一、安装protobuf

    下面的操作方法都是在 centos 环境下操作

#下载 Protocol Buffers 源代码：
#您可以从 Protocol Buffers 的 GitHub 仓库中获取特定版本的源代码。使用以下命令克隆仓库
git clone -b v3.20.3 https://github.com/protocolbuffers/protobuf.git#编译和安装：
#进入克隆的目录，然后编译和安装 Protocol Buffers：
cd protobuf
./autogen.sh
./configure
make
sudo make install#验证安装：
protoc --version#您应该看到输出，指示安装的版本为 3.20.3。

二、安装pdb库

#第三方库安装在3rd目录下
cd skynet/3rd/
git clone https://github.com/cloudwu/pbc.gitcd pbc
make#编译成功后，打开skynet/3rd/pbc/binding/lua53/Makefile文件，修改里面的lua路径
CC = gccCFLAGS = -O2 -fPIC -WallLUADIR = ../../../lua   #这个路劲就是skynet/3rd/luaTARGET = protobuf.so.PHONY : all cleanall : $(TARGET)$(TARGET) : pbc-lua53.c$(CC) $(CFLAGS) -shared -o $@ -I../.. -I$(LUADIR) -L../../build $^ -lpbcclean :rm -f $(TARGET)#去到lua53目录，编译生成protobuf.so库
cd ./binding/lua53
sudo make

三、将依赖文件放到工程目录下

   将 protobuf.so 和 protobuf.lua 分别放入 luaclib 、lualib

cp protobuf.so ../../../../luaclib/  #将protobuf.so复制到存放C模块的lualib目录中    
cp protobuf.lua ../../../../lualib/  #将protobuf.lua复制到存放Lua模块的lualib目录中

四、创建protobuf目录

在skynet目录下创建protobuf目录，用来存放原始 .proto 描述文件

  这里举例 login.proto

mkdir protobuflogin.proto的内容如下代码所示：
syntax = "proto3";  
package Login;message login {string account=1;string passwd=2;int32 result=3;
}

五、编译proto文件

protoc --descriptor_set_out login.pb login.proto

   这里写了个gen_pb.sh脚本，将protobuf目录下的所有.sproto文件转成proto文件

#!/bin/bash  # 指定要遍历的目录，这里使用当前目录"."  
dir="."  # 使用find命令查找所有.proto文件，并调用basename和cut命令来截取文件名  
find "$dir" -type f -name "*.proto" | while read -r filepath; do  # 使用basename命令获取文件名部分，然后使用cut命令去除后缀  filename=$(basename "$filepath")  filename_without_extension="${filename%.*}"  # 输出截取后的文件名  echo "$filename, $filename_without_extension"  # 在这里可以添加其他操作，比如使用protoc编译等  protoc --descriptor_set_out "$filename_without_extension.pb" "$filename" 
done

六、了解protobuf.lua 关键函数

1、 protobuf.register

• 功能：注册 Protobuf 
• 参数：buffer  .pb文件读取出来的二进制字符串
• 返回值：无。

function M.register(buffer)c._env_register(P, buffer) 
end

   备注： register需要自己去加载.pb文件内容，下面的register_file函数使用会更多

2、protobuf.register_file

• 功能：注册 Protobuf 
• 参数：filename 为  .pb文件名。  
• 返回值：无。

function M.register_file(filename)local f = assert(io.open(filename , "rb"))local buffer = f:read "*a"c._env_register(P, buffer)f:close()
end

3、protobof.encode

• 功能：将一个 Lua 表编码为 Protobuf 格式的二进制消息。
• 参数：message 是注册的 Protobuf 定义的名称，msg 是要编码的 Lua 表。
• 返回值：编码后的二进制数据。

function M.encode( message, t , func , ...)local encoder = c._wmessage_new(P, message)assert(encoder ,  message)encode_message(encoder, message, t)if func thenlocal buffer, len = c._wmessage_buffer(encoder)local ret = func(buffer, len, ...)c._wmessage_delete(encoder)return retelse    local s = c._wmessage_buffer_string(encoder)c._wmessage_delete(encoder)return send
end

