add I2PStreamSession to helper

helper/helper.go

@@ -59,3 +59,39 @@ func I2PListener(name, samaddr, keyspath string) (*sam3.StreamListener, error) {
 	}
 	return listener, err
 }
+
+// I2PStreamSession is a convenience function which returns a sam3.StreamSession instead
+// of a sam3.StreamListener. It also takes care of setting a persisitent key on behalf
+// of the user.
+func I2PStreamSession(name, samaddr, keyspath string) (*sam3.StreamSession, error) {
+	log.Printf("Starting and registering I2P service, please wait a couple of minutes...")
+	sam, err := sam3.NewSAM(samaddr)
+	if err != nil {
+		log.Fatalf("error connecting to SAM to %s: %s", samaddr, err)
+	}
+	var keys *i2pkeys.I2PKeys
+	if _, err := os.Stat(keyspath + ".i2p.private"); os.IsNotExist(err) {
+		f, err := os.Create(keyspath + ".i2p.private")
+		if err != nil {
+			log.Fatalf("unable to open I2P keyfile for writing: %s", err)
+		}
+		defer f.Close()
+		tkeys, err := sam.NewKeys()
+		if err != nil {
+			log.Fatalf("unable to generate I2P Keys, %s", err)
+		}
+		keys = &tkeys
+		err = i2pkeys.StoreKeysIncompat(*keys, f)
+		if err != nil {
+			log.Fatalf("unable to save newly generated I2P Keys, %s", err)
+		}
+	} else {
+		tkeys, err := i2pkeys.LoadKeys(keyspath + ".i2p.private")
+		if err != nil {
+			log.Fatalf("unable to load I2P Keys: %e", err)
+		}
+		keys = &tkeys
+	}
+	stream, err := sam.NewStreamSession(name, *keys, sam3.Options_Medium)
+	return stream, error
+}