github.com/miekg/dns v1.1.63: NewZoneParser, ZoneParser.Err, ZoneParser.Next

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify dns.ZoneParser in pkg:golang/github.com/miekg/dns@v1.1.63
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/miekg/dns@v1.1.63
Demonstrate these symbols/APIs:
  - dns.NewZoneParser
  - dns.ZoneParser.Err
  - dns.ZoneParser.Next

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:598694f87560a15bf3dffcd8cd3025823084d0ebb79a72385dd09de683143ab9","contract":["dns.NewZoneParser initializes a zone file parser with specified reader, origin, and filename","dns.ZoneParser.Next iterates and returns parsed resource records including SOA, NS, A, AAAA, MX, CNAME, and TXT","dns.ZoneParser.Next applies master file directives such as $ORIGIN and $TTL during parsing","dns.ZoneParser.Err reports syntax errors when invalid or malformed zone data is encountered"],"goal":"verify dns.ZoneParser in pkg:golang/github.com/miekg/dns@v1.1.63","kind":"HOW","packages":["pkg:golang/github.com/miekg/dns@v1.1.63"],"schemaVersion":1,"symbols":["dns.NewZoneParser","dns.ZoneParser.Err","dns.ZoneParser.Next"]},"contractCommand":["go","test","-v","./..."],"environment":{"arch":"amd64","compiler":"go","compilerVersion":"1.26.6","distro":"ubuntu","ecosystem":"golang","language":"go","languageVersion":"1.26.6","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/miekg/dns@v1.1.63"],"schemaVersion":1,"subject":"pkg:golang/github.com/miekg/dns@v1.1.63","symbols":["dns.NewZoneParser","dns.ZoneParser.Err","dns.ZoneParser.Next"],"verifierAdapter":"golang@1"}

module example.com/zoneparser

go 1.26.6

require github.com/miekg/dns v1.1.63

require (
	golang.org/x/mod v0.18.0 // indirect
	golang.org/x/net v0.31.0 // indirect
	golang.org/x/sync v0.7.0 // indirect
	golang.org/x/sys v0.27.0 // indirect
	golang.org/x/tools v0.22.0 // indirect
)

github.com/miekg/dns v1.1.63 h1:8M5aAw6OMZfFXTT7K5V0Eu5YiiL8l7nUAkyN6C9YwaY=
github.com/miekg/dns v1.1.63/go.mod h1:6NGHfjhpmr5lt3XPLuyfDJi5AXbNIPM9PY6H6sF1Nfs=
golang.org/x/mod v0.18.0 h1:5+9lSbEzPSdWkH32vYPBwEpX8KwDbM52Ud9xBUvNlb0=
golang.org/x/mod v0.18.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
golang.org/x/net v0.31.0 h1:68CPQngjLL0r2AlUKiSxtQFKvzRVbnzLwMUn5SzcLHo=
golang.org/x/net v0.31.0/go.mod h1:P4fl1q7dY2hnZFxEk4pPSkDHF+QqjitcnDjUQyMM+pM=
golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
golang.org/x/sys v0.27.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
golang.org/x/tools v0.22.0 h1:gqSGLZqv+AI9lIQzniJ0nZDRG5GBPsSi+DRNHWNz6yA=
golang.org/x/tools v0.22.0/go.mod h1:aCwcsjqvq7Yqt6TNyX7QMU2enbQ/Gt0bo6krSeEri+c=

{
  "schemaVersion": 1,
  "goal": "verify dns.ZoneParser in pkg:golang/github.com/miekg/dns@v1.1.63",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/miekg/dns@v1.1.63"
  ],
  "symbols": [
    "dns.NewZoneParser",
    "dns.ZoneParser.Err",
    "dns.ZoneParser.Next"
  ]
}

package test

import (
	"strings"
	"testing"

	"example.com/zoneparser"
	"github.com/miekg/dns"
)

func TestZoneParserBasicAndRecordTypes(t *testing.T) {
	zoneData := `$ORIGIN example.com.
$TTL 3600
@   IN  SOA ns1.example.com. admin.example.com. (
            2026082701 ; serial
            7200       ; refresh
            3600       ; retry
            1209600    ; expire
            3600       ; minimum
        )
@   IN  NS  ns1.example.com.
@   IN  NS  ns2.example.com.
@   IN  A   93.184.216.34
@   IN  AAAA 2606:2800:220:1:248:1893:25c8:1946
@   IN  MX  10 mail.example.com.
www IN  CNAME example.com.
txt IN  TXT "v=spf1 include:_spf.example.com ~all"
`

	records, err := zoneparser.ParseZoneString(zoneData, "example.com.", 3600)
	if err != nil {
		t.Fatalf("ParseZoneString failed: %v", err)
	}

	if len(records) != 8 {
		t.Fatalf("expected 8 resource records, got %d", len(records))
	}

	// Verify SOA record
	soa, ok := records[0].(*dns.SOA)
	if !ok {
		t.Fatalf("expected record 0 to be *dns.SOA, got %T", records[0])
	}
	if soa.Hdr.Name != "example.com." {
		t.Errorf("expected SOA name 'example.com.', got '%s'", soa.Hdr.Name)
	}
	if soa.Ns != "ns1.example.com." {
		t.Errorf("expected SOA Ns 'ns1.example.com.', got '%s'", soa.Ns)
	}
	if soa.Mbox != "admin.example.com." {
		t.Errorf("expected SOA Mbox 'admin.example.com.', got '%s'", soa.Mbox)
	}
	if soa.Serial != 2026082701 {
		t.Errorf("expected SOA Serial 2026082701, got %d", soa.Serial)
	}

