SSMP 介绍
SSMP 是 Stupid-Simple Messaging Protocol，开源消息传递协议。
语法：
message = ( request | response | event ) LF request = "LOGIN" SP id SP id [ SP payload ] | "CLOSE" | "PING" | "PONG" | forwardable response = code [ SP payload ] event = "000" SP id SP ( forwardable | "PING" | "PONG" ) forwardable = "SUBSCRIBE" SP id [ SP "PRESENCE" ] | "UNSUBSCRIBE" SP id | "UCAST" SP id SP payload | "MCAST" SP id SP payload | "BCAST" SP payload | compat compat = verb [ SP id ] [ SP payload ] code = 3DIGIT verb = 1*UPALPHA id = 1*ID payload = 1*PAYLOAD ID = UPALPHA | LOALPHA | DIGIT | "." | ":" | "@" | "/" | "_" | "-" | "+" | "=" | "~" PAYLOAD = <any 8-bit value, except US-ASCII LF> UPALPHA = <any US-ASCII uppercase letter "A".."Z"> LOALPHA = <any US-ASCII lowercase letter "a".."z"> DIGIT = <any US-ASCII digit "0".."9"> SP = <US-ASCII SP, space (32)> LF = <US-ASCII LF, linefeed (10)>