class URI::GID

def build(args)

URI::GID.build(['bcx', 'Person', '1', key: 'value'])

Using an array, the arguments must be in order [app, model_name, model_id, params]:

URI::GID.build(app: 'bcx', model_name: 'Person', model_id: '1', params: { key: 'value' })

Using a hash:

either a hash or an array.
The allowed components are app, model_name, model_id and params, which can be

Create a new URI::GID from components with argument check. 
def build(args)
  parts = Util.make_components_hash(self, args)
  parts[:host] = parts[:app]
  parts[:path] = "/#{parts[:model_name]}/#{parts[:model_id]}"
  parts[:query] = URI.encode_www_form(parts[:params]) if parts[:params]
  super parts
end

def check_host(host) 

def check_host(host)
  validate_component(host)
  super
end

def check_path(path) 

def check_path(path)
  validate_component(path)
  set_model_components(path, true)
end

def check_scheme(scheme) 

def check_scheme(scheme)
  if scheme == 'gid'
    super
  else
    raise URI::BadURIError, "Not a gid:// URI scheme: #{inspect}"
  end
end

def create(app, model, params = nil)

URI::GID.create('bcx', Person.find(5), database: 'superhumans')

Shorthand to build a URI::GID from an app, a model and optional params. 
def create(app, model, params = nil)
  build app: app, model_name: model.class.name, model_id: model.id, params: params
end

def parse(uri)

URI::GID.parse('gid://bcx/') # => raises URI::InvalidComponentError
URI.parse('gid://bcx') # => URI::GID instance
URI('gid://bcx') # => URI::GID instance

This differs from URI() and URI.parse which do not check arguments.

URI::GID.parse 'gid://bcx/Person/1?key=value'

Create a new URI::GID by parsing a gid string with argument check. 
def parse(uri)
  generic_components = URI.split(uri) << nil << true # nil parser, true arg_check
  new(*generic_components)
end

def parse_query_params(query) 

def parse_query_params(query)
  Hash[URI.decode_www_form(query)].with_indifferent_access if query
end

def query=(query)

Ruby 2.2 uses #query= instead of #set_query 
def query=(query)
  set_params parse_query_params(query)
  super
end

def set_model_components(path, validate = false) 

def set_model_components(path, validate = false)
  _, model_name, model_id = path.match(PATH_REGEXP).to_a
  validate_component(model_name) && validate_component(model_id) if validate
  @model_name = model_name
  @model_id = model_id
end

def set_params(params) 

def set_params(params)
  @params = params
end

def set_path(path) 

def set_path(path)
  set_model_components(path) unless defined?(@model_name) && @model_id
  super
end

def set_query(query)

Ruby 2.1 or less uses #set_query to assign the query 
def set_query(query)
  set_params parse_query_params(query)
  super
end

def to_s 

def to_s
  # Implement #to_s to avoid no implicit conversion of nil into string when path is nil
  "gid://#{app}#{path}#{'?' + query if query}"
end

def validate_app(app)

URI::GID.validate_app('foo/bar') # => ArgumentError
URI::GID.validate_app(nil) # => ArgumentError

URI::GID.validate_app('foo-bar') # => 'foo-bar'
URI::GID.validate_app('bcx') # => 'bcx'

and hyphens. An ArgumentError is raised if +app+ is invalid.
Validates +app+'s as URI hostnames containing only alphanumeric characters 
def validate_app(app)
  parse("gid://#{app}/Model/1").app
rescue URI::Error
  raise ArgumentError, 'Invalid app name. ' \
    'App names must be valid URI hostnames: alphanumeric and hyphen characters only.'
end

def validate_component(component) 

def validate_component(component)
  return component unless component.blank?
  raise URI::InvalidComponentError,
    "Expected a URI like gid://app/Person/1234: #{inspect}"
end