	// Verify NS records
	ns1, ok := records[1].(*dns.NS)
	if !ok || ns1.Ns != "ns1.example.com." {
		t.Errorf("unexpected NS record 1: %v", records[1])
	}

	// Verify A record
	aRec, ok := records[3].(*dns.A)
	if !ok {
		t.Fatalf("expected record 3 to be *dns.A, got %T", records[3])
	}
	if aRec.A.String() != "93.184.216.34" {
		t.Errorf("expected A IP '93.184.216.34', got '%s'", aRec.A.String())
	}

	// Verify AAAA record
	aaaaRec, ok := records[4].(*dns.AAAA)
	if !ok {
		t.Fatalf("expected record 4 to be *dns.AAAA, got %T", records[4])
	}
	if aaaaRec.AAAA.String() != "2606:2800:220:1:248:1893:25c8:1946" {
		t.Errorf("expected AAAA IP '2606:2800:220:1:248:1893:25c8:1946', got '%s'", aaaaRec.AAAA.String())
	}

	// Verify MX record
	mxRec, ok := records[5].(*dns.MX)
	if !ok {
		t.Fatalf("expected record 5 to be *dns.MX, got %T", records[5])
	}
	if mxRec.Preference != 10 || mxRec.Mx != "mail.example.com." {
		t.Errorf("expected MX 10 mail.example.com., got %d %s", mxRec.Preference, mxRec.Mx)
	}

	// Verify CNAME record
	cnameRec, ok := records[6].(*dns.CNAME)
	if !ok {
		t.Fatalf("expected record 6 to be *dns.CNAME, got %T", records[6])
	}
	if cnameRec.Hdr.Name != "www.example.com." || cnameRec.Target != "example.com." {
		t.Errorf("expected CNAME www.example.com. -> example.com., got %s -> %s", cnameRec.Hdr.Name, cnameRec.Target)
	}

	// Verify TXT record
	txtRec, ok := records[7].(*dns.TXT)
	if !ok {
		t.Fatalf("expected record 7 to be *dns.TXT, got %T", records[7])
	}
	if len(txtRec.Txt) != 1 || txtRec.Txt[0] != "v=spf1 include:_spf.example.com ~all" {
		t.Errorf("unexpected TXT payload: %v", txtRec.Txt)
	}
}

func TestZoneParserDirectivesAndDefaultTTL(t *testing.T) {
	zoneData := `
$TTL 1800
host1   IN  A   192.0.2.1
$ORIGIN sub.example.com.
host2   IN  A   192.0.2.2
`
	reader := strings.NewReader(zoneData)
	records, err := zoneparser.ParseZoneReader(reader, "example.com.", "test.zone")
	if err != nil {
		t.Fatalf("ParseZoneReader failed: %v", err)
	}

	if len(records) != 2 {
		t.Fatalf("expected 2 records, got %d", len(records))
	}

	if records[0].Header().Name != "host1.example.com." {
		t.Errorf("expected host1.example.com., got '%s'", records[0].Header().Name)
	}
	if records[0].Header().Ttl != 1800 {
		t.Errorf("expected TTL 1800, got %d", records[0].Header().Ttl)
	}

	if records[1].Header().Name != "host2.sub.example.com." {
		t.Errorf("expected host2.sub.example.com., got '%s'", records[1].Header().Name)
	}
}

func TestZoneParserErrorHandling(t *testing.T) {
	// Malformed zone data: invalid IP in A record
	invalidZoneData := `example.com. 3600 IN A not-a-valid-ip`
	_, err := zoneparser.ParseZoneString(invalidZoneData, "example.com.", 3600)
	if err == nil {
		t.Fatalf("expected error parsing invalid A record IP, got nil")
	}

	// Verify zp.Err directly
	reader := strings.NewReader("example.com. 3600 IN INVALIDTYPE foo")
	zp := dns.NewZoneParser(reader, "example.com.", "")
	for _, ok := zp.Next(); ok; _, ok = zp.Next() {
	}
	if zp.Err() == nil {
		t.Fatalf("expected zp.Err() to return non-nil error on invalid RR type")
	}
}

package zoneparser

import (
	"fmt"
	"io"
	"strings"

	"github.com/miekg/dns"
)

// ParseZoneString parses a DNS zone from a string with the given origin and default TTL.
func ParseZoneString(zoneData string, origin string, defaultTTL uint32) ([]dns.RR, error) {
	reader := strings.NewReader(zoneData)
	zp := dns.NewZoneParser(reader, origin, "")
	if defaultTTL > 0 {
		zp.SetDefaultTTL(defaultTTL)
	}

	var records []dns.RR
	for rr, ok := zp.Next(); ok; rr, ok = zp.Next() {
		records = append(records, rr)
	}

	if err := zp.Err(); err != nil {
		return nil, fmt.Errorf("zone parsing failed: %w", err)
	}

	return records, nil
}

// ParseZoneReader parses DNS resource records from an io.Reader stream.
func ParseZoneReader(r io.Reader, origin string, file string) ([]dns.RR, error) {
	zp := dns.NewZoneParser(r, origin, file)

	var records []dns.RR
	for rr, ok := zp.Next(); ok; rr, ok = zp.Next() {
		records = append(records, rr)
	}

	if err := zp.Err(); err != nil {
		return nil, fmt.Errorf("zone parsing failed: %w", err)
	}

	return records, nil
}