encode record-store keys in pubsub

Instead of using bare keys (binary), use `/record/base64url(key)`. This:

1. Pubsub keys must be UTF-8. Record-store keys definitely are not.
2. The prefix may help with validators in the future (namespace *everything*).

See: ipfs/interop#39

pubsub.go

@@ -3,6 +3,7 @@ package namesys
 import (
 	"bytes"
 	"context"
+	"encoding/base64"
 	"errors"
 	"sync"
 	"time"
@@ -48,6 +49,13 @@ type PubsubValueStore struct {
 	Validator record.Validator
 }
 
+// KeyToTopic converts a binary record key to a pubsub topic key.
+func KeyToTopic(key string) string {
+	// Record-store keys are arbitrary binary. However, pubsub requires UTF-8 string topic IDs.
+	// Encodes to "/record/base64url(key)"
+	return "/record/" + base64.RawURLEncoding.EncodeToString([]byte(key))
+}
+
 // NewPubsubPublisher constructs a new Publisher that publishes IPNS records through pubsub.
 // The constructor interface is complicated by the need to bootstrap the pubsub topic.
 // This could be greatly simplified if the pubsub implementation handled bootstrap itself
@@ -69,20 +77,24 @@ func NewPubsubValueStore(ctx context.Context, host p2phost.Host, cr routing.Cont
 
 // Publish publishes an IPNS record through pubsub with default TTL
 func (p *PubsubValueStore) PutValue(ctx context.Context, key string, value []byte, opts ...ropts.Option) error {
+	// Record-store keys are arbitrary binary. However, pubsub requires UTF-8 string topic IDs.
+	// Encode to "/record/base64url(key)"
+	topic := KeyToTopic(key)
+
 	p.mx.Lock()
 	_, bootstraped := p.subs[key]
 
 	if !bootstraped {
 		p.subs[key] = nil
 		p.mx.Unlock()
 
-		bootstrapPubsub(p.ctx, p.cr, p.host, key)
+		bootstrapPubsub(p.ctx, p.cr, p.host, topic)
 	} else {
 		p.mx.Unlock()
 	}
 
 	log.Debugf("PubsubPublish: publish value for key", key)
-	return p.ps.Publish(key, value)
+	return p.ps.Publish(topic, value)
 }
 
 func (p *PubsubValueStore) isBetter(key string, val []byte) bool {
@@ -115,15 +127,17 @@ func (p *PubsubValueStore) Subscribe(key string) error {
 		return nil
 	}
 
+	topic := KeyToTopic(key)
+
 	// Ignore the error. We have to check again anyways to make sure the
 	// record hasn't expired.
 	//
 	// Also, make sure to do this *before* subscribing.
-	p.ps.RegisterTopicValidator(key, func(ctx context.Context, msg *pubsub.Message) bool {
+	p.ps.RegisterTopicValidator(topic, func(ctx context.Context, msg *pubsub.Message) bool {
 		return p.isBetter(key, msg.GetData())
 	})
 
-	sub, err := p.ps.Subscribe(key)
+	sub, err := p.ps.Subscribe(topic)
 	if err != nil {
 		p.mx.Unlock()
 		return err
@@ -146,7 +160,7 @@ func (p *PubsubValueStore) Subscribe(key string) error {
 
 	if !bootstraped {
 		// TODO: Deal with publish then resolve case? Cancel behaviour changes.
-		go bootstrapPubsub(ctx, p.cr, p.host, key)
+		go bootstrapPubsub(ctx, p.cr, p.host, topic)
 	}
 	return nil
 }