How to protect attributes from being updated?

Rails
1

Hi!
I’m new to Rails!
Rails rox!

1 quesion so far:
I have :email attribute in User model.
I dont’ want :email to allow to be updated.

How do i do this with Rails?
Do I have to implement required validation manually?

Thanks!

2

On 1/26/07, gmarik [email protected] wrote:

Do I have to implement required validation manually?

Thanks!

classs User < ActiveRecord::Base
attr_protected :email
…
end

Docs: http://caboo.se/doc/classes/ActiveRecord/Base.html#M006884

–
Zack C.
http://depixelate.com

3

Thanks Zak, but it’s not what i need.
I don’t want it to be UPDATED(ie Edit)
And i need this attribute, when object is being CREATED(ie New).

So it could look like this(the code isnt’ valid):
…
attr_accessible :name, :description
attr_accessible :email if new_record?
…

Any ideas?
Thanks!

4

I’d say you should do something like…

attr_accessor :address
attr_protected :email

def before_create
self.email = address
end

and use User#address in the form.

RSL

5

Nice trick!
Thanks Russell!

6

On 1/29/07, gmarik [email protected] wrote:

Thanks Zak, but it’s not what i need.
I don’t want it to be UPDATED(ie Edit)
And i need this attribute, when object is being CREATED(ie New).

So it could look like this(the code isnt’ valid):
…
attr_accessible :name, :description
attr_accessible :email if new_record?
…

attr_readonly – see http://dev.rubyonrails.org/ticket/6896 – may
be what you’re looking for? I’m not overly optimistic about our
chances of getting it added, though…

Another option for emulating read only attributes could be a
before_save callback that; locks the row (select for update), then
load the model into some variable and then copy the field in question
into self.

I’m not sure Russel’s approach will work; say you load the model, the
row/column is changed by some other process, and then you save your
old model again overwriting the new value.

I’d just go with attr_protected and set that field individually on
creation, if this is all you need.

Isak

7

Well, for now Russel’s approach is just fine.

The issue with other processes modifying attribute directly can be
avoided by putting attr_reader for :email, so it’ won’t be changed
from outside. Right?

Thanks!

8

On 1/31/07, gmarik [email protected] wrote:

Well, for now Russel’s approach is just fine.

The issue with other processes modifying attribute directly can be
avoided by putting attr_reader for :email, so it’ won’t be changed
from outside. Right?

If your app is the only thing writing to that particular field,
protecting the attribute in your model - either with attr_protected,
an overridden mutator, or the dummy attribute idea - is probably
enough, yea.

Isak