Mojolicious::Guides::CUseroContributed Perl DoMojolicious::Guides::Cookbook(3)NAMEMojolicious::Guides::Cookbook - Cookbook
OVERVIEW
Cooking with Mojolicious, recipes for every taste.
DEPLOYMENT
Getting Mojolicious and Mojolicious::Lite applications running on
different platforms.
Built-in Server
Mojolicious contains a very portable HTTP 1.1 compliant web server. It
is usually used during development but is solid and fast enough for
small to mid sized applications.
$ ./script/myapp daemon
Server available at http://127.0.0.1:3000.
It has many configuration options and is known to work on every
platform Perl works on.
$ ./script/myapp help daemon
...List of available options...
Another huge advantage is that it supports TLS and WebSockets out of
the box.
$ ./script/myapp daemon --listen https://*:3000
Server available at https://127.0.0.1:3000.
A development certificate for testing purposes is built right in, so it
just works.
Hypnotoad
For bigger applications Mojolicious contains the UNIX optimized
preforking web server Mojo::Server::Hypnotoad that will allow you to
take advantage of multiple cpu cores and copy-on-write.
Mojo::Server::Hypnotoad
|- Mojo::Server::Daemon [1]
|- Mojo::Server::Daemon [2]
|- Mojo::Server::Daemon [3]
`- Mojo::Server::Daemon [4]
It is based on the normal built-in web server but optimized
specifically for production environments out of the box.
$ hypnotoad script/myapp
Server available at http://127.0.0.1:8080.
Config files are plain Perl scripts for maximal customizability.
# hypnotoad.conf
{listen => ['http://*:80'], workers => 10};
But one of its biggest advantages is the support for effortless zero
downtime software upgrades. That means you can upgrade Mojolicious,
Perl or even system libraries at runtime without ever stopping the
server or losing a single incoming connection, just by running the
command above again.
$ hypnotoad script/myapp
Starting hot deployment for Hypnotoad server 31841.
You might also want to enable proxy support if you're using Hypnotoad
behind a reverse proxy. This allows Mojolicious to automatically pick
up the "X-Forwarded-For", "X-Forwarded-Host" and "X-Forwarded-HTTPS"
headers.
# hypnotoad.conf
{proxy => 1};
Nginx
One of the most popular setups these days is the built-in web server
behind a Nginx reverse proxy.
upstream myapp {
server 127.0.0.1:8080;
}
server {
listen 80;
server_name localhost;
location / {
proxy_read_timeout 300;
proxy_pass http://myapp;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-HTTPS 0;
}
}
Apache/mod_proxy
Another good reverse proxy is Apache with "mod_proxy", the
configuration looks very similar to the Nginx one above.
<VirtualHost *:80>
ServerName localhost
<Proxy *>
Order deny,allow
Allow from all
</Proxy>
ProxyRequests Off
ProxyPreserveHost On
ProxyPass / http://localhost:8080 keepalive=On
ProxyPassReverse / http://localhost:8080/
RequestHeader set X-Forwarded-HTTPS "0"
</VirtualHost>
Apache/CGI
"CGI" is supported out of the box and your Mojolicious application will
automatically detect that it is executed as a "CGI" script.
ScriptAlias / /home/sri/myapp/script/myapp/
PSGI/Plack
PSGI is an interface between Perl web frameworks and web servers, and
Plack is a Perl module and toolkit that contains PSGI middleware,
helpers and adapters to web servers. PSGI and Plack are inspired by
Python's WSGI and Ruby's Rack. Mojolicious applications are
ridiculously simple to deploy with Plack.
$ plackup ./script/myapp
HTTP::Server::PSGI: Accepting connections at http://0:5000/
Plack provides many server and protocol adapters for you to choose from
such as "FCGI", "SCGI" and "mod_perl". Make sure to run "plackup" from
your applications home directory, otherwise libraries might not be
found.
$ plackup ./script/myapp -s FCGI -l /tmp/myapp.sock
Because "plackup" uses a weird trick to load your script, Mojolicious
is not always able to detect the applications home directory, if that's
the case you can simply use the "MOJO_HOME" environment variable. Also
note that "app->start" needs to be the last Perl statement in the
application script for the same reason.
$ MOJO_HOME=/home/sri/myapp plackup ./script/myapp
HTTP::Server::PSGI: Accepting connections at http://0:5000/
Some server adapters might ask for a ".psgi" file, if that's the case
you can just point them at your application script because it will
automatically act like one if it detects the presence of a "PLACK_ENV"
environment variable.
Plack Middleware
Wrapper scripts like "myapp.fcgi" are a great way to separate
deployment and application logic.
