contracts/ens: expose Add and SetAddr in ENS (#17661)

I am planning to use this to resolve names to user addresses for Swarm/MRU feeds.

contracts/ens/ens.go

@@ -151,6 +151,38 @@ func (self *ENS) Resolve(name string) (common.Hash, error) {
 	return common.BytesToHash(ret[:]), nil
 }
 
+// Addr is a non-transactional call that returns the address associated with a name.
+func (self *ENS) Addr(name string) (common.Address, error) {
+	node := EnsNode(name)
+
+	resolver, err := self.getResolver(node)
+	if err != nil {
+		return common.Address{}, err
+	}
+
+	ret, err := resolver.Addr(node)
+	if err != nil {
+		return common.Address{}, err
+	}
+
+	return common.BytesToAddress(ret[:]), nil
+}
+
+// SetAddress sets the address associated with a name. Only works if the caller
+// owns the name, and the associated resolver implements a `setAddress` function.
+func (self *ENS) SetAddr(name string, addr common.Address) (*types.Transaction, error) {
+	node := EnsNode(name)
+
+	resolver, err := self.getResolver(node)
+	if err != nil {
+		return nil, err
+	}
+
+	opts := self.TransactOpts
+	opts.GasLimit = 200000
+	return resolver.Contract.SetAddr(&opts, node, addr)
+}
+
 // Register registers a new domain name for the caller, making them the owner of the new name.
 // Only works if the registrar for the parent domain implements the FIFS registrar protocol.
 func (self *ENS) Register(name string) (*types.Transaction, error) {

contracts/ens/ens_test.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/contracts/ens/contract"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/crypto"
@@ -32,6 +33,7 @@ var (
 	name     = "my name on ENS"
 	hash     = crypto.Keccak256Hash([]byte("my content"))
 	addr     = crypto.PubkeyToAddress(key.PublicKey)
+	testAddr = common.HexToAddress("0x1234123412341234123412341234123412341234")
 )
 
 func TestENS(t *testing.T) {
@@ -74,4 +76,19 @@ func TestENS(t *testing.T) {
 	if vhost != hash {
 		t.Fatalf("resolve error, expected %v, got %v", hash.Hex(), vhost.Hex())
 	}
+
+	// set the address for the name
+	if _, err = ens.SetAddr(name, testAddr); err != nil {
+		t.Fatalf("can't set address: %v", err)
+	}
+	contractBackend.Commit()
+
+	// Try to resolve the name to an address
+	recoveredAddr, err := ens.Addr(name)
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+	if vhost != hash {
+		t.Fatalf("resolve error, expected %v, got %v", testAddr.Hex(), recoveredAddr.Hex())
+	}
 }