How to explore the environment?

rubyonrails-talk
1

It's my first rails project and something is broken: my action controllers can't access methods defined in the helper modules.

The only thing, I successfully verified (by setting a debugger statement at the very beginning of the helper modules) is, that the helper modules get loaded before the action controller is called.

None the less, the methods defined in the helpers, are unknown to the action controllers.

I can fix the problem by duplicating the helper methods in the controller module, but that's a hack.

Any idea, how to find the reason?

2

http://api.rubyonrails.org/classes/ActionController/Helpers/ClassMethods.html#M000490 (the documentation sort-of lies, as the helper() method does not actually "include" the specified module)

helper WhateverHelper will give the view access to the helper module's instance methods include WheteverHelper will, being plain-old-Ruby, include the WhateverHelper module into the controller

3

Fritz Trapper wrote:


It's my first rails project and something is broken: my action
controllers can't access methods defined in the helper modules.
The only thing, I successfully verified (by setting a debugger statement
at the very beginning of the helper modules) is, that the helper modules
get loaded before the action controller is called.
None the less, the methods defined in the helpers, are unknown to the
action controllers.
I can fix the problem by duplicating the helper methods in the
controller module, but that's a hack.
Any idea, how to find the reason?

The helpers are more accurately called view helper methods. They are not intended for use in the controllers.

4

If you want to use the same methods in both environments (view and controller), you can do like this (in controller):

def method_a

end

def method_b

end

helper_method :method_a, :method_b

Then the methods will be available also in views.

5

Thanks for your replies.

Now I read the API reference of ActionController::Helpers::ClassMethods and took a look into my ApplicationController, which has been generated via RadRails:

class ApplicationController < ActionController::Base   helper :all # include all helpers, all the time

  protect_from_forgery end

If I understand the doc, helper :all should do the job for all controllers.

To verify this, I set a debugger call as first statement in my crashing controller and give

  y ActionController::Base.helpers_dir

into the debugger. The response is:

  NoMethodError Exception: undefined method `helpers_dir' for   ActionController::Base:Class

So what is going wrong there?

6

As I said: ActionController::Base.helper does not actually include helper modules into the controller; it makes them accessible in the view. You'll need to

include ApplicationHelper # or whatever appropriate module

to have the methods accessible in the controller.

7

pharrington wrote:

As I said: ActionController::Base.helper does not actually include helper modules into the controller; it makes them accessible in the view. You'll need to

include ApplicationHelper # or whatever appropriate module

to have the methods accessible in the controller.

In deed, that helps. Sorry for my ignorance.

8

But there is still one annoying point:

My controllers worked using methods from ApplicationHelper until yesterday morning, when I tried to modify routes.rb and run sume rake jobs from RadRails that I didn't really understand, including rake rails:update

The changes in routes.rb have been rolled back, but that didn't help

9

Then perhaps helper() actually included the helper modules into the controller in an earlier version of Rails. Its hard for me to remember at this point, but I know since at least 2.2 helper()'s behaved as it does now.

Just curious now; what version of Rails did you have previously installed, and what version did you upgrade to before running rake rails:update?

10

pharrington wrote:

Just curious now; what version of Rails did you have previously installed, and what version did you upgrade to before running rake rails:update?

I initially installed ruby and rails using synaptic on Ubuntu 9.04. It was ruby 1.8 and rails 2.1.0-6.

11

One more issue.

class ZaehlersController < ApplicationController   def index     if keineZaehlerVorhanden        blah     end

    respond_to do |format|       format.html # index.html.erb       format.xml { render :xml => @zaehlers }     end   end

  if !keineZaehlerVorhanden     verify :session => :user_name,        :add_flash => {:error => "error"},        :redirect_to => {:controller => "authentication", :action => "login"} end end

If it gets called,

  if !keineZaehlerVorhanden     veriy...   end

fails with "NameError (undefined local variable or method `keineZaehlerVorhanden' for ZaehlersController:Class):

After removing the condition around the verify, the index action terminates successfully - including the

  if keineZaehlerVorhanden      blah   end

Why this?

12

I forgot to say: keineZaehlerVorhanden is defined in ApplicationHelper, which is included in ApplicationController.

13

Look at this carefully. You're closing the respond_to block, and then closing the index method. keineZaehlerVorhanden isn't a class method, so of course the error will be thrown.

the error message "fails with "NameError (undefined local variable or method `keineZaehlerVorhanden' for **ZaehlersController:Class**)" gives a prettttttttyyy good clue as to whats going on.

14

pharrington wrote:

� � � format.xml �{ render :xml => @zaehlers } � � end � end

Look at this carefully. You're closing the respond_to block, and then closing the index method. keineZaehlerVorhanden isn't a class method, so of course the error will be thrown.

keineZaehlerVorhanden is a method of ApplicationController and it works inside the index action.

The verify statement is written usually at class level. Right? My idea was, only to verfy, if the method keineZaehlerVorhanden fails.

The interesting story is, that the construct around the verify worked fine until I accidentally run a rake rails:update

Seems, that the updated rails version changed something in the handling of controllers.

My question: How to implement a verification, that should not be executed under a certain condition?

(Background: The action should be executable for anybody, as long as no users are added to the data base - aka installation phase of my app.)

15

pharrington wrote: >> format.xml { render :xml => @zaehlers } >> end >> end

> Look at this carefully. You're closing the respond_to block, and then > closing the index method. keineZaehlerVorhanden isn't a class method, > so of course the error will be thrown.

keineZaehlerVorhanden is a method of ApplicationController and it works inside the index action.

The verify statement is written usually at class level. Right? My idea was, only to verfy, if the method keineZaehlerVorhanden fails.

The interesting story is, that the construct around the verify worked fine until I accidentally run a rake rails:update

Seems, that the updated rails version changed something in the handling of controllers.

My question: How to implement a verification, that should not be executed under a certain condition?

Well now, verify only exists to prevent actions from even being *invoked* unless certain conditions of the request are met. If you need tighter control, to filter based on more than just the request, just use a before_filter. Either way, you should probably focus on *precisely* what you're trying to accomplish, and the solution will probably be obvious (and definitely simpler than doing the same check in two different places).

(Background: The action should be executable for anybody, as long as no users are added to the data base - aka installation phase of my app.) -- Posted viahttp://www.ruby-forum.com/.

OK yeah, this is before_filter material. Don't know if the lack of users in the DB appropriately denotes the "installation phase," but thats for you to think about.

16

Thanks, now it works as expected.