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.\" ========================================================================
.\"
.IX Title "Mojolicious::Guides::Growing 3pm"
.TH Mojolicious::Guides::Growing 3pm "2014-10-18" "perl v5.20.1" "User Contributed Perl Documentation"
.\" For nroff, turn off justification. Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
Mojolicious::Guides::Growing \- Growing
.SH "OVERVIEW"
.IX Header "OVERVIEW"
This document explains the process of starting a Mojolicious::Lite
prototype from scratch and growing it into a well-structured Mojolicious
application.
.SH "CONCEPTS"
.IX Header "CONCEPTS"
Essentials every Mojolicious developer should know.
.SS "Model View Controller"
.IX Subsection "Model View Controller"
\&\s-1MVC\s0 is a software architectural pattern for graphical user interface
programming originating in Smalltalk\-80, that separates application logic,
presentation and input.
.PP
.Vb 3
\& +\-\-\-\-\-\-\-\-\-\-\-\-+ +\-\-\-\-\-\-\-+ +\-\-\-\-\-\-+
\& Input \-> | Controller | \-> | Model | \-> | View | \-> Output
\& +\-\-\-\-\-\-\-\-\-\-\-\-+ +\-\-\-\-\-\-\-+ +\-\-\-\-\-\-+
.Ve
.PP
A slightly modified version of the pattern moving some application logic into
the \fIcontroller\fR is the foundation of pretty much every web framework these
days, including Mojolicious.
.PP
.Vb 7
\& +\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-+ +\-\-\-\-\-\-\-+
\& Request \-> | | <\-> | Model |
\& | | +\-\-\-\-\-\-\-+
\& | Controller |
\& | | +\-\-\-\-\-\-\-+
\& Response <\- | | <\-> | View |
\& +\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-+ +\-\-\-\-\-\-\-+
.Ve
.PP
The \fIcontroller\fR receives a request from a user, passes incoming data to the
\&\fImodel\fR and retrieves data from it, which then gets turned into an actual
response by the \fIview\fR. But note that this pattern is just a guideline that
most of the time results in cleaner more maintainable code, not a rule that
should be followed at all costs.
.SS "REpresentational State Transfer"
.IX Subsection "REpresentational State Transfer"
\&\s-1REST\s0 is a software architectural style for distributed hypermedia systems such
as the web. While it can be applied to many protocols it is most commonly used
with \s-1HTTP\s0 these days. In \s-1REST\s0 terms, when you are opening a \s-1URL\s0 like
\&\f(CW\*(C`http://mojolicio.us/foo\*(C'\fR with your browser, you are basically asking the web
server for the \s-1HTML \s0\fIrepresentation\fR of the \f(CW\*(C`http://mojolicio.us/foo\*(C'\fR
\&\fIresource\fR.
.PP
.Vb 5
\& +\-\-\-\-\-\-\-\-+ +\-\-\-\-\-\-\-\-+
\& | | \-> http://mojolicio.us/foo \-> | |
\& | Client | | Server |
\& | | <\- Mojo rocks! <\- | |
\& +\-\-\-\-\-\-\-\-+ +\-\-\-\-\-\-\-\-+
.Ve
.PP
The fundamental idea here is that all resources are uniquely addressable with
URLs and every resource can have different representations such as \s-1HTML, RSS\s0
or \s-1JSON.\s0 User interface concerns are separated from data storage concerns and
all session state is kept client-side.
.PP
.Vb 10
\& +\-\-\-\-\-\-\-\-\-+ +\-\-\-\-\-\-\-\-\-\-\-\-+
\& | | \-> PUT /foo \-> | |
\& | | \-> Hello world! \-> | |
\& | | | |
\& | | <\- 201 CREATED <\- | |
\& | | | |
\& | | \-> GET /foo \-> | |
\& | Browser | | Web Server |
\& | | <\- 200 OK <\- | |
\& | | <\- Hello world! <\- | |
\& | | | |
\& | | \-> DELETE /foo \-> | |
\& | | | |
\& | | <\- 200 OK <\- | |
\& +\-\-\-\-\-\-\-\-\-+ +\-\-\-\-\-\-\-\-\-\-\-\-+
.Ve
.PP
While \s-1HTTP\s0 methods such as \f(CW\*(C`PUT\*(C'\fR, \f(CW\*(C`GET\*(C'\fR and \f(CW\*(C`DELETE\*(C'\fR are not directly part
of \s-1REST\s0 they go very well with it and are commonly used to manipulate
\&\fIresources\fR.
