Class_eval method scope

Rails
1

class AssigneesController < ApplicationController

def assignees
Assignee.class_eval %Q{
def assignee_name
self["#{params[:assignee_by]}"]
end
}
end

def do_assignee_cleaning
Assignee.assignee_name
redirect_to
assignee_cleaning_project_assignees_path(params[:project_id])
end

end

I want to use assignee_name method in do_assignee_cleaning action but i
am
getting error undefined
method assignee_name' for classAssignee’ in do_assignee_cleaning

2

On 21 June 2011 11:11, mukesh singh [email protected] wrote:

redirect_to
assignee_cleaning_project_assignees_path(params[:project_id])
end

end
I want to useassignee_name method indo_assignee_cleaning action but i am
gettingerrorundefined
method assignee_name' for class Assignee’ in do_assignee_cleaning

In an effort to understand the question (not having used class_eval) I
found the following link that suggests, rather non-intuitively, that
you should be using instance_eval rather than class_eval.

http://ilikestuffblog.com/2009/01/09/fun-with-rubys-instance_eval-and-class_eval/

Colin

3

On 21 June 2011 11:45, mukesh singh [email protected] wrote:

sorry for mistake not Assignee.assignee_name
Assignee.find(1).assignee_name

Do you mean that you have fixed the problem by that change, or that
you had a mistake in the question you asked and with
Assignee.find(1).assignee_name it still fails?

Colin

4

yes still fails Assignee.find(1).assignee_name

On Tue, Jun 21, 2011 at 4:20 PM, Colin L. [email protected]
wrote:

       }

am

http://groups.google.com/group/rubyonrails-talk?hl=en.
“Ruby on Rails: Talk” group.
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–
Regards
Mukesh Paras Singh

5

sorry for mistake not Assignee.assignee_name

Assignee.find(1).assignee_name

On Tue, Jun 21, 2011 at 4:08 PM, Colin L. [email protected]
wrote:

  Assignee.assignee_name

In an effort to understand the question (not having used class_eval) I
“Ruby on Rails: Talk” group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

–
Regards
Mukesh Paras Singh

6

On 21 June 2011 11:56, mukesh singh [email protected] wrote:

yes still fails Assignee.find(1).assignee_name

I presume that you have called assignees before calling
do_assignee_cleaning.

Colin

7

On 21 June 2011 11:56, mukesh singh [email protected] wrote:

yes still fails Assignee.find(1).assignee_name

Please don’t top post, it makes it difficult to follow the thread.
Insert your reply at appropriate points in previous message. Thanks.

Can you post the full error message and the stack trace please along
with the exact code (copy/paste rather than re-type).

Colin

8

Curious why you would want to define the method that way, are you
overriding
the method assignee_name which is already defined in the Assignee class?
If not, then why not define it directly in the model like this:

def assignee_name(assigned_by)
self[“assigned_by”]
end

Controller method will be
def do_assignee_cleaning
Assignee.assignee_name(params[:assignee_by])
redirect_to
assignee_cleaning_project_assignees_path(params[:project_id])
end

9

Thanks for your reply
I thought class_eval method would permanently add assignee_name method
to
Assignee instance object and i can access from other action too.

On Tue, Jun 21, 2011 at 5:20 PM, Chirag S.
[email protected]wrote:

def do_assignee_cleaning
Assignee.assignee_name(params[:assignee_by])
redirect_to assignee_cleaning_project_assignees_path(params[:
project_id])
end

–

–
Regards
Mukesh Paras Singh

10

On 21 June 2011 14:31, mukesh singh [email protected] wrote:

Thanks for your reply

Please don’t top post, it makes it difficult to follow the thread.
Insert your reply at appropriate points in previous message. Thanks.

I thought class_eval method would permanently add assignee_name method to
Assignee instance object and i can access from other action too.

I think it will, but only when you execute the class_eval code.
Permanent means of course until you restart the server or reload the
Assignee class. Since in development mode classes are reloaded at
each action request it will not hold from one request to the next, if
that is what you are trying to do. Even in production this is a bad
thing to do as you never know when a server might get restarted and
loose the data. Not to mention the fact that once in production
successive actions are not necessarily even run by the same computer.
If you want retain information from one action to the next then put it
in the session or in the database, or in a hidden field in the
intervening view.

I think Chirag S.'s suggestion is better though unless there is
some reason you cannot use it.

Colin