Hi,
I’m hitting a wall in my ruby knowledge. When I have:
before_validation { |object| object.permalink =
object.title.parameterize }
What’s that { |object| …} thing? It’s a block, ok, but when does it
get executed? When and where does object come from?
I tried digging in the Rails source code, but there is a lot going on so
I’m getting confused.
I’m asking this question because my real problem is the following:
I’m using the paperclip plugin for one of my rails app, and here is the
code I am trying to make work:
class Asset < ActiveRecord::Base
has_attached_file :data, :styles => {
:theora => [:format => :ogv, :processors => lambda {|a| a.video? ?
[:video_converter] : []}}]
}
end
What fails is the lambda, because in Paperclip behind the scenes this is
what happens (edited for brevity):
@some_var = style.processors.inject(something) do |file, processor|
…
end
style.processors has received the lambda defined earlier. But doesn’t it
get the asset object and get executed when the interpreter hits the line
like the before_validation does?
So I get the following error message:
NoMethodError (undefined method `inject’ for #Proc:0x455d864)
How can I fix this problem?
Surprisingly if I define the following, the lambda does not cause to
crash:
has_attached_file :data, :styles => {
:theora => [:format => :ogv],
:processors => lambda {|a| a.video? ? [:video_converter] : []}
}
Can someone shed some light on this lambda thing? And after that which
book or resources can I read to get proficient in such dynamic coding
practice? Currently in use blocks all the time ([array].each { …})
without really mastering them.
Thanks for your support