.SS "Sessions"
.IX Subsection "Sessions"
\&\s-1HTTP\s0 was designed as a stateless protocol, web servers don't know anything
about previous requests, which makes user-friendly login systems very tricky.
Sessions solve this problem by allowing web applications to keep stateful
information across several \s-1HTTP\s0 requests.
.PP
.Vb 2
\& GET /login?user=sri&pass=s3cret HTTP/1.1
\& Host: mojolicio.us
\&
\& HTTP/1.1 200 OK
\& Set\-Cookie: sessionid=987654321
\& Content\-Length: 10
\& Hello sri.
\&
\& GET /protected HTTP/1.1
\& Host: mojolicio.us
\& Cookie: sessionid=987654321
\&
\& HTTP/1.1 200 OK
\& Set\-Cookie: sessionid=987654321
\& Content\-Length: 16
\& Hello again sri.
.Ve
.PP
Traditionally all session data was stored on the server-side and only session
ids were exchanged between browser and web server in the form of cookies.
.PP
.Vb 1
\& Set\-Cookie: session=hmac\-sha1(base64(json($session)))
.Ve
.PP
In Mojolicious however we are taking this concept one step further by
storing everything \s-1JSON\s0 serialized and Base64 encoded in \s-1HMAC\-SHA1\s0 signed
cookies, which is more compatible with the \s-1REST\s0 philosophy and reduces
infrastructure requirements.
.SS "Test-Driven Development"
.IX Subsection "Test-Driven Development"
\&\s-1TDD\s0 is a software development process where the developer starts writing
failing test cases that define the desired functionality and then moves on to
producing code that passes these tests. There are many advantages such as
always having good test coverage and code being designed for testability,
which will in turn often prevent future changes from breaking old code. Much
of Mojolicious was developed using \s-1TDD.\s0
.SH "PROTOTYPE"
.IX Header "PROTOTYPE"
One of the main differences between Mojolicious and other web frameworks is
that it also includes Mojolicious::Lite, a micro web framework optimized
for rapid prototyping.
.SS "Differences"
.IX Subsection "Differences"
You likely know the feeling, you've got a really cool idea and want to try it
as quickly as possible, that's exactly why Mojolicious::Lite applications
don't need more than a single file.
.PP
.Vb 1
\& myapp.pl # Templates and even static files can be inlined
.Ve
.PP
Full Mojolicious applications on the other hand are much closer to a well
organized \s-1CPAN\s0 distribution to maximize maintainability.
.PP
.Vb 10
\& myapp # Application directory
\& |\- script # Script directory
\& | +\- myapp # Application script
\& |\- lib # Library directory
\& | |\- MyApp.pm # Application class
\& | +\- MyApp # Application namespace
\& | +\- Controller # Controller namespace
\& | +\- Example.pm # Controller class
\& |\- t # Test directory
\& | +\- basic.t # Random test
\& |\- log # Log directory
\& | +\- development.log # Development mode log file
\& |\- public # Static file directory (served automatically)
\& | +\- index.html # Static HTML file
\& +\- templates # Template directory
\& |\- layouts # Template directory for layouts
\& | +\- default.html.ep # Layout template
\& +\- example # Template directory for "Example" controller
\& +\- welcome.html.ep # Template for "welcome" action
.Ve
.PP
Both application skeletons can be automatically generated with the commands
Mojolicious::Command::generate::lite_app and
Mojolicious::Command::generate::app.
.PP
.Vb 2
\& $ mojo generate lite_app myapp.pl
\& $ mojo generate app MyApp
.Ve
.PP
Feature-wise both are almost equal, the only real differences are
organizational, so each one can be gradually transformed into the other.
