Implement XEP-0084 (User Avatar) (#120)

* Implement XEP-0084 (User Avatar)

* Fix style with gofmt

xmpp.go

@@ -642,8 +642,21 @@ func (c *Client) Recv() (stanza interface{}, err error) {
 		case *clientMessage:
 			if v.Event.XMLNS == XMPPNS_PUBSUB_EVENT {
 				// Handle Pubsub notifications
+				switch v.Event.Items.Node {
+				case XMPPNS_AVATAR_PEP_METADATA:
+					return handleAvatarMetadata(v.Event.Items.Items[0].Body,
+						v.From)
+				// I am not sure whether this can even happen.
+				// XEP-0084 only specifies a subscription to
+				// the metadata node.
+				/*case XMPPNS_AVATAR_PEP_DATA:
+				return handleAvatarData(v.Event.Items.Items[0].Body,
+					v.From,
+					v.Event.Items.Items[0].ID)*/
+				default:
 					return pubsubClientToReturn(v.Event), nil
 				}
+			}
 
 			stamp, _ := time.Parse(
 				"2006-01-02T15:04:05Z",
@@ -741,11 +754,42 @@ func (c *Client) Recv() (stanza interface{}, err error) {
 						return PubsubItems{}, err
 					}
 
+					switch p.Node {
+					case XMPPNS_AVATAR_PEP_DATA:
+						return handleAvatarData(p.Items[0].Body,
+							v.From,
+							p.Items[0].ID)
+					case XMPPNS_AVATAR_PEP_METADATA:
+						return handleAvatarMetadata(p.Items[0].Body,
+							v.From)
+					default:
 						return PubsubItems{
 							p.Node,
 							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
+					// can just use items1 and items3 to do the same
+					// as an Avatar node is just a PEP (PubSub) node.
+					/*case "retrieve1":
+					var p clientPubsubItems
+					err := xml.Unmarshal([]byte(v.Query.InnerXML), &p)
+					if err != nil {
+						return PubsubItems{}, err
+					}
+
+					switch p.Node {
+					case XMPPNS_AVATAR_PEP_DATA:
+						return handleAvatarData(p.Items[0].Body,
+							v.From,
+							p.Items[0].ID)
+					case XMPPNS_AVATAR_PEP_METADATA:
+						return handleAvatarMetadata(p.Items[0].Body,
+							v
+					}*/
+				}
 			case v.Query.XMLName.Local == "":
 				return IQ{ID: v.ID, From: v.From, To: v.To, Type: v.Type}, nil
 			default:

xmpp_avatar.go

@@ -0,0 +1,125 @@
+package xmpp
+
+import (
+	"crypto/sha1"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/xml"
+	"errors"
+	"strconv"
+)
+
+const (
+	XMPPNS_AVATAR_PEP_DATA     = "urn:xmpp:avatar:data"
+	XMPPNS_AVATAR_PEP_METADATA = "urn:xmpp:avatar:metadata"
+)
+
+type clientAvatarData struct {
+	XMLName xml.Name `xml:"data"`
+	Data    []byte   `xml:",innerxml"`
+}
+
+type clientAvatarInfo struct {
+	XMLName xml.Name `xml:"info"`
+	Bytes   string   `xml:"bytes,attr"`
+	Width   string   `xml:"width,attr"`
+	Height  string   `xml:"height,attr"`
+	ID      string   `xml:"id,attr"`
+	Type    string   `xml:"type,attr"`
+	URL     string   `xml:"url,attr"`
+}
+
+type clientAvatarMetadata struct {
+	XMLName xml.Name         `xml:"metadata"`
+	XMLNS   string           `xml:"xmlns,attr"`
+	Info    clientAvatarInfo `xml:"info"`
+}
+
+type AvatarData struct {
+	Data []byte
+	From string
+}
+
+type AvatarMetadata struct {
+	From   string
+	Bytes  int
+	Width  int
+	Height int
+	ID     string
+	Type   string
+	URL    string
+}
+
+func handleAvatarData(itemsBody []byte, from, id string) (AvatarData, error) {
+	var data clientAvatarData
+	err := xml.Unmarshal(itemsBody, &data)
+	if err != nil {
+		return AvatarData{}, err
+	}
+
+	// Base64-decode the avatar data to check its SHA1 hash
+	dataRaw, err := base64.StdEncoding.DecodeString(
+		string(data.Data))
+	if err != nil {
+		return AvatarData{}, err
+	}
+
+	hash := sha1.Sum(dataRaw)
+	hashStr := hex.EncodeToString(hash[:])
+	if hashStr != id {
+		return AvatarData{}, errors.New("SHA1 hashes do not match")
+	}
+
+	return AvatarData{
+		Data: dataRaw,
+		From: from,
+	}, nil
+}
+
+func handleAvatarMetadata(body []byte, from string) (AvatarMetadata, error) {
+	var meta clientAvatarMetadata
+	err := xml.Unmarshal(body, &meta)
+	if err != nil {
+		return AvatarMetadata{}, err
+	}
+
+	return AvatarMetadata{
+		From:   from,
+		Bytes:  atoiw(meta.Info.Bytes),
+		Width:  atoiw(meta.Info.Width),
+		Height: atoiw(meta.Info.Height),
+		ID:     meta.Info.ID,
+		Type:   meta.Info.Type,
+		URL:    meta.Info.URL,
+	}, nil
+}
+
+// A wrapper for atoi which just returns -1 if an error occurs
+func atoiw(str string) int {
+	i, err := strconv.Atoi(str)
+	if err != nil {
+		return -1
+	}
+
+	return i
+}
+
+func (c *Client) AvatarSubscribeMetadata(jid string) {
+	c.PubsubSubscribeNode(XMPPNS_AVATAR_PEP_METADATA, jid)
+}
+
+func (c *Client) AvatarUnsubscribeMetadata(jid string) {
+	c.PubsubUnsubscribeNode(XMPPNS_AVATAR_PEP_METADATA, jid)
+}
+
+func (c *Client) AvatarRequestData(jid string) {
+	c.PubsubRequestLastItems(XMPPNS_AVATAR_PEP_DATA, jid)
+}
+
+func (c *Client) AvatarRequestDataByID(jid, id string) {
+	c.PubsubRequestItem(XMPPNS_AVATAR_PEP_DATA, jid, id)
+}
+
+func (c *Client) AvatarRequestMetadata(jid string) {
+	c.PubsubRequestLastItems(XMPPNS_AVATAR_PEP_METADATA, jid)
+}