Class: Protocol::Multipart::Parser

Inherits:

Object

• Object
• Protocol::Multipart::Parser

Defined in:

lib/protocol/multipart/parser.rb

Overview

A parser for multipart data based on RFC 2046 and RFC 2387. Parses multipart bodies and provides an enumerable interface to access the parts.

Defined Under Namespace

Classes: Part

Constant Summary

MAXIMUM_PREAMBLE_SIZE =

The default maximum number of preamble bytes before the first boundary.

64 * 1024

MAXIMUM_HEADER_SIZE =

The default maximum number of header bytes in each part.

64 * 1024

MAXIMUM_HEADER_COUNT =

The default maximum number of headers in each part.

64

MAXIMUM_PART_COUNT =

The default maximum number of parts.

128

Instance Method Summary

• #each ⇒ Object

  Enumerate through each part in the multipart data.

• #initialize(readable, boundary, maximum_preamble_size: MAXIMUM_PREAMBLE_SIZE, maximum_header_size: MAXIMUM_HEADER_SIZE, maximum_header_count: MAXIMUM_HEADER_COUNT, maximum_part_count: MAXIMUM_PART_COUNT) ⇒ Parser constructor

  Initialize a new multipart parser.

Constructor Details

#initialize(readable, boundary, maximum_preamble_size: MAXIMUM_PREAMBLE_SIZE, maximum_header_size: MAXIMUM_HEADER_SIZE, maximum_header_count: MAXIMUM_HEADER_COUNT, maximum_part_count: MAXIMUM_PART_COUNT) ⇒ Parser

Initialize a new multipart parser.

# File 'lib/protocol/multipart/parser.rb', line 170

def initialize(readable, boundary, maximum_preamble_size: MAXIMUM_PREAMBLE_SIZE, maximum_header_size: MAXIMUM_HEADER_SIZE, maximum_header_count: MAXIMUM_HEADER_COUNT, maximum_part_count: MAXIMUM_PART_COUNT)
	limits = [maximum_preamble_size, maximum_header_size, maximum_header_count, maximum_part_count]
	
	if limits.any?{|limit| limit and limit < 0}
		raise ArgumentError, "Multipart limits must be non-negative!"
	end
	
	@readable = IO::Stream(readable)
	@boundary = boundary
	@maximum_preamble_size = maximum_preamble_size
	@maximum_header_size = maximum_header_size
	@maximum_header_count = maximum_header_count
	@maximum_part_count = maximum_part_count
	
	@boundary_marker = "--#{@boundary}\r\n".freeze
end

Instance Method Details

#each ⇒ Object

Enumerate through each part in the multipart data. Yields each part for processing. If no block is given, returns an enumerator.

# File 'lib/protocol/multipart/parser.rb', line 191

def each
	return to_enum unless block_given?
	
	preamble_size = 0
	
	# Read lines until we find the first boundary:
	while true
		if line = read_line(preamble_size, @maximum_preamble_size, allowance: @boundary_marker.bytesize, chomp: false)
			if line == @boundary_marker
				break
			else
				preamble_size += line.bytesize
				check_limit(:preamble_size, preamble_size, @maximum_preamble_size)
			end
		else
			# End of stream reached without finding boundary:
			raise EOFError, "No multipart boundary found in stream!"
		end
	end
	
	part_count = 0
	
	while true
		part_count += 1
		check_limit(:part_count, part_count, @maximum_part_count)
		
		part = read_part
		break unless part
		
		if part.read_empty_boundary?
		else
			yield part
			
			# Advance to the next boundary after the consumer returns normally. If the consumer raises, stop parsing without draining the request body.
			part.discard
		end
		
		# Check if this was the last part:
		break if part.closing_boundary?
	end
	
	return true
end