`class Generic`

The base adapter class that provides common functionality for all Rack adapters. It handles the conversion between Protocol::HTTP and Rack environments.

Definitions

`def self.wrap(app)`

Creates a new adapter instance for the given Rack application. Wraps the adapter in a class Protocol::Rack::Rewindable instance to ensure request body can be read multiple times, which is required for Rack < 3.

Signature

parameter　app　Interface(:call): A Rack application.
returns　Rewindable: A rewindable adapter instance.

Implementation

def self.wrap(app)
	Rewindable.new(self.new(app))
end

`def self.parse_file(...)`

Parses a Rackup file and returns the application.

Signature

parameter　path　String: The path to the Rackup file.
returns　Interface(:call): The Rack application.

Implementation

def self.parse_file(...)
	# This is the old interface, which was changed in Rack 3.
	::Rack::Builder.parse_file(...).first
end

`def initialize(app)`

Initialize the rack adaptor middleware.

Signature

parameter　app　Interface(:call): The rack middleware.
raises　ArgumentError: If the app does not respond to call.

Implementation

def initialize(app)
	@app = app
	
	raise ArgumentError, "App must be callable!" unless @app.respond_to?(:call)
end

`def logger`

The logger to use for this adapter.

Signature

returns　Console: The console logger.

Implementation

def logger
	Console
end

`def unwrap_headers(headers, env)`

Unwrap HTTP headers into the CGI-style expected by Rack middleware, and add them to the rack env.

e.g. accept-encoding becomes HTTP_ACCEPT_ENCODING.

Headers keys with underscores will generate the same CGI-style header key as headers with dashes.

e.g accept_encoding becomes HTTP_ACCEPT_ENCODING too.

You should not implicitly trust the HTTP_ headers for security purposes, as they are generated by the client.

Multiple headers are combined with a comma, with one exception: HTTP_COOKIE headers are combined with a semicolon.

Signature

parameter　headers　Protocol::HTTP::Headers: The raw HTTP request headers.
parameter　env　Hash: The rack request env.

Implementation

def unwrap_headers(headers, env)
	headers.each do |key, value|
		http_key = "HTTP_#{key.upcase.tr('-', '_')}"
		
		if current_value = env[http_key]
			if http_key == CGI::HTTP_COOKIE
				env[http_key] = "#{current_value};#{value}"
			else
				env[http_key] = "#{current_value},#{value}"
			end
		else
			env[http_key] = value
		end
	end
end

`def unwrap_request(request, env)`

Process the incoming request into a valid rack env.

Set the env['CONTENT_TYPE'] and env['CONTENT_LENGTH'] based on the incoming request body.
Set the env['HTTP_HOST'] header to the request authority.
Set the env['HTTP_X_FORWARDED_PROTO'] header to the request scheme.
Set env['REMOTE_ADDR'] to the request remote adress.

Signature

parameter　request　Protocol::HTTP::Request: The incoming request.
parameter　env　Hash: The rack env.

Implementation

def unwrap_request(request, env)
	# The request protocol, either from the upgrade header or the HTTP/2 pseudo header of the same name.
	if protocol = request.protocol
		env[RACK_PROTOCOL] = protocol
	end
	
	if content_type = request.headers.delete("content-type")
		env[CGI::CONTENT_TYPE] = content_type
	end
	
	# In some situations we don't know the content length, e.g. when using chunked encoding, or when decompressing the body.
	if body = request.body and length = body.length
		env[CGI::CONTENT_LENGTH] = length.to_s
	end
	
	self.unwrap_headers(request.headers, env)
	
	# For the sake of compatibility, we set the `HTTP_UPGRADE` header to the requested protocol.
	if protocol = request.protocol and request.version.start_with?("HTTP/1")
		env[CGI::HTTP_UPGRADE] = Array(protocol).join(",")
	end
	
	if request.respond_to?(:hijack?) and request.hijack?
		env[RACK_IS_HIJACK] = true
		env[RACK_HIJACK] = proc{request.hijack!.io.dup}
	end
	
	# HTTP/2 prefers `:authority` over `host`, so we do this for backwards compatibility.
	env[CGI::HTTP_HOST] ||= request.authority
				
	if peer = request.peer
		env[CGI::REMOTE_ADDR] = peer.ip_address
	end
end

`def make_environment(request)`

Create a base environment hash for the request.

Signature

parameter　request　Protocol::HTTP::Request: The incoming request.
returns　Hash: The base environment hash.

Implementation

def make_environment(request)
	{
		request: request
	}
end

`def call(request)`

Build a rack env from the incoming request and apply it to the rack middleware.

Signature

parameter　request　Protocol::HTTP::Request: The incoming request.
returns　Protocol::HTTP::Response: The HTTP response.
raises　ArgumentError: If the status is not an integer or headers are nil.

Implementation

def call(request)
	env = self.make_environment(request)
	
	status, headers, body = @app.call(env)
	
	# The status must always be an integer.
	unless status.is_a?(Integer)
		raise ArgumentError, "Status must be an integer!"
	end
	
	# Headers must always be a hash or equivalent.
	unless headers
		raise ArgumentError, "Headers must not be nil!"
	end
	
	headers, meta = self.wrap_headers(headers)
	
	return Response.wrap(env, status, headers, meta, body, request)
rescue => exception
	Console.error(self, exception)
	
	body&.close if body.respond_to?(:close)
	
	env&.[](RACK_RESPONSE_FINISHED)&.each do |callback|
		callback.call(env, status, headers, exception)
	end
	
	return failure_response(exception)
end

`def failure_response(exception)`

Generate a suitable response for the given exception.

Signature

parameter　exception　Exception: The exception that occurred.
returns　Protocol::HTTP::Response: A response representing the error.

Implementation

def failure_response(exception)
	Protocol::HTTP::Response.for_exception(exception)
end

`def self.extract_protocol(env, response, headers)`

Extract protocol information from the environment and response.

Signature

parameter　env　Hash: The rack environment.
parameter　response　Protocol::HTTP::Response: The HTTP response.
parameter　headers　Hash: The response headers to modify.

Implementation

def self.extract_protocol(env, response, headers)
	if protocol = response.protocol
		# This is the newer mechanism for protocol upgrade:
		if env["rack.protocol"]
			headers["rack.protocol"] = protocol
		
		# Older mechanism for protocol upgrade:
		elsif env[CGI::HTTP_UPGRADE]
			headers["upgrade"] = protocol
			headers["connection"] = "upgrade"
		end
	end
end