#!/usr/bin/env plackup -s FCGI
use Plack::Builder;
builder {
enable 'Deflater';
require 'myapp.pl';
};
But you could even use middleware right in your application.
use Mojolicious::Lite;
use Plack::Builder;
get '/welcome' => sub {
my $self = shift;
$self->render(text => 'Hello Mojo!');
};
builder {
enable 'Deflater';
app->start;
};
Rewriting
Sometimes you might have to deploy your application in a blackbox
environment where you can't just change the server configuration or
behind a reverse proxy that passes along additional information with
"X-*" headers. In such cases you can use a "before_dispatch" hook to
rewrite incoming requests.
app->hook(before_dispatch => sub {
my $self = shift;
$self->req->url->base->scheme('https')
if $self->req->headers->header('X-Forwarded-Protocol') eq 'https';
});
Embedding
From time to time you might want to reuse parts of Mojolicious
applications like configuration files, database connection or helpers
for other scripts, with this little mock server you can just embed
them.
use Mojo::Server;
# Load application with mock server
my $server = Mojo::Server->new;
my $app = $server->load_app('./myapp.pl');
# Access fully initialized application
print $app->static->root;
You can also use the built-in web server to embed Mojolicious
applications into alien environments like foreign event loops.
use Mojolicious::Lite;
use Mojo::Server::Daemon;
# Normal action
get '/' => sub {
my $self = shift;
$self->render(text => 'Hello World!');
};
# Connect application with custom daemon
my $daemon =
Mojo::Server::Daemon->new(app => app, listen => ['http://*:8080']);
$daemon->prepare_ioloop;
# Call "one_tick" repeatedly from the alien environment
$daemon->ioloop->one_tick while 1;
USER AGENT
When we say Mojolicious is a web framework we actually mean it.
Web Scraping
Scraping information from web sites has never been this much fun
before. The built-in HTML5/XML parser Mojo::DOM supports all CSS3
selectors that make sense for a standalone parser.
# Fetch web site
my $ua = Mojo::UserAgent->new;
my $tx = $ua->get('mojolicio.us/perldoc');
# Extract title
print 'Title: ', $tx->res->dom->at('head > title')->text, "\n";
# Extract headings
$tx->res->dom('h1, h2, h3')->each(sub {
print 'Heading: ', shift->all_text, "\n";
});
Especially for unit testing your Mojolicious applications this can be a
very powerful tool.
JSON Web Services
Most web services these days are based on the JSON data-interchange
format. That's why Mojolicious comes with the possibly fastest pure-
Perl implementation Mojo::JSON built right in.
# Fresh user agent
my $ua = Mojo::UserAgent->new;
# Fetch the latest news about Mojolicious from Twitter
my $search = 'http://search.twitter.com/search.json?q=Mojolicious';
for $tweet (@{$ua->get($search)->res->json->{results}}) {
# Tweet text
my $text = $tweet->{text};
# Twitter user
my $user = $tweet->{from_user};
# Show both
my $result = "$text --$user\n\n";
utf8::encode $result;
print $result;
}
Basic Authentication
You can just add username and password to the URL.
my $ua = Mojo::UserAgent->new;
print $ua->get('https://sri:secret@mojolicio.us/hideout')->res->body;
Decorating Followup Requests
Mojo::UserAgent can automatically follow redirects, the "on_start"
callback allows you direct access to each transaction right after they
have been initialized and before a connection gets associated with
them.
# User agent following up to 10 redirects
my $ua = Mojo::UserAgent->new(max_redirects => 10);
# Add a witty header to every request
$ua->on_start(sub {
my ($self, $tx) = @_;
$tx->req->headers->header('X-Bender' => 'Bite my shiny metal ass!');
print 'Request: ', $tx->req->url->clone->to_abs, "\n";
});
# Request that will most likely get redirected
print 'Title: ',
$ua->get('google.com')->res->dom->at('head > title')->text, "\n";
This even works for proxy "CONNECT" requests.
Streaming Response
Receiving a streaming response can be really tricky in most HTTP
clients, Mojo::UserAgent makes it actually easy.
my $ua = Mojo::UserAgent->new;
my $tx = $ua->build_tx(GET => 'http://mojolicio.us');
$tx->res->body(sub { print $_[1] });
$ua->start($tx);
The "body" callback will be called for every chunk of data that is
received, even "chunked" encoding will be handled transparently if
necessary.
