Rails - May 2006 - Object constructors - Noob Question

Hi: Sorry if this is a painfully stupid question...

I have some data I need through the life of someone''s session.  In the 
application controller, I grab the data and store it like so:
session[:foo] = @foo

Now, whenever I need to access data about foo I don''t need to cause any
DB io, I can just grab foo from the session (it''s very small fyi).

Here''s what I have:
# Instantiate Foo
@foo = Foo.new()
@foo = session[:foo]

# Grab Bar with Foo
@bar = @foo.bar

Is this the bestest Rails way of handling this?  Is there a more concise 
way?

-- 
Posted via http://www.ruby-forum.com/.

You can make yourself some methods in application_controller.rb to have the
methods available everywhere, or in a particular controller/helper if
that''s
what you need.


To get the foo in the session (or new if there isn''t a foo in the
session)
def foo
  session[:foo] ? session[:foo] : Foo.new
end

To set the session foo
def foo=(a_foo)
  session[:foo] = a_foo
end

then call
foo.bar



On 5/12/06, Joe Cairns <joe.cairns@gmail.com>
wrote:
>
> Hi: Sorry if this is a painfully stupid question...
>
> I have some data I need through the life of someone''s session.  In
the
> application controller, I grab the data and store it like so:
> session[:foo] = @foo
>
> Now, whenever I need to access data about foo I don''t need to
cause any
> DB io, I can just grab foo from the session (it''s very small fyi).
>
> Here''s what I have:
> # Instantiate Foo
> @foo = Foo.new()
> @foo = session[:foo]
>
> # Grab Bar with Foo
> @bar = @foo.bar
>
> Is this the bestest Rails way of handling this?  Is there a more concise
> way?
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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I searched Google for this* but didn''t find anything about it from 
casual browsing! Is there an official way to delete controllers/views, 
or can I just delete folders?

*http://www.google.com/search?hl=en&q=delete+view+controller+ruby+on+rails&btnG=Google+Search

./script/destroy controller_name

On 5/11/06, c.k.lester <rails@cklester.com> wrote:
> I searched Google for this* but didn''t find anything about it from
> casual browsing! Is there an official way to delete controllers/views,
> or can I just delete folders?
>
>
*http://www.google.com/search?hl=en&q=delete+view+controller+ruby+on+rails&btnG=Google+Search
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

-- 
Ben Reubenstein
303-947-0446
http://www.benr75.com

There''s nothing wrong with just deleting files - although you might not
get all of them.  There is a destroy script you can use:

ruby script/destroy controller ThingController

or

ruby script/destroy scaffold Thing


Steve


c.k.lester wrote:
> I searched Google for this* but didn''t find anything about it from
> casual browsing! Is there an official way to delete controllers/views, 
> or can I just delete folders?
> 
>
*http://www.google.com/search?hl=en&q=delete+view+controller+ruby+on+rails&btnG=Google+Search
> 
> 
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
> 
> 
>

Daniel ----- wrote:
> You can make yourself some methods in application_controller.rb to have 
> the
> methods available everywhere, or in a particular controller/helper if 
> that''s
> what you need.
> 
> 
> To get the foo in the session (or new if there isn''t a foo in the 
> session)
> def foo
>   session[:foo] ? session[:foo] : Foo.new
> end
> 
> To set the session foo
> def foo=(a_foo)
>   session[:foo] = a_foo
> end
> 
> then call
> foo.bar
Ok I implemented that and it works for the first action, and then this 
hits:
Application error

Change this error message for exceptions thrown outside of an action 
(like in Dispatcher setups or broken Ruby code) in public/500.html


This was in the log file:

Session contains objects whose class definition isn''t available.
Remember to require the classes for all objects kept in the session.
(Original exception: uninitialized constant Generic [NameError])


./script/../config/../vendor/rails/actionpack/lib/action_controller/cgi_process.rb:147:in
`stale_session_check!''

