How do you pass data from a controller to a model with Ruby on Rails?

Question

How do you pass data from a controller to a model?

In my application_controller I grab the user\'s location (state and city) and include a before_

Answer 1

The class instance variables (those that start with @) in the controllers are separate from those in the models. This is the Model vs the Controller in MVC architecture. The Model and Controller (and view) are separated.

You move info from a controller to a model explicitly. In Rails and other object oriented systems, you have several options:

Use function parameters

# In the controller
user = User.new(:community => @community)

# In this example, :community is a database field/column of the 
# User model    

Docs

Use instance variables attribute setters

# In the controller
user = User.new
user.community = @community
# same as above, :community is a database field

Passing data to models when the data is not a database field

# In the model
class User < ActiveRecord::Base
  attr_accessor :community
  # In this example, :community is NOT a database attribute of the 
  # User model. It is an instance variable that can be used
  # by the model's calculations. It is not automatically stored in the db

# In the controller -- Note, same as above -- the controller 
# doesn't know if the field is a database attribute or not. 
# (This is a good thing)
user = User.new
user.community = @community

Docs