vendor files

vendor/golang.org/x/net/dns/dnsmessage/example_test.go

@@ -0,0 +1,132 @@
+// Copyright 2017 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 dnsmessage_test
+
+import (
+	"fmt"
+	"net"
+	"strings"
+
+	"golang.org/x/net/dns/dnsmessage"
+)
+
+func mustNewName(name string) dnsmessage.Name {
+	n, err := dnsmessage.NewName(name)
+	if err != nil {
+		panic(err)
+	}
+	return n
+}
+
+func ExampleParser() {
+	msg := dnsmessage.Message{
+		Header: dnsmessage.Header{Response: true, Authoritative: true},
+		Questions: []dnsmessage.Question{
+			{
+				Name:  mustNewName("foo.bar.example.com."),
+				Type:  dnsmessage.TypeA,
+				Class: dnsmessage.ClassINET,
+			},
+			{
+				Name:  mustNewName("bar.example.com."),
+				Type:  dnsmessage.TypeA,
+				Class: dnsmessage.ClassINET,
+			},
+		},
+		Answers: []dnsmessage.Resource{
+			{
+				dnsmessage.ResourceHeader{
+					Name:  mustNewName("foo.bar.example.com."),
+					Type:  dnsmessage.TypeA,
+					Class: dnsmessage.ClassINET,
+				},
+				&dnsmessage.AResource{[4]byte{127, 0, 0, 1}},
+			},
+			{
+				dnsmessage.ResourceHeader{
+					Name:  mustNewName("bar.example.com."),
+					Type:  dnsmessage.TypeA,
+					Class: dnsmessage.ClassINET,
+				},
+				&dnsmessage.AResource{[4]byte{127, 0, 0, 2}},
+			},
+		},
+	}
+
+	buf, err := msg.Pack()
+	if err != nil {
+		panic(err)
+	}
+
+	wantName := "bar.example.com."
+
+	var p dnsmessage.Parser
+	if _, err := p.Start(buf); err != nil {
+		panic(err)
+	}
+
+	for {
+		q, err := p.Question()
+		if err == dnsmessage.ErrSectionDone {
+			break
+		}
+		if err != nil {
+			panic(err)
+		}
+
+		if q.Name.String() != wantName {
+			continue
+		}
+
+		fmt.Println("Found question for name", wantName)
+		if err := p.SkipAllQuestions(); err != nil {
+			panic(err)
+		}
+		break
+	}
+
+	var gotIPs []net.IP
+	for {
+		h, err := p.AnswerHeader()
+		if err == dnsmessage.ErrSectionDone {
+			break
+		}
+		if err != nil {
+			panic(err)
+		}
+
+		if (h.Type != dnsmessage.TypeA && h.Type != dnsmessage.TypeAAAA) || h.Class != dnsmessage.ClassINET {
+			continue
+		}
+
+		if !strings.EqualFold(h.Name.String(), wantName) {
+			if err := p.SkipAnswer(); err != nil {
+				panic(err)
+			}
+			continue
+		}
+
+		switch h.Type {
+		case dnsmessage.TypeA:
+			r, err := p.AResource()
+			if err != nil {
+				panic(err)
+			}
+			gotIPs = append(gotIPs, r.A[:])
+		case dnsmessage.TypeAAAA:
+			r, err := p.AAAAResource()
+			if err != nil {
+				panic(err)
+			}
+			gotIPs = append(gotIPs, r.AAAA[:])
+		}
+	}
+
+	fmt.Printf("Found A/AAAA records for name %s: %v\n", wantName, gotIPs)
+
+	// Output:
+	// Found question for name bar.example.com.
+	// Found A/AAAA records for name bar.example.com.: [127.0.0.2]
+}