golang rpc的两种调用方法

golang的rpc有两种方法进行调用，一种是rpc例子中给的：

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)
}

另一种是使用NewServer

这种是当rpc已经注册的时候就要使用了另外一种了。即一个server只能在DefaultRPC中注册一种类型。

当Server使用rpc.NewServer的时候，client也需要进行下改动了

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)
}

第二个例子中的

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

可以任意设置，第一个例子其实是设置了默认的两个

这里也顺便将reply作为[]slice的例子给演示了下