add standalone pss demo

cmd/swarmDemo/main.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+	  swarm "github.com/vocdoni/go-dvote/net/swarm" 
+	  "os"
+	  "fmt"
+	  "time"
+	  "github.com/ethereum/go-ethereum/log"
+)
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Println("Use <sym|asym> <key>")
+		return
+	}
+
+	sn := new(swarm.SimplePss)
+	err := sn.Init()
+	if err != nil {
+		fmt.Printf("%v\n", err)
+		return
+	}
+	err = sn.SetLog("crit")
+	if err != nil {
+		fmt.Printf("Cannot set loglevel %v\n", err)
+	}
+
+	kind := os.Args[1]
+	topic := "vocdoni_test"
+	key := ""
+
+	if kind == "sym" || kind == "asym" || kind == "raw" {
+		if kind != "raw" {
+			key = os.Args[2]
+		}
+		sn.PssSub(kind, key, topic, "")
+		defer sn.PssTopics[topic].Unregister()
+	} else {
+		fmt.Println("First parameter must be sym or asym")
+		return
+	}
+	fmt.Printf("My PSS pubKey is %s\n", sn.PssPubKey)
+	go func() {
+		for {
+			pmsg := <-sn.PssTopics[topic].Delivery
+			fmt.Printf("<- Pss received msg:{%s}\n", pmsg.Msg)
+		}
+	}()
+
+	hostname, _ := os.Hostname()
+
+	for {
+		fmt.Printf("-> Sending %s pss to [%s]\n", kind, key)
+		currentTime := int64(time.Now().Unix())
+		err := sn.PssPub(kind, key, topic, fmt.Sprintf("Hello world from %s at %d", hostname, currentTime), "")
+		log.Info("pss send", "err", err)
+		time.Sleep(10 * time.Second)
+	}
+}