.SS "Foundation"
.IX Subsection "Foundation"
We start our new application with a single executable Perl script.
.PP
.Vb 4
\& $ mkdir myapp
\& $ cd myapp
\& $ touch myapp.pl
\& $ chmod 744 myapp.pl
.Ve
.PP
This will be the foundation for our login manager example application.
.PP
.Vb 2
\& #!/usr/bin/env perl
\& use Mojolicious::Lite;
\&
\& get \*(Aq/\*(Aq => sub {
\& my $c = shift;
\& $c\->render(text => \*(AqHello world!\*(Aq);
\& };
\&
\& app\->start;
.Ve
.PP
The built-in development web server makes working on your application a lot of
fun thanks to automatic reloading.
.PP
.Vb 2
\& $ morbo ./myapp.pl
\& Server available at http://127.0.0.1:3000.
.Ve
.PP
Just save your changes and they will be automatically in effect the next time
you refresh your browser.
.SS "A birds-eye view"
.IX Subsection "A birds-eye view"
It all starts with an \s-1HTTP\s0 request like this, sent by your browser.
.PP
.Vb 2
\& GET / HTTP/1.1
\& Host: localhost:3000
.Ve
.PP
Once the request has been received by the web server through the event loop,
it will be passed on to Mojolicious, where it will be handled in a few
simple steps.
.PP
.Vb 6
\& 1. Check if a static file exists that would meet the requirements.
\& 2. Try to find a route that would meet the requirements.
\& 3. Dispatch the request to this route, usually reaching one or more actions.
\& 4. Process the request, maybe generating a response with the renderer.
\& 5. Return control to the web server, and if no response has been generated
\& yet, wait for a non\-blocking operation to do so through the event loop.
.Ve
.PP
With our application the router would have found an action in step 2, and
rendered some text in step 4, resulting in an \s-1HTTP\s0 response like this being
sent back to the browser.
.PP
.Vb 3
\& HTTP/1.1 200 OK
\& Content\-Length: 12
\& Hello world!
.Ve
.SS "Model"
.IX Subsection "Model"
In Mojolicious we consider web applications simple frontends for existing
business logic, that means Mojolicious is by design entirely \fImodel\fR layer
agnostic and you just use whatever Perl modules you like most.
.PP
.Vb 3
\& $ mkdir \-p lib/MyApp/Model
\& $ touch lib/MyApp/Model/Users.pm
\& $ chmod 644 lib/MyApp/Model/Users.pm
.Ve
.PP
Our login manager will simply use a plain old Perl module abstracting away all
logic related to matching usernames and passwords. The name
\&\f(CW\*(C`MyApp::Model::Users\*(C'\fR is an arbitrary choice, and is simply used to make the
separation of concerns more visible.
.PP
.Vb 1
\& package MyApp::Model::Users;
\&
\& use strict;
\& use warnings;
\&
\& my $USERS = {
\& sri => \*(Aqsecr3t\*(Aq,
\& marcus => \*(Aqlulz\*(Aq,
\& yko => \*(Aqzeecaptain\*(Aq
\& };
\&
\& sub new { bless {}, shift }
\&
\& sub check {
\& my ($self, $user, $pass) = @_;
\&
\& # Success
\& return 1 if $USERS\->{$user} && $USERS\->{$user} eq $pass;
\&
\& # Fail
\& return undef;
\& }
\&
\& 1;
.Ve
.PP
A simple helper can be registered with the function
\&\*(L"helper\*(R" in Mojolicious::Lite to make our model available to all actions and
templates.
.PP
.Vb 2
\& #!/usr/bin/env perl
\& use Mojolicious::Lite;
\&
\& use lib \*(Aqlib\*(Aq;
\& use MyApp::Model::Users;
\&
\& # Helper to lazy initialize and store our model object
\& helper users => sub { state $users = MyApp::Model::Users\->new };
\&
\& # /?user=sri&pass=secr3t
\& any \*(Aq/\*(Aq => sub {
\& my $c = shift;
\&
\& # Query parameters
\& my $user = $c\->param(\*(Aquser\*(Aq) || \*(Aq\*(Aq;
\& my $pass = $c\->param(\*(Aqpass\*(Aq) || \*(Aq\*(Aq;
\&
\& # Check password
\& return $c\->render(text => "Welcome $user.")
