Mojolicious::Guides::Routing(3)
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/admin/(\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/admin/: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/:role/:id
A fundamental concept of the Mojolicious router is that extracted
placeholder values are turned into a hash.
/user/admin/23 -> /user/:role/:id -> {role => 'admin', 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/admin/:id -> qr/(?-xism:^\/user\/admin\/([^\/.]+))/
A trailing slash in the path is always optional.
/user/admin/23/ -> /user/:role/:id -> {role => 'admin', 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 "<" and ">" 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 "<" and ">".
/iaYmojolicious -> /<one>aY<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'}
They can be useful for manually matching entire file paths.
/music/rock/song.mp3 -> /music/*filepath -> {filepath => 'rock/song.mp3'}
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', -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.
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 /a (Unicode snowman) -> {controller => 'foo', action => 'snowman'}
$r->get('/a')->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');
}
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');
$cats->get('/lol');
With a few common prefixes you can also greatly improve the routing
performance of applications with many routes, because children are only
tried if the prefix matched first.
Special stash values
When the dispatcher sees "controller" and "action" values in the stash
it will always try to turn them into a class and method to dispatch to.
The "controller" value gets converted from "snake_case" to "CamelCase"
using "camelize" in Mojo::Util and appended to one or more namespaces,
defaulting to a controller namespace based on the application class
("MyApp::Controller"), as well as the bare application class ("MyApp"),
and these namespaces are searched in that order. The action value is
not changed at all, so both values are case-sensitive.
# Application
package MyApp;
use Mojo::Base 'Mojolicious', -signatures;
sub startup ($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']);
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.
$r->get('/bye')->to(cb => sub ($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.');
});
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" (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');
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.
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.
Placeholder types
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-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.
# * /*
$r->any('/*whatever' => {whatever => ''} => sub ($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');
}
1;
Post-processing the response to add or remove headers is a very common
use.
# Make sure static files are cached
$app->hook(after_static => sub ($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.
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
$r->add_shortcut(resource => sub ($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
$r->add_condition(random => sub ($route, $c, $captures, $num) {
# Loser
return undef if int rand $num;
# Winner
return 1;
});
# /maybe (25% chance)
$r->get('/maybe')->requires(random => 4)->to('foo#bar');
Use whatever request information you need.
# A condition to check query parameters (useful for mock web services)
$r->add_condition(query => sub ($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
$r->get('/hello')->requires(query => {test => 1, to => 'world'})->to('foo#bar');
Condition plugins
You can also package your conditions as reusable plugins.
# Plugin
package Mojolicious::Plugin::WerewolfCondition;
use Mojo::Base 'Mojolicious::Plugin', -signatures;
use Astro::MoonPhase;
sub register ($self, $app, $conf) {
# Add "werewolf" condition
$app->routes->add_condition(werewolf => sub ($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', -signatures;
sub startup ($self) {
# Plugin
$self->plugin('WerewolfCondition');
# /hideout (keep them out for 4 days after full moon)
$self->routes->get('/hideout')->requires(werewolf => 4)->to(controller => 'foo', action => 'bar');
}
1;
Mount applications
The easiest way to embed one application into another is
Mojolicious::Plugin::Mount, which allows you to mount whole self-
contained applications under a domain and/or prefix.
use Mojolicious::Lite -signatures;
# Whole application mounted under "/prefix"
plugin Mount => {'/prefix' => '/home/sri/myapp/script/myapp'};
# Mount application with subdomain
plugin Mount => {'test.example.com' => '/home/sri/myapp2.pl'};
# Normal route
get '/' => sub ($c) {
$c->render(text => 'Hello World!');
};
app->start;
Embed applications
For a little more power you can also embed applications by using them
instead of a controller. This allows for example, the use of the
Mojolicious::Lite domain specific language in normal Mojolicious
controllers.
# Controller
package MyApp::Controller::Bar;
use Mojolicious::Lite -signatures;
# /hello
get '/hello' => sub ($c) {
my $name = $c->param('name');
$c->render(text => "Hello $name.");
};
1;
With the attribute "partial" 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/*
$r->any('/foo')->partial(1)->to('bar#', name => 'Mojo');
A minimal embeddable application is nothing more than a subclass of
Mojolicious, containing a "handler" method accepting
Mojolicious::Controller objects.
package MyApp::Controller::Bar;
use Mojo::Base 'Mojolicious', -signatures;
sub handler ($self, $c) {
$c->res->code(200);
my $name = $c->param('name');
$c->res->body("Hello $name.");
}
1;
The host application will only share very little information with the
embedded application through the stash. So you cannot currently use
route placeholders in routes leading to embedded applications, since
that would cause problems with "url_for" in Mojolicious::Controller.
Application plugins
You can even package applications as self-contained reusable plugins.
# Plugin
package Mojolicious::Plugin::MyEmbeddedApp;
use Mojo::Base 'Mojolicious::Plugin', -signatures;
sub register ($self, $app, $conf) {
# Automatically add route
$app->routes->any('/foo')->partial(1)->to(app => EmbeddedApp::app());
}
package EmbeddedApp;
use Mojolicious::Lite;
get '/bar' => 'bar';
1;
__DATA__
@@ bar.html.ep
Hello World!
The "app" stash value, which won't be inherited by nested routes, can
be used for already instantiated applications. Now just load the
plugin and you're done.
# Application
package MyApp;
use Mojo::Base 'Mojolicious', -signatures;
sub startup ($self) {
# Plugin
$self->plugin('MyEmbeddedApp');
}
1;
MORE
You can continue with Mojolicious::Guides now or take a look at the
Mojolicious wiki <https://github.com/mojolicious/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 in the Forum <https://forum.mojolicious.org>, on Matrix
<https://matrix.to/#/#mojo:matrix.org>, or IRC
<https://web.libera.chat/#mojo>.
perl v5.32.1 2022-04-25 Mojolicious::Guides::Routing(3)
mojolicious 9.260.0 - Generated Mon May 30 15:50:38 CDT 2022