How do you handle RESTful URL parameters in a Ruby on Rails application?

Question

I am dealing with a very simple RESTful Rails application. There is a User model and I need to update it. Rails coders like to do:

if @user.update_attributes(params[:user])
...

And from what I understand about REST, this URL request should work:

curl -d "first_name=tony&last_name=something2&v=1.0&_method=put" http://localhost:3000/users/1.xml

However, it's quite obvious that will not work because each URL parameter will be parsed to the variable "params" and not "params[:user]"

I have a hackish fix for now, but I wanted to know how people usually handle this.

Thanks

Answer 1

It's just a matter of how Rails parses parameters. You can nest parameters in a hash using square brackets. Something like this should work:

curl -d "user[first_name]=tony&user[last_name]=something2&v=1.0&_method=put" http://localhost:3000/users/1.xml

This should turn into

{:user=>{:last_name=>"something", :first_name=>"tony"}}

in your params hash. This is how Rails form helpers build the params hash as well, they use the square brackets in the form input tag name attribute.

Answer 2

It's a tradeoff; You can have slightly ugly urls, but very simple controller/models. Or you can have nice urls but slightly ugly controller/models (for making custom parsing of parameters).

For example, you could add this method on your User model:

class User < ActiveRecord::Base

  #class method
  def self.new_from_params(params)
    [:action, :method, :controller].each{|m| params.delete(m)}
    # you might need to do more stuff nere - like removing additional params, etc
    return new(params)
  end
end

Now on your controller you can do this:

class UsersController < ApplicationController
  def create
    #handles nice and ugly urls
    if(params[:user]) @user=User.new(params[:user])
    else @user = User.new_from_params(params)
    end

    if(@user.valid?)
    ... etc
    end
  end
end

This will handle your post nicely, and also posts coming from forms.

I usually have this kind of behaviour when I need my clients to "copy and paste" urls around (i.e. on searches that they can send via email).