Query REST

rubyonrails-talk
1

New to Rails and REST here.

Say I have a simple Rails app called Todos. I generate a controller for Todos and so via REST I can obtain Todo at index 1 by calling say, localhost:3000/todos/1

I can also obtain all todos by doing localhost:3000/todos

so how can I use REST by querying for a todo that has a specific title? I'm not sure how to do this.

regards, Michael

2

So you're still interested in a list of todos, but this time filtered depending on the title.

You can have the index action receive a search string via params. And to keep your controller lean, pass this on to a class method or even better, a named_scope in your Todo model which will return filtered results.

Regards, Franz

3

Franz Strebel wrote in post #991045:

so how can I use REST by querying for a todo that has a specific title? I'm not sure how to do this.

So you're still interested in a list of todos, but this time filtered depending on the title.

You can have the index action receive a search string via params. And to keep your controller lean, pass this on to a class method or even better, a named_scope in your Todo model which will return filtered results.

This is a good approach for relatively basic search requirements, which in a lot of cases is all one needs.

In cases where more complex search is required it is also possible to create a new resource used to perform search. Say, for example, you wanted to be able to save searches for later use, or provide an advanced search form. I think it's important to keep in mind, even though this might seem like a more advanced approach for someone new to Ruby on Rails and REST.

It is also worth taking the time to read though Fielding's Dissertation:

http://www.ics.uci.edu/~fielding/pubs/dissertation/rest_arch_style.htm

Especially these sections: 5.2.1.1 Resources and Resource Identifiers 5.2.1.2 Representations

4

Do you know of a quick and dirty example? I understand the concept you're describing, but I don't know where I can find an example of the syntax in the Rails controller to get it right. Also, I'm interested in possibly making the REST call from an abstracted view/controller framework like SproutCore, not necessarily from a Form..

regards, Michael

5

OK, in your Todo model, create a named scope

named_scope :search, lambda { |s|   options = { :order => :title }   options[:conditions] = [ "upper(title) like :search_string", { :search_string => "%#{s.strip.upcase}%" } ] unless s.blank?   options }

Then in your controller's index action

def index   @todos = Todo.search(params[:search])

end

Since params is a Hash, it will return nil if it does not contain a key called :search, so the named_scope won't set any conditions and just return your Todos sorted alphabetically by title.

You can quickly test if it works by appending a search param to the URL, eg http://localhost:3000/todos?search=code

BTW, my code may have errors as I just quickly wrote that up without proper testing. I hope this gives you a good idea of how it works.

Regards, Franz