Preview: example_test.go
Size: 8.45 KB
/proc/thread-self/root/opt/golang/1.22.0/src/net/example_test.go
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package net_test
import (
"context"
"fmt"
"io"
"log"
"net"
"time"
)
func ExampleListener() {
// Listen on TCP port 2000 on all available unicast and
// anycast IP addresses of the local system.
l, err := net.Listen("tcp", ":2000")
if err != nil {
log.Fatal(err)
}
defer l.Close()
for {
// Wait for a connection.
conn, err := l.Accept()
if err != nil {
log.Fatal(err)
}
// Handle the connection in a new goroutine.
// The loop then returns to accepting, so that
// multiple connections may be served concurrently.
go func(c net.Conn) {
// Echo all incoming data.
io.Copy(c, c)
// Shut down the connection.
c.Close()
}(conn)
}
}
func ExampleDialer() {
var d net.Dialer
ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
defer cancel()
conn, err := d.DialContext(ctx, "tcp", "localhost:12345")
if err != nil {
log.Fatalf("Failed to dial: %v", err)
}
defer conn.Close()
if _, err := conn.Write([]byte("Hello, World!")); err != nil {
log.Fatal(err)
}
}
func ExampleDialer_unix() {
// DialUnix does not take a context.Context parameter. This example shows
// how to dial a Unix socket with a Context. Note that the Context only
// applies to the dial operation; it does not apply to the connection once
// it has been established.
var d net.Dialer
ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
defer cancel()
d.LocalAddr = nil // if you have a local addr, add it here
raddr := net.UnixAddr{Name: "/path/to/unix.sock", Net: "unix"}
conn, err := d.DialContext(ctx, "unix", raddr.String())
if err != nil {
log.Fatalf("Failed to dial: %v", err)
}
defer conn.Close()
if _, err := conn.Write([]byte("Hello, socket!")); err != nil {
log.Fatal(err)
}
}
func ExampleIPv4() {
fmt.Println(net.IPv4(8, 8, 8, 8))
// Output:
// 8.8.8.8
}
func ExampleParseCIDR() {
ipv4Addr, ipv4Net, err := net.ParseCIDR("192.0.2.1/24")
if err != nil {
log.Fatal(err)
}
fmt.Println(ipv4Addr)
fmt.Println(ipv4Net)
ipv6Addr, ipv6Net, err := net.ParseCIDR("2001:db8:a0b:12f0::1/32")
if err != nil {
log.Fatal(err)
}
fmt.Println(ipv6Addr)
fmt.Println(ipv6Net)
// Output:
// 192.0.2.1
// 192.0.2.0/24
// 2001:db8:a0b:12f0::1
// 2001:db8::/32
}
func ExampleParseIP() {
fmt.Println(net.ParseIP("192.0.2.1"))
fmt.Println(net.ParseIP("2001:db8::68"))
fmt.Println(net.ParseIP("192.0.2"))
// Output:
// 192.0.2.1
// 2001:db8::68
// <nil>
}
func ExampleIP_DefaultMask() {
ip := net.ParseIP("192.0.2.1")
fmt.Println(ip.DefaultMask())
// Output:
// ffffff00
}
func ExampleIP_Equal() {
ipv4DNS := net.ParseIP("8.8.8.8")
ipv4Lo := net.ParseIP("127.0.0.1")
ipv6DNS := net.ParseIP("0:0:0:0:0:FFFF:0808:0808")
fmt.Println(ipv4DNS.Equal(ipv4DNS))
fmt.Println(ipv4DNS.Equal(ipv4Lo))
fmt.Println(ipv4DNS.Equal(ipv6DNS))
// Output:
// true
// false
// true
}
func ExampleIP_IsGlobalUnicast() {
ipv6Global := net.ParseIP("2000::")
ipv6UniqLocal := net.ParseIP("2000::")
ipv6Multi := net.ParseIP("FF00::")
ipv4Private := net.ParseIP("10.255.0.0")
ipv4Public := net.ParseIP("8.8.8.8")
ipv4Broadcast := net.ParseIP("255.255.255.255")
fmt.Println(ipv6Global.IsGlobalUnicast())
fmt.Println(ipv6UniqLocal.IsGlobalUnicast())
fmt.Println(ipv6Multi.IsGlobalUnicast())
fmt.Println(ipv4Private.IsGlobalUnicast())
fmt.Println(ipv4Public.IsGlobalUnicast())
fmt.Println(ipv4Broadcast.IsGlobalUnicast())
// Output:
// true
// true
// false
// true
// true
// false
}
func ExampleIP_IsInterfaceLocalMulticast() {
ipv6InterfaceLocalMulti := net.ParseIP("ff01::1")
ipv6Global := net.ParseIP("2000::")
ipv4 := net.ParseIP("255.0.0.0")
fmt.Println(ipv6InterfaceLocalMulti.IsInterfaceLocalMulticast())
fmt.Println(ipv6Global.IsInterfaceLocalMulticast())
fmt.Println(ipv4.IsInterfaceLocalMulticast())
// Output:
// true
// false
// false
}
func ExampleIP_IsLinkLocalMulticast() {
ipv6LinkLocalMulti := net.ParseIP("ff02::2")
ipv6LinkLocalUni := net.ParseIP("fe80::")
ipv4LinkLocalMulti := net.ParseIP("224.0.0.0")
ipv4LinkLocalUni := net.ParseIP("169.254.0.0")
fmt.Println(ipv6LinkLocalMulti.IsLinkLocalMulticast())
fmt.Println(ipv6LinkLocalUni.IsLinkLocalMulticast())
