CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-3
rfsbsb
rfsbsb

Reputation: 519

Rails 3 right place to create a utility method

I'm creating an App where I would have some kind of scheduled (cron) methods (I guess it would be invoked by rake) to fetch and parse some remote data (mostly HTML) and then store it in my models.

I created a method in my model to fetch the remote data, and another method in the same model to parse and save this data. I feel it's wrong, and that's my question:

Where should be my fetch and parsing methods? Should I create a module? Should I create a Lib?

I think there should be a "rails way" to do it, but I haven't figured it out yet. Can you give me some tips?

Upvotes: 1

Views: 235

Answers (3)

Simone Carletti
Simone Carletti

Reputation: 176412

My suggestion is to keep inside the model only the methods strictly associated with the persistence scope of the model.

Your new code is not strictly persistence related. It can be considered as a data importer. You can easily create a new class/module only for that.

For example, assuming your library will download some HTML, parse it and save the content as Model instances.

This file should live in /lib, for example /lib/crawler.rb.

class Crawler
  def run(url)
    # ...
    fetch( ... )
    parse( ... )
    import( ... )
  end

  def fetch(...)
    # ...
  end

  def parse(...)
    # ...
  end

  def import(...)
    # ...
    result.each do |result|
      Model.create( ... )
    end
  end
end

This ensures your Model class does not quickly become full of methods belonging to several different features.

Moreover, you will be able to test this library in isolation from the Model.

In your rake task or worker, simply create a new instance of the crawler (again, this is just an example) and run it.

tast :crawler => [:environment] do
  craweler = Crawler.new
  craweler.run( ... )
end

Upvotes: 2

raddrick
raddrick

Reputation: 4453

There are a couple things you could do, depending on how many of your models will be using your new model.

You could add them to your model 'helper' or you can create a new module and place it in your lib directory. You can then include the lib/module in your model. Nice; clean code.

enter image description here

Upvotes: 0

AfDev
AfDev

Reputation: 1242

You may want to watch Ryan Bates railscast on cron/scheduling/polling

http://railscasts.com/episodes/164-cron-in-ruby-revised http://railscasts.com/episodes/271-resque

Very good guides.

Upvotes: 1

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