module HTTPClient::Util

def argument_to_hash(args, *field)

includes defined keys.
including undefined keys. When an Array given, returns a Hash which only
Returns hash which has defined keys. When a Hash given, returns it

*field:: a list of arguments to be extracted.
args:: given arguments.
Keyword argument to hash helper. 
def argument_to_hash(args, *field)
  return nil if args.empty?
  if args.size == 1 and Hash === args[0]
    h = args[0]
    if field.any? { |f| h.key?(f) }
      return h
    end
  end
  h = {}
  field.each_with_index do |e, idx|
    h[e] = args[idx]
  end
  h
end

def hash_find_value(hash, &block)

Finds a value of a Hash. 
def hash_find_value(hash, &block)
  v = hash.find(&block)
  v ? v[1] : nil
end

def http?(uri) 

def http?(uri)
  uri.scheme && uri.scheme.downcase == 'http'
end

def https?(uri)

Checks if the given URI is https. 
def https?(uri)
  uri.scheme && uri.scheme.downcase == 'https'
end

def keyword_argument(args, *field)


end
...
def my_method(a, b, c)

instead of;

my_method(:b => 2, :a = 1)
my_method(1, 2, 3)
end
...
a, b, c = keyword_argument(args, :a, :b, :c)
def my_method(*args)
include Util

You can extract 3 arguments (a, b, c) with:

*field:: a list of arguments to be extracted.
args:: given arguments.
Keyword argument helper. 
def keyword_argument(args, *field)
  if args.size == 1 and Hash === args[0]
    h = args[0]
    if field.any? { |f| h.key?(f) }
      return h.values_at(*field)
    end
  end
  args
end

def try_require(feature)

require returns false if the feature is already loaded.
It returns 'true' for the second require in contrast of the standard

Try to require a feature and returns true/false if loaded 
def try_require(feature)
  require feature
  true
rescue LoadError
  false
end

def uri_dirname(uri)

Returns parent directory URI of the given URI. 
def uri_dirname(uri)
  uri = uri.clone
  uri.path = uri.path.sub(/\/[^\/]*\z/, '/')
  uri
end

def uri_part_of(uri, part)

* target URI's path starts with base URI's path.
* the same port number
* the same host String (no host resolution or IP-addr conversion)
* the same scheme
Returns true if the given 2 URIs have a part_of relationship. 
def uri_part_of(uri, part)
  ((uri.scheme == part.scheme) and
   (uri.host == part.host) and
   (uri.port == part.port) and
   uri.path.upcase.index(part.path.upcase) == 0)
end

def urify(uri)

Gets an URI instance. 
def urify(uri)
  if uri.nil?
    nil
  elsif uri.is_a?(URI)
    uri
  elsif AddressableEnabled
    AddressableURI.parse(uri.to_s)
  else
    URI.parse(uri.to_s)
  end
end

def warning(message) 

def warning(message)
  return if @@__warned.key?(message)
  warn(message)
  @@__warned[message] = true
end