#Your star is my power!! 🚀 ###Discribe lhttp is a http like protocol using websocket to provide long live, bulid your IM service quickly scalable without XMPP!

Everything is customizable.

###Features

• simple easy but powerful!
• fast, 10000 messages send using 0.04s(single-core CPU,1G memory).
• support cluster.
• easy to customize and expansion.
• work well with HTTP. So LHTTP can work with other language like php java python etc,.

A simple chat room demo

with lhttp javascript sdk we complete a simple chat room within 40 lines code!!

###SDKs if you want to join us, contact me! My Email is [email protected]

• javascript SDK webapp or website.
• TODO c SDK ARM application or some c/c++ application.
• TODO swift SDK ios app
• TODO object-c SDK ios app
• TODO java SDK andriod app or java application.

####Protocol stack:

+--------------------+
|       lhttp        |
+--------------------+
|     websocket      |
+--------------------+
|        TCP         |
+--------------------+

####Architecture

        +---------------------------------------+
        |    message center cluster (gnatsd)    |
        +---------------------------------------+
 ........|.................|...............|..................
| +-------------+   +-------------+   +-------------+        | 
| |lhttp server |   |lhttp server |   |lhttp server |   ...  |  lhttp server cluster
| +-------------+   +-------------+   +-------------+        | 
 .....|..........._____|  |___.............|  |_________......
      |          |            |            |            |       <----using websocket link
 +--------+  +--------+   +--------+   +--------+   +--------+   
 | client |  | client |   | client |   | client |   | client |   
 +--------+  +--------+   +--------+   +--------+   +--------+  

####Quick start

go get github.com/nats-io/nats
go get github.com/fanux/lhttp

We need run gnatsd first:

cd bin
./gnatsd &
./lhttpd 

Open anohter bash run lhttpClient, then input your command:

cd bin
./lhttpClient

###Protocol

LHTTP/1.0 Command\r\n                --------start line, define command, and protocol [protocol/version] [command]\r\n
Header1:value\r\n                    --------headers
Header2:value\r\n
\r\n
body                                 --------message body

for example:

LHTTP/1.0 chat\r\n
content-type:json\r\n
publish:channel_jack\r\n
\r\n
{
    to:jack,
    from:mike,
    message:hello jack,
    time:1990-1210 5:30:48
}

###Usage

1. define your processor, you need combine BaseProcessor

type ChatProcessor struct {
    *lhttp.BaseProcessor
}

if you don't like BaseProcessor, define your struct witch must has OnOpen(*WsHandler) OnClose(*WsHandler) method like this:(don't recommand)

type ChatProcessor struct {
}
func (p ChatProcessor)OnOpen(h *WsHandler) {
    //your logic
}
func (p ChatProcessor)OnClose(h *WsHandler) {
    //your logic
}
func (p ChatProcessor)OnMessage(h *WsHandler) {
    //your logic
}

2. regist your processor

lhttp.Regist("chat",&ChatProcessor{&lhttp.BaseProcessor{}})

then if command is "chat" ChatProcessor will handle it 3. define your onmessage handle

func (p *ChatProcessor)OnMessage(h *WsHandler) {
    h.Send(h.GetBody())
}

###Start websocket server

http.Handler("/echo",lhttp.Handler(lhttp.StartServer))
http.ListenAndServe(":8081")

Example , echo

type ChatProcessor struct {
    *lhttp.BaseProcessor
}

func (p *ChatProcessor) OnMessage (h *lhttp.WsHandler) {
    log.Print("on message :", h.GetBody())
    h.Send(h.GetBody())
}

func main(){
    lhttp.Regist("chat", &ChatProcessor{&lhttp.BaseProcessor{}})

    http.Handle("/echo",lhttp.Handler(lhttp.StartServer))
    http.ListenAndServe(":8081",nil)
}

###Test open websocketServer and run:

cd websocketServer
go run test.go

as we can see, both of the new header are added and new command are set by the server. If we don't set a header or command ,then they will return the same result as they requested.

open an other bash, and run client in websocketClient

cd websocketClient
go run test.go

###Subscribe/Publish client1:

