skynet实践（8）-接入websocket

    我从开源项目（https://github.com/lipp/lua-websockets，这里我们简称LWS）中抽出了websocket的部分处理，步骤如下：

    1）首先是解决LWS的几个依赖问题。LWS在握手阶段的base64编解码使用了luasocket中的mime，因此在3rd文件夹中建立mime文件夹，将mime.h和mime.c文件放进去，修改skynet的Makefile文件，作为一个单独的动态库编译：

1 LUA_CLIB = skynet \
2   client \
3   bson md5 sproto lpeg mime

1 $(LUA_CLIB_PATH)/mime.so : 3rd/mime/mime.c | $(LUA_CLIB_PATH)
2     $(CC) $(CFLAGS) $(SHARED) -I3rd/mime $^ -o $@ 

    在tools.lua中引用了mime，由于我们只用了C文件，因此修改require "mime" 为： require "mime.core" 。

对于luabitop，skynet自带的lua5.3源码已经支持（在lbitlib.c文件中），但是默认是关闭的，修改lua5.3的Makefile，增加LUA_COMPAT_BITLIB宏并重新编译：

1 MYCFLAGS=-I../../skynet-src -g -DLUA_COMPAT_BITLIB

    这样在bit.lua中对bit32就能正确引用了。

    2）下一步则是在skynet端侦听tcp连接：

 1 local skynet = require "skynet"
 2 local socket = require "skynet.socket"
 3 
 4 skynet.start(function()
 5     local id = socket.listen("0.0.0.0", 8001)
 6     skynet.error("web server listen on web port 8001")
 7 
 8     socket.start(id, function(id, addr)
 9         local agent = skynet.newservice("wsagent")
10         skynet.error(string.format("%s connected, pass it to agent :%08x", addr, agent))
11         skynet.send(agent, "lua", id, "start")
12     end)
13 end)

    这里每次侦听到一个新连接后就建立wsagent，后续的握手及数据传输一并交给其处理。

    3）在lualib下建立websocket文件夹，放入handshake.lua（握手协议）、frame.lua（帧数据格式解析）、bit.lua、tools.lua。在wsagent.lua中实现握手、数据传输、关闭连接如下：

  1 local skynet = require "skynet"
  2 local socket = require "skynet.socket"
  4 local frame  = require "websocket.frame"
  5 local handshake = require "websocket.handshake"
  6 local sockethelper = require "http.sockethelper"
  7 
  8 local agent = { }
  9 local REQUEST = { }
 10 local FD, read, write
 11 
 12 local function _send(message)
 13     local encoded = frame.encode(message, frame.TEXT)
 14     write(encoded)
 15 end
 16 
 17 local function _handshake(fd)
 18     FD = fd
 19     read  = sockethelper.readfunc(fd)
 20     write = sockethelper.writefunc(fd)
 21 
 22     local header = ""
 23     while true do
 24         local bytes = read()
 25         header = header .. bytes
 26         if #header > 8192 then
 27             skynet.error("<websocket.handshake>error: header size > 8192")
 28             return
 29         end
 30 
 31         local _, to = header:find("\r\n\r\n", -#bytes-3, true)
 32         if to then
 33             header = header:sub(1, to)
 34             break
 35         end
 36     end
 37 
 38     print("accept handshake http request:" .. header)
 39 
 40     local protocols = { } -- todo: how to set protocols?
 41     local response, protocol = handshake.accept_upgrade(header, protocols)
 42     if not response then
 43         skynet.error("<websocket.handshake>error: handshake parse header fault")
 44         return
 45     end
 46 
 47     print("send handshake http response:" .. response)
 48 
 49     write(response)
 50     skynet.error(string.format("<websocket.handshake>web socket %q connection established", fd))
 51 
 52     return true
 53 end
 54 
 55 local function _close()
 56     local encoded = frame.encode_close(1000, 'force close')
 57     encoded = frame.encode(encoded, frame.CLOSE)
 58 
 59     print("force close:" .. encoded)
 60 
 61     write(encoded)
 62     socket.close(FD)
 63 end
 64 
 65 local function _dispatch(text, opcode)
 66     print(string.format("<websocket>opcode:%q message:%q", opcode, text))
 67 
 68     local TEXT  = assert(frame.TEXT)
 69     local CLOSE = assert(frame.CLOSE)
 70     assert(opcode == TEXT or opcode == CLOSE, opcode)
 71 
 72     if opcode == TEXT then
 81         -- todo: logic
 82         return true
 83     end
 84 
 85     if opcode == CLOSE then
 86         local code, reason = frame.decode_close(message)
 87         print(string.format("<websocket>CLOSE code:%q reason:%q", code, reason))
 88         local encoded = frame.encode_close(code)
 89         encoded = frame.encode(encoded, frame.CLOSE)
 90 
 91         local ok, err = pcall(write, encoded)
 92         if not ok then
 93             -- remote endpoint may has closed tcp-connection already
 94             skynet.error("write close protocol failure:" .. tostring(err))
 95         end
 96         socket.close(assert(FD))
 97     end
 98 end
 99 
100 local function _recv()
101     local last
102     local frames = {}
103     local first_opcode
104 
105     while true do
106         -- skynet will report error and close socket if socket error (see socket.lua)
107         local encoded = read()
108         if last then
109             encoded = last .. encoded
110             last = nil
111         end
112 
113         repeat
114             local decoded, fin, opcode, rest = frame.decode(encoded)
115             if decoded then

116                 if not first_opcode then
117                     first_opcode = opcode
118                 end
119                 table.insert(frames, decoded)
120                 encoded = rest
121                 if fin == true then
122                     if not _dispatch(table.concat(frames), first_opcode) then
123                         -- socket closed in [_dispatch]
124                         return
125                     end
126                     frames = { }
127                     first_opcode = nil
128                 end
129             end
130         until (not decoded)
131         
132         if #encoded > 0 then
133             last = encoded
134         end
135     end
136 end
137 
138 function agent.start(fd)
139     socket.start(fd)
140 
141     skynet.error("<websocket>start handshake")
142     if not _handshake(fd) then
143         socket.close(fd)
144         skynet.exit()
145         return
146     end
147 
148     skynet.error("<websocket>receive and dispatch")
149     _recv()
150 
151     skynet.error("<websocket>exit")
152     skynet.exit()
153 end
154 
155 skynet.start(function()
156     skynet.dispatch("lua", function (_, _, fd, method, ...)
157         local f = assert(agent[method])
158         skynet.retpack(f(fd, ...))
159     end)
160 end)

    代码我已放到git上：https://github.com/zhoujijian/skynet-websocket

转载于:https://www.cnblogs.com/Jackie-Snow/p/7122037.html