Implement Disco queries against other entities (#124)

* Improve support for XEP-0030

This commit allows the user to query information about the server
or a node belonging to the server as per XEP-0030.

* Fix broken PubSub functionality

xmpp.go

@@ -733,18 +733,10 @@ func (c *Client) Recv() (stanza interface{}, err error) {
 					return IQ{ID: v.ID, From: v.From, To: v.To, Type: v.Type,
 						Query: res}, nil
 				}
-			case v.Type == "result" && v.ID == "unsub1":
-				// Unsubscribing MAY contain a pubsub element. But it does
-				// not have to
-				return PubsubUnsubscription{
-					SubID:  "",
-					JID:    v.From,
-					Node:   "",
-					Errors: nil,
-				}, nil
-			case v.Query.XMLName.Local == "pubsub":
+			case v.Type == "result":
 				switch v.ID {
 				case "sub1":
+					if v.Query.XMLName.Local == "pubsub" {
 						// Subscription or unsubscription was successful
 						var sub clientPubsubSubscription
 						err := xml.Unmarshal([]byte(v.Query.InnerXML), &sub)
@@ -758,7 +750,9 @@ func (c *Client) Recv() (stanza interface{}, err error) {
 							Node:   sub.Node,
 							Errors: nil,
 						}, nil
+					}
 				case "unsub1":
+					if v.Query.XMLName.Local == "pubsub" {
 						var sub clientPubsubSubscription
 						err := xml.Unmarshal([]byte(v.Query.InnerXML), &sub)
 						if err != nil {
@@ -771,7 +765,44 @@ func (c *Client) Recv() (stanza interface{}, err error) {
 							Node:   sub.Node,
 							Errors: nil,
 						}, nil
+					} else {
+						// Unsubscribing MAY contain a pubsub element. But it does
+						// not have to
+						return PubsubUnsubscription{
+							SubID:  "",
+							JID:    v.From,
+							Node:   "",
+							Errors: nil,
+						}, nil
+					}
+				case "info1":
+					if v.Query.XMLName.Space == XMPPNS_DISCO_ITEMS {
+						var itemsQuery clientDiscoItemsQuery
+						err := xml.Unmarshal(v.InnerXML, &itemsQuery)
+						if err != nil {
+							return []DiscoItem{}, err
+						}
+
+						return DiscoItems{
+							Jid:   v.From,
+							Items: clientDiscoItemsToReturn(itemsQuery.Items),
+						}, nil
+					}
+				case "info3":
+					if v.Query.XMLName.Space == XMPPNS_DISCO_INFO {
+						var disco clientDiscoQuery
+						err := xml.Unmarshal(v.InnerXML, &disco)
+						if err != nil {
+							return DiscoResult{}, err
+						}
+
+						return DiscoResult{
+							Features:   clientFeaturesToReturn(disco.Features),
+							Identities: clientIdentitiesToReturn(disco.Identities),
+						}, nil
+					}
 				case "items1", "items3":
+					if v.Query.XMLName.Local == "pubsub" {
 						var p clientPubsubItems
 						err := xml.Unmarshal([]byte(v.Query.InnerXML), &p)
 						if err != nil {
@@ -800,6 +831,7 @@ func (c *Client) Recv() (stanza interface{}, err error) {
 							pubsubItemsToReturn(p.Items),
 						}, nil
 					}
+
 					// Note: XEP-0084 states that metadata and data
 					// should be fetched with an id of retrieve1.
 					// Since we already have PubSub implemented, we
@@ -1072,6 +1104,8 @@ type clientIQ struct {
 	Query   XMLElement `xml:",any"`
 	Error   clientError
 	Bind    bindBind
+
+	InnerXML []byte `xml:",innerxml"`
 }
 
