Rails - Mar 2006 - How to write manage created_on and created_by via mixin?

Hi!

Definite newbie here - I''m working through this like-hate relationship
with
Ruby and Rails right now... sometimes things work really well (like blobs
seem to rock) but other times, I dunno!  :-)

Anyway, I''d like put in create and update user timestamps on all my
primary
domain tables and allow them to be updated automatically by ActiveRecord.
Coming from Hibernate, I just place an interceptor that dynamically
discovers the column names and sets it up. In Ruby, I''m totally lost.
However, I hold out hope - I just don''t know the terminology for what
I''m
looking for since what I''m doing has to be relatively common.

So, I''ve created a mixin called UserTimestamp.rb:
module UserTimestamp
  def mark_created
    self.created_on = Time.new
    self.created_by = @user.user_id
  end

  def mark_updated
    self.updated_on = Time.new
    self.updated_by = @user.user_id
  end
end

And, then I include it and setup the before_create and after_create macros:
require ''lib/UserTimestamp.rb''

class Video < ActiveRecord::Base
  include UserTimestamp
  before_create :mark_created
  before_update :mark_updated
  # ... etc...
end

Of course, this doesn''t work, but that seemed logical. Neither @user or
user
is present, nor do I have any way to get the user_id. User is identified in
my ApplicationController by a filter which is available in all my
controllers. However, I have absolutely no way of locating the User object
from an ActiveRecord class... or do I? Do I need to pass it in on create or
something weird like that? (Or, yuck, manually invoke it??)

Is there a better way to do this? This does work, but I wonder if
there''s a
more appropriate manner.

Thanks for any feedback!
-Rob
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Heh.. you''re gonna laugh... or cry...

http://wiki.rubyonrails.com/rails/pages/MagicFieldNames

(also pg 277 in AWDWR)

It''s all done for ya baby...... I''m finding that any time I
think of a cool thing to do in
rails, it''s already been done.

b

Rob Greene wrote:
> Hi!
> 
> Definite newbie here - I''m working through this like-hate
relationship
> with Ruby and Rails right now... sometimes things work really well (like 
> blobs seem to rock) but other times, I dunno!  :-)
> 
> Anyway, I''d like put in create and update user timestamps on all
my
> primary domain tables and allow them to be updated automatically by 
> ActiveRecord. Coming from Hibernate, I just place an interceptor that 
> dynamically discovers the column names and sets it up. In Ruby,
I''m
> totally lost. However, I hold out hope - I just don''t know the 
> terminology for what I''m looking for since what I''m doing
has to be
> relatively common.
> 
> So, I''ve created a mixin called UserTimestamp.rb:
> module UserTimestamp
>   def mark_created
>     self.created_on = Time.new
>     self.created_by = @user.user_id
>   end
>  
>   def mark_updated
>     self.updated_on = Time.new
>     self.updated_by = @user.user_id
>   end
> end
> 
> And, then I include it and setup the before_create and after_create macros:
> require ''lib/UserTimestamp.rb''
> 
> class Video < ActiveRecord::Base
>   include UserTimestamp
>   before_create :mark_created
>   before_update :mark_updated
>   # ... etc...
> end
> 
> Of course, this doesn''t work, but that seemed logical. Neither
@user or
> user is present, nor do I have any way to get the user_id. User is 
> identified in my ApplicationController by a filter which is available in 
> all my controllers. However, I have absolutely no way of locating the 
> User object from an ActiveRecord class... or do I? Do I need to pass it 
> in on create or something weird like that? (Or, yuck, manually invoke it??)
> 
> Is there a better way to do this? This does work, but I wonder if 
> there''s a more appropriate manner.
> 
> Thanks for any feedback!
> -Rob
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Hey, excellent! I''m actually close to going down the right path?! (Ok,
well
the timestamps will take care of themself...)

Anyway, I chased down the user-level information to this post:

http://livsey.org/2005/07/16/adding_created_by_and_updated_by_to_rails/

The current_user is simply stored in a class-level attribute on User which,
in turn, is set by a before_filter on the application controller. Neat an
nifty... except - that''s not thread safe, right??  If two people hit
the
site at the same time, User.current_user holds the last one, and all record
updates will be attributed to that person. (Maybe I''m thinking too much
like
a Java person here...)

