Overwriting modifiers methods with Rails

Rails
1

Hi everyone!

I’m a little bit new to Rails development and I am looking for a
solution
for this issue.

Let’s say that I have a model called Person and the person has an
attribute
name. But I want to put a surname with this name. Something like this:

class Unit < ActiveRecord::Base

def name= name
@name = name + ‘bla bla’
end

end

In Ruby I could do this, but this doesn’t affect my object at all…

How can I do that?

Thanks in advance

Marco Antonio

2

On Apr 8, 9:54 am, Marco Antonio F. [email protected] wrote:

class Unit < ActiveRecord::Base

def name= name
@name = name + ‘bla bla’
end

end

In Ruby I could do this, but this doesn’t affect my object at all…

The key thing is that ActiveRecord attributes aren’t instance
variables. You can use write_attribute to write to the store of
attributes.

Fred

3

So you would do

def name= name
write_attribute :name, name
end

–
Jeremy C.
http://twitter.com/jeremychase

On Thu, Apr 8, 2010 at 9:04 AM, Frederick C.
<[email protected]

4

On Apr 8, 2:32 pm, Andy J. [email protected] wrote:

I’m sure I’ve seen it in later versions, but thought I’d post it anyway.

If it is deprecated, another way is:

self.attributes[‘name’] = name + ‘blah blah’

It’s not exactly the same as write_attribute (it doesn’t typecast to numbers
for numeric columns) but it will work the same in your case.

actually it is the same: active_record/base.rb says (in 2.3.5)

  def []=(attr_name, value)
    write_attribute(attr_name, value)
  end

Couldn’t see any trace in the source of write attribute being marked
as deprecated.

Fred

5

:Frederick C.:

Couldn’t see any trace in the source of write attribute being marked
as deprecated.

It (ActiveRecord::Base#write_attribute) is not just deperecated, it is
gone.
But another method with the same name in a different class
(ActiveRecord::AttributeMethods#write_attribute) replaced it. The new
function has the same functionality and is in scope virtually everywhere
the
old one was. Thus to the end user, it is just the same as it has always
been.

In other words the function moved.

6

The key thing is that ActiveRecord attributes aren’t instance
variables. You can use write_attribute to write to the store of
attributes.

“This method is deprecated on the latest stable version of Rails. The
last
existing version (v1.2.6) is shown here.”
http://apidock.com/rails/ActiveRecord/Base/write_attribute

I’m sure I’ve seen it in later versions, but thought I’d post it anyway.

If it is deprecated, another way is:

self.attributes[‘name’] = name + ‘blah blah’

It’s not exactly the same as write_attribute (it doesn’t typecast to
numbers
for numeric columns) but it will work the same in your case.

Cheers,

Andy

7

Ahh OK, useful to know.

It would be helpful (in languages/frameworks in general) if a
deprecation
always had a comment on where to look for more information.

Generally Rails is good at this, but maybe that information isn’t
filtered
through to APIDock.com.

Cheers,

Andy

–
Andy J.
http://andyjeffries.co.uk/ #rubyonrails #mysql #jquery
Registered address: 64 Sish Lane, Stevenage, Herts, SG1 3LS
Company number: 5452840