 type clientError struct {

xmpp_disco.go

@@ -0,0 +1,99 @@
+package xmpp
+
+import (
+	"encoding/xml"
+)
+
+const (
+	XMPPNS_DISCO_ITEMS = "http://jabber.org/protocol/disco#items"
+	XMPPNS_DISCO_INFO  = "http://jabber.org/protocol/disco#info"
+)
+
+type clientDiscoFeature struct {
+	XMLName xml.Name `xml:"feature"`
+	Var     string   `xml:"var,attr"`
+}
+
+type clientDiscoIdentity struct {
+	XMLName  xml.Name `xml:"identity"`
+	Category string   `xml:"category,attr"`
+	Type     string   `xml:"type,attr"`
+	Name     string   `xml:"name,attr"`
+}
+
+type clientDiscoQuery struct {
+	XMLName    xml.Name              `xml:"query"`
+	Features   []clientDiscoFeature  `xml:"feature"`
+	Identities []clientDiscoIdentity `xml:"identity"`
+}
+
+type clientDiscoItem struct {
+	XMLName xml.Name `xml:"item"`
+	Jid     string   `xml:"jid,attr"`
+	Node    string   `xml:"node,attr"`
+	Name    string   `xml:"name,attr"`
+}
+
+type clientDiscoItemsQuery struct {
+	XMLName xml.Name          `xml:"query"`
+	Items   []clientDiscoItem `xml:"item"`
+}
+
+type DiscoIdentity struct {
+	Category string
+	Type     string
+	Name     string
+}
+
+type DiscoItem struct {
+	Jid  string
+	Name string
+	Node string
+}
+
+type DiscoResult struct {
+	Features   []string
+	Identities []DiscoIdentity
+}
+
+type DiscoItems struct {
+	Jid   string
+	Items []DiscoItem
+}
+
+func clientFeaturesToReturn(features []clientDiscoFeature) []string {
+	var ret []string
+
+	for _, feature := range features {
+		ret = append(ret, feature.Var)
+	}
+
+	return ret
+}
+
+func clientIdentitiesToReturn(identities []clientDiscoIdentity) []DiscoIdentity {
+	var ret []DiscoIdentity
+
+	for _, id := range identities {
+		ret = append(ret, DiscoIdentity{
+			Category: id.Category,
+			Type:     id.Type,
+			Name:     id.Name,
+		})
+	}
+
+	return ret
+}
+
+func clientDiscoItemsToReturn(items []clientDiscoItem) []DiscoItem {
+	var ret []DiscoItem
+	for _, item := range items {
+		ret = append(ret, DiscoItem{
+			Jid:  item.Jid,
+			Name: item.Name,
+			Node: item.Node,
+		})
+	}
+
+	return ret
+}

xmpp_information_query.go

@@ -10,10 +10,26 @@ const IQTypeSet = "set"
 const IQTypeResult = "result"
 
 func (c *Client) Discovery() (string, error) {
-	const namespace = "http://jabber.org/protocol/disco#items"
 	// use getCookie for a pseudo random id.
 	reqID := strconv.FormatUint(uint64(getCookie()), 10)
-	return c.RawInformationQuery(c.jid, c.domain, reqID, IQTypeGet, namespace, "")
+	return c.RawInformationQuery(c.jid, c.domain, reqID, IQTypeGet, XMPPNS_DISCO_ITEMS, "")
+}
+
+// Discover information about a node
+func (c *Client) DiscoverNodeInfo(node string) (string, error) {
+	query := fmt.Sprintf("<query xmlns='%s' node='%s'/>", XMPPNS_DISCO_INFO, node)
+	return c.RawInformation(c.jid, c.domain, "info3", IQTypeGet, query)
+}
+
+// Discover items that the server exposes
+func (c *Client) DiscoverServerItems() (string, error) {
+	return c.DiscoverEntityItems(c.domain)
+}
+
+// Discover items that an entity exposes
+func (c *Client) DiscoverEntityItems(jid string) (string, error) {
+	query := fmt.Sprintf("<query xmlns='%s'/>", XMPPNS_DISCO_ITEMS)
+	return c.RawInformation(c.jid, jid, "info1", IQTypeGet, query)
 }
 
 // RawInformationQuery sends an information query request to the server.