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funny-falcon/a copyright

Created July 31, 2012 09:52
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Writing a minimalistic web-server using event machine
Raw
server.rb
require 'rubygems'
require 'eventmachine'
require_relative './thin_http_parser.rb'
# Freeze some HTTP header names & values
KEEPALIVE = "Connection: Keep-Alive\r\n".freeze
class RequestHandler < EM::Connection
def post_init
@parser = RequestParser.new
end
def receive_data(data)
handle_http_request if @parser.parse(data)
end
def handle_http_request
p [@parser.env, @parser.body.string]
keep_alive = @parser.persistent?
data = "OK"
send_data("HTTP/1.1 200 OK\r\nContent-Type: text/html\r\nContent-Length: #{data.bytesize}\r\n#{ keep_alive ? KEEPALIVE.clone : nil}\r\n#{data}")
if keep_alive
post_init
else
close_connection_after_writing
end
end
end
host,port = "0.0.0.0", 8083
puts "Starting server on #{host}:#{port}, #{EM::set_descriptor_table_size(32768)} sockets"
EM.run do
EM.start_server host, port, RequestHandler
if ARGV.size > 0
forks = ARGV[0].to_i
puts "... forking #{forks} times => #{2**forks} instances"
forks.times { fork }
end
end
Raw
thin_http_parser.rb
require 'rubygems'
# Uncomment this line if 'thin_parser' is not found
# require 'thin'
require 'thin_parser'
require 'stringio'
# Freeze some HTTP header names & values
HTTP_VERSION = 'HTTP_VERSION'.freeze
HTTP_1_0 = 'HTTP/1.0'.freeze
CONTENT_LENGTH = 'CONTENT_LENGTH'.freeze
CONNECTION = 'HTTP_CONNECTION'.freeze
KEEP_ALIVE_REGEXP = /\bkeep-alive\b/i.freeze
CLOSE_REGEXP = /\bclose\b/i.freeze
# Freeze some Rack header names
RACK_INPUT = 'rack.input'.freeze
# A request sent by the client to the server.
class RequestParser
INITIAL_BODY = ''
# Force external_encoding of request's body to ASCII_8BIT
INITIAL_BODY.encode!(Encoding::ASCII_8BIT) if INITIAL_BODY.respond_to?(:encode!)
# CGI-like request environment variables
attr_reader :env
# Unparsed data of the request
attr_reader :data
# Request body
attr_reader :body
def initialize
@parser = Thin::HttpParser.new
@data = ''
@nparsed = 0
@body = StringIO.new(INITIAL_BODY.dup)
@env = {
RACK_INPUT => @body,
}
end
# Parse a chunk of data into the request environment
# Returns +true+ if the parsing is complete.
def parse(data)
if @parser.finished? # Header finished, can only be some more body
body << data
else # Parse more header using the super parser
@data << data
@nparsed = @parser.execute(@env, @data, @nparsed)
end
if finished? # Check if header and body are complete
@data = nil
@body.rewind
true # Request is fully parsed
else
false # Not finished, need more data
end
end
# +true+ if headers and body are finished parsing
def finished?
@parser.finished? && @body.size >= content_length
end
# Expected size of the body
def content_length
@env[CONTENT_LENGTH].to_i
end
# Returns +true+ if the client expect the connection to be persistent.
def persistent?
# Clients and servers SHOULD NOT assume that a persistent connection
# is maintained for HTTP versions less than 1.1 unless it is explicitly
# signaled. (http://www.w3.org/Protocols/rfc2616/rfc2616-sec8.html)
if @env[HTTP_VERSION] == HTTP_1_0
@env[CONNECTION] =~ KEEP_ALIVE_REGEXP
# HTTP/1.1 client intends to maintain a persistent connection unless
# a Connection header including the connection-token "close" was sent
# in the request
else
@env[CONNECTION].nil? || @env[CONNECTION] !~ CLOSE_REGEXP
end
end
end
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