Merge pull request #10 from ipfs/feat/custom-resolver

make DNS resolver pluggable

Author: Stebalien

README.md

@@ -10,9 +10,9 @@
 
 Package namesys defines `Resolver` and `Publisher` interfaces for IPNS paths, that is, paths in the form of `/ipns/<name_to_be_resolved>`. A "resolved" IPNS path becomes an `/ipfs/<cid>` path.
 
-Traditionally, these paths would be in the form of `/ipns/peer_id`, which references an IPNS record in a distributed `ValueStore` (usually the IPFS DHT).
+Traditionally, these paths would be in the form of `/ipns/{libp2p-key}`, which references an IPNS record in a distributed `ValueStore` (usually the IPFS DHT).
 
-Additionally, the /ipns/ namespace can also be used with domain names that use DNSLink (/ipns/my.domain.example, see https://dnslink.io) and proquint strings.
+Additionally, the `/ipns/` namespace can also be used with domain names that use DNSLink (`/ipns/en.wikipedia-on-ipfs.org`, see https://docs.ipfs.io/concepts/dnslink/).
 
 The package provides implementations for all three resolvers.
 

dns.go

@@ -10,14 +10,11 @@ import (
 
 	path "github.com/ipfs/go-path"
 	opts "github.com/ipfs/interface-go-ipfs-core/options/namesys"
-	isd "github.com/jbenet/go-is-domain"
+	dns "github.com/miekg/dns"
 )
 
-const ethTLD = "eth"
-const linkTLD = "domains"
-
-// LookupTXTFunc is a generic type for a function that lookups TXT record values.
-type LookupTXTFunc func(name string) (txt []string, err error)
+// LookupTXTFunc is a function that lookups TXT record values.
+type LookupTXTFunc func(ctx context.Context, name string) (txt []string, err error)
 
 // DNSResolver implements a Resolver on DNS domains
 type DNSResolver struct {
@@ -27,8 +24,8 @@ type DNSResolver struct {
 }
 
 // NewDNSResolver constructs a name resolver using DNS TXT records.
-func NewDNSResolver() *DNSResolver {
-	return &DNSResolver{lookupTXT: net.LookupTXT}
+func NewDNSResolver(lookup LookupTXTFunc) *DNSResolver {
+	return &DNSResolver{lookupTXT: lookup}
 }
 
 // Resolve implements Resolver.
@@ -55,7 +52,7 @@ func (r *DNSResolver) resolveOnceAsync(ctx context.Context, name string, options
 	segments := strings.SplitN(name, "/", 2)
 	domain := segments[0]
 
-	if !isd.IsDomain(domain) {
+	if _, ok := dns.IsDomainName(domain); !ok {
 		out <- onceResult{err: fmt.Errorf("not a valid domain name: %s", domain)}
 		close(out)
 		return out
@@ -68,17 +65,11 @@ func (r *DNSResolver) resolveOnceAsync(ctx context.Context, name string, options
 		fqdn = domain + "."
 	}
 
-	if strings.HasSuffix(fqdn, "."+ethTLD+".") {
-		// This is an ENS name.  As we're resolving via an arbitrary DNS server
-		// that may not know about .eth we need to add our link domain suffix.
-		fqdn += linkTLD + "."
-	}
-
 	rootChan := make(chan lookupRes, 1)
-	go workDomain(r, fqdn, rootChan)
+	go workDomain(ctx, r, fqdn, rootChan)
 
 	subChan := make(chan lookupRes, 1)
-	go workDomain(r, "_dnslink."+fqdn, subChan)
+	go workDomain(ctx, r, "_dnslink."+fqdn, subChan)
 
 	appendPath := func(p path.Path) (path.Path, error) {
 		if len(segments) > 1 {
@@ -139,10 +130,10 @@ func (r *DNSResolver) resolveOnceAsync(ctx context.Context, name string, options
 	return out
 }
 
-func workDomain(r *DNSResolver, name string, res chan lookupRes) {
+func workDomain(ctx context.Context, r *DNSResolver, name string, res chan lookupRes) {
 	defer close(res)
 
-	txt, err := r.lookupTXT(name)
+	txt, err := r.lookupTXT(ctx, name)
 	if err != nil {
 		if dnsErr, ok := err.(*net.DNSError); ok {
 			// If no TXT records found, return same error as when no text

dns_test.go

@@ -1,6 +1,7 @@
 package namesys
 
 import (
+	"context"
 	"fmt"
 	"testing"
 
