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Brad Haywood

NAME

Pulp - Give your Kelp applications more juice

DESCRIPTION

Kelp is good. Kelp is great. But what if you could give it more syntactic sugar and separate your routes from the logic in a cleaner way? Pulp attempts to do just that.

SIMPLE TUTORIAL

For the most part, your original app.psgi will remain the same as Kelps.

MyApp.pm

  package MyApp;
  use Pulp;

  maps ['Main'];

Yep, that's the complete code for your base. You pass maps an array reference of the routes you want to include. It will look for them in MyApp::Route::. So the above example will load MyApp::Route::Main. Next, let's create that file

MyApp/Route/Main.pm

  package MyApp::Route::Main;

  use Pulp::Route;

  get '/' => 'Controller::Root::hello';
  get '/nocontroller' => sub { 'Hello, world from no controller!' };

Simply use Pulp::Route, then create your route definitions here. You're welcome to put your logic inside code refs, but that makes the whole idea of this module pointless ;) It will load MyApp:: then whatever you pass to it. So the '/' above will call MyApp::Controller::Root::hello. Don't worry, any of your arguments will also be sent the method inside that controller, so you don't need to do anything else!

Finally, we can create the controller

MyApp/Controller/Root.pm

  package MyApp::Controller::Root;

  use Pulp::Controller;

  sub hello {
      my ($self) = @_;
      return "Hello, world!";
  }

You now have a fully functional Kelp app! Remember, because this module is just a wrapper, you can do pretty much anything Kelp can, like $self->param> for example.

SUGARY SYNTAX

By sugar, we mean human readable and easy to use. You no longer need a build method, then to call ->add on an object for your routes. It uses a similar syntax to Kelp::Less. You'll also find one called bridge.

get

This will trigger a standard GET request.

  get '/mypage' => sub { 'It works' };

post

Will trigger on POST requests only

  post '/someform' => sub { 'Posted like a boss' };

any

Will trigger on POST or GET requests

  any '/omni' => sub { 'Hit me up on any request' };

bridge

Bridges are cool, so please check out the Kelp documentation for more information on what they do and how they work.

  bridge '/users/:id' => sub {
      unless ($self->user->logged_in) {
          return;
      }

      return 1;
  };

  get '/users/:id/view' => 'Controller::Users::view';

has

If you only want basic accessors and Pulp detects you don't have any OOP frameworks activated with has, then it will import its own little method which works similar to Moo's. Currently, it only supports is, required and default.

  package MyApp;
    
  use Pulp;
  has 'x' => ( is => 'rw', default => sub { "Hello, world" } );

  package MyApp::Controller::Main;
    
  use Pulp::Controller;
  
  sub hello { shift->x; } # Hello, world

around

Need more power? Want to modify the default build method? No problem. Similar to has, if Pulp detects you have no around method, it will import one. This allows you to tap into build if you really want to for some reason.

  package MyApp;

  use Pulp;

  around 'build' => sub {
      my $method = shift;
      my $self   = shift;
      my $routes = $self->routes;
      $routes->add('/manual' => sub { "Manually added" });

      $self->$method(@_);
  };

MODELS

You can always use an attribute to create a database connection, or separate them using models in a slightly cleaner way. In your config you supply a hash reference with the models alias (what you will reference it as in code), the full path, and finally any arguments it might have (like the dbi line, username and password).

  # config.pl
  models => {
      'LittleDB' => {
          'model' => 'TestApp::Model::LittleDB',
          'args'  => ['dbi:SQLite:testapp.db'],
      },
  },

Then, you create TestApp::Model::LittleDB

  package TestApp::Model::LittleDB;

  use Pulp::Model;
  use DBIx::Lite;

  sub build {
      my ($self, @args) = @_;
      return DBIx::Lite->connect(@args);
  }

As you can see, the build function returns the DB object you want. You can obviously use DBIx::Class or whatever you want here.

That's all you need. Now you can pull that model instance out at any time in your controllers with model.

  package TestApp::Controller::User;

  use Pulp::Controller;

  sub users {
      my ($self) = @_;
      my @users  = $self->model('LittleDB')->table('users')->all;
      return join ', ', map { $_->name } @users;
  }

Named ResultSets

If you're not using DBIx::Class, you can still have similar styled resultsets. Simply return a standard hash reference instead of a blessed object from the build method, like so

  package TestApp::Model::LittleDB;

  use Pulp::Model;
  use DBIx::Lite;

  sub build {
      my ($self, @args) = @_;
      my $schema = DBIx::Lite->connect(@args);
      return {
          'User'       => $schema->table('users'),
          'Product'    => $schema->table('products'),
      };
  }