./script/../config/../vendor/rails/actionpack/lib/action_controller/cgi_process.rb:107:in
`session''

./script/../config/../vendor/rails/actionpack/lib/action_controller/base.rb:887:in
`assign_shortcuts_without_flash''

./script/../config/../vendor/rails/actionpack/lib/action_controller/flash.rb:141:in
`assign_shortcuts''

./script/../config/../vendor/rails/actionpack/lib/action_controller/base.rb:375:in
`process_without_filters''

./script/../config/../vendor/rails/actionpack/lib/action_controller/filters.rb:377:in
`process_without_session_management_support''

./script/../config/../vendor/rails/actionpack/lib/action_controller/session_management.rb:117:in
`process''

./script/../config/../vendor/rails/railties/lib/dispatcher.rb:38:in 
`dispatch''

./script/../config/../vendor/rails/railties/lib/webrick_server.rb:115:in 
`handle_dispatch''

./script/../config/../vendor/rails/railties/lib/webrick_server.rb:81:in 
`service''

c:/ruby/lib/ruby/1.8/webrick/httpserver.rb:104:in `service''

c:/ruby/lib/ruby/1.8/webrick/httpserver.rb:65:in `run''

c:/ruby/lib/ruby/1.8/webrick/server.rb:155:in `start_thread''

c:/ruby/lib/ruby/1.8/webrick/server.rb:144:in `start''

c:/ruby/lib/ruby/1.8/webrick/server.rb:144:in `start_thread''

c:/ruby/lib/ruby/1.8/webrick/server.rb:94:in `start''

c:/ruby/lib/ruby/1.8/webrick/server.rb:89:in `each''

c:/ruby/lib/ruby/1.8/webrick/server.rb:89:in `start''

c:/ruby/lib/ruby/1.8/webrick/server.rb:79:in `start''

c:/ruby/lib/ruby/1.8/webrick/server.rb:79:in `start''

./script/../config/../vendor/rails/railties/lib/webrick_server.rb:67:in 
`dispatch''

./script/../config/../vendor/rails/railties/lib/commands/servers/webrick.rb:59

c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:18:in 
`require__''

c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:18:in 
`require''

./script/../config/../vendor/rails/activesupport/lib/active_support/dependencies.rb:147:in
`require''

./script/../config/../vendor/rails/railties/lib/commands/server.rb:30

c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:18:in 
`require__''

c:/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:18:in 
`require''

script/server:3

-- 
Posted via http://www.ruby-forum.com/.

I did some research and am coming up small on the error:
"Session contains objects whose class definition isn''t available.
Remember to require the classes for all objects kept in the session.
(Original exception: uninitialized constant Generic [NameError])"

I added "require foo.rb" to all of my controllers, but this error 
persists.  I''ve also tried require_dependencies.

This error creeps up on the second time a controller is called.  The 
cause of this problem is when I reference an object in the session like 
so:

     @foo= foo.new()
     @foo = session[:foo]
     @bar = @foo.bar

Or even when I use the method a previous poster mentioned, like so:
def foo
  session[:foo] ? session[:foo] : Foo.new
end

def foo=(a_foo)
  session[:foo] = a_foo
end

foo.bar

If I do this:
@foo = Foo.find( session[:site][:id] )

...the problem stops.  The trouble is this defeats my purpose of putting 
the object into the session in the first place.  Any ideas would be 
great, I''m at the end of my rope on this one.

-- 
Posted via http://www.ruby-forum.com/.

Following up on this, does this delete the associated tests as well and
other items that are created when you do script/generate controller
myController?

Also, it would be nice to have a script/rename controller OrigName NewName

I know I''ve screwed up more than once naming my stuff the Rails way ;)

On 5/11/06, Stephen Bartholomew <sb@2404.co.uk>
wrote:
>
> There''s nothing wrong with just deleting files - although you
might not
> get all of them.  There is a destroy script you can use:
>
> ruby script/destroy controller ThingController
>
> or
>
> ruby script/destroy scaffold Thing
>
>
> Steve
>
>
> c.k.lester wrote:
> > I searched Google for this* but didn''t find anything about it
from
> > casual browsing! Is there an official way to delete controllers/views,
> > or can I just delete folders?
> >
> > *
>
http://www.google.com/search?hl=en&q=delete+view+controller+ruby+on+rails&btnG=Google+Search
> >
> >
> > _______________________________________________
> > 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
>


-- 
Ryan Prins
rprins@gmail.com
http://www.lazyi.net
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> Following up on this, does this delete the associated tests as well
 > and  other items that are created when you do script/generate
 > controller myController?
As far as i''m aware it does, yeah.