-Rob

On 3/26/06, Ben Munat <bent@munat.com> wrote:
>
> Heh.. you''re gonna laugh... or cry...
>
> http://wiki.rubyonrails.com/rails/pages/MagicFieldNames
>
> (also pg 277 in AWDWR)
>
> It''s all done for ya baby...... I''m finding that any time
I think of a
> cool thing to do in
> rails, it''s already been done.
>
> b
>
> Rob Greene wrote:
> > Hi!
> >
> > Definite newbie here - I''m working through this like-hate
relationship
> > with Ruby and Rails right now... sometimes things work really well
(like
> > blobs seem to rock) but other times, I dunno!  :-)
> >
> > Anyway, I''d like put in create and update user timestamps on
all my
> > primary domain tables and allow them to be updated automatically by
> > ActiveRecord. Coming from Hibernate, I just place an interceptor that
> > dynamically discovers the column names and sets it up. In Ruby,
I''m
> > totally lost. However, I hold out hope - I just don''t know
the
> > terminology for what I''m looking for since what I''m
doing has to be
> > relatively common.
> >
> > So, I''ve created a mixin called UserTimestamp.rb:
> > module UserTimestamp
> >   def mark_created
> >     self.created_on = Time.new
> >     self.created_by = @user.user_id
> >   end
> >
> >   def mark_updated
> >     self.updated_on = Time.new
> >     self.updated_by = @user.user_id
> >   end
> > end
> >
> > And, then I include it and setup the before_create and after_create
> macros:
> > require ''lib/UserTimestamp.rb''
> >
> > class Video < ActiveRecord::Base
> >   include UserTimestamp
> >   before_create :mark_created
> >   before_update :mark_updated
> >   # ... etc...
> > end
> >
> > Of course, this doesn''t work, but that seemed logical.
Neither @user or
> > user is present, nor do I have any way to get the user_id. User is
> > identified in my ApplicationController by a filter which is available
in
> > all my controllers. However, I have absolutely no way of locating the
> > User object from an ActiveRecord class... or do I? Do I need to pass
it
> > in on create or something weird like that? (Or, yuck, manually invoke
> it??)
> >
> > Is there a better way to do this? This does work, but I wonder if
> > there''s a more appropriate manner.
> >
> > Thanks for any feedback!
> > -Rob
> >
> >
> >
------------------------------------------------------------------------
> >
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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rails is process-based, not thread based. There are no issues with
multi-threading because each process handles 1 request.

