add client logging + improve logging

client/auth.go

@@ -22,6 +22,7 @@ func (client *Client) auth(password string) error {
 	challenge := &messages.SASLChallenge{}
 	response := &messages.SASLResponse{}
 	for _, m := range f.Mechanisms.Mechanism {
+		client.Logging.Debugf("try auth with '%s'", m)
 		if m == "SCRAM-SHA-1" {
 			/*
 				mechanism = m
@@ -33,10 +34,10 @@ func (client *Client) auth(password string) error {
 		if m == "DIGEST-MD5" {
 			mechanism = m
 			// Digest-MD5 authentication
-			client.Out.Encode(&messages.SASLAuth{
+			client.Send(&messages.SASLAuth{
 				Mechanism: m,
 			})
-			if err := client.ReadElement(challenge); err != nil {
+			if err := client.ReadDecode(challenge); err != nil {
 				return err
 			}
 			b, err := base64.StdEncoding.DecodeString(challenge.Body)
@@ -65,7 +66,7 @@ func (client *Client) auth(password string) error {
 				"\", nc=" + nonceCount + ", qop=" + qop + ", digest-uri=\"" + digestURI + "\", response=" + digest + ", charset=" + charset
 
 			response.Body = base64.StdEncoding.EncodeToString([]byte(message))
-			client.Out.Encode(response)
+			client.Send(response)
 			break
 		}
 		if m == "PLAIN" {
@@ -74,7 +75,7 @@ func (client *Client) auth(password string) error {
 			raw := "\x00" + client.JID.Local + "\x00" + password
 			enc := make([]byte, base64.StdEncoding.EncodedLen(len(raw)))
 			base64.StdEncoding.Encode(enc, []byte(raw))
-			client.Out.Encode(&messages.SASLAuth{
+			client.Send(&messages.SASLAuth{
 				Mechanism: "PLAIN",
 				Body:      string(enc),
 			})
@@ -85,15 +86,17 @@ func (client *Client) auth(password string) error {
 	if mechanism == "" {
 		return fmt.Errorf("PLAIN authentication is not an option: %s", f.Mechanisms.Mechanism)
 	}
+	client.Logging.Info("used auth with '%s'", mechanism)
+
 	element, err := client.Read()
 	if err != nil {
 		return err
 	}
 	fail := messages.SASLFailure{}
-	if err := client.In.DecodeElement(&fail, element); err == nil {
+	if err := client.Decode(&fail, element); err == nil {
 		return errors.New(messages.XMLChildrenString(fail) + " : " + fail.Body)
 	}
-	if err := client.In.DecodeElement(&messages.SASLSuccess{}, element); err != nil {
+	if err := client.Decode(&messages.SASLSuccess{}, element); err != nil {
 		return errors.New("auth failed - with unexpected answer")
 	}
 	return nil

client/client.go

@@ -3,32 +3,41 @@ package client
 import (
 	"crypto/tls"
 	"encoding/xml"
-	"errors"
 	"fmt"
 	"net"
 	"strings"
 	"time"
 
-	"dev.sum7.eu/genofire/yaja/messages"
+	log "github.com/sirupsen/logrus"
+
 	"dev.sum7.eu/genofire/yaja/model"
 )
 
 // Client holds XMPP connection opitons
 type Client struct {
+	Protocol string // tcp tcp4 tcp6 are supported
+	Timeout  time.Duration
 	conn     net.Conn // connection to server
-	Out  *xml.Encoder
+	out      *xml.Encoder
-	In   *xml.Decoder
+	in       *xml.Decoder
+
+	Logging *log.Logger
 
 	JID *model.JID
 }
 
 func NewClient(jid *model.JID, password string) (*Client, error) {
-	return NewClientProtocolDuration(jid, password, "tcp", 0)
+	client := &Client{
+		Protocol: "tcp",
+		JID:      jid,
+		Logging:  log.New(),
 	}
+	return client, client.Connect(password)
 
