Mojolicious::Guides::Tutorial - Tutorial
A quick example driven introduction to the wonders of Mojolicious::Lite. Almost everything you'll learn here also applies to full Mojolicious applications.
A simple Hello World application can look like this, strict, warnings, utf8 and Perl 5.10 features are automatically enabled and a few functions imported when you use Mojolicious::Lite, turning your script into a full featured web application.
#!/usr/bin/env perl use Mojolicious::Lite; get '/' => sub { my $c = shift; $c->render(text => 'Hello World!'); }; app->start;
There is also a helper command to generate a small example application.
$ mojo generate lite_app myapp.pl
All the normal Mojolicious::Commands are available from the command line. Note that CGI and PSGI environments can usually be auto detected and will just work without commands.
$ ./myapp.pl daemon Server available at http://127.0.0.1:3000 $ ./myapp.pl daemon -l http://*:8080 Server available at http://127.0.0.1:8080 $ ./myapp.pl cgi ...CGI output... $ ./myapp.pl get / Hello World! $ ./myapp.pl ...List of available commands (or automatically detected environment)...
The app->start call that starts the Mojolicious command system should usually be the last expression in your application and can be customized to override normal @ARGV use.
app->start
@ARGV
app->start('daemon');
Your application will automatically reload itself if you start it with the morbo development web server, so you don't have to restart the server after every change.
morbo
$ morbo ./myapp.pl Server available at http://127.0.0.1:3000
For more information about how to deploy your application see also "DEPLOYMENT" in Mojolicious::Guides::Cookbook.
Routes are basically just fancy paths that can contain different kinds of placeholders and usually lead to an action, if they match the path part of the request URL. The first argument passed to all actions $c is a Mojolicious::Controller object containing both the HTTP request and response.
$c
use Mojolicious::Lite; # Route leading to an action that renders some text get '/foo' => sub { my $c = shift; $c->render(text => 'Hello World!'); }; app->start;
Response content is often generated by actions with "render" in Mojolicious::Controller, but more about that later.
All GET and POST parameters sent with the request are accessible via "param" in Mojolicious::Controller.
GET
POST
use Mojolicious::Lite; # /foo?user=sri get '/foo' => sub { my $c = shift; my $user = $c->param('user'); $c->render(text => "Hello $user."); }; app->start;
The "stash" in Mojolicious::Controller is used to pass data to templates, which can be inlined in the DATA section. A few stash values like template, text and data are reserved and will be used by "render" in Mojolicious::Controller to decide how a response should be generated.
DATA
template
text
data
use Mojolicious::Lite; # Route leading to an action that renders a template get '/foo' => sub { my $c = shift; $c->stash(one => 23); $c->render(template => 'magic', two => 24); }; app->start; __DATA__ @@ magic.html.ep The magic numbers are <%= $one %> and <%= $two %>.
For more information about templates see also "Embedded Perl" in Mojolicious::Guides::Rendering.
"req" in Mojolicious::Controller and "res" in Mojolicious::Controller give you full access to all HTTP features and information.
use Mojolicious::Lite; # Access request information get '/agent' => sub { my $c = shift; my $host = $c->req->url->to_abs->host; my $ua = $c->req->headers->user_agent; $c->render(text => "Request by $ua reached $host."); }; # Echo the request body and send custom header with response post '/echo' => sub { my $c = shift; $c->res->headers->header('X-Bender' => 'Bite my shiny metal ass!'); $c->render(data => $c->req->body); }; app->start;
You can test the more advanced examples right from the command line with Mojolicious::Command::get.
$ ./myapp.pl get -v -M POST -c 'test' /echo
exception
not_found
During development you will encounter these pages whenever you make a mistake, they are gorgeous and contain a lot of valuable information that will aid you in debugging your application.
use Mojolicious::Lite; # Not found (404) get '/missing' => sub { shift->render(template => 'does_not_exist') }; # Exception (500) get '/dies' => sub { die 'Intentional error' }; app->start;
You can even use CSS selectors with Mojolicious::Command::get to extract only the information you're actually interested in.