4、protobof.decode

• 功能：将一个 Protobuf 编码的二进制消息解码为 Lua 表。
• 参数：typename 是注册的 Protobuf 定义的名称，buf 是包含 Protobuf 编码消息的二进制数据。
• 返回值：解码后的 Lua 表。

function M.decode(typename, buffer, length)local ret = {}local ok = c._decode(P, decode_message_cb , ret , typename, buffer, length)if ok thenreturn setmetatable(ret , default_table(typename))elsereturn false , c._last_error(P)end
end

七、protobuf测试用例

   在examples 目录下新建 test_protobuf.lua 

package.path = package.path .. ";./lualib/?.lua"
package.cpath = package.cpath .. ";./luaclib/?.so"local protobuf = require "protobuf"      --引入文件protobuf.lua
protobuf.register_file "./protobuf/common.pb" --注册pb文件
protobuf.register_file "./protobuf/login.pb" --注册pb文件local loginInfo = { account = "test", passwd = "pw"} local encodeData = protobuf.encode("Login.login", loginInfo)
print("encodeData:", encodeData)local decodeData = protobuf.decode("Login.login", encodeData)
print("decodeData account:", decodeData.account)
print("decodeData passwd:", decodeData.passwd)

八、skynet 使用protobuf进行网络通信

1、 将数据打包成二进制数据

--[[big endianhead    2 byte body size2 byte protonamesizen byte protonamebody    n byte data@desc: 将lua格式的协议序列化为二进制数据
]] 
function protobufDataHelper.encode( name,data )local stringbuffer =  protobuf.encode(name, data)         -- protobuf序列化 返回lua stringlocal body = string.pack(">s2s",name,stringbuffer)       -- 打包包体 协议名 + 协议数据local head = string.pack(">I2",#body)                     -- 打包包体长度print("encode proto_name:", name, ",data_size:", #body, ",totalSize:", #head+#body)return head .. body                                       -- 包体长度 + 协议名 + 协议数据
end

2、将二进制数据解包

--[[@desc: 将二进制数据反序列化为lua string--@msg: C Point @return:协议名字，协议数据
]]
function protobufDataHelper.decode( msg  )--- 前两个字节在netpack.filter 已经解析print("msg size:", #msg)local proto_name,stringbuffer = string.unpack(">s2s",msg)print("proto_name", proto_name, "data:", stringbuffer)local body = protobuf.decode(proto_name, stringbuffer)return proto_name,body
end

3、skyent unpack类型指定为二进制字符串

     这里在agent.lua 注册消息协议类型时处理

skynet.register_protocol {name = "client",id = skynet.PTYPE_CLIENT,   unpack = skynet.tostring,   --- 将C point 转换为lua 二进制字符串
}

  在dispatch_message消息地方反序列化消息

--- 分发消息
local function  dispatch_message(msg)--- 反序列化二进制string数据local pack_name,data = dataHelper.decode(msg)     --   pack_name = c2s.testlocal sub_name = pack_name:match(".+%.(%w+)$")    --   sub_name = test......local f = REQUEST[sub_name]if f == nil thenprint("not function define handle package:", pack_name)returnendf(data)
end

