caller. handler's args are optional.

README.md

@@ -18,7 +18,7 @@ Examples directory contains simple client and server.
 	server := gosocketio.NewServer(transport.GetDefaultWebsocketTransport())
 
 	//handle connected
-	server.On(gosocketio.OnConnection, func(c *gosocketio.Channel, args interface{}) {
+	server.On(gosocketio.OnConnection, func(c *gosocketio.Channel) {
 		log.Println("New client connected")
 		//join them to room
 		c.Join("chat")
@@ -89,7 +89,9 @@ var socket = io('ws://yourdomain.com', {transports: ['websocket']});
 		log.Println(len(channels), "clients in room")
 	})
 	//on disconnection handler, if client hangs connection unexpectedly, it will still occurs
-	server.On(gosocketio.OnDisconnection, func(c *gosocketio.Channel, args interface{}) {
+	//you can omit function args if you do not need them
+	//you can return string value for ack, or return nothing for emit
+	server.On(gosocketio.OnDisconnection, func(c *gosocketio.Channel) {
 		//this is not necessary, client will be removed from rooms
 		//automatically on disconnect
 		//but you can remove client from room whenever you need to
@@ -98,7 +100,7 @@ var socket = io('ws://yourdomain.com', {transports: ['websocket']});
 		log.Println("Disconnected")
 	})
 	//error catching handler
-	server.On(gosocketio.OnError, func(c *gosocketio.Channel, args interface{}) {
+	server.On(gosocketio.OnError, func(c *gosocketio.Channel) {
 		log.Println("Error occurs")
 	})
 

caller.go

@@ -6,14 +6,15 @@ import (
 )
 
 type caller struct {
-	Func reflect.Value
-	Args reflect.Type
-	Out  bool
+	Func        reflect.Value
+	Args        reflect.Type
+	ArgsPresent bool
+	Out         bool
 }
 
 var (
 	ErrorCallerNotFunc     = errors.New("f is not function")
-	ErrorCallerNot2Args    = errors.New("f should have 2 args")
+	ErrorCallerNot2Args    = errors.New("f should have 1 or 2 args")
 	ErrorCallerMaxOneValue = errors.New("f should return not more than one value")
 )
 
@@ -28,19 +29,25 @@ func newCaller(f interface{}) (*caller, error) {
 	}
 
 	fType := fVal.Type()
-	if fType.NumIn() != 2 {
-		return nil, ErrorCallerNot2Args
-	}
-
 	if fType.NumOut() > 1 {
 		return nil, ErrorCallerMaxOneValue
 	}
 
-	return &caller{
+	curCaller := &caller{
 		Func: fVal,
-		Args: fType.In(1),
 		Out:  fType.NumOut() == 1,
-	}, nil
+	}
+	if fType.NumIn() == 1 {
+		curCaller.Args = nil
+		curCaller.ArgsPresent = false
+	} else if fType.NumIn() == 2 {
+		curCaller.Args = fType.In(1)
+		curCaller.ArgsPresent = true
+	} else {
+		return nil, ErrorCallerNot2Args
+	}
+
+	return curCaller, nil
 }
 
 /**
@@ -55,6 +62,9 @@ calls function with given arguments from its representation using reflection
 */
 func (c *caller) callFunc(h *Channel, args interface{}) []reflect.Value {
 	a := []reflect.Value{reflect.ValueOf(h), reflect.ValueOf(args).Elem()}
+	if !c.ArgsPresent {
+		a = a[0:1]
+	}
 
 	return c.Func.Call(a)
 }

examples/client.go

@@ -45,14 +45,14 @@ func main() {
 		log.Fatal(err)
 	}
 
-	err = c.On(gosocketio.OnDisconnection, func(h *gosocketio.Channel, args interface{}) {
+	err = c.On(gosocketio.OnDisconnection, func(h *gosocketio.Channel) {
 		log.Fatal("Disconnected")
 	})
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	err = c.On(gosocketio.OnConnection, func(h *gosocketio.Channel, args interface{}) {
+	err = c.On(gosocketio.OnConnection, func(h *gosocketio.Channel) {
 		log.Println("Connected")
 	})
 	if err != nil {

examples/server.go

@@ -21,7 +21,7 @@ type Message struct {
 func main() {
 	server := gosocketio.NewServer(transport.GetDefaultWebsocketTransport())
 
-	server.On(gosocketio.OnConnection, func(c *gosocketio.Channel, args interface{}) {
+	server.On(gosocketio.OnConnection, func(c *gosocketio.Channel) {
 		log.Println("Connected")
 
 		c.Emit("/message", Message{10, "main", "using emit"})
@@ -29,12 +29,13 @@ func main() {
 		c.Join("test")
 		c.BroadcastTo("test", "/message", Message{10, "main", "using broadcast"})
 	})
-	server.On(gosocketio.OnDisconnection, func(c *gosocketio.Channel, args interface{}) {
+	server.On(gosocketio.OnDisconnection, func(c *gosocketio.Channel) {
 		log.Println("Disconnected")
 	})
 
 	server.On("/join", func(c *gosocketio.Channel, channel Channel) string {
 		time.Sleep(2 * time.Second)
+		log.Println("Client joined to ", channel.Channel)
 		return "joined to " + channel.Channel
 	})
 

handler.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"github.com/graarh/golang-socketio/protocol"
 	"sync"
+	"reflect"
 )
 
 const (
@@ -92,6 +93,11 @@ func (m *methods) processIncomingMessage(c *Channel, msg *protocol.Message) {
 			return
 		}
 
+		if !f.ArgsPresent {
+			f.callFunc(c, &struct{}{})
+			return
+		}
+
 		data := f.getArgs()
 		err := json.Unmarshal([]byte(msg.Args), &data)
 		if err != nil {
@@ -106,13 +112,20 @@ func (m *methods) processIncomingMessage(c *Channel, msg *protocol.Message) {
 			return
 		}
 
-		data := f.getArgs()
-		err := json.Unmarshal([]byte(msg.Args), &data)
-		if err != nil {
-			return
+		var result []reflect.Value
+		if f.ArgsPresent {
+			//data type should be defined for unmarshall
+			data := f.getArgs()
+			err := json.Unmarshal([]byte(msg.Args), &data)
+			if err != nil {
+				return
+			}
+
+			result = f.callFunc(c, data)
+		} else {
+			result = f.callFunc(c, &struct{}{})
 		}
 
-		result := f.callFunc(c, data)
 		ack := &protocol.Message{
 			Type:  protocol.MessageTypeAckResponse,
 			AckId: msg.AckId,