Streaming Request
Sending a streaming request is almost just as easy.
my $ua = Mojo::UserAgent->new;
my $tx = $ua->build_tx(GET => 'http://mojolicio.us');
my $content = 'Hello world!';
$tx->req->headers->content_length(length $content);
my $drain;
$drain = sub {
my $req = shift;
my $chunk = substr $content, 0, 1, '';
$drain = undef unless length $content;
$req->write($chunk, $drain);
};
$drain->($tx->req);
$ua->start($tx);
The drain callback passed to "write" will be invoked whenever the
entire previous chunk has been written to the kernel send buffer.
Large File Downloads
When downloading large files with Mojo::UserAgent you don't have to
worry about memory usage at all, because it will automatically stream
everything above "250KB" into a temporary file.
# Lets fetch the latest Mojolicious tarball
my $ua = Mojo::UserAgent->new(max_redirects => 5);
my $tx = $ua->get('latest.mojolicio.us');
$tx->res->content->asset->move_to('mojo.tar.gz');
To protect you from excessively large files there is also a global
limit of "5MB" by default, which you can tweak with the
"MOJO_MAX_MESSAGE_SIZE" environment variable.
# Increase limit to 1GB
$ENV{MOJO_MAX_MESSAGE_SIZE} = 1073741824;
Large File Upload
Uploading a large file is even easier.
# Upload file via POST and "multipart/form-data"
my $ua = Mojo::UserAgent->new;
$ua->post_form('mojolicio.us/upload',
{image => {file => '/home/sri/hello.png'}});
And once again you don't have to worry about memory usage, all data
will be streamed directly from the file.
# Upload file via PUT
my $ua = Mojo::UserAgent->new;
my $asset = Mojo::Asset::File->new(path => '/home/sri/hello.png');
my $tx = $ua->build_tx(PUT => 'mojolicio.us/upload');
$tx->req->content->asset($asset);
$ua->start($tx);
Non-Blocking
Mojo::UserAgent has been designed from the ground up to be non-
blocking, the whole blocking API is just a simple convenience wrapper.
Especially for high latency tasks like web crawling this can be
extremely useful, because you can keep many parallel connections active
at the same time.
# FIFO queue
my @urls = qw/google.com/;
# User agent following up to 5 redirects
my $ua = Mojo::UserAgent->new(max_redirects => 5);
# Crawler
my $crawl;
$crawl = sub {
my $id = shift;
# Dequeue or wait for more URLs
return Mojo::IOLoop->timer(2 => sub { $crawl->($id) })
unless my $url = shift @urls;
# Fetch non-blocking just by adding a callback
$ua->get($url => sub {
my ($self, $tx) = @_;
# Extract URLs
print "[$id] $url\n";
$tx->res->dom('a[href]')->each(sub {
my $e = shift;
# Build absolute URL
my $url = Mojo::URL->new($e->{href})->to_abs($tx->req->url);
print " -> $url\n";
# Enqueue
push @urls, $url;
});
# Next
$crawl->($id);
});
};
# Start a bunch of parallel crawlers sharing the same user agent
$crawl->($_) for 1 .. 3;
# Start event loop
Mojo::IOLoop->start;
You can take full control of the Mojo::IOLoop event loop.
Parallel Blocking Requests
You can emulate blocking behavior by using a Mojo::IOLoop trigger to
synchronize multiple non-blocking requests.
# Synchronize non-blocking requests and capture result
my $ua = Mojo::UserAgent->new;
my $t = Mojo::IOLoop->trigger;
$ua->get('http://mojolicio.us' => $t->begin);
$ua->get('http://mojolicio.us/perldoc' => $t->begin);
my ($tx, $tx2) = $t->start;
Just be aware that the resulting transactions will be in random order.
Command Line
Don't you hate checking huge HTML files from the command line? Thanks
to the "mojo get" command that is about to change. You can just pick
the parts that actually matter with the CSS3 selectors from Mojo::DOM.
$ mojo get http://mojolicio.us 'head > title'
How about a list of all id attributes?
$ mojo get http://mojolicio.us '*' attr id
Or the text content of all heading tags?
$ mojo get http://mojolicio.us 'h1, h2, h3' text
Maybe just the text of the third heading?
$ mojo get http://mojolicio.us 'h1, h2, h3' 3 text
You can also extract all text from nested child elements.
$ mojo get http://mojolicio.us '#mojobar' all
The request can be customized as well.
$ mojo get --method post --content 'Hello!' http://mojolicio.us
$ mojo get --header 'X-Bender: Bite my shiny metal ass!' http://google.com
You can follow redirects and view the headers for all messages.
$ mojo get --redirect --verbose http://reddit.com 'head > title'
This can be an invaluable tool for testing your applications.
