restrictive placeholders, they are just reusable with the
"<placeholder:type>" notation.
# A type adjusting the regular expression
$r->add_type(upper => qr/[A-Z]+/);
# /user/ROOT -> {controller => 'users', action => 'show', name => 'ROOT'}
# /user/root -> undef
# /user/23 -> undef
$r->get('/user/<name:upper>')->to('users#show');
Some types like "num" are used so commonly that they are available by default.
# /article/12 -> {controller => 'article', action => 'show', id => 12}
# /article/test -> undef
$r->get('/article/<id:num>')->to('articles#show');
For a full list of available placeholder types see also "TYPES" in Mojolicious::Routes.
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 = $r->under('/' => sub ($c) {
# 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 "continue" in Mojolicious::Controller, this allows for
example, non-blocking operations to finish before reaching the next dispatch cycle.
my $maybe = $r->under('/maybe' => sub ($c) {
# 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 can be detected and stored in the stash
value "format". Use a restrictive placeholder to declare the possible values.
# /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');
This for example, allows multiple templates in different formats to share the same action code. And just
like with placeholders you can use a default value to make the format optional.
# /foo -> {controller => 'foo', action => 'bar'}
# /foo.html -> {controller => 'foo', action => 'bar', format => 'html'}
# /foo.txt -> {controller => 'foo', action => 'bar', format => 'txt'}
$r->get('/foo' => [format => ['html', 'txt']])->to('foo#bar', format => undef);
Formats can be inherited by nested routes.
# /foo -> {controller => 'foo', action => 'one', format => undef}
# /foo.html -> {controller => 'foo', action => 'one', format => 'html'}
# /foo.json -> {controller => 'foo', action => 'one', format => 'json'}
# /bar -> {controller => 'bar', action => 'two', format => undef}
# /bar.html -> {controller => 'bar', action => 'two', format => 'html'}
# /bar.json -> {controller => 'bar', action => 'two', format => 'json'}
my $with_format = $r->any('/' => [format => ['html', 'json']])->to(format => undef);
$with_format->get('/foo')->to('foo#one');
$with_format->get('/bar')->to('bar#two');
A "format" value can also be passed to "url_for" in Mojolicious::Controller.
# /foo/23.txt -> {controller => 'foo', action => 'bar', id => 23, format => 'txt'}
$r->get('/foo/:id')->to('foo#bar')->name('baz');
# Generate URL "/foo/24.txt" for route "baz"
my $url = $c->url_for('baz', id => 24, format => 'txt');
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)
$r->websocket('/echo')->to('foo#echo');
# Controller
package MyApp::Controller::Foo;
use Mojo::Base 'Mojolicious::Controller', -signatures;
# Action
sub echo ($self) {
$self->on(message => sub ($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-allroute
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.
# * /*
$r->any('/*whatever' => {whatever => ''} => sub ($c) {
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 "requires" in Mojolicious::Routes::Route, and allow even more powerful route
constructs.
# / (Origin: http://perl.org)
$r->get('/')->requires(headers => {Origin => qr/perl\.org/})->to('foo#bar');
# / (Firefox)
$r->get('/')->requires(agent => qr/Firefox/)->to('browser-test#firefox');
# / (Internet Explorer)
$r->get('/')->requires(agent => qr/Internet Explorer/)->to('browser-test#ie');
# http://docs.mojolicious.org/Mojolicious
$r->get('/')->requires(host => 'docs.mojolicious.org')->to('perldoc#index');
Just be aware that conditions are too complex for the routing cache, which normally speeds up recurring
requests, and can therefore reduce performance.
Hooks
Hooks operate outside the routing system and allow you to extend the framework itself by sharing code
with all requests indiscriminately through "hook" in Mojolicious, which makes them a very powerful tool
especially for plugins.
# Application
package MyApp;
use Mojo::Base 'Mojolicious', -signatures;
sub startup ($self) {
# Check all requests for a "/test" prefix
$self->hook(before_dispatch => sub ($c) {
$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');
}
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Post-processing the response to add or remove headers is a very common use.
# Make sure static files are cached
$app->hook(after_static => sub ($c) {
$c->res->headers->cache_control('max-age=3600, must-revalidate');
});
# Remove a default header
$app->hook(after_dispatch => sub ($c) {
$c->res->headers->remove('Server');
});
Same for pre-processing the request.
# Choose template variant based on request headers
$app->hook(before_dispatch => sub ($c) {
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
$app->hook(after_dispatch => sub ($c) {
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 $_
$app->hook(around_action => sub ($next, $c, $action, $last) {
local $_ = $c;
return $next->();
});
# Pass route name as argument to actions
$app->hook(around_action => sub ($next, $c, $action, $last) {
return $c->$action($c->current_route);
});
For a full list of available hooks see "HOOKS" in Mojolicious.
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