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Rails Forum - Ruby on Rails Help and Discussion Forum » Controllers and Views » Global var for use in controllers and views?
Where can I put an array so it can be used from all my controllers and views?
SERVICE_TYPE = ['public', 'commerical']
I tried putting it in application.rb but it does not appear to be extend to views?
I also tried @SERVICE_TYPE.
Many thanks, AFM.
I use environment.rb, but I'm not sure if that's the "standard" approach.
You could also add it to a model object, and reference it like Service.SERVICE_TYPES.
Last edited by thabenksta (2006-06-27 10:05:52)
You might try setting it up as a session variable in your application.rb file.
app/controllers/application.rb
class ApplicationController < ActionController::Base
def create_default_variables
session[:service_type] = %w{ public commericial }
end
end
class YourController < ActionController::Base
before_filter :create_default_variables
end
Be careful about session variables for global storage because they don't scale particularly well. If your site gets much traffic, you can multiply the 10 bytes or so for this variable by the number of unexpired sessions and you start seeing a potential performance problem.
Also, Rails hasn't historically garbage collected session cookies, so you could have a boatload of those laying around on your server.
environment.rb is a great place for truly global variables.
Just a thought.
This is the thing, I tried putting it in application.rb but could not use it in the views, let me show you:
class ApplicationController < ActionController::Base
@SERVICE_TYPES = ['bus', 'coach']
# ^ views can not see this??
end
<%= @SERVICE_TYPES[1] %>
Can you spot the mistake or give me a working example?
Many thanks, AFM.
Last edited by afm (2006-06-28 05:26:23)
I wasn't thinking about scaling, that's for the tip cwd. I realized looking at this problem today that you are attempting to pass this variable off as an instance variable. Try this:
app/application.rb
class ApplicationController < ActionController::Base
$SERVICE_TYPES = %w{ public commercial }
end
class TestController < ApplicationController
def index
logger.info "Service Types Equal: " + $SERVICE_TYPES.join(' and ')
end
end
<%= debug $SERVICE_TYPES %>
log/development.log
Processing TestController#index (for 127.0.0.1 at 2006-06-28 09:02:17) [GET]
Session ID: 9bce7eccb192b544c88104867d3adb86
Parameters: {"action"=>"index", "controller"=>"test"}
Service Types Equal: public and commercial
Rendering test/index
Last edited by Reedy (2006-06-28 10:14:08)
Should learn to type faster, that pretty much covers it I guess ^_^
Last edited by marsvin (2006-06-28 10:54:29)
Merci bocue!
To get an drop down box from the array I used:
<select id="search_service_type" name="search[service_type]">
<% $SERVICE_TYPES.length.times do |ctr| %>
<option value="<%= ctr.to_s %>"><%= $SERVICE_TYPES[ctr] %></option>
<% end %>
</select>
Last edited by afm (2006-07-04 08:42:40)
class ApplicationController < ActionController::Base
$SERVICE_TYPES = %w{ public commercial }
end
Global variables don't work well with Rails because they aren't shared across multiple FastCGI instances. Therefore, if one instance changes the variable, the other instance will not show the change. If you don't plan on changing the global variable, then best to use a constant.
# put this outside your class definition so it applies to everything
SERVICE_TYPES = %w[public commercial]
<select id="search_service_type" name="search[service_type]">
<% $SERVICE_TYPES.length.times do |ctr| %>
<option value="<%= ctr.to_s %>"><%= $SERVICE_TYPES[ctr] %></option>
<% end %>
</select>
You can make the code a little more concise using the "each_with_index" method.
<select id="search_service_type" name="search[service_type]">
<% SERVICE_TYPES.each_with_index do |service_type, index| %>
<option value="<%= index %>"><%=h service_type %></option>
<% end %>
</select>
<select id="search_service_type" name="search[service_type]">
<%= options_for_select(SERVICE_TYPES) %>
</select>
Global variables don't work well with Rails because they aren't shared across multiple FastCGI instances. Therefore, if one instance changes the variable, the other instance will not show the change. If you don't plan on changing the global variable, then best to use a constant.
Thanks for the heads up. Is this particular to FastCGI because I intend to use Mongrel, which I think is pure HTTP.
And if I want the global to be a constant I just put it in uppercase ie. $SERVICE_TYPES
ya the global vbariable that can be declared using @@ is not shared across different instances.if one action modifies it then an other calling action cannot access the modified.
if this support was there then there was no need of using databases.we would store everything in a global variable and serve ppl without letting them access databases["provided the server never shuts down"].
Why not just use a constant?
If the values aren't going to change, you could put the variable as a constant in any class you like, as follows:
class ServiceTypes
SERVICE_TYPES = %w{ public commercial }
end
ServiceTypes::SERVICE_TYPES
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