read_socket.rb

# Run this program with `ruby`. It will print a port number, e.g. `[:port, 56789]`. Take
# that number and open a WebSocket to it in Chrome and Firefox:
# 
#     new WebSocket('ws://localhost:56789/')
# 
# For the Chrome socket, the program prints the HTTP handshake headers from the socket
# then exists. For Firefox it prints nothing. Why? And what should I be doing differently
# to read data from it?
# 
# This EventMachine TCP server receives data from Firefox correctly:
# 
#    require 'eventmachine'
# 
#    module Connection
#      def receive_data(data)
#        puts data
#      end
#    end
# 
#    EM.run {
#      EM.start_server('0.0.0.0', 80, Connection)
#    }
# 
# Here are the Wireshark captures of what each browser is sending:

=begin
Chrome:
0000  00 00 00 00 00 00 00 00  00 00 00 00 08 00 45 00   ........ ......E.
0010  01 1f e2 37 40 00 40 06  59 9f 7f 00 00 01 7f 00   ...7@.@. Y.......
0020  00 01 c3 19 00 50 fb 39  60 4b 1f d5 f3 eb 80 18   .....P.9 `K......
0030  01 01 ff 13 00 00 01 01  08 0a 07 81 82 7f 07 81   ........ ........
0040  82 7f 47 45 54 20 2f 20  48 54 54 50 2f 31 2e 31   ..GET /  HTTP/1.1
0050  0d 0a 55 70 67 72 61 64  65 3a 20 77 65 62 73 6f   ..Upgrad e: webso
0060  63 6b 65 74 0d 0a 43 6f  6e 6e 65 63 74 69 6f 6e   cket..Co nnection
0070  3a 20 55 70 67 72 61 64  65 0d 0a 48 6f 73 74 3a   : Upgrad e..Host:
0080  20 6c 6f 63 61 6c 68 6f  73 74 0d 0a 4f 72 69 67    localho st..Orig
0090  69 6e 3a 20 68 74 74 70  3a 2f 2f 6e 65 77 73 2e   in: http ://news.
00a0  79 63 6f 6d 62 69 6e 61  74 6f 72 2e 63 6f 6d 0d   ycombina tor.com.
00b0  0a 53 65 63 2d 57 65 62  53 6f 63 6b 65 74 2d 4b   .Sec-Web Socket-K
00c0  65 79 3a 20 64 38 4d 61  7a 6b 37 7a 65 41 50 4e   ey: d8Ma zk7zeAPN
00d0  48 31 4e 6c 49 75 4b 71  72 41 3d 3d 0d 0a 53 65   H1NlIuKq rA==..Se
00e0  63 2d 57 65 62 53 6f 63  6b 65 74 2d 56 65 72 73   c-WebSoc ket-Vers
00f0  69 6f 6e 3a 20 31 33 0d  0a 53 65 63 2d 57 65 62   ion: 13. .Sec-Web
0100  53 6f 63 6b 65 74 2d 45  78 74 65 6e 73 69 6f 6e   Socket-E xtension
0110  73 3a 20 78 2d 77 65 62  6b 69 74 2d 64 65 66 6c   s: x-web kit-defl
0120  61 74 65 2d 66 72 61 6d  65 0d 0a 0d 0a            ate-fram e....  

