`module Padded`

Certain frames can have padding: https://http2.github.io/http2-spec/#padding

+---------------+ |Pad Length? (8)| +---------------+-----------------------------------------------+ | Data () ... +---------------------------------------------------------------+ | Padding () ... +---------------------------------------------------------------+

Provides padding functionality for HTTP/2 frames. Padding can be used to obscure the actual size of frame payloads.

Definitions

`def padded?`

Check if the frame has padding enabled.

Signature

returns　Boolean: True if the PADDED flag is set.

Implementation

def padded?
	flag_set?(PADDED)
end

`def pack(data, padding_size: nil, maximum_size: nil)`

Pack data with optional padding into the frame.

Signature

parameter　data　String: The data to pack.
parameter　padding_size　Integer | Nil: Number of padding bytes to add.
parameter　maximum_size　Integer | Nil: Maximum frame size limit.

Implementation

def pack(data, padding_size: nil, maximum_size: nil)
	if padding_size
		set_flags(PADDED)
		
		buffer = String.new.b
		
		buffer << padding_size
		buffer << data
		
		if padding_size
			buffer << ("\0" * padding_size)
		end
		
		super buffer
	else
		clear_flags(PADDED)
		
		super data
	end
end

`def unpack`

Unpack frame data, removing padding if present.

Signature

returns　String: The unpacked data without padding.
raises　ProtocolError: If padding length is invalid.

Implementation

def unpack
	if padded?
		padding_size = @payload[0].ord
		
		# 1 byte for the padding octet, and padding_size bytes for the padding itself:
		data_size = @payload.bytesize - (1 + padding_size)
		
		if data_size < 0
			raise ProtocolError, "Invalid padding length: #{padding_size}"
		end
		
		return @payload.byteslice(1, data_size)
	else
		return @payload
	end
end