Refactor and move parsing and stanza to a separate package

stanza/error.go

@@ -0,0 +1,114 @@
+package stanza
+
+import (
+	"encoding/xml"
+	"strconv"
+)
+
+// ============================================================================
+// XMPP Errors
+
+// Err is an XMPP stanza payload that is used to report error on message,
+// presence or iq stanza.
+// It is intended to be added in the payload of the erroneous stanza.
+type Err struct {
+	XMLName xml.Name  `xml:"error"`
+	Code    int       `xml:"code,attr,omitempty"`
+	Type    ErrorType `xml:"type,attr"` // required
+	Reason  string
+	Text    string `xml:"urn:ietf:params:xml:ns:xmpp-stanzas text,omitempty"`
+}
+
+func (x *Err) Namespace() string {
+	return x.XMLName.Space
+}
+
+// UnmarshalXML implements custom parsing for IQs
+func (x *Err) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	x.XMLName = start.Name
+
+	// Extract attributes
+	for _, attr := range start.Attr {
+		if attr.Name.Local == "type" {
+			x.Type = ErrorType(attr.Value)
+		}
+		if attr.Name.Local == "code" {
+			if code, err := strconv.Atoi(attr.Value); err == nil {
+				x.Code = code
+			}
+		}
+	}
+
+	// Check subelements to extract error text and reason (from local namespace).
+	for {
+		t, err := d.Token()
+		if err != nil {
+			return err
+		}
+
+		switch tt := t.(type) {
+
+		case xml.StartElement:
+			elt := new(Node)
+
+			err = d.DecodeElement(elt, &tt)
+			if err != nil {
+				return err
+			}
+
+			textName := xml.Name{Space: "urn:ietf:params:xml:ns:xmpp-stanzas", Local: "text"}
+			if elt.XMLName == textName {
+				x.Text = string(elt.Content)
+			} else if elt.XMLName.Space == "urn:ietf:params:xml:ns:xmpp-stanzas" {
+				x.Reason = elt.XMLName.Local
+			}
+
+		case xml.EndElement:
+			if tt == start.End() {
+				return nil
+			}
+		}
+	}
+}
+
+func (x Err) MarshalXML(e *xml.Encoder, start xml.StartElement) (err error) {
+	if x.Code == 0 {
+		return nil
+	}
+
+	// Encode start element and attributes
+	start.Name = xml.Name{Local: "error"}
+
+	code := xml.Attr{
+		Name:  xml.Name{Local: "code"},
+		Value: strconv.Itoa(x.Code),
+	}
+	start.Attr = append(start.Attr, code)
+
+	if len(x.Type) > 0 {
+		typ := xml.Attr{
+			Name:  xml.Name{Local: "type"},
+			Value: string(x.Type),
+		}
+		start.Attr = append(start.Attr, typ)
+	}
+	err = e.EncodeToken(start)
+
+	// SubTags
+	// Reason
+	if x.Reason != "" {
+		reason := xml.Name{Space: "urn:ietf:params:xml:ns:xmpp-stanzas", Local: x.Reason}
+		e.EncodeToken(xml.StartElement{Name: reason})
+		e.EncodeToken(xml.EndElement{Name: reason})
+	}
+
+	// Text
+	if x.Text != "" {
+		text := xml.Name{Space: "urn:ietf:params:xml:ns:xmpp-stanzas", Local: "text"}
+		e.EncodeToken(xml.StartElement{Name: text})
+		e.EncodeToken(xml.CharData(x.Text))
+		e.EncodeToken(xml.EndElement{Name: text})
+	}
+
+	return e.EncodeToken(xml.EndElement{Name: start.Name})
+}