\& if $c\->users\->check($user, $pass);
\&
\& # Failed
\& $c\->render(text => \*(AqWrong username or password.\*(Aq);
\& };
\&
\& app\->start;
.Ve
.PP
The method \*(L"param\*(R" in Mojolicious::Controller is used to access query
parameters, \f(CW\*(C`POST\*(C'\fR parameters, file uploads and route placeholders, all at
once.
.SS "Testing"
.IX Subsection "Testing"
In Mojolicious we take testing very serious and try to make it a pleasant
experience.
.PP
.Vb 3
\& $ mkdir t
\& $ touch t/login.t
\& $ chmod 644 t/login.t
.Ve
.PP
Test::Mojo is a scriptable \s-1HTTP\s0 user agent designed specifically for
testing, with many fun state of the art features such as \s-1CSS\s0 selectors based
on Mojo::DOM.
.PP
.Vb 2
\& use Test::More;
\& use Test::Mojo;
\&
\& # Include application
\& use FindBin;
\& require "$FindBin::Bin/../myapp.pl";
\&
\& # Allow 302 redirect responses
\& my $t = Test::Mojo\->new;
\& $t\->ua\->max_redirects(1);
\&
\& # Test if the HTML login form exists
\& $t\->get_ok(\*(Aq/\*(Aq)
\& \->status_is(200)
\& \->element_exists(\*(Aqform input[name="user"]\*(Aq)
\& \->element_exists(\*(Aqform input[name="pass"]\*(Aq)
\& \->element_exists(\*(Aqform input[type="submit"]\*(Aq);
\&
\& # Test login with valid credentials
\& $t\->post_ok(\*(Aq/\*(Aq => form => {user => \*(Aqsri\*(Aq, pass => \*(Aqsecr3t\*(Aq})
\& \->status_is(200)\->text_like(\*(Aqhtml body\*(Aq => qr/Welcome sri/);
\&
\& # Test accessing a protected page
\& $t\->get_ok(\*(Aq/protected\*(Aq)\->status_is(200)\->text_like(\*(Aqa\*(Aq => qr/Logout/);
\&
\& # Test if HTML login form shows up again after logout
\& $t\->get_ok(\*(Aq/logout\*(Aq)\->status_is(200)
\& \->element_exists(\*(Aqform input[name="user"]\*(Aq)
\& \->element_exists(\*(Aqform input[name="pass"]\*(Aq)
\& \->element_exists(\*(Aqform input[type="submit"]\*(Aq);
\&
\& done_testing();
.Ve
.PP
Your application won't pass these tests, but from now on you can use them to
check your progress with the command Mojolicious::Command::test.
.PP
.Vb 3
\& $ ./myapp.pl test
\& $ ./myapp.pl test t/login.t
\& $ ./myapp.pl test \-v t/login.t
.Ve
.PP
Or perform quick requests right from the command line with
Mojolicious::Command::get.
.PP
.Vb 2
\& $ ./myapp.pl get /
\& Wrong username or password.
\&
\& $ ./myapp.pl get \-v \*(Aq/?user=sri&pass=secr3t\*(Aq
\& GET /?user=sri&pass=secr3t HTTP/1.1
\& User\-Agent: Mojolicious (Perl)
\& Connection: keep\-alive
\& Accept\-Encoding: gzip
\& Content\-Length: 0
\& Host: localhost:59472
\&
\& HTTP/1.1 200 OK
\& Connection: keep\-alive
\& Date: Sun, 18 Jul 2010 13:09:58 GMT
\& Server: Mojolicious (Perl)
\& Content\-Length: 12
\& Content\-Type: text/plain
\&
\& Welcome sri.
.Ve
.SS "State keeping"
.IX Subsection "State keeping"
Sessions in Mojolicious pretty much just work out of the box once you start
using the method \*(L"session\*(R" in Mojolicious::Controller, there is no setup
required, but we suggest setting a more secure passphrase with
\&\*(L"secrets\*(R" in Mojolicious.