agent.lua 改造测试代码如下

local skynet = require "skynet"
local socket = require "skynet.socket"
local sproto = require "sproto"
local sprotoloader = require "sprotoloader"
local login = require "login"
local tableutil = require "tableutil"local dataHelper = require "protobufDataHelper"local WATCHDOG
local host
local send_requestlocal CMD = {}
local REQUEST = {}
local client_fdfunction REQUEST:get()print("get", self.what)local r = skynet.call("SIMPLEDB", "lua", "get", self.what)return { result = r }
endfunction REQUEST:set()print("set", self.what, self.value)local r = skynet.call("SIMPLEDB", "lua", "set", self.what, self.value)
endfunction REQUEST:handshake()return { msg = "Welcome to skynet, I will send heartbeat every 5 sec." }
endfunction REQUEST:quit()skynet.call(WATCHDOG, "lua", "close", client_fd)
endlocal function send_data(name, args)local data = dataHelper.encode(name, args)-- 发送数据socket.write(client_fd,data)
endfunction REQUEST:login()print("login account,passwd:", self.account, self.passwd)local result = login.loginRequest(self.account, self.passwd)if result ~= 0 thenprint("kill client, client_fd:", client_fd)REQUEST:quit()endlocal loginInfo = { account = "kk", passwd = "haha"}send_data("Login.login", loginInfo)return {result = result}
endfunction REQUEST:loginTest()print("loginTest:", tableutil.tPrint(self))
endlocal function request(name, args, response)local f = assert(REQUEST[name])print("recieve request, protoName:", name, tableutil.tPrint(args))local r = f(args)if response thenreturn response(r)end
endlocal function send_package(pack)local package = string.pack(">s2", pack)socket.write(client_fd, package)
end--[[
skynet.register_protocol {name = "client",id = skynet.PTYPE_CLIENT,unpack = function (msg, sz)return host:dispatch(msg, sz)end,dispatch = function (fd, _, type, ...)assert(fd == client_fd)	-- You can use fd to reply messageskynet.ignoreret()	-- session is fd, don't call skynet.retskynet.trace()if type == "REQUEST" thenlocal ok, result  = pcall(request, ...)if ok thenif result thensend_package(result)endelseskynet.error(result)endelseassert(type == "RESPONSE")error "This example doesn't support request client"endend
}--]]skynet.register_protocol {name = "client",id = skynet.PTYPE_CLIENT,	unpack = skynet.tostring,   --- 将C point 转换为lua 二进制字符串
}function CMD.start(conf)local fd = conf.clientlocal gate = conf.gateWATCHDOG = conf.watchdog-- slot 1,2 set at main.luahost = sprotoloader.load(1):host "package"send_request = host:attach(sprotoloader.load(2))skynet.fork(function()local index = 1while true do--send_package(send_request "heartbeat")index = index + 1local loginInfo = { account = "kk"..index, passwd = "haha"}send_data("Login.login", loginInfo)skynet.sleep(500)endend)client_fd = fdskynet.call(gate, "lua", "forward", fd)
endfunction CMD.disconnect()-- todo: do something before exitskynet.exit()
end--- 分发消息
local function  dispatch_message(msg)--- 反序列化二进制string数据local pack_name,data = dataHelper.decode(msg)     --   pack_name = c2s.testlocal sub_name = pack_name:match(".+%.(%w+)$")    --   sub_name = testprint("recieve request, protoName:", pack_name, tableutil.tPrint(data))local f = REQUEST[sub_name]if f == nil thenprint("not function define handle package:", pack_name)returnendf(data)
endskynet.start(function()skynet.dispatch("lua", function(_,_, command, ...)skynet.trace()local f = CMD[command]skynet.ret(skynet.pack(f(...)))end)skynet.dispatch("client", function (session, address, msg)dispatch_message(msg)end)
end)

4、客户端测试代码

client_protobuf.lua

package.cpath = "luaclib/?.so;skynet/luaclib/?.so"
package.path = "lualib/common/?.lua;lualib/?.lua;skynet/lualib/?.lua;skynet/examples/?.lua"local tableutil = require "tableutil"if _VERSION ~= "Lua 5.4" thenerror "Use lua 5.4"
endlocal socket = require "client.socket"
local dataHelper = require "protobufDataHelper"local fd = assert(socket.connect("127.0.0.1", 8888))local function send_data(name, args)local data = dataHelper.encode(name, args)-- 发送数据socket.send(fd,data)
endlocal loginInfo = { account = "test", passwd = "haha"}
send_data("Login.login", loginInfo)
send_data("Common.heartbeat", {})local function unpack_package(text)local size = #textif size < 2 thenreturn nil, textendlocal s = text:byte(1) * 256 + text:byte(2)if size < s+2 thenreturn nil, textendreturn text:sub(3,2+s), text:sub(3+s)
endlocal function recv_package(last)local resultresult, last = unpack_package(last)if result thenreturn result, lastendlocal r = socket.recv(fd)if not r thenreturn nil, lastendif r == "" thenerror "Server closed"endreturn unpack_package(last .. r)
endlocal last = ""
local function dispatch_package()while true dolocal vv, last = recv_package(last)if not v thenbreakendlocal packName, data = dataHelper.decode(v)print("packName:", packName)print("data:", tableutil.tPrint(data) )end
endwhile true dodispatch_package()socket.usleep(1000000)
end