Hello ! This week we talk about exceptions. An Exception is an event that could be thrown in particular circumstances and that goes up all the application stack until someone rescue it.
Exceptions are commonly used for very exceptional events and could happen that we need to create a new Exception class for our programming purpose.
Ok, let’s suppose we need to raise a “PersonalException” exception at some point and rescue it in exactly the same way for all the controllers, the code is here:
Creating the Exception class
To create our “PersonalException” we just need to extend “Exception” class.
class PersonalException < Exception
end
Raise our Exception
raise PersonalException.new, "message"
Rescue our exception
We can do this by overwriting rescue_action_in_public and local_request?
functions to our application.rb file:
class ApplicationController < ActionController::Base
def rescue_action_in_public(exception)
if exception.to_s =~ /PersonalException/
# do your stuff here
else
raise exception
end
end
def local_request?
false
end
end
Some notes
As wrote on the Ruby on Rails wiki when you test this in development mode be sure to set to false this line in your “environments/development.rb”
config.action_controller.consider_all_requests_local = false
Also, if the server is on the same machine you’re developing you need to use the “-b ” option assoicated with your lan ip ( no 127.0.0.1 neither localhost) when starting the WEBrick server.
Conclusion
I’m still looking on how variables stored in our PersonalException instance can be retrieved. So, if someone wants to make suggestions please post a comment.
