Rails - Apr 2006 - Accessing Rails Models/app from command line script

Hi,

Can someone point me to some info on how to access Rails models /
ActiveRecord classes from a Ruby command line script?

Say I have a plain text file that is put into some directory by an
outside process, and I want to have a Ruby script run, via a cron job,
that can open and parse that data file. It would then delete all
records in some lookup table in my database and load it with the data
from the text file.

Hope that made sense!  Thanks!

jt

script/runner can do this for you.

--
Benjamin Curtis
http://www.tesly.com/ -- Collaborative test case management
http://www.agilewebdevelopment.com/ -- Resources for the Rails community



On Apr 27, 2006, at 5:15 PM, John Tsombakos wrote:
> Hi,
>
> Can someone point me to some info on how to access Rails models /
> ActiveRecord classes from a Ruby command line script?
>
> Say I have a plain text file that is put into some directory by an
> outside process, and I want to have a Ruby script run, via a cron job,
> that can open and parse that data file. It would then delete all
> records in some lookup table in my database and load it with the data
> from the text file.
>
> Hope that made sense!  Thanks!
>
> jt
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

On 4/28/06, Benjamin Curtis <rails@bencurtis.com>
wrote:
> script/runner can do this for you.
Hi,

Thanks. I did find reference to that. It looks like it can run a
method of a model(? .. Book.dosomething). Is it able to run methods of
controllers? I guess that could work with what I have in mind. If it
can only run model-based methods, I suppose I can access other models
from the one I''m running the script for.

(anyone got any examples out there?)

Thanks,

jt

On Apr 28, 2006, at 10:41 AM, John Tsombakos wrote:
> On 4/28/06, Benjamin Curtis <rails@bencurtis.com> wrote:
>> script/runner can do this for you.
>
> Thanks. I did find reference to that. It looks like it can run a
> method of a model(? .. Book.dosomething).
You could also run a method available in any classes you have in your  
lib directory, since those are automatically loaded when your Rails  
app loads. I use this all the time and I keep meaning to move my  
custom "model" classes to /lib. :)
> Is it able to run methods of controllers?
No. Your controller methods (aka. actions) only run in the context of  
a web request. If you really need to do that, you could use a command- 
line tool like curl, or wget, to make an http request into your Rails  
app. Personally, I''m not really a fan of this.
> I guess that could work with what I have in mind. If it can only  
> run model-based methods, I suppose I can access other models from  
> the one I''m running the script for.
Again, don''t think about it as just "model-based" methods.
The
methods that you call don''t actually have to do anything with your  
model classes, if you don''t want them to. Although, that kind of  
thing would be a little strange. :)
> (anyone got any examples out there?)
Sure. Here''s a class I use for performing a data export from the  
command line. I use this, largely as a crutch, when I don''t feel like  
building an admin interface into one of my survey-esque Rails apps.

require ''csv''
class DataExport
   def self.export_ratings
     path = "#{RAILS_ROOT}/tmp/my_export.csv"
     count = 0
     File.open( path, "w+" ) do |p|
       CSV::Writer.generate(p, '','', "\r\n") do |csv|
         csv << Student.cols_to_csv
         count += 1
         Student.get_completed.each do |student|
           courses = student.to_csv_list
           courses.each do |course|
             count += 1
             csv << course
           end
         end
       end
     end
     count
   end
end

In case anyone is wondering about the count variable, I actually use  
that for my unit tests on this method. It''s a quick way to make sure  
the export file has the correct number of lines, which tells me that  
the entire export process has worked. There are also tests on the  
Student class method "cols_to_csv" and instance method
"to_csv_list".

-Brian

On 4/28/06, Brian Hughes <brianvh@alum.dartmouth.org> wrote:
> You could also run a method available in any classes you have in your
> lib directory, since those are automatically loaded when your Rails
> app loads. I use this all the time and I keep meaning to move my
> custom "model" classes to /lib. :)
Ahh.. Cool. Didn''t think of that. That would work quite well.
> Sure. Here''s a class I use for performing a data export from the
> command line. I use this, largely as a crutch, when I don''t feel
like
> building an admin interface into one of my survey-esque Rails apps.
...

Thanks for the example too!

jt