Then, you can do this stuff in your controllers

  package TestApp::Controller::Assets;

  sub users {
      my  ($self) = @_;
      my @users   = $self->model('LittleDB::User')->all;
      return join "<br>", map { $_->name . " (" . $_->email . ")" } @users;
  }

  sub products {
      my ($self) = @_;
      my @products = $self->model('LittleDB::Product')->all;
      return join "<br>", map { $_->name . " (" . sprintf("%.2f", $_->value) . ")" } @products;
  }

Models and DBIx::Class

If you enjoy the way Catalyst handles DBIx::Class models, you're going to love this (I hope so, at least). Pulp will automagically create models based on the sources of your schema if it detects it's a DBIx::Class::Schema. Nothing really has to change, Pulp will figure it out on its own.

  package TestApp::Model::LittleDB;

  use Pulp::Model;
  use LittleDB::Schema;

  sub build {
      my ($self, @args) = @_;
      return LittleDB::Schema->connect(@args);
  }

Then just use it as you normally would in Catalyst (except we store it in $self, not $c).

  package TestApp::Controller::User;
  
  use Pulp::Controller;
  
  sub users {
      my ($self) = @_;
      my @users = $self->model('LittleDB::User')->all;
      return join ', ', map { $_->name } @users;
  }

Pulp will loop through all your schemas sources and create models based on your alias, and the sources name. So, Alias::SourceName.

When we start our app, even though we've only added LittleDB, you'll see we have the new ones based on our Schema. Neat!

  .----------------------------------------------------------.
  | Model                                | Alias             |
  +--------------------------------------+-------------------+
  | TestApp::Model::LittleDB             | LittleDB          |
  | LittleDB::Schema::ResultSet::User    | LittleDB::User    |
  | LittleDB::Schema::ResultSet::Product | LittleDB::Product |
  '--------------------------------------+-------------------'

Automated API generation

Did you know Pulp can automatically create an API for your DBIx::Class schema? Currently this feature is still in beta, and only works with searching. Simply pass -api as an import option like so.

  package TestApp::Model::LittleDB;
  
  use Pulp::Model -api => 1;
  ...

This will tell Pulp to do all the work for you, and generates a basic JSON API. Some of the commands are below:

list

Lists all rows found for a particular resultset

  # curl http://localhost:5000/api/user/list
  [
     {
        "email" : "admin@company.ltd",
        "name" : "Admin User",
        "id" : 1
     },
     {
        "email" : "user@company.ltd",
        "name" : "Normal User",
        "id" : 2
     }
  ] 

find

Obtain a single row based on an id.

  # curl http://localhost:5000/api/user/find/2
  {
     "email" : "user@company.ltd",
     "name" : "Normal User",
     "id" : 2
  }

You can also perform a search, passing query parameters as your search arguments. If no parameters are passed, you'll get all results back.

  # curl http://localhost:5000/api/user/search?email=admin@company.ltd&id=1
  [
     {
        "email" : "admin@company.ltd",
        "name" : "Admin User",
        "id" : 1
     }
  ]

VIEWS

OK, so to try and not separate too much, I've chosen not to include views. Just use the standard Kelp modules (ie: Kelp::Module::Template::Toolkit). However, there is a convenience method mentioned below.

detach

This method will call template for you with the added benefit of automatically filling out the filename and including whatever is in the stash for you.

  package MyApp::Controller::Awesome;
 
  use Pulp::Controller;

  sub hello {
      my ($self) = @_;
      $self->stash->{name} = 'World';
      $self->detach;
  }

Then, you just create hello.tt.

  <h2>Hello, [% name %]</h2>

While not really required, it does save a bit of typing and can come in quite useful.

IMPORT OPTIONS

-auto

Importing -auto will automatically include any route modules within your MyApp::Route namespace. For example, we have two controllers, Main and New

  package MyApp::Route::Main;

  use Pulp::Route;
  
  get '/' => sub { "Hi" };

  package MyApp::Route::New;
  
  use Pulp::Route;
  
  get '/new/url' => sub { "New one" };
  

Then to kick off our app, all we need is

  package MyApp;
  use Pulp -auto => 1;

That's it. Pulp will complain if you attempt to use maps at the same time, because obviously that's just redundant.

REALLY COOL THINGS TO NOTE

Default imports

You should be aware that Pulp will import warnings, strict and true for you. Because of this, there is no requirement to add a true value to the end of your file. I chose this because it just makes things look a little cleaner.

Pulp starter

On installation of Pulp, you'll receive a file called pulp. Simply run this, passing it the name of your module and it will create a working test app with minimal boilerplate so you can get started straight away. Just run it as:

  $ pulp MyApp
  $ pulp Something::With::A::Larger::Namespace

SEE ALSO

Kelp - At the very heart of Pulp is Kelp, a minimalistic web framework created around Plack. Definitely check this out. The excellent documentation will come in handy if you're using Pulp as well.

AUTHOR

Brad Haywood <brad@perlpowered.com>

LICENSE

You may distribute this code under the same terms as Perl itself.