Rails - Nov 2005 - learning to write plugins

Hi,

I''m interested in learning to write acts_as_* plugins. Is there any
more info out there than what is currently on the rubyonrails wiki or
Jamis Buck''s site?

Thanks,
Peter

Peter Michaux wrote:
> Hi,
>
> I''m interested in learning to write acts_as_* plugins. Is there
any
> more info out there than what is currently on the rubyonrails wiki or
> Jamis Buck''s site?
>
> Thanks,
> Peter
>
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
Here''s what I did (assuming a fox plugin - no chunky bacon this time)
(A 5 step program to acting foxy...)

1 -
under your_app/vender/plugins
create a directory "acts_as_fox"

2 -
in this directory create a lib directory

so now you should have

your_app/vender/plugins/acts_as_fox/lib

3 -
in the acts_as_fox directory create the following file

your_app/vender/plugins/acts_as_fox/init.rb
#------
require ''acts_as_fox''

4 -
in the lib subdirectory add your code to a file called acts_as_fox.rb
your_app/vender/plugins/acts_as_fox/lib/acts_as_fox.rb
#------
require ''active_record''

module ActiveRecord
  module Acts #:nodoc:
    module Fox#:nodoc:
   
      def self.append_features(base)
        super
        base.extend(ClassMethods)
      end
   
      # Adds a find_all_visible method which finds all records which are 
not hidden
      module ClassMethods
        def acts_as_hidable
          class_eval do
            extend ActiveRecord::Acts::Hidable::SingletonMethods
          end
        end
      end
       
     #add in your methods here...
      module SingletonMethods
          def catch_chickens
            find(:all, :conditions => ''chickens = true'')
          end
        #etc...
      end
    end
  end
end

ActiveRecord::Base.class_eval do
  include ActiveRecord::Acts::Fox
end

5 -
Finally use your method in your classes

class Thing < ActiveRecord::Base
  acts_as_fox
end

You''ve got to be running 0.14.x (not sure which final point release)
but
it doesn''t work with 0.13.1

Hope this helps
Kev

Kev Jackson wrote:
> Peter Michaux wrote:
>
>> Hi,
>>
>> I''m interested in learning to write acts_as_* plugins. Is
there any
>> more info out there than what is currently on the rubyonrails wiki or
>> Jamis Buck''s site?
>>
>> Thanks,
>> Peter
>>
>> _______________________________________________
>> Rails mailing list
>> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
>> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
> Here''s what I did (assuming a fox plugin - no chunky bacon this
time)
> (A 5 step program to acting foxy...)
>
> 1 -
> under your_app/vender/plugins
> create a directory "acts_as_fox"
>
> 2 -
> in this directory create a lib directory
>
> so now you should have
>
> your_app/vender/plugins/acts_as_fox/lib
>
> 3 -
> in the acts_as_fox directory create the following file
>
> your_app/vender/plugins/acts_as_fox/init.rb
> #------
> require ''acts_as_fox''
>
> 4 -
> in the lib subdirectory add your code to a file called acts_as_fox.rb
> your_app/vender/plugins/acts_as_fox/lib/acts_as_fox.rb
> #------
> require ''active_record''
>
> module ActiveRecord
>  module Acts #:nodoc:
>    module Fox#:nodoc:
>        def self.append_features(base)
>        super
>        base.extend(ClassMethods)
>      end
>        # Adds a find_all_visible method which finds all records which 
> are not hidden
>      module ClassMethods

Sorry this should of course be
>        def acts_as_hidable
def acts_as_fox
>          class_eval do
and similarly this should be
>            extend ActiveRecord::Acts::Hidable::SingletonMethods
extend ActiveRecord::Acts::Fox::SingletonMethods
>          end
>        end
>      end
>           #add in your methods here...
>      module SingletonMethods
>          def catch_chickens
>            find(:all, :conditions => ''chickens =
true'')
>          end
>        #etc...
>      end
>    end
>  end
> end
>
> ActiveRecord::Base.class_eval do
>  include ActiveRecord::Acts::Fox
> end
>
> 5 -
> Finally use your method in your classes
>
> class Thing < ActiveRecord::Base
>  acts_as_fox
> end
>
> You''ve got to be running 0.14.x (not sure which final point
release)
> but it doesn''t work with 0.13.1
>
> Hope this helps
> Kev
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

On Nov 3, 2005, at 12:39 AM, Kev Jackson wrote:
> 4 -
> in the lib subdirectory add your code to a file called acts_as_fox.rb
> your_app/vender/plugins/acts_as_fox/lib/acts_as_fox.rb
> #------
> require ''active_record''
>
> module ActiveRecord
>  module Acts #:nodoc:
>    module Fox#:nodoc:
>        def self.append_features(base)
>        super
>        base.extend(ClassMethods)
>      end
>        # Adds a find_all_visible method which finds all records  
> which are not hidden
>      module ClassMethods
>        def acts_as_hidable
>          class_eval do
>            extend ActiveRecord::Acts::Hidable::SingletonMethods
>          end
>        end
>      end
>           #add in your methods here...
>      module SingletonMethods
>          def catch_chickens
>            find(:all, :conditions => ''chickens =
true'')
>          end
>        #etc...
>      end
>    end
>  end
> end
>
> ActiveRecord::Base.class_eval do
>  include ActiveRecord::Acts::Fox
> end
I''ve noticed many plugin developers taking this particular route, and  
I''d like to discourage it, strenuously. There really is no need to  
add your own acts to the ActiveRecord::Acts namespace. Instead, I''d  
encourage the creation of your own Acts namespace:

   module Foo
     module Acts
       class Fox
       end
     end
   end

   Foo::Acts::Fox

This will allow (potentially) multiple developers to develop  
identically-named features without conflict.

(Otherwise, great summary, Kev! Please don''t think I''m picking
on you
specifically--I''ve seen lots of developers taking this route lately.)

- Jamis

>
> I''ve noticed many plugin developers taking this particular route,
and
> I''d like to discourage it, strenuously. There really is no need to
> add your own acts to the ActiveRecord::Acts namespace. Instead,
I''d
> encourage the creation of your own Acts namespace:
>
>   module Foo
>     module Acts
>       class Fox
>       end
>     end
>   end
>
>   Foo::Acts::Fox
>
> This will allow (potentially) multiple developers to develop  
> identically-named features without conflict.
>
> (Otherwise, great summary, Kev! Please don''t think I''m
picking on you
> specifically--I''ve seen lots of developers taking this route
lately.)
No problems, I used another plugin to copy the format of my first plugin 
- I suppose that most people go through this - find an example and copy 
the structure route whilst they are learning.

Kev

Thank Kev and Jamis for the info. I''ve got foxes that can catch
chickens! Since I couldn''t find a wiki page on this and I thought it
was worth preserving your info I made a page.

http://wiki.rubyonrails.com/rails/pages/HowToWriteAnActsAsPlugIn

I''d like to know a little more about the anatomy of a plugin. Why are
three top level moduals nested? I''ve seen inside these three, modual
ClassMethods, modual InstanceMethods and modual SingletonMethods. What are the
differences? And also a trick that prevents the plugin from being called more
than once which maybe is essential?

def acts_as_fox(options = {}) 
                        ## this prevents acts_as_fox from being called multiple
times
                        return if
self.included_modules.include?(Foo::Acts::Fox::InstanceMethods)


Maybe a plugin template for best practices or even better

ruby script/generate plugin acts_as_fox

With some testing files or something. That would be cool!

Thanks,

Peter