Use an approach to build stanza that do not require a "builder" abstraction

stanza/iq_disco.go

@@ -1,27 +1,80 @@
 package stanza
 
-import "encoding/xml"
-
-// ============================================================================
-// Disco
-
-const (
-	NSDiscoInfo  = "http://jabber.org/protocol/disco#info"
-	NSDiscoItems = "http://jabber.org/protocol/disco#items"
+import (
+	"encoding/xml"
 )
 
+// ============================================================================
 // Disco Info
+
+const (
+	NSDiscoInfo = "http://jabber.org/protocol/disco#info"
+)
+
+// ----------
+// Namespaces
+
 type DiscoInfo struct {
-	XMLName  xml.Name  `xml:"http://jabber.org/protocol/disco#info query"`
-	Node     string    `xml:"node,attr,omitempty"`
-	Identity Identity  `xml:"identity"`
-	Features []Feature `xml:"feature"`
+	XMLName  xml.Name   `xml:"http://jabber.org/protocol/disco#info query"`
+	Node     string     `xml:"node,attr,omitempty"`
+	Identity []Identity `xml:"identity"`
+	Features []Feature  `xml:"feature"`
 }
 
 func (d *DiscoInfo) Namespace() string {
 	return d.XMLName.Space
 }
 
+// ---------------
+// Builder helpers
+
+// DiscoInfo builds a default DiscoInfo payload
+func (iq *IQ) DiscoInfo() *DiscoInfo {
+	d := DiscoInfo{
+		XMLName: xml.Name{
+			Space: NSDiscoInfo,
+			Local: "query",
+		},
+	}
+	iq.Payload = &d
+	return &d
+}
+
+func (d *DiscoInfo) AddIdentity(name, category, typ string) {
+	identity := Identity{
+		XMLName:  xml.Name{Local: "identity"},
+		Name:     name,
+		Category: category,
+		Type:     typ,
+	}
+	d.Identity = append(d.Identity, identity)
+}
+
+func (d *DiscoInfo) AddFeatures(namespace ...string) {
+	for _, ns := range namespace {
+		d.Features = append(d.Features, Feature{Var: ns})
+	}
+}
+
+func (d *DiscoInfo) SetNode(node string) {
+	d.Node = node
+}
+
+func (d *DiscoInfo) SetIdentities(ident ...Identity) *DiscoInfo {
+	d.Identity = ident
+	return d
+}
+
+func (d *DiscoInfo) SetFeatures(namespace ...string) *DiscoInfo {
+	for _, ns := range namespace {
+		d.Features = append(d.Features, Feature{Var: ns})
+	}
+	return d
+}
+
+// -----------
+// SubElements
+
 type Identity struct {
 	XMLName  xml.Name `xml:"identity,omitempty"`
 	Name     string   `xml:"name,attr,omitempty"`
@@ -34,7 +87,13 @@ type Feature struct {
 	Var     string   `xml:"var,attr"`
 }
 
-// Disco Items
+// ============================================================================
+// Disco Info
+
+const (
+	NSDiscoItems = "http://jabber.org/protocol/disco#items"
+)
+
 type DiscoItems struct {
 	XMLName xml.Name    `xml:"http://jabber.org/protocol/disco#items query"`
 	Node    string      `xml:"node,attr,omitempty"`