 > I know I''ve screwed up more than once naming my stuff the Rails
way ;)
Not using the ''Rails'' way? I sense the darkside in you... :0)

Steve

Ryan Prins wrote:
> Following up on this, does this delete the associated tests as well and 
> other items that are created when you do script/generate controller 
> myController?
> 
> Also, it would be nice to have a script/rename controller OrigName NewName
> 
> I know I''ve screwed up more than once naming my stuff the Rails
way ;)
> 
> On 5/11/06, *Stephen Bartholomew* <sb@2404.co.uk
<mailto:sb@2404.co.uk>>
> wrote:
> 
>     There''s nothing wrong with just deleting files - although you
might not
>     get all of them.  There is a destroy script you can use:
> 
>     ruby script/destroy controller ThingController
> 
>     or
> 
>     ruby script/destroy scaffold Thing
> 
> 
>     Steve
> 
> 
>     c.k.lester wrote:
>      > I searched Google for this* but didn''t find anything
about it from
>      > casual browsing! Is there an official way to delete
>     controllers/views,
>      > or can I just delete folders?
>      >
>      > *
>    
http://www.google.com/search?hl=en&q=delete+view+controller+ruby+on+rails&btnG=Google+Search
>    
<http://www.google.com/search?hl=en&q=delete+view+controller+ruby+on+rails&btnG=Google+Search>
>      >
>      >
>      > _______________________________________________
>      > Rails mailing list
>      > Rails@lists.rubyonrails.org
<mailto:Rails@lists.rubyonrails.org>
>      > http://lists.rubyonrails.org/mailman/listinfo/rails
>      >
>      >
>      >
>     _______________________________________________
>     Rails mailing list
>     Rails@lists.rubyonrails.org <mailto:Rails@lists.rubyonrails.org>
>     http://lists.rubyonrails.org/mailman/listinfo/rails
> 
> 
> 
> 
> -- 
> Ryan Prins
> rprins@gmail.com <mailto:rprins@gmail.com>
> http://www.lazyi.net
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
> 
> 
> ------------------------------------------------------------------------
> 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
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>From memory you need to put in your application controller.
model Foo
to tell the controllers that they need to have access to the Foo model.

One thing to look out for tho is that if foo changes part way through a
session, you will need to update the session object.

On 5/12/06, Joe Cairns <joe.cairns@gmail.com>
wrote:
>
> I did some research and am coming up small on the error:
> "Session contains objects whose class definition isn''t
available.
> Remember to require the classes for all objects kept in the session.
> (Original exception: uninitialized constant Generic [NameError])"
>
> I added "require foo.rb" to all of my controllers, but this error
> persists.  I''ve also tried require_dependencies.
>
> This error creeps up on the second time a controller is called.  The
> cause of this problem is when I reference an object in the session like
> so:
>
>      @foo= foo.new()
>      @foo = session[:foo]
>      @bar = @foo.bar
>
> Or even when I use the method a previous poster mentioned, like so:
> def foo
>   session[:foo] ? session[:foo] : Foo.new
> end
>
> def foo=(a_foo)
>   session[:foo] = a_foo
> end
>
> foo.bar
>
> If I do this:
> @foo = Foo.find( session[:site][:id] )
>
> ...the problem stops.  The trouble is this defeats my purpose of putting
> the object into the session in the first place.  Any ideas would be
> great, I''m at the end of my rope on this one.
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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Joe wrote
> Here''s what I have:
> # Instantiate Foo
> @foo = Foo.new()
> @foo = session[:foo]
> 
> # Grab Bar with Foo
> @bar = @foo.bar
> 
> Is this the bestest Rails way of handling this?  Is there a 
> more concise 
> way?
@foo = Foo.new	# this is redundant you don''t need to create an object
@foo = session[:foo] # just get the already created one out of the session