-func NewClientProtocolDuration(jid *model.JID, password string, proto string, timeout time.Duration) (*Client, error) {
+}
-	_, srvEntries, err := net.LookupSRV("xmpp-client", "tcp", jid.Domain)
+func (client *Client) Connect(password string) error {
-	addr := jid.Domain + ":5222"
+	_, srvEntries, err := net.LookupSRV("xmpp-client", "tcp", client.JID.Domain)
+	addr := client.JID.Domain + ":5222"
 	if err == nil && len(srvEntries) > 0 {
 		bestSrv := srvEntries[0]
 		for _, srv := range srvEntries {
@@ -42,23 +51,20 @@ func NewClientProtocolDuration(jid *model.JID, password string, proto string, ti
 	if len(a) == 1 {
 		addr += ":5222"
 	}
-	conn, err := net.DialTimeout(proto, addr, timeout)
+	if client.Protocol == "" {
-	if err != nil {
+		client.Protocol = "tcp"
-		return nil, err
 	}
-	client := &Client{
+	conn, err := net.DialTimeout(client.Protocol, addr, client.Timeout)
-		conn: conn,
+	client.setConnection(conn)
-		In:   xml.NewDecoder(conn),
+	if err != nil {
-		Out:  xml.NewEncoder(conn),
+		return err
-
-		JID: jid,
 	}
 
 	if err = client.connect(password); err != nil {
 		client.Close()
-		return nil, err
+		return err
 	}
-	return client, nil
+	return nil
 }
 
 // Close closes the XMPP connection
@@ -68,94 +74,3 @@ func (c *Client) Close() error {
 	}
 	return nil
 }
-
-func (client *Client) startStream() (*messages.StreamFeatures, error) {
-	// XMPP-Connection
-	_, err := fmt.Fprintf(client.conn, "<?xml version='1.0'?>\n"+
-		"<stream:stream to='%s' xmlns='%s'\n"+
-		" xmlns:stream='%s' version='1.0'>\n",
-		model.XMLEscape(client.JID.Domain), messages.NSClient, messages.NSStream)
-	if err != nil {
-		return nil, err
-	}
-	element, err := client.Read()
-	if err != nil {
-		return nil, err
-	}
-	if element.Name.Space != messages.NSStream || element.Name.Local != "stream" {
-		return nil, errors.New("is not stream")
-	}
-	f := &messages.StreamFeatures{}
-	if err := client.ReadElement(f); err != nil {
-		return nil, err
-	}
-	return f, nil
-}
-
-func (client *Client) connect(password string) error {
-	if _, err := client.startStream(); err != nil {
-		return err
-	}
-	if err := client.Out.Encode(&messages.TLSStartTLS{}); err != nil {
-		return err
-	}
-
-	var p messages.TLSProceed
-	if err := client.ReadElement(&p); err != nil {
-		return err
-	}
-	// Change tcp to tls
-	tlsconn := tls.Client(client.conn, &tls.Config{
-		ServerName: client.JID.Domain,
-	})
-	client.conn = tlsconn
-	client.In = xml.NewDecoder(client.conn)
-	client.Out = xml.NewEncoder(client.conn)
-
-	if err := tlsconn.Handshake(); err != nil {
-		return err
-	}
-	if err := tlsconn.VerifyHostname(client.JID.Domain); err != nil {
-		return err
-	}
-	if err := client.auth(password); err != nil {
-		return err
-	}
-
-	if _, err := client.startStream(); err != nil {
-		return err
-	}
-	// bind to resource
-	bind := &messages.Bind{}
-	if client.JID.Resource != "" {
-		bind.Resource = client.JID.Resource
-	}
-	if err := client.Out.Encode(&messages.IQClient{
-		Type: messages.IQTypeSet,
-		From: client.JID,
-		To:   model.NewJID(client.JID.Domain),
-		Bind: bind,
-	}); err != nil {
-		return err
-	}
-
-	var iq messages.IQClient
-	if err := client.ReadElement(&iq); err != nil {
-		return err
-	}
-	if iq.Error != nil {
-		if iq.Error.ServiceUnavailable == nil {
-			return errors.New(fmt.Sprintf("recv error on iq>bind: %s[%s]: %s -> %s -> %s", iq.Error.Code, iq.Error.Type, iq.Error.Text, messages.XMLChildrenString(iq.Error.StanzaErrorGroup), messages.XMLChildrenString(iq.Error.Other)))
-		}
-	} else if iq.Bind == nil {
-		return errors.New("<iq> result missing <bind>")
-	} else if iq.Bind.JID != nil {
-		client.JID.Local = iq.Bind.JID.Local
-		client.JID.Domain = iq.Bind.JID.Domain
-		client.JID.Resource = iq.Bind.JID.Resource
-	} else {
-		return errors.New(messages.XMLChildrenString(iq.Other))
-	}
-	// set status
-	return client.Send(&messages.PresenceClient{Show: messages.PresenceShowXA, Status: "online"})
-}

