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Go net包之RPC

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net 包中关于 rpc 的简单应用

rpc 包介绍

Package rpc provides access to the exported methods of an object across a network or other I/O connection. A server registers an object, making it visible as a service with the name of the type of the object. After registration, exported methods of the object will be accessible remotely. A server may register multiple objects (services) of different types but it is an error to register multiple objects of the same type.

rpc规则：

  • 方法有且只有两个可序列化参数，且第二个参数必须是指针，作为方法的返回结果
  • 方法返回一个 error
  • 上述的所有类型、方法、字段都是公开的 ( exported )

方法示例

func (t *T) MethodName(argType T1, replyType *T2) error {}

rpc 示例

rpc 服务端

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type Req struct {
    NumOne, NumTwo int
}

type Res struct {
    Num int
}

type Server struct {}

func (s *Server) Add(req Req, res *Res) error {
    res.Num = req.NumOne + req.NumTwo
    time.Sleep(3*time.Second)
    return nil
}

func main() {
    rpc.Register(new(Server))
    rpc.HandleHTTP()
    listener, err := net.Listen("tcp", ":8888")
    if err != nil {
        log.Fatalln("listen error: ", err)
    }
    http.Serve(listener, nil)
}

rpc 客户端

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type Req struct {
    NumOne, NumTwo int
}

type Res struct {
    Num int
}

func main() {
    client, err := rpc.DialHTTP("tcp", ":8888")
    if err != nil {
        log.Fatalln("dial error: ", err)
    }
    req := Req{1,2}
    var res Res
    // Synchronous call
    //client.Call("Server.Add", req, &res)
    //fmt.Println(res)

    // Asynchronous call
    addCall := client.Go("Server.Add", req, &res, nil)
    LOOP: for {
        select {
            case <-addCall.Done:
                break LOOP
            default:
                time.Sleep(1*time.Second)
                fmt.Println("waiting...")
        }
    }
    fmt.Println(res)
}