PubSub protocol support (#142)

* PubSub protocol support
Added support for :
- XEP-0050   (Command))
- XEP-0060   (PubSub)
- XEP-0004   (Forms)

Fixed the NewClient function by adding parsing of the domain from the JID if no domain is provided in transport config.
Updated xmpp_jukebox example

* Delete useless pubsub errors

* README.md update
Fixed import in echo example

* Typo

* Fixed raw send on client example

* Fixed jukebox example and added a README.md

_examples/xmpp_jukebox/README.md

@@ -0,0 +1,37 @@
+# Jukebox example  
+
+## Requirements
+- You need mpg123 installed on your computer because the example runs it as a command :
+[Official MPG123 website](https://mpg123.de/)  
+Most linux distributions have a package for it.  
+- You need a soundcloud ID to play a music from the website through mpg123. You currently cannot play music files with this example.  
+Your user ID is available in your account settings on the [soundcloud website](https://soundcloud.com/)  
+**One is provided for convenience.**
+- You need a running jabber server. You can run your local instance of [ejabberd](https://www.ejabberd.im/) for example. 
+- You need a registered user on the running jabber server.
+
+## Run
+You can edit the soundcloud ID in the example file with your own, or use the provided one :
+```go
+const scClientID = "dde6a0075614ac4f3bea423863076b22"
+``` 
+
+To run the example, build it with (while in the example directory) :
+```
+go build xmpp_jukebox.go
+```
+
+then run it with (update the command arguments accordingly):
+```
+./xmpp_jukebox -jid=MY_USERE@MY_DOMAIN/jukebox -password=MY_PASSWORD -address=MY_SERVER:MY_SERVER_PORT
+```
+Make sure to have a resource, for instance "/jukebox", on your jid.
+
+Then you can send the following stanza to "MY_USERE@MY_DOMAIN/jukebox" (with the resource) to play a song (update the soundcloud URL accordingly) :
+```xml
+<iq id="1" to="MY_USERE@MY_DOMAIN/jukebox" type="set">
+    <set xml:lang="en" xmlns="urn:xmpp:iot:control">
+        <string name="url" value="https://soundcloud.com/UPDATE/ME"/>
+    </set>
+</iq>
+```   

_examples/xmpp_jukebox/xmpp_jukebox.go

@@ -3,6 +3,7 @@
 package main
 
 import (
+	"encoding/xml"
 	"flag"
 	"fmt"
 	"log"
@@ -19,7 +20,7 @@ import (
 const scClientID = "dde6a0075614ac4f3bea423863076b22"
 
 func main() {
-	jid := flag.String("jid", "", "jukebok XMPP JID, resource is optional")
+	jid := flag.String("jid", "", "jukebok XMPP Jid, resource is optional")
 	password := flag.String("password", "", "XMPP account password")
 	address := flag.String("address", "", "If needed, XMPP server DNSName or IP and optional port (ie myserver:5222)")
 	flag.Parse()
@@ -48,7 +49,7 @@ func main() {
 			handleMessage(s, p, player)
 		})
 	router.NewRoute().
-		Packet("message").
+		Packet("iq").
 		HandlerFunc(func(s xmpp.Sender, p stanza.Packet) {
 			handleIQ(s, p, player)
 		})
@@ -108,11 +109,29 @@ func handleIQ(s xmpp.Sender, p stanza.Packet, player *mpg123.Player) {
 }
 
 func sendUserTune(s xmpp.Sender, artist string, title string) {
-	tune := stanza.Tune{Artist: artist, Title: title}
-	iq := stanza.NewIQ(stanza.Attrs{Type: stanza.IQTypeSet, Id: "usertune-1", Lang: "en"})
-	payload := stanza.PubSub{Publish: &stanza.Publish{Node: "http://jabber.org/protocol/tune", Item: stanza.Item{Tune: &tune}}}
-	iq.Payload = &payload
-	_ = s.Send(iq)
+	rq, err := stanza.NewPublishItemRq("localhost",
+		"http://jabber.org/protocol/tune",
+		"",
+		stanza.Item{
+			XMLName: xml.Name{Space: "http://jabber.org/protocol/tune", Local: "tune"},
+			Any: &stanza.Node{
+				Nodes: []stanza.Node{
+					{
+						XMLName: xml.Name{Local: "artist"},
+						Content: artist,
+					},
+					{
+						XMLName: xml.Name{Local: "title"},
+						Content: title,
+					},
+				},
+			},
+		})
+	if err != nil {
+		fmt.Printf("failed to build the publish request : %s", err.Error())
+		return
+	}
+	_ = s.Send(rq)
 }
 
 func playSCURL(p *mpg123.Player, rawURL string) {
@@ -120,7 +139,7 @@ func playSCURL(p *mpg123.Player, rawURL string) {
 	// TODO: Maybe we need to check the track itself to get the stream URL from reply ?
 	url := soundcloud.FormatStreamURL(songID)
 
-	_ = p.Play(url)
+	_ = p.Play(strings.ReplaceAll(url, "YOUR_SOUNDCLOUD_CLIENTID", scClientID))
 }
 
 // TODO