Add the websocket module to skynet and skynetwebsocket

Add the websocket module to skynet and skynetwebsocket

Recently, I became fascinated by skynet, with a high code quality and outstanding computing in open-source game server frameworks, whether it's Python firefly, C ++/Python's kbengine, C #'s scut, or nodejs's pomelo, skynet has great advantages in concurrency and commercial applications.

Recently, I have been playing h5 games. tornado/django is more than enough. I plan to try skynet in the next game. skynet does not contain the websocket library, so I went to the wheel happily. Although there is the nginx extension library lua-resty-websocket, I don't like it for two reasons.

1. lua-resty-websocket is too old. Now it is the era of lua53.

2. I still like the callback-based method of tornado websocket. Of course, I can either use the callback method or use lua-resty-websocket.

Direct recv-based approach

In fact, it is relatively simple to parse websocket. What is more complicated is the close operation of websocket. Like handshaking, close also requires client-server

Confirm.

local skynet = require "skynet"local string = require "string"local crypt = require "crypt"local socket = require "socket"local httpd = require "http.httpd"local sockethelper = require "http.sockethelper"local urllib = require "http.url"local ws = {}local ws_mt = { __index = ws }local function response(id, ...)    return httpd.write_response(sockethelper.writefunc(id), ...)endlocal function write(id, data)    socket.write(id, data)endlocal function read(id, sz)    return socket.read(id, sz)endlocal function challenge_response(key, protocol)    local accept = crypt.base64encode(crypt.sha1(key .. "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"))    return string.format("HTTP/1.1 101 Switching Protocols\r\n" ..                        "Upgrade: websocket\r\n" ..                        "Connection: Upgrade\r\n" ..                        "Sec-WebSocket-Accept: %s\r\n" ..                        "%s\r\n", accept, protocol or "")    endlocal function accept_connection(header, check_origin, check_origin_ok)    -- Upgrade header should be present and should be equal to WebSocket    if not header["upgrade"] or header["upgrade"]:lower() ~= "websocket" then        return 400, "Can \"Upgrade\" only to \"WebSocket\"."    end    -- Connection header should be upgrade. Some proxy servers/load balancers    -- might mess with it.    if not header["connection"] or not header["connection"]:lower():find("upgrade", 1,true) then        return 400, "\"Connection\" must be \"Upgrade\"."    end    -- Handle WebSocket Origin naming convention differences    -- The difference between version 8 and 13 is that in 8 the    -- client sends a "Sec-Websocket-Origin" header and in 13 it's    -- simply "Origin".    local origin = header["origin"] or header["sec-websocket-origin"]    if origin and check_origin and not check_origin_ok(origin, header["host"]) then        return 403, "Cross origin websockets not allowed"    end    if not header["sec-websocket-version"] or header["sec-websocket-version"] ~= "13" then        return 400, "HTTP/1.1 Upgrade Required\r\nSec-WebSocket-Version: 13\r\n\r\n"    end    local key = header["sec-websocket-key"]    if not key then        return 400, "\"Sec-WebSocket-Key\" must not be  nil."    end    local protocol = header["sec-websocket-protocol"]     if protocol then        local i = protocol:find(",", 1, true)        protocol = "Sec-WebSocket-Protocol: " .. protocol:sub(1, i or i-1)    end    return nil, challenge_response(key, protocol)endlocal H = {}function H.check_origin_ok(origin, host)    return urllib.parse(origin) == hostendfunction H.on_open(ws)    endfunction H.on_message(ws, message)   endfunction H.on_close(ws, code, reason)    endfunction H.on_pong(ws, data)    -- Invoked when the response to a ping frame is received.endfunction ws.new(id, header, handler, conf)    local conf = conf or {}    local handler = handler or {}    setmetatable(handler, { __index = H })    local code, result = accept_connection(header, conf.check_origin, handler.check_origin_ok)    if code then        response(id, code, result)        socket.close(id)    else        write(id, result)    end    local self = {        id = id,        handler = handler,        mask_outgoing = conf.mask_outgoing,        check_origin = conf.check_origin    }    self.handler.on_open(self)     return setmetatable(self, ws_mt)endfunction ws:send_frame(fin, opcode, data)    if fin then        finbit = 0x80    else        finbit = 0    end    frame = string.pack("B", finbit | opcode)    l = #data    if self.mask_outgoing then        mask_bit = 0x80    else        mask_bit = 0    end    if l < 126 then        frame = frame .. string.pack("B", l | mask_bit)    elseif l < 0xFFFF then        frame = frame .. string.pack("!BH", 126 | mask_bit, l)    else         frame = frame .. string.pack("!BL", 127 | mask_bit, l)    end    if self.mask_outgoing then    end    frame = frame .. data    write(self.id, frame)    endfunction ws:send_text(data)    self:send_frame(true, 0x1, data)endfunction ws:send_binary(data)    self:send_frame(true, 0x2, data)endfunction ws:send_ping(data)    self:send_frame(true, 0x9, data)endfunction ws:send_pong(data)    self:send_frame(true, 0xA, data)endfunction ws:close(code, reason)    -- 1000  "normal closure" status code    if code == nil and reason ~= nil then        code = 1000    end    local data = ""    if code ~= nil then        data = string.pack(">H", code)    end    if reason ~= nil then        data = data .. reason    end    self:send_frame(true, 0x8, data)endfunction ws:recv()    local data = ""    while true do        local success, final, message = self:recv_frame()        if not success then            return success, message        end        if final then            data = data .. message            break        else            data = data .. message        end    end    self.handler.on_message(self, data)    return dataendlocal function websocket_mask(mask, data, length)    umasked = {}    for i=1, length do        umasked[i] = string.char(string.byte(data, i) ~ string.byte(mask, (i-1)%4 + 1))    end    return table.concat(umasked)endfunction ws:recv_frame()    local data, err = read(self.id, 2)    if not data then        return false, nil, "Read first 2 byte error: " .. err    end    local header, payloadlen = string.unpack("BB", data)    local final_frame = header & 0x80 ~= 0    local reserved_bits = header & 0x70 ~= 0    local frame_opcode = header & 0xf    local frame_opcode_is_control = frame_opcode & 0x8 ~= 0    if reserved_bits then        -- client is using as-yet-undefined extensions        return false, nil, "Reserved_bits show using undefined extensions"    end    local mask_frame = payloadlen & 0x80 ~= 0    payloadlen = payloadlen & 0x7f    if frame_opcode_is_control and payloadlen >= 126 then        -- control frames must have payload < 126        return false, nil, "Control frame payload overload"    end    if frame_opcode_is_control and not final_frame then        return false, nil, "Control frame must not be fragmented"    end    local frame_length, frame_mask    if payloadlen < 126 then        frame_length = payloadlen    elseif payloadlen == 126 then        local h_data, err = read(self.id, 2)        if not h_data then            return false, nil, "Payloadlen 126 read true length error:" .. err        end        frame_length = string.pack("!H", h_data)    else --payloadlen == 127        local l_data, err = read(self.id, 8)        if not l_data then            return false, nil, "Payloadlen 127 read true length error:" .. err        end        frame_length = string.pack("!L", l_data)    end    if mask_frame then        local mask, err = read(self.id, 4)        if not mask then            return false, nil, "Masking Key read error:" .. err        end        frame_mask = mask    end    --print('final_frame:', final_frame, "frame_opcode:", frame_opcode, "mask_frame:", mask_frame, "frame_length:", frame_length)    local  frame_data = ""    if frame_length > 0 then        local fdata, err = read(self.id, frame_length)        if not fdata then            return false, nil, "Payload data read error:" .. err        end        frame_data = fdata    end    if mask_frame and frame_length > 0 then        frame_data = websocket_mask(frame_mask, frame_data, frame_length)    end    if not final_frame then        return true, false, frame_data    else        if frame_opcode  == 0x1 then -- text            return true, true, frame_data        elseif frame_opcode == 0x2 then -- binary            return true, true, frame_data        elseif frame_opcode == 0x8 then -- close            local code, reason            if #frame_data >= 2 then                code = string.unpack(">H", frame_data:sub(1,2))            end            if #frame_data > 2 then                reason = frame_data:sub(3)            end            self:close()            socket.close(self.id)            self.handler.on_close(self, code, reason)        elseif frame_opcode == 0x9 then --Ping            self:send_pong()        elseif frame_opcode == 0xA then -- Pong            self.handler.on_pong(self, frame_data)        end        return true, true, nil    endendfunction ws:start()    while true do        local message, err = self:recv()        if not message then            --print('recv eror:', message, err)            socket.close(self.id)        end    endendreturn ws

The method is also very simple, and the callback-based method is really comfortable to use.

local skynet = require "skynet"local socket = require "socket"local string = require "string"local websocket = require "websocket"local httpd = require "http.httpd"local urllib = require "http.url"local sockethelper = require "http.sockethelper"local handler = {}function handler.on_open(ws)    print(string.format("%d::open", ws.id))endfunction handler.on_message(ws, message)    print(string.format("%d receive:%s", ws.id, message))    ws:send_text(message .. "from server")endfunction handler.on_close(ws, code, reason)    print(string.format("%d close:%d  %s", ws.id, code, reason))endlocal function handle_socket(id)    -- limit request body size to 8192 (you can pass nil to unlimit)    local code, url, method, header, body = httpd.read_request(sockethelper.readfunc(id), 8192)    if code then                if url == "/ws" then            local ws = websocket.new(id, header, handler)            ws:start()        end    endendskynet.start(function()    local address = "0.0.0.0:8001"    skynet.error("Listening "..address)    local id = assert(socket.listen(address))    socket.start(id , function(id, addr)       socket.start(id)       pcall(handle_socket, id)    end)end)

Go to https://github.com/Skycrab/skynet_websocket for details