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Diffstat (limited to '')
-rw-r--r-- | src/net/example_test.go | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/src/net/example_test.go b/src/net/example_test.go new file mode 100644 index 0000000..72c7183 --- /dev/null +++ b/src/net/example_test.go @@ -0,0 +1,181 @@ +// 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_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 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) + } +} |