.PP
.Vb 1
\& $app\->secrets([\*(AqMojolicious rocks\*(Aq]);
.Ve
.PP
This passphrase is used by the \s-1HMAC\-SHA1\s0 algorithm to make signed cookies
secure and can be changed at any time to invalidate all existing sessions.
.PP
.Vb 2
\& $c\->session(user => \*(Aqsri\*(Aq);
\& my $user = $c\->session(\*(Aquser\*(Aq);
.Ve
.PP
By default all sessions expire after one hour, for more control you can use
the \f(CW\*(C`expiration\*(C'\fR session value to set an expiration date in seconds from now.
.PP
.Vb 1
\& $c\->session(expiration => 3600);
.Ve
.PP
And the whole session can be deleted by using the \f(CW\*(C`expires\*(C'\fR session value to
set an absolute expiration date in the past.
.PP
.Vb 1
\& $c\->session(expires => 1);
.Ve
.PP
For data that should only be visible on the next request, like a confirmation
message after a \f(CW302\fR redirect performed with
\&\*(L"redirect_to\*(R" in Mojolicious::Controller, you can use the flash, accessible
through the method \*(L"flash\*(R" in Mojolicious::Controller.
.PP
.Vb 2
\& $c\->flash(message => \*(AqEverything is fine.\*(Aq);
\& $c\->redirect_to(\*(Aqgoodbye\*(Aq);
.Ve
.PP
Just remember that all session data gets serialized with Mojo::JSON and
stored in \s-1HMAC\-SHA1\s0 signed cookies, which usually have a \f(CW4096\fR byte (4KB)
limit, depending on browser.
.SS "Final prototype"
.IX Subsection "Final prototype"
A final \f(CW\*(C`myapp.pl\*(C'\fR prototype passing all of the tests above could look like
this.
.PP
.Vb 2
\& #!/usr/bin/env perl
\& use Mojolicious::Lite;
\&
\& use lib \*(Aqlib\*(Aq;
\& use MyApp::Model::Users;
\&
\& # Make signed cookies secure
\& app\->secrets([\*(AqMojolicious rocks\*(Aq]);
\&
\& helper users => sub { state $users = MyApp::Model::Users\->new };
\&
\& # Main login action
\& any \*(Aq/\*(Aq => sub {
\& my $c = shift;
\&
\& # Query or POST parameters
\& my $user = $c\->param(\*(Aquser\*(Aq) || \*(Aq\*(Aq;
\& my $pass = $c\->param(\*(Aqpass\*(Aq) || \*(Aq\*(Aq;
\&
\& # Check password and render "index.html.ep" if necessary
\& return $c\->render unless $c\->users\->check($user, $pass);
\&
\& # Store username in session
\& $c\->session(user => $user);
\&
\& # Store a friendly message for the next page in flash
\& $c\->flash(message => \*(AqThanks for logging in.\*(Aq);
\&
\& # Redirect to protected page with a 302 response
\& $c\->redirect_to(\*(Aqprotected\*(Aq);
\& } => \*(Aqindex\*(Aq;
\&
\& # Make sure user is logged in for actions in this group
\& group {
\& under sub {
\& my $c = shift;
\&
\& # Redirect to main page with a 302 response if user is not logged in
\& return 1 if $c\->session(\*(Aquser\*(Aq);
\& $c\->redirect_to(\*(Aqindex\*(Aq);
\& return undef;
\& };
\&
\& # A protected page auto rendering "protected.html.ep"
\& get \*(Aq/protected\*(Aq;
\& };
\&
\& # Logout action
\& get \*(Aq/logout\*(Aq => sub {
\& my $c = shift;
\&
\& # Expire and in turn clear session automatically
\& $c\->session(expires => 1);
\&
\& # Redirect to main page with a 302 response
\& $c\->redirect_to(\*(Aqindex\*(Aq);
\& };
\&
\& app\->start;
\& _\|_DATA_\|_
\&
\& @@ index.html.ep
\& % layout \*(Aqdefault\*(Aq;
\& %= form_for index => begin
\& % if (param \*(Aquser\*(Aq) {
\& Wrong name or password, please try again.
