Hi, I'm doing a SIP server (listening in TCP) so I receive messages as the 
following:

----------------------------------------------------------
  INVITE sip:user@ip SIP/2.0 CRLF
  From: xxxxx CRLF
  To: xxxxx CRLF
  Content-Lenght: 235 CRLF
  CRLF
  body body body body body body body body body body body body body body body
  body body body body body body body body body body body body body body body
  body body body body body body 
  body body body body body body body body body

  body body body body body body body body body body body body body body body 
  body body
----------------------------------------------------------

I receive and parse correctly the headers and when I detect an empty line I 
must read the number of bytes indicated in "Content-Length" header (235 the 
example). This is like SMTP or HTTP.

I wonder which method is better in order to receive the body: io.read or 
io.readlines.

io.read blocks after read the 235 bytes while io.readparti

**** io.read
Reads at most length bytes from the I/O stream (blocks).

**** io.readpartial
Reads at most maxlen bytes from the I/O stream. It blocks only if ios has no 
data immediately available. It doesn block if some data available.

The code I use to read the body is:

	begin
		request.body = io.readpartial(request.hdr_content_length)
	rescue EOFError
		return
	end


For now it works perfectly in both ways but there is an obvious difference:

With io.readpartial my code reads all the bytes indicated in Content-Length 
(235) just if they come "together", but if they come "discontinnuated" 
io.readpartial return with the read bytes (in the example it can be less than 
235 bytes). Note that I don't use a loop for io.readpartial.

With io.read the code blocks until read 235 bytes. If the data comes "not 
together" it waits for the 235 bytes.


For now io.readpartial works perfectly and I like it since there could be 
SIP error (a client sends a body with less bytes than "Content-Length" says) 
and in this way I can detect it inmediately.
But I just do my test in localhost and so, not in real network which can be 
congested, etc.


Any opinion with this please? Thanks a lot.




-- 
Iñaki Baz Castillo