Rails from the command line

[corywilkerson]

All,

I know we have the wonderful ‘console’ with Rails - and I know we’ve
irbwith Ruby; but is there some means by which I can effectively write a
shell script and utilize my existing model classes within my Rails
application context?

The problem I’m trying to solve is notifying some set of subscribers
when a given model, let’s call it ‘Asset’, is updated. I know I can use
the after_update callback, but I don’t want to cloud my model with
subscription functionality; I’d rather have some scheduled job that
checks timestamps every x often and takes some action.

Ideally, I could just write code that reads:

Somehow load up rails context <this is the part I’m missing>

assets = Asset.find(:all, :condtions => [“updated > ?”, sometimestamp])
assets.each {|asset| do_something}

Or, because I’m fairly new to Rails, I could be missing some simple
listener concepet, or really, I guess I could just go and write my own.
But, regardless, I know it will be useful for me to use a rails
application context in a script at some point so if I could get any
pointers, I’d be most grateful.

Thanks friends.

[corywilkerson]

Look into script/runner. It sounds like what you need.

[corywilkerson]

script/console does this for you. It loads the rails environment and
allows
you to do anything you would usually do in your models/controllers.

[corywilkerson]

Ok, sorry I didn’t read your post correctly the first time.

What’s wrong with putting it in the model? Models are designed to be
fat.
after_update sounds perfect for this!

[corywilkerson]

Ryan B. wrote:

script/console does this for you. It loads the rails environment and
allows
you to do anything you would usually do in your models/controllers.

Ryan - I get that, but what I want to do is basically schedule something
on cron here…i.e., I won’t be sitting in front of a console to
interact with it

I’m going to go read up on script/runner - sounds like that’s the
ticket!

[corywilkerson]

Have you looked into backgroundrb

http://backgroundrb.rubyforge.org/

?

Peace,
Phillip

[corywilkerson]

Hi,

I know we have the wonderful ‘console’ with Rails - and I know we’ve
irbwith Ruby; but is there some means by which I can effectively write a
shell script and utilize my existing model classes within my Rails
application context?

depending on the complexity and on your personal taste you could write a
rake task (loading the rails environment as a dependency) or you could
use script/runner either for calling a class method or for executing a
.rb script. Either way your rails environment/models would be available.

regards,

javier ramírez

[corywilkerson]

What’s wrong with putting it in the model? Models are designed to be
fat.
after_update sounds perfect for this!

Again - probably due to my lack of production-grade experience with
rails; I’ve tended to keep my models focused only on the job at hand:
validating data and moving data into/out of a database.

It seems bit awkward to me to place application logic in my model, ie:

def after_update
self.subscribers.each {|subscriber| Notifier.deliver_notification
subscriber}
end

Now that I’ve written it out - it doesn’t seem so bad after all - but it
would seem this should be rolled up in my controller. There are going
to be a number of times that I use this Asset and I won’t want to send
updates out in every single case.

After talking this through - adding it to the controller makes much more
sense but now I fear blocking. Let’s say an asset has 1,000 subscribers
and that deliver_notification method blocks for each send (I don’t know
whether or not ActionMailer blocks); that’d tie up a thread for quite
some time.

Looks like I need to check out backgroundDrb.

Thoughts?

[corywilkerson]

There are going
to be a number of times that I use this Asset and I won’t want to send
updates out in every single case.

rails gives you a few methods like “update_without_callbacks” or
“save_without_callbacks” with avoid the “after_update” or
“before_save”-like
functions.

i doubt this will resolve your problem, but it was woth mentioning ; )

[corywilkerson]

On Jan 2, 2008 6:30 AM, Cory W.
[email protected] wrote:

After talking this through - adding it to the controller makes much more
sense but now I fear blocking. Let’s say an asset has 1,000 subscribers
and that deliver_notification method blocks for each send (I don’t know
whether or not ActionMailer blocks); that’d tie up a thread for quite
some time.

Looks like I need to check out backgroundDrb.

Sending 1000 mails from live rails environment will be bad and will
certainly tie up things. Try BackgrounDRb, its not terribly complex
and should fit the bill. For any help, you can hop over to the mailing
list and feel free to ask.

–
Let them talk of their oriental summer climes of everlasting
conservatories; give me the privilege of making my own summer with my
own coals.

http://gnufied.org