2018-08-10 14:56:59 1544浏览
今天扣丁学堂区块链培训给大家关于Go语言中TCP/IP网络编程的相关资料，文中通过示例代码介绍的非常详细，首先通过TCP/IP层连接两个进程会感觉可怕，但是在Go语言中可可能比你想象的要简单的多。下面话不多说了，来一起看看详细的介绍吧。
客户端 服务端
待发送结构体 解码后结构体
testStruct结构体 testStruct结构体
| ^
V |
gob编码 ----------------------------> gob解码
| ^
V |
发送 ============网络================= 接收
func ResolveTCPAddr(network, address string) (*TCPAddr, error) {
switch network {
case "tcp", "tcp4", "tcp6":
case "": // a hint wildcard for Go 1.0 undocumented behavior
network = "tcp"
default:
return nil, UnknownNetworkError(network)
}
addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address)
if err != nil {
return nil, err
}
return addrs.forResolve(network, address).(*TCPAddr), nil
}
func DialTCP(network string, laddr, raddr *TCPAddr) (*TCPConn, error) {
switch network {
case "tcp", "tcp4", "tcp6":
default:
return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)}
}
if raddr == nil {
return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: nil, Err: errMissingAddress}
}
c, err := dialTCP(context.Background(), network, laddr, raddr)
if err != nil {
return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
}
return c, nil
}
func Dial(network, address string) (Conn, error) {
var d Dialer
return d.Dial(network, address)
}
func Open(addr string) (*bufio.ReadWriter, error) {
conn, err := net.Dial("tcp", addr)
if err != nil {
return nil, errors.Wrap(err, "Dialing "+addr+" failed")
}
// 将net.Conn对象包装到bufio.ReadWriter中
return bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn)), nil
}
type Dialer struct {
Timeout time.Duration
Deadline time.Time
LocalAddr Addr
DualStack bool
FallbackDelay time.Duration
KeepAlive time.Duration
Resolver *Resolver
Cancel <-chan struct{}
}
type Conn interface {
Read(b []byte) (n int, err error)
Write(b []byte) (n int, err error)
Close() error
LocalAddr() Addr
RemoteAddr() Addr
SetDeadline(t time.Time) error
SetReadDeadline(t time.Time) error
SetWriteDeadline(t time.Time) error
}
type Listener interface {
// Accept waits for and returns the next connection to the listener.
Accept() (Conn, error)
// Close closes the listener.
// Any blocked Accept operations will be unblocked and return errors.
Close() error
// Addr returns the listener's network address.
Addr() Addr
}
func Listen(network, address string) (Listener, error) {
addrs, err := DefaultResolver.resolveAddrList(context.Background(), "listen", network, address, nil)
if err != nil {
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: nil, Err: err}
}
var l Listener
switch la := addrs.first(isIPv4).(type) {
case *TCPAddr:
l, err = ListenTCP(network, la)
case *UnixAddr:
l, err = ListenUnix(network, la)
default:
return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: la, Err: &AddrError{Err: "unexpected address type", Addr: address}}
}
if err != nil {
return nil, err // l is non-nil interface containing nil pointer
}
return l, nil
}
package main
import (
"bufio"
"encoding/gob"
"flag"
"github.com/pkg/errors"
"io"
"log"
"net"
"strconv"
"strings"
"sync"
)
type complexData struct {
N int
S string
M map[string]int
P []byte
C *complexData
}
const (
Port = ":61000"
)
func Open(addr string) (*bufio.ReadWriter, error) {
log.Println("Dial " + addr)
conn, err := net.Dial("tcp", addr)
if err != nil {
return nil, errors.Wrap(err, "Dialing " + addr + " failed")
}
return bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn)), nil
}
type Endpoint struct {
listener net.Listener
handler map[string]HandleFunc
m sync.RWMutex // Maps不是线程安全的，因此需要互斥锁来控制访问。
}
func NewEndpoint() *Endpoint {
return &Endpoint{
handler: map[string]HandleFunc{},
}
}
func (e *Endpoint) AddHandleFunc(name string, f HandleFunc) {
e.m.Lock()
e.handler[name] = f
e.m.Unlock()
}
func (e *Endpoint) Listen() error {
var err error
e.listener, err = net.Listen("tcp", Port)
if err != nil {
return errors.Wrap(err, "Unable to listen on "+e.listener.Addr().String()+"\n")
}
log.Println("Listen on", e.listener.Addr().String())
for {
log.Println("Accept a connection request.")
conn, err := e.listener.Accept()
if err != nil {
log.Println("Failed accepting a connection request:", err)
continue
}
log.Println("Handle incoming messages.")
