Yanick Champoux > Dancer2-Plugin-Adapter > Dancer2::Plugin::Adapter

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Module Version: 0.006   Source  

NAME ^

Dancer2::Plugin::Adapter - Wrap any simple class as a service for Dancer2

VERSION ^

version 0.006

SYNOPSIS ^

  # in config.yml

  plugins:
    Adapter:
      ua:
        class: HTTP::Tiny
        scope: request
        options:
          max_redirect: 3

  # in your app

  use Dancer2::Plugin::Adapter;

  get '/proxy/:url' => sub {
    my $res = service('ua')->get( params->{'url'} );
    if ( $res->{success} ) {
      return $res->{content};
    }
    else {
      template 'error' => { response => $res };
    }
  };

DESCRIPTION ^

The problem: you want to use some perl class in your Dancer2 app, but there's no plugin for it.

The solution: as long as the class needs only static data to construct an object, then Dancer2::Plugin::Adaptor can do the wrapping for you. Think of it as a "just-in-time" plugin (or maybe a poor-man's Bread::Board).

Here's another example: you want to send emails via Postmark using WWW::Postmark.

In your config.yml, you put this:

  plugins:
    Adapter:
      postmark:
        class: WWW::Postmark
        scope: singleton
        options: POSTMARK_API_TEST

In your production config.yml, you can replace 'POSTMARK_API_TEST' with your real Postmark API key.

Then, in your application, here's how you use it:

    get '/' => sub {
      eval {
        service("postmark")->send(
          from    => 'me@domain.tld',
          to      => 'you@domain.tld, them@domain.tld',
          subject => 'an email message',
          body    => "hi guys, what's up?"
        );
      };

      return $@ ? "Error: $@" : "Mail sent";
    };

Dancer2::Plugin::Adapter takes care of constructing and caching the WWW::Postmark object based on the configuration data, and lets you access the object with the service() function.

CONFIGURATION ^

One or more objects are defined by NAME => HASHREF pairs. The hash reference for each NAME must contain a 'class' key, whose value is the class to wrap.

The 'scope' key determines how long the generated object persists. The choice of scope will depend on whether the object holds onto any state that should not last across requests. The following scope values are allowed:

request

(default) the object persists in the vars hash for the duration of the request

singleton

the objects persists in a private, lexical hash for the duration of the process

none

the object is not cached; a fresh object is created on each call

If the hash reference contains an 'options' key, its value will be dereferenced (if it is a hash or array reference) and passed to new() when the object is created. Note that if the class requires a reference for the constructor, you have to wrap it in an extra array. E.g.

  # config.yml:
  plugins:
    Adapter:
      foo:
        class: Foo::Bar
        scope: request 
        options:
          -
            wibble: wobble
            biff: boff

  # constructor called as:
  Foo::Bar->new( { wibble => wobble, biff => boff } );

If the class does not use 'new' as the name of its constructor, an alternate can be specified with the 'constructor' key.

  # config.yml:
  plugins:
    Adapter:
      tmpdir:
        class: File::Temp
        constructor: newdir

  # constructor called as:
  File::Temp->newdir()

When caching under request scope, Dancer2::Plugin::Adaptor uses the key _dpa in the vars.

USAGE ^

service

  $object = service($name);

This function returns the object corresponding to the name defined in the configuration file. The object is created on demand and may be cached for future use based on its scope configuration option.

SEE ALSO ^

Dancer2
Dancer2::Plugin

ACKNOWLEDGMENTS ^

Thank you to Matt S. Trout for suggesting the 'scope' controls.

AUTHOR ^

David Golden <dagolden@cpan.org>

COPYRIGHT AND LICENSE ^

This software is Copyright (c) 2012 by David Golden.

This is free software, licensed under:

  The Apache License, Version 2.0, January 2004
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