使用lua表设计简单RPC协议
lua protocol

协议设计

• 协议类型：schema

• 支持类型：int, string, array

• 采用lua table定义协议

   p = {
       name = "hanxi",
       tel = 1383838,
       addresslist = {
           address = "gz",
           addtype = "work",
       },
   }

p 是定义一个协议格式，其中，addresslist是array类型，定义的内容表示array的元素的格式。协议的实际内容格式如下：

  p = {
      name = "hanxi",
      tel = 1383838,
      addresslist = {
          {
              address = "gz",
              addtype = "work",
          },
          { 
              address = "jj",
              addtype = "home", 
          },
  }

协议打包

• 只打包value，key不打包

• 协议模板做预处理，把key排序，添加字段_keysort.

p = {
      _keysort = {"addresslist","name","tel"},
      name = "hanxi",
      tel = 1383838,
      addresslist = {
          _keysort = {"addtype","address"},
          address = "gz",
          addtype = "work",
      },
}

协议解包

• 根据协议模板，解析协议

• 遍历顺序按照_keysort

实现

在c中提供接口：

    luaL_Reg l[] ={
        { "packinit", lpackinit },
        { "write", lwrite },
        { "getpack", lgetpack },
        { "unpackinit", lunpackinit },
        { "read", lread },
        { NULL, NULL },
    };

packinit, write, getpack三个函数用于打包协议

unpackinit, read 两个函数用于解包协议

• 打包int时分64位，32位，16位，8位。第一个字节存储int位数和正负数标志

• 打包sting时，先存储字符串长度，按int的方式打包，然后打包string

全部代码： https://github.com/hanxi/lproto