$ ./myapp.pl get /welcome 'head > title'
HACKS
Fun hacks you might not use very often but that might come in handy
some day.
Faster Tests
Don't you hate waiting for "make test" to finally finish? In newer
Perl versions you can set the "HARNESS_OPTIONS" environment variable to
take advantage of multiple cpu cores and run tests parallel.
$ HARNESS_OPTIONS=j5 make test
...
The "j5" allows 5 tests to run at the same time, which makes for
example the Mojolicious test suite finish 3 times as fast on a dual
core laptop!
Adding Commands To Mojolicious
By now you've propably used many of the built-in commands described in
Mojolicious::Commands, but did you know that you can just add new ones
and that they will be picked up automatically by the command line
interface?
package Mojolicious::Command::spy;
use Mojo::Base 'Mojo::Command';
sub run {
my ($self, $whatever) = @_;
# Leak secret passphrase
if ($whatever eq 'secret') {
my $secret = $self->app->secret;
print qq/The secret of this application is "$secret".\n/;
}
}
1;
There are many more useful methods and attributes in Mojo::Command that
you can use or overload.
$ mojo spy secret
The secret of this application is "Mojolicious::Lite".
$ ./myapp.pl spy secret
The secret of this application is "secr3t".
Running Code Against Your Application
Ever thought about running a quick oneliner against your Mojolicious
application to test something? Thanks to the "eval" command you can do
just that, the application instance itself can be accessed via "app".
$ mojo generate lite_app
$ ./myapp.pl eval 'print app->static->root, "\n"'
The "verbose" option will automatically print the return value to
"STDOUT".
$ ./myapp.pl eval -v 'app->static->root'
Making Your Application Installable
Ever thought about releasing your Mojolicious application to CPAN?
It's actually much easier than you might think.
$ mojo generate app
$ cd my_mojolicious_app
$ mv public lib/MyMojoliciousApp/
$ mv templates lib/MyMojoliciousApp/
The trick is to move the "public" and "templates" directories so they
can get automatically installed with the modules.
package MyMojoliciousApp;
use Mojo::Base 'Mojolicious';
use File::Basename 'dirname';
use File::Spec;
# Every CPAN module needs a version
our $VERSION = '1.0';
sub startup {
my $self = shift;
# Switch to installable home directory
$self->home->parse(
File::Spec->catdir(dirname(__FILE__), 'MyMojoliciousApp'));
# Switch to installable "public" directory
$self->static->root($self->home->rel_dir('public'));
# Switch to installable "templates" directory
$self->renderer->root($self->home->rel_dir('templates'));
$self->plugin('PODRenderer');
my $r = $self->routes;
$r->route('/welcome')->to('example#welcome');
}
1;
That's really everything, now you can package your application like any
other CPAN module.
$ ./script/my_mojolicious_app generate makefile
$ perl Makefile.PL
$ make test
$ make manifest
$ make dist
And if you have a "PAUSE" account (which can be requested at
<http://pause.perl.org>) even upload it.
$ mojo cpanify -u USER -p PASS MyMojoliciousApp-0.01.tar.gz
Hello World
If every byte matters this is the smallest "Hello World" application
you can write with Mojolicious::Lite.
use Mojolicious::Lite;
any {text => 'Hello World!'};
app->start;
It works because all routes without a pattern default to "/" and
automatic rendering kicks in even if no actual code gets executed by
the router. The renderer just picks up the "text" value from the stash
and generates a response.
Hello World Oneliner
The "Hello World" example above can get even a little bit shorter in an
ojo oneliner.
perl -Mojo -e'a({text => "Hello World!"})->start' daemon
And you can use all the commands from Mojolicious::Commands.
perl -Mojo -e'a({text => "Hello World!"})->start' get -v /
Keeping Mojolicious Up-To-Date
This tasty oneliner will keep your Mojolicious as fresh as possible.
$ sudo sh -c "curl -L cpanmin.us | perl - http://latest.mojolicio.us"
jQuery (Content Distribution Network)
These days Mojolicious ships with a bundled version of jQuery, which
you can easily use as a fallback for applications that might be used
offline from time to time.
<%= javascript
'http://ajax.googleapis.com/ajax/libs/jquery/1.6/jquery.min.js' %>
<%= javascript begin %>
if (typeof jQuery == 'undefined') {
var e = document.createElement('script');
e.src = '/js/jquery.js';
e.type = 'text/javascript';
document.getElementsByTagName("head")[0].appendChild(e);
}
<% end %>
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.
perl v5.14.1 2011-09-12 Mojolicious::Guides::Cookbook(3)