$ ./myapp.pl get /dies '#error'
All routes can have a name associated with them, this allows automatic template detection and backreferencing with "url_for" in Mojolicious::Controller, on which many methods and helpers like "link_to" in Mojolicious::Plugin::TagHelpers rely.
use Mojolicious::Lite; # Render the template "index.html.ep" get '/' => sub { my $c = shift; $c->render; } => 'index'; # Render the template "hello.html.ep" get '/hello'; app->start; __DATA__ @@ index.html.ep <%= link_to Hello => 'hello' %>. <%= link_to Reload => 'index' %>. @@ hello.html.ep Hello World!
Nameless routes get an automatically generated one assigned that is simply equal to the route itself without non-word characters.
Templates can have layouts too, you just select one with the helper "layout" in Mojolicious::Plugin::DefaultHelpers and place the result of the current template with the helper "content" in Mojolicious::Plugin::DefaultHelpers.
use Mojolicious::Lite; get '/with_layout'; app->start; __DATA__ @@ with_layout.html.ep % title 'Green'; % layout 'green'; Hello World! @@ layouts/green.html.ep <!DOCTYPE html> <html> <head><title><%= title %></title></head> <body><%= content %></body> </html>
The stash or helpers like "title" in Mojolicious::Plugin::DefaultHelpers can be used to pass additional data to the layout.
Template blocks can be used like normal Perl functions and are always delimited by the begin and end keywords, they are the foundation for many helpers.
begin
end
use Mojolicious::Lite; get '/with_block' => 'block'; app->start; __DATA__ @@ block.html.ep % my $link = begin % my ($url, $name) = @_; Try <%= link_to $url => begin %><%= $name %><% end %>. % end <!DOCTYPE html> <html> <head><title>Sebastians frameworks</title></head> <body> %= $link->('http://mojolicio.us', 'Mojolicious') %= $link->('http://catalystframework.org', 'Catalyst') </body> </html>
Helpers are little functions you can reuse throughout your whole application, from actions to templates.
use Mojolicious::Lite; # A helper to identify visitors helper whois => sub { my $c = shift; my $agent = $c->req->headers->user_agent || 'Anonymous'; my $ip = $c->tx->remote_address; return "$agent ($ip)"; }; # Use helper in action and template get '/secret' => sub { my $c = shift; my $user = $c->whois; $c->app->log->debug("Request from $user"); }; app->start; __DATA__ @@ secret.html.ep We know who you are <%= whois %>.
A list of all built-in ones can be found in Mojolicious::Plugin::DefaultHelpers and Mojolicious::Plugin::TagHelpers.
Route placeholders allow capturing parts of a request path until a / or . separator occurs, similar to the regular expression ([^/.]+). Results are accessible via "stash" in Mojolicious::Controller and "param" in Mojolicious::Controller.
/
.
([^/.]+)
use Mojolicious::Lite; # /foo/test # /foo/test123 get '/foo/:bar' => sub { my $c = shift; my $bar = $c->stash('bar'); $c->render(text => "Our :bar placeholder matched $bar"); }; # /testsomething/foo # /test123something/foo get '/(:bar)something/foo' => sub { my $c = shift; my $bar = $c->param('bar'); $c->render(text => "Our :bar placeholder matched $bar"); }; app->start;
Relaxed placeholders allow matching of everything until a / occurs, similar to the regular expression ([^/]+).
([^/]+)
use Mojolicious::Lite; # /hello/test # /hello/test.html get '/hello/#you' => 'groovy'; app->start; __DATA__ @@ groovy.html.ep Your name is <%= $you %>.
Wildcard placeholders allow matching absolutely everything, including / and ., similar to the regular expression (.+).
(.+)
use Mojolicious::Lite; # /hello/test # /hello/test123 # /hello/test.123/test/123 get '/hello/*you' => 'groovy'; app->start; __DATA__ @@ groovy.html.ep Your name is <%= $you %>.
Routes can be restricted to specific request methods with different keywords.
use Mojolicious::Lite; # GET /hello get '/hello' => sub { my $c = shift; $c->render(text => 'Hello World!'); }; # PUT /hello put '/hello' => sub { my $c = shift; my $size = length $c->req->body; $c->render(text => "You uploaded $size bytes to /hello."); }; # GET|POST|PATCH /bye any [qw(GET POST PATCH)] => '/bye' => sub { my $c = shift; $c->render(text => 'Bye World!'); }; # * /whatever any '/whatever' => sub { my $c = shift; my $method = $c->req->method; $c->render(text => "You called /whatever with $method."); }; app->start;
All placeholders require a value, but by assigning them default values you can make capturing optional.
use Mojolicious::Lite; # /hello # /hello/Sara get '/hello/:name' => {name => 'Sebastian', day => 'Monday'} => sub { my $c = shift; $c->render(template => 'groovy', format => 'txt'); }; app->start; __DATA__ @@ groovy.txt.ep My name is <%= $name %> and it is <%= $day %>.