\& % }
\& Name:
\& %= text_field \*(Aquser\*(Aq
\&
Password:
\& %= password_field \*(Aqpass\*(Aq
\&
\& %= submit_button \*(AqLogin\*(Aq
\& % end
\&
\& @@ protected.html.ep
\& % layout \*(Aqdefault\*(Aq;
\& % if (my $msg = flash \*(Aqmessage\*(Aq) {
\& <%= $msg %>
\& % }
\& Welcome <%= session \*(Aquser\*(Aq %>.
\& %= link_to Logout => \*(Aqlogout\*(Aq
\&
\& @@ layouts/default.html.ep
\&
\&
\& Login Manager
\& <%= content %>
\&
.Ve
.PP
And the directory structure should be looking like this now.
.PP
.Vb 8
\& myapp
\& |\- myapp.pl
\& |\- lib
\& | +\- MyApp
\& | +\- Model
\& | +\- Users.pm
\& +\- t
\& +\- login.t
.Ve
.PP
Our templates are using quite a few features of the renderer,
Mojolicious::Guides::Rendering explains them all in great detail.
.SH "WELL-STRUCTURED APPLICATION"
.IX Header "WELL-STRUCTURED APPLICATION"
Due to the flexibility of Mojolicious there are many variations of the
actual growing process, but this should give you a good overview of the
possibilities.
.SS "Inflating templates"
.IX Subsection "Inflating templates"
All templates and static files inlined in the \f(CW\*(C`DATA\*(C'\fR section can be
automatically turned into separate files in the \f(CW\*(C`templates\*(C'\fR and \f(CW\*(C`public\*(C'\fR
directories with the command Mojolicious::Command::inflate.
.PP
.Vb 1
\& $ ./myapp.pl inflate
.Ve
.PP
Those directories have a higher precedence, so inflating can also be a great
way to allow your users to customize their applications.
.SS "Simplified application class"
.IX Subsection "Simplified application class"
This is the heart of every full Mojolicious application and always gets
instantiated during server startup.
.PP
.Vb 2
\& $ touch lib/MyApp.pm
\& $ chmod 644 lib/MyApp.pm
.Ve
.PP
We will start by extracting all actions from \f(CW\*(C`myapp.pl\*(C'\fR and turn them into
simplified hybrid routes in the Mojolicious::Routes router, none of the
actual action code needs to be changed.
.PP
.Vb 2
\& package MyApp;
\& use Mojo::Base \*(AqMojolicious\*(Aq;
\&
\& use MyApp::Model::Users;
\&
\& sub startup {
\& my $self = shift;
\&
\& $self\->secrets([\*(AqMojolicious rocks\*(Aq]);
\& $self\->helper(users => sub { state $users = MyApp::Model::Users\->new });
\&
\& my $r = $self\->routes;
\&
\& $r\->any(\*(Aq/\*(Aq => sub {
\& my $c = shift;
\&
\& my $user = $c\->param(\*(Aquser\*(Aq) || \*(Aq\*(Aq;
\& my $pass = $c\->param(\*(Aqpass\*(Aq) || \*(Aq\*(Aq;
\& return $c\->render unless $c\->users\->check($user, $pass);
\&
\& $c\->session(user => $user);
\& $c\->flash(message => \*(AqThanks for logging in.\*(Aq);
\& $c\->redirect_to(\*(Aqprotected\*(Aq);
\& } => \*(Aqindex\*(Aq);
\&
\& my $logged_in = $r\->under(sub {
\& my $c = shift;
\& return 1 if $c\->session(\*(Aquser\*(Aq);
\& $c\->redirect_to(\*(Aqindex\*(Aq);
\& return undef;
\& });
\& $logged_in\->get(\*(Aq/protected\*(Aq);
\&
\& $r\->get(\*(Aq/logout\*(Aq => sub {
\& my $c = shift;
\& $c\->session(expires => 1);
\& $c\->redirect_to(\*(Aqindex\*(Aq);
\& });
\& }
\&
\& 1;
.Ve
.PP
The \f(CW\*(C`startup\*(C'\fR method gets called right after instantiation and is the place
where the whole application gets set up. Since full Mojolicious
applications can use nested routes they have no need for \f(CW\*(C`group\*(C'\fR blocks.
