Add example server that passes the test fixtures

Signed-off-by: Jake Sanders <i@am.so-aweso.me>

example/dns.go

@@ -1 +1,59 @@
 package example
+
+import (
+	"fmt"
+	"github.com/miekg/dns"
+)
+
+func (e *exampleSolver) handleDNSRequest(w dns.ResponseWriter, req *dns.Msg) {
+	msg := new(dns.Msg)
+	msg.SetReply(req)
+	switch req.Opcode {
+	case dns.OpcodeQuery:
+		for _, q := range msg.Question {
+			switch q.Qtype {
+			case dns.TypeA:
+				rr, err := dns.NewRR(fmt.Sprintf("%s 5 IN A 127.0.0.1", q.Name))
+				if err != nil {
+					msg.SetRcode(req, dns.RcodeNameError)
+				} else {
+					msg.Answer = append(msg.Answer, rr)
+				}
+			case dns.TypeTXT:
+				// get record
+				e.RLock()
+				record, found := e.txtRecords[q.Name]
+				e.RUnlock()
+				if !found {
+					msg.SetRcode(req, dns.RcodeNameError)
+				} else {
+					rr, err := dns.NewRR(fmt.Sprintf("%s 5 IN TXT %s", q.Name, record))
+					if err != nil {
+						msg.SetRcode(req, dns.RcodeServerFailure)
+						break
+					}
+					msg.Answer = append(msg.Answer, rr)
+				}
+			case dns.TypeNS:
+				rr, err := dns.NewRR(fmt.Sprintf("%s 5 IN NS ns.example-acme-webook.invalid.", q.Name))
+				if err != nil {
+					msg.SetRcode(req, dns.RcodeServerFailure)
+					break
+				} else {
+					msg.Answer = append(msg.Answer, rr)
+				}
+			case dns.TypeSOA:
+				rr, err := dns.NewRR(fmt.Sprintf("%s 5 IN SOA %s 20 5 5 5 5", "ns.example-acme-webook.invalid.", "ns.example-acme-webook.invalid."))
+				if err != nil {
+					msg.SetRcode(req, dns.RcodeServerFailure)
+					break
+				}
+				msg.Answer = append(msg.Answer, rr)
+			default:
+				msg.SetRcode(req, dns.RcodeServerFailure)
+				break
+			}
+		}
+	}
+	w.WriteMsg(msg)
+}