SSMP 开源消息传递协议

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)>