LHTTP/1.0 command\r\n
subscribe:channelID\r\n
\r\n
body optional

client2:

LHTTP/1.0 command\r\n
publish:channelID\r\n
\r\n
body require

client1:

LHTTP/1.0 command\r\n
unsubscribe:channelID\r\n
\r\n
body optional

client2 publish a message by channelID, client1 subscribe it, so client 1 will receive the message. if client1 send unsubscribe channelID, he will not recevie message any more in channelID

support multiple channelID:

LHTTP/1.0 chat\r\n
subscribe:channelID1 channelID2 channelID3\r\n
\r\n

####Using HTTP publish message! lhttp support publish message by standard HTTP. url: /publish . method: POST . body: use lhttp publish message as HTTP body. for example I wan't send a message to who subscribe channel_test by HTTP.

    resp,err := http.POST("https://www.yourserver.com/publish", "text/plain",
    "LHTTP/1.0 chat\r\npublish:channel_test\r\n\r\nhello channel_test guys!")

when lhttp server receive this message, will publish whole body to channel_test.

your can use Publish function in tools.go

//func Publish(channelID []string, command string, header map[string]string, body string) (err error) {
//}
//send message to who subscribe mike.

Publish("mike", "yourCommand", nil, "hello mike!")

###Upstream we can use lhttp as a proxy:

LHTTP/1.0 command\r\n
upstream:POST http://www.xxx.com\r\n
\r\n
body

lhttp will use hole message as http body, post to http://www.xxx.com if method is GET, lhttp send http GET request ignore lhttp message body:

LHTTP/1.0 command\r\n
upstream:GET http://www.xxx.com?user=user_a&age=26\r\n
\r\n
body

####This case will show you about upstream proxy: jack use lhttp chat with mike, lhttp is third part module, we can't modify lhttp server but we want save the chat record, how can we do?

        +----+                  +----+
        |jack|                  |mike|
        +----+                  +----+
         |_____________    _______|
                       |  |
                   +------------+
                   |lhttp server|
                   +------------+
                         |(http request with chat record)
                         V
                   +------------+
                   | http server|  upstream server(http://www.xxx.com/record)
                   +------------+
                   (save chat record)
    

jack: MESSAGE_UPSTREAM:=

LHTTP/1.0 chat\r\n
upstream:POST http://www.xxx.com/record\r\n
publish:channel_mike\r\n
\r\n
hello mike,I am jack

mike:

LHTTP/1.0 chat\r\n
subscribe:channel_mike\r\n
\r\n

when jack send publish message, not only mike will receive the message, the http server will also receive it. witch http body is:MESSAGE_UPSTREAM, so http serve can do anything about message include save the record

###Multipart data forexample a file upload message, the multipart header record the offset of each data part, each part can has it own headers

LHTTP/1.0 upload\r\n
multipart:0 56\r\n
\r\n
content-type:text/json\r\n
\r\n
{filename:file.txt,fileLen:5}
content-type:text/plain\r\n
\r\n
hello

content-type:text/json\r\n\r\n{filename:file.txt,fileLen:5}content-type:text/plain\r\n\r\nhello
^                                                          ^
|<---------------------first part------------------------->|<---------second part------------>|
0                                                          56                           

why not boundary but use offset? if use boundary lhttp need ergodic hole message, that behaviour is poor efficiency. instead we use offset to cut message

####How to get multipart data for example this is client message.

LHTTP/1.0 upload\r\nmultipart:0 14\r\n\r\nk1:v1\r\n\r\nbody1k2:v2\r\n\r\nbody2

server code:

type UploadProcessor struct {
	*lhttp.BaseProcessor
}

func (*UploadProcessor) OnMessage(ws *lhttp.WsHandler) {
	for m := ws.GetMultipart(); m != nil; m = m.GetNext() {
		log.Print("multibody:", m.GetBody(), " headers:", m.GetHeaders())
	}
}

//don't forget to tegist your command processor

lhttp.Regist("upload", &UploadProcessor{&lhttp.BaseProcessor{}})