# Trouble writing a plugin with view helpers

**URL:** <https://www.ruby-forum.com/t/trouble-writing-a-plugin-with-view-helpers/120708>\
**Category:** Rails\
**Created:** [November 20, 2007, 12:34am UTC](https://www.ruby-forum.com/t/trouble-writing-a-plugin-with-view-helpers/120708 "2007-11-20T00:34:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![alan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/a87d85/32.png) [@alan](https://www.ruby-forum.com/u/alan)\
**Post date:** [November 20, 2007, 12:34am UTC](https://www.ruby-forum.com/t/trouble-writing-a-plugin-with-view-helpers/120708/1 "2007-11-20T00:34:53Z")

</div>

Hi,

I am writing a plugin with some view helpers, and have hit a wall. The  
helper method uses a class that specifies specific behavior depending  
on an model object. The problem is that I need that class to be able  
to use the rest of Rails helpers, such as content\_tag.

The class extends a general class which is mixed with a module. It  
uses method\_missing to define methods to the class used by the helper  
method if it hasn’t been defined.

## This is the code with the problem:

## init.rb

#The other stuff plus  
ActionView::Base.send :include, Microformat::ViewHelpers

* * *

## microformat\_helper.rb

module Microformat  
module ViewHelpers

```
# User will type:
# <% geo_for location, "Location:", :geo_tag

```

=\> :div, :internal\_tag =\> :span do |g| %\>  
# \<% g.latitude "Latitude: #{location.latitude}, " %\>  
# \<% g.longitude “Longitude: #{location.longitude}” %\>  
# \<% end %\>

```
# Output
# <div class="geo">GEO:
# <span class="latitude">37.386013</span>,
# <span class="longitude">-122.082932</span>
# </div>

def geo_for(geo_obj, text, options = {})
  raise ArgumentError, "Missing block" unless block_given?
  geo_tag = options.delete :geo_tag
  internal_tag = options.delete :internal_tag
  content_tag geo_tag, :class => "geo" do
    text
    yield GeoInternal.new(internal_tag, geo_obj)
  end
end

```

end

module MicroformatCreator

```
def method_missing(name, *args)
  block = Proc.new{|b_args, b_name|
    tag, text = b_args.pop, b_args.pop
    content_tag tag, :class => b_name do
      text unless text.nil?
    end
  }
  self.class.send(:define_method, name, block)
  block.call(args, name)
end

```

end

class InvalidMicroformatField \< StandardError  
end

class Microformat  
include MicroformatCreator

```
def initialize(tag, m_obj)
  @i_tag = tag
  @m_obj = m_obj
end

def method_missing(name, *args)
  raise InvalidMicroformatField, "The field #{name} does not

```

exist" unless @m\_obj.attribute\_names.include?(name.to\_s)  
args.push @i\_tag  
super(name, args)  
end  
end

class GeoInternal \< Microformat  
def initialize(tag, g\_obj)  
super(tag, g\_obj)  
end  
end  
end

What is happening right now when I use ‘geo\_for’ in a view is that the  
content\_tag in the MicroformatCreator method\_missing is caught by the  
raise of the Microformat class. I need to find a way to make the rails  
helper methods to the GeoInternal class.

I have tried including MicroformatGenerator in init.rb, hoping then  
that method missing could call content\_tag, but it didn’t work. I also  
tried including to MicroformatGenerator the necessary Rails helpers,  
such as TagHelper, but then I got an error related to \_erbout.

If anyone has a workaround to make the helpers available to  
GeoInternal it would be great, or let me know if this is not possible.

Thanks,

Alan