From: Yacin Nadji <ynadji@...>
Date: 2006-02-28T17:52:15+09:00
Subject: Sending Binary Data?

Hello Ruby Gurus!

My friend and I are writing a chat/IM client in Ruby. It's nothing 
special, but it's helping us learn the language, especially the lower 
level networking parts really well and I'm thoroughly enjoying the 
project so far. I thought implementing file transfers would be pretty 
nifty, but I'm running into some problems. I did a simple copy by 
reading the file (a picture) and adding the lines to a string, and 
writing that string out to a new file:

a = String.new

IO.foreach("lighter.jpg") do |line|
  a += line
end

file = File.open("new.jpg","w")
file.write(a)
file.close

And it worked swimmingly, however, when I tried to do this over a 
TCPClient/Server:

server.rb

require 'socket'
port = 9191
file = File.open("omgnew.jpg","w+")
server = TCPServer.new('localhost', port)
while session = server.accept
  file.write(session.gets)
  server.close
  file.close
end

client.rb

require 'socket'

server = TCPSocket.new('localhost',9191)
file = String.new
IO.foreach("lighter.jpg") do |line|
  file += line.chomp
end

server.send(file,0)


It works for a bit, then I get this error:

server.rb:7:in `accept': closed stream (IOError)
        from server.rb:7

The file sizes are nearly identical, I'm off by 479 bytes:

ynadji@onizuka:file_transfer$ du -b *  
122753  lighter.jpg
122274  omgnew.jpg

Any ideas? I could be doing this entirely wrong, searching didn't yield 
any helpful results, so I figured I'd turn here. I was reading around 
with Array#pack and String#unpack which seems to be heading in the right 
direction, but I'm completely lost :P.

Thanks!

Yacin Nadji