Not a Ruby developer yet but I suspect you could

@bar = session[:foo].bar

Which would be about as lean as you could get

Ross

Ross Dawson wrote:
> Joe wrote
>> way?
> @foo = Foo.new	# this is redundant you don''t need to create an
object
> @foo = session[:foo] # just get the already created one out of the 
> session
> 
> Not a Ruby developer yet but I suspect you could
> 
> @bar = session[:foo].bar
> 
> Which would be about as lean as you could get
> 
> Ross
Hi and thanks!  However, I was doing that way and it caused this error 
on invoking the second action:

"Session contains objects whose class definition isn''t available.
Remember to require the classes for all objects kept in the session.
(Original exception: uninitialized constant Generic [NameError])"


I have been told to add a model line in every controller where I 
reference that object in the session, but I have added the code below to 
all of my controllers with no change of behavior:
Model :foo

I ended up removing the object from the session and only save foo_id, 
but then I need to foo.find(session[:foo_id]) on every controller where 
I need foo.  This will cause a lot of unneeded database io.


-- 
Posted via http://www.ruby-forum.com/.

On May 12, 2006, at 3:33 PM, Joe Cairns wrote:
> Ross Dawson wrote:
>> Joe wrote
>>> way?
>> @foo = Foo.new	# this is redundant you don''t need to create an
object
>> @foo = session[:foo] # just get the already created one out of the
>> session
>>
>> Not a Ruby developer yet but I suspect you could
>>
>> @bar = session[:foo].bar
>>
>> Which would be about as lean as you could get
>>
>> Ross
>
> Hi and thanks!  However, I was doing that way and it caused this error
> on invoking the second action:
>
> "Session contains objects whose class definition isn''t
available.
> Remember to require the classes for all objects kept in the session.
> (Original exception: uninitialized constant Generic [NameError])"
>
>
> I have been told to add a model line in every controller where I
> reference that object in the session, but I have added the code  
> below to
> all of my controllers with no change of behavior:
> Model :foo
that needs to be :

model :foo

not upcase.

-Ezra

Ezra Zygmuntowicz wrote:
> On May 12, 2006, at 3:33 PM, Joe Cairns wrote:
> 
>> I have been told to add a model line in every controller where I
>> reference that object in the session, but I have added the code  
>> below to
>> all of my controllers with no change of behavior:
>> Model :foo
> 
> that needs to be :
> 
> model :foo
> 
> not upcase.
> 
> -Ezra
Hi, it is lower case in code, and looking back on my message, lower case 
there as well.

-- 
Posted via http://www.ruby-forum.com/.

Joe Cairns wrote:
> Ezra Zygmuntowicz wrote:
>> On May 12, 2006, at 3:33 PM, Joe Cairns wrote:
>> 
> 
>>> I have been told to add a model line in every controller where I
>>> reference that object in the session, but I have added the code  
>>> below to
>>> all of my controllers with no change of behavior:
>>> Model :foo
>> 
>> that needs to be :
>> 
>> model :foo
>> 
>> not upcase.
>> 
>> -Ezra
> 
> Hi, it is lower case in code, and looking back on my message, lower case 
> there as well.
Hi sorry "Model" is upercase in the message only...  thought you were 
talking about :foo.

-- 
Posted via http://www.ruby-forum.com/.

Hi, I''ve narrowed this problem down further, and I probably should have
mentioned a few of these details before.

"bar" is inherited from "thing" in a single table
inheritance structure.