.SS "Simplified application script"
.IX Subsection "Simplified application script"
\&\f(CW\*(C`myapp.pl\*(C'\fR itself can now be turned into a simplified application script to
allow running tests again.
.PP
.Vb 1
\& #!/usr/bin/env perl
\&
\& use strict;
\& use warnings;
\&
\& use lib \*(Aqlib\*(Aq;
\& use Mojolicious::Commands;
\&
\& # Start command line interface for application
\& Mojolicious::Commands\->start_app(\*(AqMyApp\*(Aq);
.Ve
.PP
And the directory structure of our hybrid application should be looking like
this.
.PP
.Vb 10
\& myapp
\& |\- myapp.pl
\& |\- lib
\& | |\- MyApp.pm
\& | +\- MyApp
\& | +\- Model
\& | +\- Users.pm
\& |\- t
\& | +\- login.t
\& +\- templates
\& |\- layouts
\& | +\- default.html.ep
\& |\- index.html.ep
\& +\- protected.html.ep
.Ve
.SS "Controller class"
.IX Subsection "Controller class"
Hybrid routes are a nice intermediate step, but to maximize maintainability it
makes sense to split our action code from its routing information.
.PP
.Vb 3
\& $ mkdir lib/MyApp/Controller
\& $ touch lib/MyApp/Controller/Login.pm
\& $ chmod 644 lib/MyApp/Controller/Login.pm
.Ve
.PP
Once again the actual action code does not need to change, we just rename
\&\f(CW$c\fR to \f(CW$self\fR since the controller is now the invocant.
.PP
.Vb 2
\& package MyApp::Controller::Login;
\& use Mojo::Base \*(AqMojolicious::Controller\*(Aq;
\&
\& sub index {
\& my $self = shift;
\&
\& my $user = $self\->param(\*(Aquser\*(Aq) || \*(Aq\*(Aq;
\& my $pass = $self\->param(\*(Aqpass\*(Aq) || \*(Aq\*(Aq;
\& return $self\->render unless $self\->users\->check($user, $pass);
\&
\& $self\->session(user => $user);
\& $self\->flash(message => \*(AqThanks for logging in.\*(Aq);
\& $self\->redirect_to(\*(Aqprotected\*(Aq);
\& }
\&
\& sub logged_in {
\& my $self = shift;
\& return 1 if $self\->session(\*(Aquser\*(Aq);
\& $self\->redirect_to(\*(Aqindex\*(Aq);
\& return undef;
\& }
\&
\& sub logout {
\& my $self = shift;
\& $self\->session(expires => 1);
\& $self\->redirect_to(\*(Aqindex\*(Aq);
\& }
\&
\& 1;
.Ve
.PP
All Mojolicious::Controller controllers are plain old Perl classes and get
instantiated on demand.
.SS "Application class"
.IX Subsection "Application class"
The application class \f(CW\*(C`lib/MyApp.pm\*(C'\fR can now be reduced to model and routing
information.
.PP
.Vb 2
\& package MyApp;
\& use Mojo::Base \*(AqMojolicious\*(Aq;
\&
\& use MyApp::Model::Users;
\&
\& sub startup {
\& my $self = shift;
\&
\& $self\->secrets([\*(AqMojolicious rocks\*(Aq]);
\& $self\->helper(users => sub { state $users = MyApp::Model::Users\->new });
\&
\& my $r = $self\->routes;
\& $r\->any(\*(Aq/\*(Aq)\->to(\*(Aqlogin#index\*(Aq)\->name(\*(Aqindex\*(Aq);
\&
\& my $logged_in = $r\->under(\*(Aq/\*(Aq)\->to(\*(Aqlogin#logged_in\*(Aq);
\& $logged_in\->get(\*(Aq/protected\*(Aq)\->to(\*(Aqlogin#protected\*(Aq);
\&
\& $r\->get(\*(Aq/logout\*(Aq)\->to(\*(Aqlogin#logout\*(Aq);
\& }
\&
\& 1;
.Ve
.PP
The router allows many different route variations,
Mojolicious::Guides::Routing explains them all in great detail.