client/comm.go

@@ -2,26 +2,34 @@ package client
 
 import (
 	"encoding/xml"
-	"log"
 
 	"dev.sum7.eu/genofire/yaja/messages"
 )
 
 func (client *Client) Read() (*xml.StartElement, error) {
 	for {
-		nextToken, err := client.In.Token()
+		nextToken, err := client.in.Token()
 		if err != nil {
 			return nil, err
 		}
 		switch nextToken.(type) {
 		case xml.StartElement:
 			element := nextToken.(xml.StartElement)
+			client.Logging.Debug("recv xml: ", messages.XMLStartElementToString(&element))
 			return &element, nil
 		}
 	}
 }
-
+func (client *Client) Decode(p interface{}, element *xml.StartElement) error {
-func (client *Client) ReadElement(p interface{}) error {
+	err := client.in.DecodeElement(p, element)
+	if err != nil {
+		client.Logging.Debugf("decode failed xml: %s to: %v", messages.XMLStartElementToString(element), p)
+	} else {
+		client.Logging.Debugf("decode xml: %s to: %v with children %s", messages.XMLStartElementToString(element), p, messages.XMLChildrenString(p))
+	}
+	return err
+}
+func (client *Client) ReadDecode(p interface{}) error {
 	element, err := client.Read()
 	if err != nil {
 		return err
@@ -31,36 +39,45 @@ func (client *Client) ReadElement(p interface{}) error {
 	if !ok {
 		iq = &messages.IQClient{}
 	}
-	err = client.In.DecodeElement(iq, element)
+	err = client.Decode(iq, element)
 	if err == nil && iq.Ping != nil {
-		log.Println("answer ping")
+		client.Logging.Info("ReadElement: auto answer ping")
 		iq.Type = messages.IQTypeResult
 		iq.To = iq.From
 		iq.From = client.JID
-		client.Out.Encode(iq)
+		client.Send(iq)
 		return nil
 	}
 	if ok {
 		return err
 	}
-	return client.In.DecodeElement(p, element)
+	return client.Decode(p, element)
+}
+func (client *Client) encode(p interface{}) error {
+	err := client.out.Encode(p)
+	if err != nil {
+		client.Logging.Debugf("encode failed %v", p)
+	} else {
+		client.Logging.Debugf("encode %v with children %s", p, messages.XMLChildrenString(p))
+	}
+	return err
 }
 
 func (client *Client) Send(p interface{}) error {
 	msg, ok := p.(*messages.MessageClient)
 	if ok {
 		msg.From = client.JID
-		return client.Out.Encode(msg)
+		return client.encode(msg)
 	}
 	iq, ok := p.(*messages.IQClient)
 	if ok {
 		iq.From = client.JID
-		return client.Out.Encode(iq)
+		return client.encode(iq)
 	}
 	pc, ok := p.(*messages.PresenceClient)
 	if ok {
 		pc.From = client.JID
-		return client.Out.Encode(pc)
+		return client.encode(pc)
 	}
-	return client.Out.Encode(p)
+	return client.encode(p)
 }

