only resolve dnslinks once in the gateway

If the domain has a DNS-Link, we want to use it even if it points to, e.g., an
IPNS address that doesn't resolve.

fixes #4973

License: MIT
Signed-off-by: Steven Allen <steven@stebalien.com>

core/corehttp/ipns_hostname.go

@@ -6,7 +6,8 @@ import (
 	"net/http"
 	"strings"
 
-	"github.com/ipfs/go-ipfs/core"
+	core "github.com/ipfs/go-ipfs/core"
+	nsopts "github.com/ipfs/go-ipfs/namesys/opts"
 
 	isd "gx/ipfs/QmZmmuAXgX73UQmX1jRKjTGmjzq24Jinqkq8vzkBtno4uX/go-is-domain"
 )
@@ -24,7 +25,7 @@ func IPNSHostnameOption() ServeOption {
 			host := strings.SplitN(r.Host, ":", 2)[0]
 			if len(host) > 0 && isd.IsDomain(host) {
 				name := "/ipns/" + host
-				if _, err := n.Namesys.Resolve(ctx, name); err == nil {
+				if _, err := n.Namesys.Resolve(ctx, name, nsopts.Depth(1)); err == nil {
 					r.Header["X-Ipns-Original-Path"] = []string{r.URL.Path}
 					r.URL.Path = name + r.URL.Path
 				}