.SS "Templates"
.IX Subsection "Templates"
Templates are our views, and usually bound to controllers, so they need to be
moved into the appropriate directories.
.PP
.Vb 3
\& $ mkdir templates/login
\& $ mv templates/index.html.ep templates/login/index.html.ep
\& $ mv templates/protected.html.ep templates/login/protected.html.ep
.Ve
.SS "Script"
.IX Subsection "Script"
Finally \f(CW\*(C`myapp.pl\*(C'\fR can be replaced with a proper Mojolicious script.
.PP
.Vb 4
\& $ rm myapp.pl
\& $ mkdir script
\& $ touch script/myapp
\& $ chmod 744 script/myapp
.Ve
.PP
Only a few small details change, since installable scripts can't use lib
without breaking updated dual-life modules.
.PP
.Vb 1
\& #!/usr/bin/env perl
\&
\& use strict;
\& use warnings;
\&
\& use FindBin;
\& BEGIN { unshift @INC, "$FindBin::Bin/../lib" }
\&
\& # Start command line interface for application
\& require Mojolicious::Commands;
\& Mojolicious::Commands\->start_app(\*(AqMyApp\*(Aq);
.Ve
.SS "Simplified tests"
.IX Subsection "Simplified tests"
Full Mojolicious applications are a little easier to test, so \f(CW\*(C`t/login.t\*(C'\fR
can be simplified.
.PP
.Vb 2
\& use Test::More;
\& use Test::Mojo;
\&
\& # Load application class
\& my $t = Test::Mojo\->new(\*(AqMyApp\*(Aq);
\& $t\->ua\->max_redirects(1);
\&
\& $t\->get_ok(\*(Aq/\*(Aq)
\& \->status_is(200)
\& \->element_exists(\*(Aqform input[name="user"]\*(Aq)
\& \->element_exists(\*(Aqform input[name="pass"]\*(Aq)
\& \->element_exists(\*(Aqform input[type="submit"]\*(Aq);
\&
\& $t\->post_ok(\*(Aq/\*(Aq => form => {user => \*(Aqsri\*(Aq, pass => \*(Aqsecr3t\*(Aq})
\& \->status_is(200)\->text_like(\*(Aqhtml body\*(Aq => qr/Welcome sri/);
\&
\& $t\->get_ok(\*(Aq/protected\*(Aq)\->status_is(200)\->text_like(\*(Aqa\*(Aq => qr/Logout/);
\&
\& $t\->get_ok(\*(Aq/logout\*(Aq)\->status_is(200)
\& \->element_exists(\*(Aqform input[name="user"]\*(Aq)
\& \->element_exists(\*(Aqform input[name="pass"]\*(Aq)
\& \->element_exists(\*(Aqform input[type="submit"]\*(Aq);
\&
\& done_testing();
.Ve
.PP
And our final directory structure should be looking like this.
.PP
.Vb 10
\& myapp
\& |\- script
\& | +\- myapp
\& |\- lib
\& | |\- MyApp.pm
\& | +\- MyApp
\& | |\- Controller
\& | | +\- Login.pm
\& | +\- Model
\& | +\- Users.pm
\& |\- t
\& | +\- login.t
\& +\- templates
\& |\- layouts
\& | +\- default.html.ep
\& +\- login
\& |\- index.html.ep
\& +\- protected.html.ep
.Ve
.PP
Test-driven development takes a little getting used to, but can be a very
powerful tool.
.SH "MORE"
.IX Header "MORE"
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.
.SH "SUPPORT"
.IX Header "SUPPORT"
If you have any questions the documentation might not yet answer, don't
hesitate to ask on the
mailing-list or the official \s-1IRC\s0
channel \f(CW\*(C`#mojo\*(C'\fR on \f(CW\*(C`irc.perl.org\*(C'\fR.