From 409b61fe3c8046dc26f3442846e9f7032bebb9c5 Mon Sep 17 00:00:00 2001
From: holisticode <holistic.computing@gmail.com>
Date: Thu, 13 Apr 2017 04:06:19 -0500
Subject: [PATCH] swarm/api: better name resolver handling  (#3754)

Fixes #3608
---
 cmd/swarm/main.go             |  2 ++
 swarm/api/api.go              | 28 +++++++++++++++-------------
 swarm/api/http/server_test.go | 28 ++++++++++++++++++++++++++++
 swarm/swarm.go                | 11 ++++++++---
 4 files changed, 53 insertions(+), 16 deletions(-)

diff --git a/cmd/swarm/main.go b/cmd/swarm/main.go
index 833083b91..26aa3e50f 100644
--- a/cmd/swarm/main.go
+++ b/cmd/swarm/main.go
@@ -358,6 +358,8 @@ func registerBzzService(ctx *cli.Context, stack *node.Node) {
 			if err != nil {
 				utils.Fatalf("Can't connect: %v", err)
 			}
+		} else {
+			swapEnabled = false
 		}
 		return swarm.NewSwarm(ctx, client, bzzconfig, swapEnabled, syncEnabled, cors)
 	}
diff --git a/swarm/api/api.go b/swarm/api/api.go
index f58b7a53d..26a9445d5 100644
--- a/swarm/api/api.go
+++ b/swarm/api/api.go
@@ -17,7 +17,6 @@
 package api
 
 import (
-	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -84,25 +83,28 @@ type ErrResolve error
 // DNS Resolver
 func (self *Api) Resolve(uri *URI) (storage.Key, error) {
 	log.Trace(fmt.Sprintf("Resolving : %v", uri.Addr))
+
+	var err error
+	if !uri.Immutable() {
+		if self.dns != nil {
+			resolved, err := self.dns.Resolve(uri.Addr)
+			if err == nil {
+				return resolved[:], nil
+			}
+		} else {
+			err = fmt.Errorf("no DNS to resolve name")
+		}
+	}
 	if hashMatcher.MatchString(uri.Addr) {
-		log.Trace(fmt.Sprintf("addr is a hash: %q", uri.Addr))
 		return storage.Key(common.Hex2Bytes(uri.Addr)), nil
 	}
-	if uri.Immutable() {
-		return nil, errors.New("refusing to resolve immutable address")
-	}
-	if self.dns == nil {
-		return nil, fmt.Errorf("unable to resolve addr %q, resolver not configured", uri.Addr)
-	}
-	hash, err := self.dns.Resolve(uri.Addr)
 	if err != nil {
-		log.Warn(fmt.Sprintf("DNS error resolving addr %q: %s", uri.Addr, err))
-		return nil, ErrResolve(err)
+		return nil, fmt.Errorf("'%s' does not resolve: %v but is not a content hash", uri.Addr, err)
 	}
-	log.Trace(fmt.Sprintf("addr lookup: %v -> %v", uri.Addr, hash))
-	return hash[:], nil
+	return nil, fmt.Errorf("'%s' is not a content hash", uri.Addr)
 }
 
+
 // Put provides singleton manifest creation on top of dpa store
 func (self *Api) Put(content, contentType string) (storage.Key, error) {
 	r := strings.NewReader(content)
diff --git a/swarm/api/http/server_test.go b/swarm/api/http/server_test.go
index 942f3ba0b..ceb8db75b 100644
--- a/swarm/api/http/server_test.go
+++ b/swarm/api/http/server_test.go
@@ -99,4 +99,32 @@ func TestBzzrGetPath(t *testing.T) {
 		}
 	}
 
+	nonhashtests := []string{
+		srv.URL + "/bzz:/name",
+		srv.URL + "/bzzi:/nonhash",
+		srv.URL + "/bzzr:/nonhash",
+	}
+
+	nonhashresponses := []string{
+		"error resolving name: 'name' does not resolve: no DNS to resolve name but is not a content hash\n",
+		"error resolving nonhash: 'nonhash' is not a content hash\n",
+		"error resolving nonhash: 'nonhash' does not resolve: no DNS to resolve name but is not a content hash\n",
+	}
+
+	for i, url := range nonhashtests {
+		var resp *http.Response
+		var respbody []byte
+
+		resp, err = http.Get(url)
+
+		if err != nil {
+			t.Fatalf("Request failed: %v", err)
+		}
+		defer resp.Body.Close()
+		respbody, err = ioutil.ReadAll(resp.Body)
+		if string(respbody) != nonhashresponses[i] {
+			t.Fatalf("Non-Hash response body does not match, expected: %v, got: %v", nonhashresponses[i], string(respbody))
+		}
+	}
+
 }
diff --git a/swarm/swarm.go b/swarm/swarm.go
index eedac93f3..442e68d51 100644
--- a/swarm/swarm.go
+++ b/swarm/swarm.go
@@ -27,6 +27,7 @@ import (
 	"github.com/ethereum/go-ethereum/contracts/chequebook"
 	"github.com/ethereum/go-ethereum/contracts/ens"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/node"
 	"github.com/ethereum/go-ethereum/p2p"
@@ -134,9 +135,13 @@ func NewSwarm(ctx *node.ServiceContext, backend chequebook.Backend, config *api.
 	// set up high level api
 	transactOpts := bind.NewKeyedTransactor(self.privateKey)
 
-	self.dns, err = ens.NewENS(transactOpts, config.EnsRoot, self.backend)
-	if err != nil {
-		return nil, err
+	if backend == (*ethclient.Client)(nil) {
+		log.Warn("No ENS, please specify non-empty --ethapi to use domain name resolution")
+	} else {
+		self.dns, err = ens.NewENS(transactOpts, config.EnsRoot, self.backend)
+		if err != nil {
+			return nil, err
+		}
 	}
 	log.Debug(fmt.Sprintf("-> Swarm Domain Name Registrar @ address %v", config.EnsRoot.Hex()))