On 3/26/06, Rob Greene <robgreene@gmail.com>
wrote:
>
> Hey, excellent! I''m actually close to going down the right path?!
(Ok,
> well the timestamps will take care of themself...)
>
> Anyway, I chased down the user-level information to this post:
>
> http://livsey.org/2005/07/16/adding_created_by_and_updated_by_to_rails/
>
> The current_user is simply stored in a class-level attribute on User
> which, in turn, is set by a before_filter on the application controller.
> Neat an nifty... except - that''s not thread safe, right??  If two
people hit
> the site at the same time, User.current_user holds the last one, and all
> record updates will be attributed to that person. (Maybe I''m
thinking too
> much like a Java person here...)
>
>
> -Rob
>
>
> On 3/26/06, Ben Munat <bent@munat.com> wrote:
> >
> > Heh.. you''re gonna laugh... or cry...
> >
> > http://wiki.rubyonrails.com/rails/pages/MagicFieldNames
> >
> > (also pg 277 in AWDWR)
> >
> > It''s all done for ya baby...... I''m finding that any
time I think of a
> > cool thing to do in
> > rails, it''s already been done.
> >
> > b
> >
> > Rob Greene wrote:
> > > Hi!
> > >
> > > Definite newbie here - I''m working through this
like-hate relationship
> > > with Ruby and Rails right now... sometimes things work really
well
> > (like
> > > blobs seem to rock) but other times, I dunno!  :-)
> > >
> > > Anyway, I''d like put in create and update user
timestamps on all my
> > > primary domain tables and allow them to be updated automatically
by
> > > ActiveRecord. Coming from Hibernate, I just place an interceptor
that
> > > dynamically discovers the column names and sets it up. In Ruby,
I''m
> > > totally lost. However, I hold out hope - I just don''t
know the
> > > terminology for what I''m looking for since what
I''m doing has to be
> > > relatively common.
> > >
> > > So, I''ve created a mixin called UserTimestamp.rb:
> > > module UserTimestamp
> > >   def mark_created
> > >     self.created_on = Time.new
> > >     self.created_by = @user.user_id
> > >   end
> > >
> > >   def mark_updated
> > >     self.updated_on = Time.new
> > >     self.updated_by = @user.user_id
> > >   end
> > > end
> > >
> > > And, then I include it and setup the before_create and
after_create
> > macros:
> > > require ''lib/UserTimestamp.rb''
> > >
> > > class Video < ActiveRecord::Base
> > >   include UserTimestamp
> > >   before_create :mark_created
> > >   before_update :mark_updated
> > >   # ... etc...
> > > end
> > >
> > > Of course, this doesn''t work, but that seemed logical.
Neither @user
> > or
> > > user is present, nor do I have any way to get the user_id. User
is
> > > identified in my ApplicationController by a filter which is
available
> > in
> > > all my controllers. However, I have absolutely no way of locating
the
> > > User object from an ActiveRecord class... or do I? Do I need to
pass
> > it
> > > in on create or something weird like that? (Or, yuck, manually
invoke
> > it??)
> > >
> > > Is there a better way to do this? This does work, but I wonder if
> > > there''s a more appropriate manner.
> > >
> > > Thanks for any feedback!
> > > -Rob
> > >
> > >
> > >
> >
------------------------------------------------------------------------
> > >
> > > _______________________________________________
> > > Rails mailing list
> > > Rails@lists.rubyonrails.org
> > > http://lists.rubyonrails.org/mailman/listinfo/rails
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> >
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>
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Rob Greene wrote:
[...]
> Anyway, I chased down the user-level information to this post:
> 
> http://livsey.org/2005/07/16/adding_created_by_and_updated_by_to_rails/
> 
> The current_user is simply stored in a class-level attribute on User 
> which, in turn, is set by a before_filter on the application controller. 
> Neat an nifty... except - that''s not thread safe, right??  If two
people
> hit the site at the same time, User.current_user holds the last one, and 
> all record updates will be attributed to that person. (Maybe I''m 
> thinking too much like a Java person here...)
Yes, you would be right if Rails worked like Java servlets.

Rails is single-threaded (at least for the moment), so the approach of 
using a model class variable is safe. In Rails running under Webrick, 
only one request is processed at a time.

In production envvironments there may be multiple FastCGI (or SCGI) 
processes, but each  process only handles one request at a time. It 
would be quite possible for multiple users'' requests to be handled 
concurrently, but in separate processes, each with its own User class 
and current_user class variable.

regards

   Justin

Wow, what a concept! That opens up a few doors I wouldn''t otherwise
consider...

Thanks!
-Rob

On 3/26/06, Justin Forder <justin@justinforder.me.uk>
wrote:
>
> Rob Greene wrote:
> [...]
> > Anyway, I chased down the user-level information to this post:
> >
> >
http://livsey.org/2005/07/16/adding_created_by_and_updated_by_to_rails/
> >
> > The current_user is simply stored in a class-level attribute on User
> > which, in turn, is set by a before_filter on the application
controller.
> > Neat an nifty... except - that''s not thread safe, right??  If
two people
> > hit the site at the same time, User.current_user holds the last one,
and
> > all record updates will be attributed to that person. (Maybe
I''m
> > thinking too much like a Java person here...)
>
> Yes, you would be right if Rails worked like Java servlets.
>
> Rails is single-threaded (at least for the moment), so the approach of
> using a model class variable is safe. In Rails running under Webrick,
> only one request is processed at a time.
>
> In production envvironments there may be multiple FastCGI (or SCGI)
> processes, but each  process only handles one request at a time. It
> would be quite possible for multiple users'' requests to be handled
> concurrently, but in separate processes, each with its own User class
> and current_user class variable.
>
> regards
>
>    Justin
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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