I got rid of the error when I took "bar" out of the picture.  So I can
do the following for example:
@foo = session[:foo]
puts @foo.id

The second I reference "bar" I get zapped with the above message (i.e.
bar = @foo.bar).  Here is how the models are set up:

class Thing < ActiveRecord::Base
  belongs_to :foo
end
class Bar < Thing
end
class Yadda < Thing
end

class Foo < ActiveRecord::Base
  has_many :things
  has_one :yadda
  has_one :bar
  validates_uniqueness_of :name
end

This works the first time that I call @foo.bar (no errors, no warnings), 
but after the first call all I get is a 500 error and the following in 
the log file:
"Session contains objects whose class definition isn''t available.
Remember to require the classes for all objects kept in the session.
(Original exception: uninitialized constant Generic [NameError])"

In all of my controllers I''ve included:
requires ''foo.rb''
requires ''thing.rb''
model :foo
model :thing


I''m not sure if I''m doing something wrong or if I''m
running into some
esoteric bug.

-- 
Posted via http://www.ruby-forum.com/.

Hi!

On May 14, 2006, at 10:31 AM, Joe Cairns wrote:
> Hi, I''ve narrowed this problem down further, and I probably should
> have
> mentioned a few of these details before.
>
> "bar" is inherited from "thing" in a single table
inheritance
> structure.
>
> I got rid of the error when I took "bar" out of the picture.  So
I can
> do the following for example:
> @foo = session[:foo]
> puts @foo.id
>
> The second I reference "bar" I get zapped with the above message
(i.e.
> bar = @foo.bar).  Here is how the models are set up:
>
> class Thing < ActiveRecord::Base
>   belongs_to :foo
> end
> class Bar < Thing
> end
> class Yadda < Thing
> end
>
> class Foo < ActiveRecord::Base
>   has_many :things
>   has_one :yadda
>   has_one :bar
>   validates_uniqueness_of :name
> end
>
> This works the first time that I call @foo.bar (no errors, no  
> warnings),
> but after the first call all I get is a 500 error and the following in
> the log file:
> "Session contains objects whose class definition isn''t
available.
> Remember to require the classes for all objects kept in the session.
> (Original exception: uninitialized constant Generic [NameError])"
>
> In all of my controllers I''ve included:
> requires ''foo.rb''
> requires ''thing.rb''
> model :foo
> model :thing
>
>
> I''m not sure if I''m doing something wrong or if
I''m running into some
> esoteric bug.
>
> -- 
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails


	I wonder if you are running into rails autorequire feature. One  
thing to try is to split up your Thing, Bar and Yadda model classes  
into three separate files called thing.rb, foo.rb and yadda.rb. Try  
this and see if it helps the problem. You might still need the  
model :foo declarations as well.


-Ezra

Ezra Zygmuntowicz wrote:
> Hi!
> 
> On May 14, 2006, at 10:31 AM, Joe Cairns wrote:
> 
> 
> 
> 	I wonder if you are running into rails autorequire feature. One
> thing to try is to split up your Thing, Bar and Yadda model classes
> into three separate files called thing.rb, foo.rb and yadda.rb. Try
> this and see if it helps the problem. You might still need the
> model :foo declarations as well.
> 
> 
> -Ezra
Hi and thanks, I tried this right away as it seemed to be a good 
solution, but the exact same behavior is happening.  It works the first 
time, and the second I get the 500 error.  The only way to get the app 
running again is to delete the session or clear the browser cache.

The very weird thing about this is the message in the log file 
mentioning the session.  The error only occurs when I introduce bar into 
the equation, running @bar = @foo.bar and bar never touches the session 
at all.

@foo is instantiated from the session, by @foo = session[:foo] but this 
_doesn''t_ cause the error.  In fact I can use @foo in views and other 
ways and no error occurs.

I really have no idea what''s going on with this.

-- 
Posted via http://www.ruby-forum.com/.

> @foo is instantiated from the session, by @foo = 
> session[:foo] but this 
> _doesn''t_ cause the error.  In fact I can use @foo in views and
other
> ways and no error occurs.
> 
> I really have no idea what''s going on with this.
Try using breakpoint to inspect @foo

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

can tell you lots. 

As a general "why doesn''t my blah work" response have a look
at your code running using breakpoint.  I''m guessing from the noise on
the list that breakpoint would be the most underutilized tool in Rails.

Ross