CODEWITHSUNDEEP
ruby-on-rails-4class-variables
lmatejic
lmatejic

Reputation: 81

Accessing class variables in views

What is the correct syntax for storing something in my class variable from a view ? Let's say that this is the code:

Controller:

class FooController < ApplicationController
@@myvar = "I'm a string"

*
*
*
methods
*
*
*
end

Form:

<%= form_for(@something) do |f| %>
    <%= f.text_field :myvar %>
    <%= f.submit %>
<% end %>

This is just an example of a form as it is not functional, I cannot find what the correct syntax is for accesssing @@myvar from the view. Thanks !

Upvotes: 1

Views: 1977

Answers (2)

Tim Kretschmer
Tim Kretschmer

Reputation: 2280

as on request i edited, including attr_accessor

Rails way. Ill just fly over, hope you get it. you defenitely need to read more introductions to rails and its concept.

you have a rails-model, lets call it Animal

class Animal < ActiveRecord::Base
  attr_accessor :non_saved_variable

end

this is having a database-table, lets say in this table we store race, name and age.

now we need a controller, to create/edit/update/delete animals

class AnimalController < ActionController::Base
   def new
     # this creates a new animal with blank values
     @animal = Animal.new
   end
end

now you need to go into your routes.rb and create a route for animals

resources :animal

this will create all (restful) routes for every actions of an animal.

now you need to have your template to render a form

form_for is a rails helper, to create a form, associated with the @animal (which is a new Animal). You pass |f| into the block, so with f you can access the form

=form_for @animal do |f|

then you can go for each field you need to call another rails helper you can also access attr_accessors.

=f.text_field :race
=f.text_field :name
=f.text_field :age
=f.text_field :non_saved_variable

by that you get the stuff

dont fortget f.submit because your form needs a submit button

if you now click on your button, the form will be posted to the create method of rails. so you need to bring it into your controller

def create
   # create a new animal with the values sended by the form
   @animal = Animal.new params[:animal]

   # here you can access the attr_accessor
   @animal.do_something if @animal.non_saved_variable == "1337"

   if @animal.save
     # your animal was saved. you can now redirect or do whatever you want
   else
     #couldnt be saved, maybe validations have been wrong
     #render the same form again
     render action: :new
   end
end

i hope that gave you a first insight of rails ?!

Upvotes: 2

Yule
Yule

Reputation: 9774

DO NOT DO THIS

You can get or set class variables from any class by: 

<%= FooController.class_variable_get(:@@myvar) %>
<%= FooController.class_variable_set(:@@myvar, 'value') %>

This is probably not what you want. Do not do it. What are you trying to achieve?

DO THIS INSTEAD:

If it's a variable that you want to be available to all actions in that controller consider an instance variable set in a a before filter:

class FooController < ApplicationController

  before_filter :set_var

  private
    def set_var
      @my_var = "I'm a string"
    end
end

Then in your view, just call <%= @my_var %>

Upvotes: 2

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