cache public keys and use better method for fetching

dht/records.go

@@ -18,7 +18,7 @@ func KeyForPublicKey(id peer.ID) u.Key {
 	return u.Key("/pk/" + string(id))
 }
 
-func (dht *IpfsDHT) getPublicKeyOnline(ctx context.Context, p peer.ID) (ci.PubKey, error) {
+func (dht *IpfsDHT) GetPublicKey(ctx context.Context, p peer.ID) (ci.PubKey, error) {
 	log.Debugf("getPublicKey for: %s", p)
 
 	// check locally.
@@ -42,7 +42,6 @@ func (dht *IpfsDHT) getPublicKeyOnline(ctx context.Context, p peer.ID) (ci.PubKe
 	log.Debugf("pk for %s not in peerstore, and peer failed. trying dht.", p)
 	pkkey := KeyForPublicKey(p)
 
-	// ok, now try the dht. Anyone who has previously fetched the key should have it
 	val, err := dht.GetValue(ctxT, pkkey)
 	if err != nil {
 		log.Warning("Failed to find requested public key.")
@@ -132,7 +131,7 @@ func (dht *IpfsDHT) verifyRecordOnline(ctx context.Context, r *pb.Record) error
 	if len(r.Signature) > 0 {
 		// get the public key, search for it if necessary.
 		p := peer.ID(r.GetAuthor())
-		pk, err := dht.getPublicKeyOnline(ctx, p)
+		pk, err := dht.GetPublicKey(ctx, p)
 		if err != nil {
 			return err
 		}

routing.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	context "github.com/ipfs/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
+	ci "github.com/ipfs/go-ipfs/p2p/crypto"
 	peer "github.com/ipfs/go-ipfs/p2p/peer"
 	u "github.com/ipfs/go-ipfs/util"
 )
@@ -46,3 +47,7 @@ type IpfsRouting interface {
 
 	// TODO expose io.Closer or plain-old Close error
 }
+
+type PubKeyFetcher interface {
+	GetPublicKey(context.Context, peer.ID) (ci.PubKey, error)
+}