Default values that don't belong to a placeholder simply get merged into the stash all the time.
The easiest way to make placeholders more restrictive are alternatives, you just make a list of possible values.
use Mojolicious::Lite; # /test # /123 any '/:foo' => [foo => [qw(test 123)]] => sub { my $c = shift; my $foo = $c->param('foo'); $c->render(text => "Our :foo placeholder matched $foo"); }; app->start;
All placeholders get compiled to a regular expression internally, this process can also be customized. Just make sure not to use ^ and $, or capturing groups (...), non-capturing groups (?:...) are fine though.
^
$
(...)
(?:...)
use Mojolicious::Lite; # /1 # /123 any '/:bar' => [bar => qr/\d+/] => sub { my $c = shift; my $bar = $c->param('bar'); $c->render(text => "Our :bar placeholder matched $bar"); }; app->start;
You can take a closer look at all the generated regular expressions with the command Mojolicious::Command::routes.
$ ./myapp.pl routes -v
Authentication and code shared between multiple routes can be realized easily with routes generated by "under" in Mojolicious::Lite. All following routes are only evaluated if the callback returned a true value.
use Mojolicious::Lite; # Authenticate based on name parameter under sub { my $c = shift; # Authenticated my $name = $c->param('name') || ''; return 1 if $name eq 'Bender'; # Not authenticated $c->render(template => 'denied'); return undef; }; # Only reached when authenticated get '/' => 'index'; app->start; __DATA__ @@ denied.html.ep You are not Bender, permission denied. @@ index.html.ep Hi Bender.
Prefixing multiple routes is another good use for it.
use Mojolicious::Lite; # /foo under '/foo'; # /foo/bar get '/bar' => {text => 'foo bar'}; # /foo/baz get '/baz' => {text => 'foo baz'}; # / (reset) under '/' => {msg => 'whatever'}; # /bar get '/bar' => {inline => '<%= $msg %> works'}; app->start;
You can also group related routes with "group" in Mojolicious::Lite, which allows nesting of routes generated with "under" in Mojolicious::Lite.
use Mojolicious::Lite; # Global logic shared by all routes under sub { my $c = shift; return 1 if $c->req->headers->header('X-Bender'); $c->render(text => "You're not Bender."); return undef; }; # Admin section group { # Local logic shared only by routes in this group under '/admin' => sub { my $c = shift; return 1 if $c->req->headers->header('X-Awesome'); $c->render(text => "You're not awesome enough."); return undef; }; # GET /admin/dashboard get '/dashboard' => {text => 'Nothing to see here yet.'}; }; # GET /welcome get '/welcome' => {text => 'Hi Bender.'}; app->start;
Formats can be automatically detected from file extensions, they are used to find the right template and generate the correct Content-Type header.
Content-Type
use Mojolicious::Lite; # /detection # /detection.html # /detection.txt get '/detection' => sub { my $c = shift; $c->render(template => 'detected'); }; app->start; __DATA__ @@ detected.html.ep <!DOCTYPE html> <html> <head><title>Detected</title></head> <body>HTML was detected.</body> </html> @@ detected.txt.ep TXT was detected.
The default format is html, restrictive placeholders can be used to limit possible values.
html
use Mojolicious::Lite; # /hello.json # /hello.txt get '/hello' => [format => [qw(json txt)]] => sub { my $c = shift; return $c->render(json => {hello => 'world'}) if $c->stash('format') eq 'json'; $c->render(text => 'hello world'); }; app->start;
Or you can just disable format detection.
use Mojolicious::Lite; # /hello get '/hello' => [format => 0] => {text => 'No format detection.'}; # Disable detection and allow the following routes selective re-enabling under [format => 0]; # /foo get '/foo' => {text => 'No format detection again.'}; # /bar.txt get '/bar' => [format => 'txt'] => {text => ' Just one format.'}; app->start;
For resources with different representations and that require truly RESTful content negotiation you can also use "respond_to" in Mojolicious::Controller.
