Refactor and move parsing and stanza to a separate package

stanza/message.go

@@ -0,0 +1,148 @@
+package stanza
+
+import (
+	"encoding/xml"
+	"reflect"
+)
+
+// ============================================================================
+// Message Packet
+
+// Message implements RFC 6120 - A.5 Client Namespace (a part)
+type Message struct {
+	XMLName xml.Name `xml:"message"`
+	Attrs
+
+	Subject    string         `xml:"subject,omitempty"`
+	Body       string         `xml:"body,omitempty"`
+	Thread     string         `xml:"thread,omitempty"`
+	Error      Err            `xml:"error,omitempty"`
+	Extensions []MsgExtension `xml:",omitempty"`
+}
+
+func (Message) Name() string {
+	return "message"
+}
+
+func NewMessage(a Attrs) Message {
+	return Message{
+		XMLName: xml.Name{Local: "message"},
+		Attrs:   a,
+	}
+}
+
+// Get search and extracts a specific extension on a message.
+// It receives a pointer to an MsgExtension. It will panic if the caller
+// does not pass a pointer.
+// It will return true if the passed extension is found and set the pointer
+// to the extension passed as parameter to the found extension.
+// It will return false if the extension is not found on the message.
+//
+// Example usage:
+//   var oob xmpp.OOB
+//   if ok := msg.Get(&oob); ok {
+//     // oob extension has been found
+//	 }
+func (msg *Message) Get(ext MsgExtension) bool {
+	target := reflect.ValueOf(ext)
+	if target.Kind() != reflect.Ptr {
+		panic("you must pass a pointer to the message Get method")
+	}
+
+	for _, e := range msg.Extensions {
+		if reflect.TypeOf(e) == target.Type() {
+			source := reflect.ValueOf(e)
+			if source.Kind() != reflect.Ptr {
+				source = source.Elem()
+			}
+			target.Elem().Set(source.Elem())
+			return true
+		}
+	}
+	return false
+}
+
+type messageDecoder struct{}
+
+var message messageDecoder
+
+func (messageDecoder) decode(p *xml.Decoder, se xml.StartElement) (Message, error) {
+	var packet Message
+	err := p.DecodeElement(&packet, &se)
+	return packet, err
+}
+
+// XMPPFormat with all Extensions
+func (msg *Message) XMPPFormat() string {
+	out, err := xml.MarshalIndent(msg, "", "")
+	if err != nil {
+		return ""
+	}
+	return string(out)
+}
+
+// UnmarshalXML implements custom parsing for messages
+func (msg *Message) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	msg.XMLName = start.Name
+
+	// Extract packet attributes
+	for _, attr := range start.Attr {
+		if attr.Name.Local == "id" {
+			msg.Id = attr.Value
+		}
+		if attr.Name.Local == "type" {
+			msg.Type = StanzaType(attr.Value)
+		}
+		if attr.Name.Local == "to" {
+			msg.To = attr.Value
+		}
+		if attr.Name.Local == "from" {
+			msg.From = attr.Value
+		}
+		if attr.Name.Local == "lang" {
+			msg.Lang = attr.Value
+		}
+	}
+
+	// decode inner elements
+	for {
+		t, err := d.Token()
+		if err != nil {
+			return err
+		}
+
+		switch tt := t.(type) {
+
+		case xml.StartElement:
+			if msgExt := TypeRegistry.GetMsgExtension(tt.Name); msgExt != nil {
+				// Decode message extension
+				err = d.DecodeElement(msgExt, &tt)
+				if err != nil {
+					return err
+				}
+				msg.Extensions = append(msg.Extensions, msgExt)
+			} else {
+				// Decode standard message sub-elements
+				var err error
+				switch tt.Name.Local {
+				case "body":
+					err = d.DecodeElement(&msg.Body, &tt)
+				case "thread":
+					err = d.DecodeElement(&msg.Thread, &tt)
+				case "subject":
+					err = d.DecodeElement(&msg.Subject, &tt)
+				case "error":
+					err = d.DecodeElement(&msg.Error, &tt)
+				}
+				if err != nil {
+					return err
+				}
+			}
+
+		case xml.EndElement:
+			if tt == start.End() {
+				return nil
+			}
+		}
+	}
+}