Parsing HTML5 EventSource stream from network - html

Question

I've studied HTML5 EventSource specification and can't figure out how to parse and handle carriage return at end of received data.
App receives data stream that is composed of lines. Each line can be terminated by \r\n, \n or \r. On blank line, event should be considered ready and fired to listeners.
data: foobar\r\n
id: 1\r\n
\r\n
Equally valid event with same content
data: foobar\n
id: 1\r\n
\r
Full spec here, http://dev.w3.org/html5/eventsource/ The chapter 6. describes the BNF of the input.
Problem is the carriage return when it's seen at end of received data. Now, as far as I can understand, proper way of parsing is to do longest match search and thua wait for next data batch. Problem is, that if \r truly was the empty line marker, the event wont be fired until next data batch arrives and parser has enough data to attempt longest match.
Current data batch
data: foobar\r\n
id: 1\r\n
\r
Next data batch
\n
data: foobar2\r\n
id: 1\r\n
\r\n
Alternative Case. Next data batch
data: foobar2\r\n
id: 1\r\n
\r\n
This would not be problem in traditional parsing, but it's in EventSource because I need to trigger events as soon as possible, so if implementation waits for next data batch to get longest match, it might wait for a long time if sender used single character '\r' as empty line marker and it's not going to send anything else for a while.

Answer 1

Interesting problem! I assume you are not using a browser but writing your own client? (If writing server-side code, always send just \n or just \r!!)
The solution is when reading from the socket, to convert any "\r\n" sequence to "\r".
In other words, as soon as you get the "\r" you can treat it as end-of-line, do whatever processing you need, and set a CR_just_received flag. If you receive a "\n" and CR_just_received==true then quietly swallow it. Make sure CR_just_received is cleared whenever any byte except \r is received.