use Mojolicious::Lite; # /hello (Accept: application/json) # /hello (Accept: application/xml) # /hello.json # /hello.xml # /hello?format=json # /hello?format=xml get '/hello' => sub { my $c = shift; $c->respond_to( json => {json => {hello => 'world'}}, xml => {text => '<hello>world</hello>'}, any => {data => '', status => 204} ); }; app->start;
MIME type mappings can be extended or changed easily with "types" in Mojolicious.
app->types->type(rdf => 'application/rdf+xml');
Similar to templates, but with only a single file extension and optional Base64 encoding, static files can be inlined in the DATA section and are served automatically.
use Mojolicious::Lite; app->start; __DATA__ @@ something.js alert('hello!'); @@ test.txt (base64) dGVzdCAxMjMKbGFsYWxh
External static files are not limited to a single file extension and will be served automatically from a public directory if it exists.
public
$ mkdir public $ mv something.js public/something.js $ mv mojolicious.tar.gz public/mojolicious.tar.gz
Both have a higher precedence than routes for GET and HEAD requests. Content negotiation with Range, If-None-Match and If-Modified-Since headers is supported as well and can be tested very easily with Mojolicious::Command::get.
HEAD
Range
If-None-Match
If-Modified-Since
$ ./myapp.pl get /something.js -v -H 'Range: bytes=2-4'
External templates will be searched by the renderer in a templates directory if it exists and have a higher precedence than those in the DATA section.
templates
use Mojolicious::Lite; # Render template "templates/foo/bar.html.ep" any '/external' => sub { my $c = shift; $c->render(template => 'foo/bar'); }; app->start;
Conditions such as agent and host from Mojolicious::Plugin::HeaderCondition allow even more powerful route constructs.
agent
host
use Mojolicious::Lite; # Firefox get '/foo' => (agent => qr/Firefox/) => sub { my $c = shift; $c->render(text => 'Congratulations, you are using a cool browser.'); }; # Internet Explorer get '/foo' => (agent => qr/Internet Explorer/) => sub { my $c = shift; $c->render(text => 'Dude, you really need to upgrade to Firefox.'); }; # http://mojolicio.us/bar get '/bar' => (host => 'mojolicio.us') => sub { my $c = shift; $c->render(text => 'Hello Mojolicious.'); }; app->start;
Cookie based sessions just work out of the box, as soon as you start using them through the helper "session" in Mojolicious::Plugin::DefaultHelpers. Just be aware that all session data gets serialized with Mojo::JSON and stored client-side, with a cryptographic signature to prevent tampering.
use Mojolicious::Lite; # Access session data in action and template get '/counter' => sub { my $c = shift; $c->session->{counter}++; }; app->start; __DATA__ @@ counter.html.ep Counter: <%= session 'counter' %>
Note that you should use custom "secrets" in Mojolicious to make signed cookies really secure.
app->secrets(['My secret passphrase here']);
All files uploaded via multipart/form-data request are automatically available as Mojo::Upload objects. And you don't have to worry about memory usage, because all files above 250KB will be automatically streamed into a temporary file.
multipart/form-data
use Mojolicious::Lite; # Upload form in DATA section get '/' => 'form'; # Multipart upload handler post '/upload' => sub { my $c = shift; # Check file size return $c->render(text => 'File is too big.', status => 200) if $c->req->is_limit_exceeded; # Process uploaded file return $c->redirect_to('form') unless my $example = $c->param('example'); my $size = $example->size; my $name = $example->filename; $c->render(text => "Thanks for uploading $size byte file $name."); }; app->start; __DATA__ @@ form.html.ep <!DOCTYPE html> <html> <head><title>Upload</title></head> <body> %= form_for upload => (enctype => 'multipart/form-data') => begin %= file_field 'example' %= submit_button 'Upload' % end </body> </html>
To protect you from excessively large files there is also a limit of 16MB by default, which you can tweak with the attribute "max_message_size" in Mojo::Message or MOJO_MAX_MESSAGE_SIZE environment variable.