@@ -11,7 +12,7 @@ type mockDNS struct {
 	entries map[string][]string
 }
 
-func (m *mockDNS) lookupTXT(name string) (txt []string, err error) {
+func (m *mockDNS) lookupTXT(ctx context.Context, name string) (txt []string, err error) {
 	txt, ok := m.entries[name]
 	if !ok {
 		return nil, fmt.Errorf("no TXT entry for %s", name)
@@ -126,7 +127,16 @@ func newMockDNS() *mockDNS {
 			"fqdn.example.com.": {
 				"dnslink=/ipfs/QmYvMB9yrsSf7RKBghkfwmHJkzJhW2ZgVwq3LxBXXPasFr",
 			},
-			"www.wealdtech.eth.domains.": {
+			"en.wikipedia-on-ipfs.org.": {
+				"dnslink=/ipfs/bafybeiaysi4s6lnjev27ln5icwm6tueaw2vdykrtjkwiphwekaywqhcjze",
+			},
+			"custom.non-icann.tldextravaganza.": {
+				"dnslink=/ipfs/bafybeieto6mcuvqlechv4iadoqvnffondeiwxc2bcfcewhvpsd2odvbmvm",
+			},
+			"singlednslabelshouldbeok.": {
+				"dnslink=/ipfs/bafybeih4a6ylafdki6ailjrdvmr7o4fbbeceeeuty4v3qyyouiz5koqlpi",
+			},
+			"www.wealdtech.eth.": {
 				"dnslink=/ipns/ipfs.example.com",
 			},
 		},
@@ -166,7 +176,10 @@ func TestDNSResolution(t *testing.T) {
 	testResolution(t, r, "double.example.com", opts.DefaultDepthLimit, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjD", nil)
 	testResolution(t, r, "conflict.example.com", opts.DefaultDepthLimit, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjE", nil)
 	testResolution(t, r, "fqdn.example.com.", opts.DefaultDepthLimit, "/ipfs/QmYvMB9yrsSf7RKBghkfwmHJkzJhW2ZgVwq3LxBXXPasFr", nil)
+	testResolution(t, r, "en.wikipedia-on-ipfs.org", 2, "/ipfs/bafybeiaysi4s6lnjev27ln5icwm6tueaw2vdykrtjkwiphwekaywqhcjze", nil)
+	testResolution(t, r, "custom.non-icann.tldextravaganza.", 2, "/ipfs/bafybeieto6mcuvqlechv4iadoqvnffondeiwxc2bcfcewhvpsd2odvbmvm", nil)
+	testResolution(t, r, "singlednslabelshouldbeok", 2, "/ipfs/bafybeih4a6ylafdki6ailjrdvmr7o4fbbeceeeuty4v3qyyouiz5koqlpi", nil)
 	testResolution(t, r, "www.wealdtech.eth", 1, "/ipns/ipfs.example.com", ErrResolveRecursion)
 	testResolution(t, r, "www.wealdtech.eth", 2, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjD", nil)
-	testResolution(t, r, "www.wealdtech.eth.domains", 2, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjD", nil)
+	testResolution(t, r, "www.wealdtech.eth", 2, "/ipfs/QmY3hE8xgFCjGcz6PHgnvJz5HZi1BaKRfPkn1ghZUcYMjD", nil)
 }

go.mod

@@ -1,7 +1,6 @@
 module github.com/ipfs/go-namesys
 
 require (
-	github.com/bren2010/proquint v0.0.0-20160323162903-38337c27106d
 	github.com/gogo/protobuf v1.3.2
 	github.com/hashicorp/golang-lru v0.5.4
 	github.com/ipfs/go-cid v0.0.7
@@ -13,15 +12,16 @@ require (
 	github.com/ipfs/go-log v1.0.4
 	github.com/ipfs/go-path v0.0.9
 	github.com/ipfs/interface-go-ipfs-core v0.4.0
-	github.com/jbenet/go-is-domain v1.0.5
 	github.com/jbenet/goprocess v0.1.4
 	github.com/libp2p/go-libp2p v0.13.0
 	github.com/libp2p/go-libp2p-core v0.8.0
 	github.com/libp2p/go-libp2p-kad-dht v0.11.1
 	github.com/libp2p/go-libp2p-peerstore v0.2.6
 	github.com/libp2p/go-libp2p-record v0.1.3
 	github.com/libp2p/go-libp2p-testing v0.4.0
+	github.com/miekg/dns v1.1.41
 	github.com/multiformats/go-multiaddr v0.3.1
+	github.com/multiformats/go-multiaddr-dns v0.3.1
 	github.com/multiformats/go-multihash v0.0.14
 	github.com/whyrusleeping/base32 v0.0.0-20170828182744-c30ac30633cc
 )