fmt.Println(ipv4LinkLocalMulti.IsLinkLocalMulticast())
fmt.Println(ipv4LinkLocalUni.IsLinkLocalMulticast())
// Output:
// true
// false
// true
// false
}
func ExampleIP_IsLinkLocalUnicast() {
ipv6LinkLocalUni := net.ParseIP("fe80::")
ipv6Global := net.ParseIP("2000::")
ipv4LinkLocalUni := net.ParseIP("169.254.0.0")
ipv4LinkLocalMulti := net.ParseIP("224.0.0.0")
fmt.Println(ipv6LinkLocalUni.IsLinkLocalUnicast())
fmt.Println(ipv6Global.IsLinkLocalUnicast())
fmt.Println(ipv4LinkLocalUni.IsLinkLocalUnicast())
fmt.Println(ipv4LinkLocalMulti.IsLinkLocalUnicast())
// Output:
// true
// false
// true
// false
}
func ExampleIP_IsLoopback() {
ipv6Lo := net.ParseIP("::1")
ipv6 := net.ParseIP("ff02::1")
ipv4Lo := net.ParseIP("127.0.0.0")
ipv4 := net.ParseIP("128.0.0.0")
fmt.Println(ipv6Lo.IsLoopback())
fmt.Println(ipv6.IsLoopback())
fmt.Println(ipv4Lo.IsLoopback())
fmt.Println(ipv4.IsLoopback())
// Output:
// true
// false
// true
// false
}
func ExampleIP_IsMulticast() {
ipv6Multi := net.ParseIP("FF00::")
ipv6LinkLocalMulti := net.ParseIP("ff02::1")
ipv6Lo := net.ParseIP("::1")
ipv4Multi := net.ParseIP("239.0.0.0")
ipv4LinkLocalMulti := net.ParseIP("224.0.0.0")
ipv4Lo := net.ParseIP("127.0.0.0")
fmt.Println(ipv6Multi.IsMulticast())
fmt.Println(ipv6LinkLocalMulti.IsMulticast())
fmt.Println(ipv6Lo.IsMulticast())
fmt.Println(ipv4Multi.IsMulticast())
fmt.Println(ipv4LinkLocalMulti.IsMulticast())
fmt.Println(ipv4Lo.IsMulticast())
// Output:
// true
// true
// false
// true
// true
// false
}
func ExampleIP_IsPrivate() {
ipv6Private := net.ParseIP("fc00::")
ipv6Public := net.ParseIP("fe00::")
ipv4Private := net.ParseIP("10.255.0.0")
ipv4Public := net.ParseIP("11.0.0.0")
fmt.Println(ipv6Private.IsPrivate())
fmt.Println(ipv6Public.IsPrivate())
fmt.Println(ipv4Private.IsPrivate())
fmt.Println(ipv4Public.IsPrivate())
// Output:
// true
// false
// true
// false
}
func ExampleIP_IsUnspecified() {
ipv6Unspecified := net.ParseIP("::")
ipv6Specified := net.ParseIP("fe00::")
ipv4Unspecified := net.ParseIP("0.0.0.0")
ipv4Specified := net.ParseIP("8.8.8.8")
fmt.Println(ipv6Unspecified.IsUnspecified())
fmt.Println(ipv6Specified.IsUnspecified())
fmt.Println(ipv4Unspecified.IsUnspecified())
fmt.Println(ipv4Specified.IsUnspecified())
// Output:
// true
// false
// true
// false
}
func ExampleIP_Mask() {
ipv4Addr := net.ParseIP("192.0.2.1")
// This mask corresponds to a /24 subnet for IPv4.
ipv4Mask := net.CIDRMask(24, 32)
fmt.Println(ipv4Addr.Mask(ipv4Mask))
ipv6Addr := net.ParseIP("2001:db8:a0b:12f0::1")
// This mask corresponds to a /32 subnet for IPv6.
ipv6Mask := net.CIDRMask(32, 128)
fmt.Println(ipv6Addr.Mask(ipv6Mask))
// Output:
// 192.0.2.0
// 2001:db8::
}
func ExampleIP_String() {
ipv6 := net.IP{0xfc, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
ipv4 := net.IPv4(10, 255, 0, 0)
fmt.Println(ipv6.String())
fmt.Println(ipv4.String())
// Output:
// fc00::
// 10.255.0.0
}
func ExampleIP_To16() {
ipv6 := net.IP{0xfc, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
ipv4 := net.IPv4(10, 255, 0, 0)
fmt.Println(ipv6.To16())
fmt.Println(ipv4.To16())
// Output:
// fc00::
// 10.255.0.0
}
func ExampleIP_to4() {
ipv6 := net.IP{0xfc, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
ipv4 := net.IPv4(10, 255, 0, 0)
fmt.Println(ipv6.To4())
fmt.Println(ipv4.To4())
// Output:
// <nil>
// 10.255.0.0
}
func ExampleCIDRMask() {
// This mask corresponds to a /31 subnet for IPv4.
fmt.Println(net.CIDRMask(31, 32))
// This mask corresponds to a /64 subnet for IPv6.
fmt.Println(net.CIDRMask(64, 128))
// Output:
// fffffffe
// ffffffffffffffff0000000000000000
}
func ExampleIPv4Mask() {
fmt.Println(net.IPv4Mask(255, 255, 255, 0))
// Output:
// ffffff00
}
func ExampleUDPConn_WriteTo() {
// Unlike Dial, ListenPacket creates a connection without any
// association with peers.
conn, err := net.ListenPacket("udp", ":0")
if err != nil {
log.Fatal(err)
}
defer conn.Close()
dst, err := net.ResolveUDPAddr("udp", "192.0.2.1:2000")
if err != nil {
log.Fatal(err)
}
// The connection can write data to the desired address.
_, err = conn.WriteTo([]byte("data"), dst)
if err != nil {
log.Fatal(err)
}
}
Directory Contents
Dirs: 9 × Files: 214