MOJO_MAX_MESSAGE_SIZE
# Increase limit to 1GB $ENV{MOJO_MAX_MESSAGE_SIZE} = 1073741824;
With Mojo::UserAgent, which is available through the helper "ua" in Mojolicious::Plugin::DefaultHelpers, there's a full featured HTTP and WebSocket user agent built right in. Especially in combination with Mojo::JSON and Mojo::DOM this can be a very powerful tool.
use Mojolicious::Lite; # Blocking get '/headers' => sub { my $c = shift; my $url = $c->param('url') || 'http://mojolicio.us'; my $dom = $c->ua->get($url)->res->dom; $c->render(json => $dom->find('h1, h2, h3')->map('text')->to_array); }; # Non-blocking get '/title' => sub { my $c = shift; $c->ua->get('mojolicio.us' => sub { my ($ua, $tx) = @_; $c->render(data => $tx->res->dom->at('title')->text); }); }; # Concurrent non-blocking get '/titles' => sub { my $c = shift; $c->delay( sub { my $delay = shift; $c->ua->get('http://mojolicio.us' => $delay->begin); $c->ua->get('https://metacpan.org' => $delay->begin); }, sub { my ($delay, $mojo, $cpan) = @_; $c->render(json => { mojo => $mojo->res->dom->at('title')->text, cpan => $cpan->res->dom->at('title')->text }); } ); }; app->start;
For more information about the user agent see also "USER AGENT" in Mojolicious::Guides::Cookbook.
WebSocket applications have never been this simple before. Just receive messages by subscribing to events such as "json" in Mojo::Transaction::WebSocket with "on" in Mojolicious::Controller and return them with "send" in Mojolicious::Controller.
use Mojolicious::Lite; websocket '/echo' => sub { my $c = shift; $c->on(json => sub { my ($c, $hash) = @_; $hash->{msg} = "echo: $hash->{msg}"; $c->send({json => $hash}); }); }; get '/' => 'index'; app->start; __DATA__ @@ index.html.ep <!DOCTYPE html> <html> <head> <title>Echo</title> <script> var ws = new WebSocket('<%= url_for('echo')->to_abs %>'); ws.onmessage = function (event) { document.body.innerHTML += JSON.parse(event.data).msg; }; ws.onopen = function (event) { ws.send(JSON.stringify({msg: 'I ♥ Mojolicious!'})); }; </script> </head> </html>
For more information about real-time web features see also "REAL-TIME WEB" in Mojolicious::Guides::Cookbook.
You can use the Mojo::Log object from "log" in Mojo to portably collect debug messages and automatically disable them later in a production setup by changing the Mojolicious operating mode, which can also be retrieved from the attribute "mode" in Mojolicious.
use Mojolicious::Lite; # Prepare mode specific message during startup my $msg = app->mode eq 'development' ? 'Development!' : 'Something else!'; get '/' => sub { my $c = shift; $c->app->log->debug('Rendering mode specific message'); $c->render(text => $msg); }; app->log->debug('Starting application'); app->start;
The default operating mode will usually be development and can be changed with command line options or the MOJO_MODE and PLACK_ENV environment variables. A mode other than development will raise the log level from debug to info.
development
MOJO_MODE
PLACK_ENV
debug
info
$ ./myapp.pl daemon -m production
All messages will be written to STDERR or a log/$mode.log file if a log directory exists.
STDERR
log/$mode.log
log
$ mkdir log
Mode changes also affect a few other aspects of the framework, such as mode specific exception and not_found templates.
Testing your application is as easy as creating a t directory and filling it with normal Perl tests, which can be a lot of fun thanks to Test::Mojo.
t
use Test::More; use Test::Mojo; use FindBin; require "$FindBin::Bin/../myapp.pl"; my $t = Test::Mojo->new; $t->get_ok('/')->status_is(200)->content_like(qr/Funky/); done_testing();
Run all tests with the command Mojolicious::Command::test.
$ ./myapp.pl test $ ./myapp.pl test -v
You can continue with Mojolicious::Guides now or take a look at the Mojolicious wiki, which contains a lot more documentation and examples by many different authors.
If you have any questions the documentation might not yet answer, don't hesitate to ask on the mailing-list or the official IRC channel #mojo on irc.perl.org.
#mojo
irc.perl.org
To install Mojolicious, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Mojolicious
CPAN shell
perl -MCPAN -e shell install Mojolicious
For more information on module installation, please visit the detailed CPAN module installation guide.