Firefox:
0000  00 00 00 00 00 00 00 00  00 00 00 00 08 00 45 00   ........ ......E.
0010  02 04 76 c3 40 00 40 06  c4 2e 7f 00 00 01 7f 00   ..v.@.@. ........
0020  00 01 c3 1c 00 50 2d 96  ff 63 28 d5 ac 19 80 18   .....P-. .c(.....
0030  01 01 ff f8 00 00 01 01  08 0a 07 81 89 a3 07 81   ........ ........
0040  89 a3 47 45 54 20 2f 20  48 54 54 50 2f 31 2e 31   ..GET /  HTTP/1.1
0050  0d 0a 48 6f 73 74 3a 20  6c 6f 63 61 6c 68 6f 73   ..Host:  localhos
0060  74 0d 0a 55 73 65 72 2d  41 67 65 6e 74 3a 20 4d   t..User- Agent: M
0070  6f 7a 69 6c 6c 61 2f 35  2e 30 20 28 58 31 31 3b   ozilla/5 .0 (X11;
0080  20 55 62 75 6e 74 75 3b  20 4c 69 6e 75 78 20 78    Ubuntu;  Linux x
0090  38 36 5f 36 34 3b 20 72  76 3a 31 35 2e 30 29 20   86_64; r v:15.0) 
00a0  47 65 63 6b 6f 2f 32 30  31 30 30 31 30 31 20 46   Gecko/20 100101 F
00b0  69 72 65 66 6f 78 2f 31  35 2e 30 2e 31 0d 0a 41   irefox/1 5.0.1..A
00c0  63 63 65 70 74 3a 20 74  65 78 74 2f 68 74 6d 6c   ccept: t ext/html
00d0  2c 61 70 70 6c 69 63 61  74 69 6f 6e 2f 78 68 74   ,applica tion/xht
00e0  6d 6c 2b 78 6d 6c 2c 61  70 70 6c 69 63 61 74 69   ml+xml,a pplicati
00f0  6f 6e 2f 78 6d 6c 3b 71  3d 30 2e 39 2c 2a 2f 2a   on/xml;q =0.9,*/*
0100  3b 71 3d 30 2e 38 0d 0a  41 63 63 65 70 74 2d 4c   ;q=0.8.. Accept-L
0110  61 6e 67 75 61 67 65 3a  20 65 6e 2d 67 62 2c 65   anguage:  en-gb,e
0120  6e 3b 71 3d 30 2e 35 0d  0a 41 63 63 65 70 74 2d   n;q=0.5. .Accept-
0130  45 6e 63 6f 64 69 6e 67  3a 20 67 7a 69 70 2c 20   Encoding : gzip, 
0140  64 65 66 6c 61 74 65 0d  0a 43 6f 6e 6e 65 63 74   deflate. .Connect
0150  69 6f 6e 3a 20 6b 65 65  70 2d 61 6c 69 76 65 2c   ion: kee p-alive,
0160  20 55 70 67 72 61 64 65  0d 0a 53 65 63 2d 57 65    Upgrade ..Sec-We
0170  62 53 6f 63 6b 65 74 2d  56 65 72 73 69 6f 6e 3a   bSocket- Version:
0180  20 31 33 0d 0a 4f 72 69  67 69 6e 3a 20 68 74 74    13..Ori gin: htt
0190  70 3a 2f 2f 6c 6f 63 61  6c 2e 64 65 76 3a 37 30   p://loca l.dev:70
01a0  30 34 0d 0a 53 65 63 2d  57 65 62 53 6f 63 6b 65   04..Sec- WebSocke
01b0  74 2d 4b 65 79 3a 20 66  70 71 66 34 7a 72 71 59   t-Key: f pqf4zrqY
01c0  63 63 2f 6c 2b 58 33 6e  71 36 44 48 77 3d 3d 0d   cc/l+X3n q6DHw==.
01d0  0a 50 72 61 67 6d 61 3a  20 6e 6f 2d 63 61 63 68   .Pragma:  no-cach
01e0  65 0d 0a 43 61 63 68 65  2d 43 6f 6e 74 72 6f 6c   e..Cache -Control
01f0  3a 20 6e 6f 2d 63 61 63  68 65 0d 0a 55 70 67 72   : no-cac he..Upgr
0200  61 64 65 3a 20 77 65 62  73 6f 63 6b 65 74 0d 0a   ade: web socket..
0210  0d 0a                                              ..  
=end

require 'socket'

server = TCPServer.open(0)
p [:port, server.addr[1]]
socket = server.accept

while msg = socket.gets
  puts msg
  break if msg == "\r\n"
end