class Errors < Protocol::HTTP::Middleware

Inherits from
Protocol::HTTP::Middleware

A middleware which performs internal redirects based on error status codes.

Place this middleware after client-visible redirection middleware in the application configuration. Internal error-document requests invoke the delegate directly, bypassing middleware configured before this one.

Definitions

def initialize(app, codes = {})

Implementation

 
def initialize(app, codes = {})
	super(app)
	
	@codes = codes
end

def freeze

Freeze this object and its internal state.

Signature
returns　self

This object.

Implementation

 
def freeze
	return self if frozen?
	
	@codes.freeze
	
	super
end

def unhandled_error?(response)

Check whether the response status requires error handling.

Signature
parameter　response　Protocol::HTTP::Response

The response.

returns　Boolean

Whether the response is an error without handler-provided headers.

Implementation

 
def unhandled_error?(response)
	response.status >= 400 && response.headers.empty?
end

def call(request)

Replace an unhandled error response with its configured error document.

Signature
parameter　request　Utopia::Request

The request.

returns　Protocol::HTTP::Response

The original or error-document response.

raises　RequestFailure

If the configured error document also fails.

Implementation

 
def call(request)
	response = Response.wrap(@delegate.call(request))
	
	if unhandled_error?(response) && location = @codes[response.status]
		resource_status = response.status
		
		# The original response is replaced by the configured error document:
		response.close
		
		error_request = request.with(method: "GET", path: location)
		
		error_response = Response.wrap(@delegate.call(error_request))
		
		if error_response.status >= 400
			error = RequestFailure.new(request.url.path.encoded, resource_status, location, error_response.status)
			
			# The failed error document will not be returned to the server:
			error_response.close(error)
			
			raise error
		else
			# Feed the error code back with the error document:
			error_response.status = resource_status
			return error_response
		end
	else
		return response
	end
end