Handle failure in rake task without aborting - ruby-on-rails

Question

I have this rake task:
desc "get product image urls from ItemMaster"
task :get_product_image_urls => :environment do
require 'item_master'
ItemMaster.get_image
end
It calls this API method that iterates over several thousand database items like so:
class ItemMaster
include HTTParty
format :xml
base_uri 'https://api.myapi.com/v2'
def self.get_image
#items = Item.all
#items.each do |item|
response = get("/item?upc=#{item.upc}&epl=100&ef=png", :headers => {"username" => "myname", "password" => "mypass"})
image_link = response["items"]["item"]["media"]["medium"]["url"]
item_image = ItemImage.where(:upc => item.upc).first_or_create
item_image.update_attributes(:url => "#{image_link}")
end
end
end
The rake task starts up when I call it, until it hits this error about 22 items in:
undefined method `[]' for nil:NilClass
/Users/name/Rails/SG/lib/item_master.rb:12:in `block in get_image'
/Users/name/Rails/SG/lib/item_master.rb:10:in `each'
/Users/name/Rails/SG/lib/item_master.rb:10:in `get_image'
/Users/name/Rails/SG/lib/tasks/get_product_image_urls.rake:4:in `block in <top (required)>'
/Users/name/.rvm/gems/ruby-1.9.3-p429/bin/ruby_noexec_wrapper:14:in `eval'
/Users/name/.rvm/gems/ruby-1.9.3-p429/bin/ruby_noexec_wrapper:14:in `<main>'
Line 12 is this guy: image_link = response["items"]["item"]["media"]["medium"]["url"] so I'm thinking that probably a url is missing in the api and it's causing the rake task to fail. Is there a way to move past an error like this and continue on with the rest of the rake task? Thanks in advance!

Answer 1

The ItemMaster.get_image method will need to be edited to either not create the exception condition in the first place, or to rescue on a proper exception and move on. For more on exception handling: http://www.tutorialspoint.com/ruby/ruby_exceptions.htm
An example would be:
def self.get_image
#items = Item.all
#items.each do |item|
response = get("/item?upc=#{item.upc}&epl=100&ef=png", :headers => {"username" => "myname", "password" => "mypass"})
begin
image_link = response["items"]["item"]["media"]["medium"]["url"]
item_image = ItemImage.where(:upc => item.upc).first_or_create
item_image.update_attributes(:url => "#{image_link}")
rescue NoMethodError => ex
logger.error "Failed to locate image link ..." # Customize this to your liking
end
end
end
end
For extra goodness, consider handling the code for each item within a separate method so you can isolate responsibility for handling item-related code within the Item model itself!