/ 
Dancer2-Plugin-Adapter-0.007
River stage zero No dependents
/ Dancer2::Plugin::Adapter

NAME

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

VERSION

version 0.007

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.

AUTHORS

  • David Golden <dagolden@cpan.org>

  • Yanick Champoux <yanick@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