go e.handleMessages(conn)
}
}
// handleMessages读取连接到第一个换行符。 基于这个字符串，它会调用恰当的HandleFunc。
func (e *Endpoint) handleMessages(conn net.Conn) {
// 将连接包装到缓冲reader以便于读取
rw := bufio.NewReadWrite(bufio.NewReader(conn), bufio.NewWriter(conn))
defer conn.Close()
// 从连接读取直到遇到EOF. 期望下一次输入是命令名。调用注册的用于该命令的处理器。
for {
log.Print("Receive command '")
cmd, err := rw.ReadString('\n')
switch {
case err == io.EOF:
log.Println("Reached EOF - close this connection.\n ---")
return
case err != nil:
log.Println("\nError reading command. Got: '" + cmd + "'\n", err)
}
// 修剪请求字符串中的多余回车和空格- ReadString不会去掉任何换行。
cmd = strings.Trim(cmd, "\n ")
log.Println(cmd + "'")
// 从handler映射中获取恰当的处理器函数, 并调用它。
e.m.Lock()
handleCommand, ok := e.handler[cmd]
e.m.Unlock()
if !ok {
log.Println("Command '" + cmd + "' is not registered.")
return
}
handleCommand(rw)
}
}
func handleStrings(rw *bufio.ReadWriter) {
log.Print("Receive STRING message:")
s, err := rw.ReadString('\n')
if err != nil {
log.Println("Cannot read from connection.\n", err)
}
s = strings.Trim(s, "\n ")
log.Println(s)
-, err = rw.WriteString("Thank you.\n")
if err != nil {
log.Println("Cannot write to connection.\n", err)
}
err = rw.Flush()
if err != nil {
log.Println("Flush failed.", err)
}
}
func handleGob(rw *bufio.ReadWriter) {
log.Print("Receive GOB data:")
var data complexData
dec := gob.NewDecoder(rw)
err := dec.Decode(&data)
if err != nil {
log.Println("Error decoding GOB data:", err)
return
}
log.Printf("Outer complexData struct: \n%#v\n", data)
log.Printf("Inner complexData struct: \n%#v\n", data.C)
}
// 当应用程序使用-connect=ip地址的时候被调用
func client(ip string) error {
testStruct := complexData{
N: 23,
S: "string data",
M: map[string]int{"one": 1, "two": 2, "three": 3},
P: []byte("abc"),
C: &complexData{
N: 256,
S: "Recursive structs? Piece of cake!",
M: Map[string]int{"01": "10": 2, "11": 3},
},
}
rw, err := Open(ip + Port)
if err != nil {
return errors.Wrap(err, "Client: Failed to open connection to " + ip + Port)
}
log.Println("Send the string request.")
n, err := rw.WriteString("STRING\n")
if err != nil {
return errors.Wrap(err, "Could not send the STRING request (" + strconv.Itoa(n) + " bytes written)")
}
// 发送STRING请求。发送请求名并发送数据。
log.Println("Send the string request.")
n, err = rw.WriteString("Additional data.\n")
if err != nil {
return errors.Wrap(err, "Could not send additional STRING data (" + strconv.Itoa(n) + " bytes written)")
}
log.Println("Flush the buffer.")
err = rw.Flush()
if err != nil {
return errors.Wrap(err, "Flush failed.")
}
// 读取响应
log.Println("Read the reply.")
response, err := rw.ReadString('\n')
if err != nil {
return errors.Wrap(err, "Client: Failed to read the reply: '" + response + "'")
}
log.Println("STRING request: got a response:", response)
// 发送GOB请求。 创建一个encoder直接将它转换为rw.Send的请求名。发送GOB
log.Println("Send a struct as GOB:")
log.Printf("Outer complexData struct: \n%#v\n", testStruct)
log.Printf("Inner complexData struct: \n%#v\n", testStruct.C)
enc := gob.NewDecoder(rw)
n, err = rw.WriteString("GOB\n")
if err != nil {
return errors.Wrap(err, "Could not write GOB data (" + strconv.Itoa(n) + " bytes written)")
}
err = enc.Encode(testStruct)
if err != nil {
return errors.Wrap(err, "Encode failed for struct: %#v", testStruct)
}
err = rw.Flush()
if err != nil {
return errors.Wrap(err, "Flush failed.")
}
return nil
}
func server() error {
endpoint := NewEndpoint()
// 添加处理器函数
endpoint.AddHandleFunc("STRING", handleStrings)
endpoint.AddHandleFunc("GOB", handleGOB)
// 开始监听
return endpoint.Listen()
}
func main() {
connect := flag.String("connect", "", "IP address of process to join. If empty, go into the listen mode.")
flag.Parse()
// 如果设置了connect标志，进入客户端模式
if *connect != '' {
err := client(*connect)
if err != nil {
log.Println("Error:", errors.WithStack(err))
}
log.Println("Client done.")
return
}
// 否则进入服务端模式
err := server()
if err != nil {
log.Println("Error:", errors.WithStack(err))
}
log.Println("Server done.")
}
// 设置日志记录的字段标志
func init() {
log.SetFlags(log.Lshortfile)
}
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