fetch(key, *args, &block)public
Returns the value for the given key mapped to @env.
If the key is not found and an optional code block is not provided, raises a KeyError exception.
If the code block is provided, then it will be run and its result returned.
# File actionpack/lib/action_dispatch/http/headers.rb, line 61 def fetch(key, *args, &block) @env.fetch env_name(key), *args, &block end