Returns a TMail::AddressHeader object of the field you are querying. Examples:

@mail['from']  #=> #<TMail::AddressHeader "mikel@test.com.au">
@mail['to']    #=> #<TMail::AddressHeader "mikel@test.com.au">

You can get the string value of this by passing "to_s" to the query: Example:

@mail['to'].to_s #=> "mikel@test.com.au"

Source Code

# File action_mailer/vendor/tmail-1.2.2/tmail/mail.rb, line 190
def []( key )
  @header[key.downcase]
end