Go实现简易RPC框架的方法步骤

type Server struct {
 addr string
 funcs map[string]reflect.Value
}

// Register a method via name
func (s *Server) Register(name string, f interface{}) {
 if _, ok := s.funcs[name]; ok {
 return
 }
 s.funcs[name] = reflect.ValueOf(f)
}

package main

import (
 "fmt"
 "reflect"
)

func main() {
 // Register methods
 funcs := make(map[string]reflect.Value)
 funcs["add"] = reflect.ValueOf(add)

 // When receives client's request
 req := []reflect.Value{reflect.ValueOf(1), reflect.ValueOf(2)}
 vals := funcs["add"].Call(req)
 var rsp []interface{}
 for _, val := range vals {
 rsp = append(rsp, val.Interface())
 }

 fmt.Println(rsp)
}

func add(a, b int) (int, error) {
 return a + b, nil
}

package main

import (
 "fmt"
 "reflect"
)

func main() {
 add := func(args []reflect.Value) []reflect.Value {
 result := args[0].Interface().(int) + args[1].Interface().(int)
 return []reflect.Value{reflect.ValueOf(result)}
 }

 var addptr func(int, int) int
 container := reflect.ValueOf(&addptr).Elem()
 v := reflect.MakeFunc(container.Type(), add)
 container.Set(v)

 fmt.Println(addptr(1, 2))
}

type Data struct {
 Name string    // service name
 Args []interface{} // request's or response's body except error
 Err string    // remote server error
}

func encode(data Data) ([]byte, error) {
 var buf bytes.Buffer
 encoder := gob.NewEncoder(&buf)
 if err := encoder.Encode(data); err != nil {
 return nil, err
 }
 return buf.Bytes(), nil
}

func decode(b []byte) (Data, error) {
 buf := bytes.NewBuffer(b)
 decoder := gob.NewDecoder(buf)
 var data Data
 if err := decoder.Decode(&data); err != nil {
 return Data{}, err
 }
 return data, nil
}

// Transport struct
type Transport struct {
 conn net.Conn
}

// NewTransport creates a transport
func NewTransport(conn net.Conn) *Transport {
 return &Transport{conn}
}

// Send data
func (t *Transport) Send(req Data) error {
 b, err := encode(req) // Encode req into bytes
 if err != nil {
 return err
 }
 buf := make([]byte, 4+len(b))
 binary.BigEndian.PutUint32(buf[:4], uint32(len(b))) // Set Header field
 copy(buf[4:], b)                  // Set Data field
 _, err = t.conn.Write(buf)
 return err
}

// Receive data
func (t *Transport) Receive() (Data, error) {
 header := make([]byte, 4)
 _, err := io.ReadFull(t.conn, header)
 if err != nil {
 return Data{}, err
 }
 dataLen := binary.BigEndian.Uint32(header) // Read Header filed
 data := make([]byte, dataLen)       // Read Data Field
 _, err = io.ReadFull(t.conn, data)
 if err != nil {
 return Data{}, err
 }
 rsp, err := decode(data) // Decode rsp from bytes
 return rsp, err
}