golang rpc的兩種調用方法

golang的rpc有兩種方法進行調用，一種是rpc例子中給的：

package main

import (
        "net/rpc"
        "net/http"
        "log"
        "net"
        "time"
)


type Args struct {
        A, B int
}

type Arith int

func (t *Arith) Multiply(args *Args, reply *([]string)) error {
        *reply = append(*reply, "test")
        return nil
}

func main() {
        arith := new(Arith)

        rpc.Register(arith)
        rpc.HandleHTTP()
        
        l, e := net.Listen("tcp", ":1234")
        if e != nil {
                log.Fatal("listen error:", e)
        }
        go http.Serve(l, nil)
        time.Sleep(5 * time.Second)

        client, err := rpc.DialHTTP("tcp", "127.0.0.1" + ":1234")
        if err != nil {
                log.Fatal("dialing:", err)
        }
        
        args := &Args{7,8}
        reply := make([]string, 10)
        err = client.Call("Arith.Multiply", args, &reply)
        if err != nil {
                log.Fatal("arith error:", err)
        }
        log.Println(reply)
}

 

 

另一種是使用NewServer

這種是當rpc已經注冊的時候就要使用了另外一種了。即一個server只能在DefaultRPC中注冊一種類型。

當Server使用rpc.NewServer的時候，client也需要進行下改動了

package main

import (
        "net/rpc"
        //"net/http"
        "log"
        "net"
        "time"
)


type Args struct {
        A, B int
}

type Arith int

func (t *Arith) Multiply(args *Args, reply *([]string)) error {
        *reply = append(*reply, "test")
        return nil
}

func main() {
        newServer := rpc.NewServer()
        newServer.Register(new(Arith))

        l, e := net.Listen("tcp", "127.0.0.1:1234") // any available address
        if e != nil {
                log.Fatalf("net.Listen tcp :0: %v", e)
        }

        go newServer.Accept(l)
        newServer.HandleHTTP("/foo", "/bar")
        time.Sleep(2 * time.Second)

        address, err := net.ResolveTCPAddr("tcp", "127.0.0.1:1234")
        if err != nil {
                panic(err)
        }
        conn, _ := net.DialTCP("tcp", nil, address)
        defer conn.Close()

        client := rpc.NewClient(conn)
        defer client.Close()

        args := &Args{7,8}
        reply := make([]string, 10)
        err = client.Call("Arith.Multiply", args, &reply)
        if err != nil {
                log.Fatal("arith error:", err)
        }
        log.Println(reply)
}

第二個例子中的

newServer.HandleHTTP("/foo", "/bar") 

可以任意設置，第一個例子其實是設置了默認的兩個

這里也順便將reply作為[]slice的例子給演示了下