Question

What does it mean when the bang method is in front? What is this shorthand for?

!post.save

Answer 1

It is equivalent to

not post.save

Usually used in if clauses, like:

if !post.save               #if the post could not be saved for some reason
   puts 'could not save post!'
end

It’s because the function save from ActiveResource::Base returns true if the POST request succeeded and false if it didn’t. Read here for some more information about the function.