`class Handler < Protocol::HTTP::Middleware`

Inherits from: Protocol::HTTP::Middleware

A middleware which catches exceptions and performs an internal redirect.

Definitions

`def initialize(app, location = "/errors/exception")`

Implementation

def initialize(app, location = "/errors/exception")
	super(app)
	
	@location = location
end

`def freeze`

Freeze this object and its internal state.

Signature

returns　self: This object.

Implementation

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

`def call(request)`

Convert application exceptions into internal-server-error responses.

Signature

parameter　request　Utopia::Request: The request.
returns　Protocol::HTTP::Response: The application response or a generated error response.

Implementation

def call(request)
	begin
		return @delegate.call(request)
	rescue Exception => exception
		Console.warn(self, "An error occurred while processing the request.", error: exception)
		
		begin
			# We do an internal redirection to the error location:
			error_request = request.with(
				method: "GET",
				path: @location
			)
			error_request.exception = exception
			
			error_response = Response.wrap(@delegate.call(error_request))
			error_response.status = 500
			
			return error_response
		rescue Exception => exception
			# If redirection fails, we also finish with a fatal error:
			Console.error(self, "An error occurred while invoking the error handler.", error: exception)
			return Response[500, {"content-type" => "text/plain"}, ["An error occurred while processing the request."]]
		end
	end
end