client/connect.go

@@ -0,0 +1,122 @@
+package client
+
+import (
+	"crypto/tls"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"net"
+
+	"dev.sum7.eu/genofire/yaja/messages"
+	"dev.sum7.eu/genofire/yaja/model"
+)
+
+func (client *Client) setConnection(conn net.Conn) {
+	client.conn = conn
+	client.in = xml.NewDecoder(client.conn)
+	client.out = xml.NewEncoder(client.conn)
+}
+
+func (client *Client) startStream() (*messages.StreamFeatures, error) {
+	// XMPP-Connection
+	_, err := fmt.Fprintf(client.conn, "<?xml version='1.0'?>\n"+
+		"<stream:stream to='%s' xmlns='%s'\n"+
+		" xmlns:stream='%s' version='1.0'>\n",
+		model.XMLEscape(client.JID.Domain), messages.NSClient, messages.NSStream)
+	if err != nil {
+		return nil, err
+	}
+	element, err := client.Read()
+	if err != nil {
+		return nil, err
+	}
+	if element.Name.Space != messages.NSStream || element.Name.Local != "stream" {
+		return nil, errors.New("is not stream")
+	}
+	f := &messages.StreamFeatures{}
+	if err := client.ReadDecode(f); err != nil {
+		return nil, err
+	}
+	debug := "stream start >"
+	if f.StartTLS != nil {
+		debug += " tls"
+	}
+	debug += " mechanism("
+	for _, m := range f.Mechanisms.Mechanism {
+		debug += m
+	}
+	debug += ")"
+	if f.Bind != nil {
+		debug += " bind"
+	}
+	client.Logging.Info(debug)
+	return f, nil
+}
+
+func (client *Client) connect(password string) error {
+	if _, err := client.startStream(); err != nil {
+		return err
+	}
+	if err := client.Send(&messages.TLSStartTLS{}); err != nil {
+		return err
+	}
+
+	var p messages.TLSProceed
+	if err := client.ReadDecode(&p); err != nil {
+		return err
+	}
+	// Change tcp to tls
+	tlsconn := tls.Client(client.conn, &tls.Config{
+		ServerName: client.JID.Domain,
+	})
+	client.setConnection(tlsconn)
+
+	if err := tlsconn.Handshake(); err != nil {
+		return err
+	}
+	if err := tlsconn.VerifyHostname(client.JID.Domain); err != nil {
+		return err
+	}
+	if err := client.auth(password); err != nil {
+		return err
+	}
+
+	if _, err := client.startStream(); err != nil {
+		return err
+	}
+	// bind to resource
+	bind := &messages.Bind{}
+	if client.JID.Resource != "" {
+		bind.Resource = client.JID.Resource
+	}
+	if err := client.Send(&messages.IQClient{
+		Type: messages.IQTypeSet,
+		To:   model.NewJID(client.JID.Domain),
+		Bind: bind,
+	}); err != nil {
+		return err
+	}
+
+	var iq messages.IQClient
+	if err := client.ReadDecode(&iq); err != nil {
+		return err
+	}
+	if iq.Error != nil {
+		if iq.Error.ServiceUnavailable == nil {
+			return errors.New(fmt.Sprintf("recv error on iq>bind: %s[%s]: %s -> %s -> %s", iq.Error.Code, iq.Error.Type, iq.Error.Text, messages.XMLChildrenString(iq.Error.StanzaErrorGroup), messages.XMLChildrenString(iq.Error.Other)))
+		} else {
+			client.Logging.Warn("connected without setting resource with bind after auth: service-unavailable")
+		}
+	} else if iq.Bind == nil {
+		return errors.New("<iq> result missing <bind>")
+	} else if iq.Bind.JID != nil {
+		client.JID.Local = iq.Bind.JID.Local
+		client.JID.Domain = iq.Bind.JID.Domain
+		client.JID.Resource = iq.Bind.JID.Resource
+		client.Logging.Info("set resource by server bind")
+	} else {
+		return errors.New(messages.XMLChildrenString(iq.Other))
+	}
+	// set status
+	return client.Send(&messages.PresenceClient{Show: messages.PresenceShowXA, Status: "online"})
+}

daemon/tester.go

@@ -38,8 +38,18 @@ var TesterCMD = &cobra.Command{
 		if err := file.ReadJSON(configTester.AccountsPath, testerInstance); err != nil {
 			log.Warn("unable to load state file:", err)
 		}
+		testerInstance.Admins = configTester.Admins
+		testerInstance.LoggingBots = configTester.LoggingBots
+		clientLogger := log.New()
+		clientLogger.SetLevel(configTester.LoggingClients)
+		testerInstance.LoggingClients = clientLogger
 
-		mainClient, err := client.NewClientProtocolDuration(configTester.Client.JID, configTester.Client.Password, "tcp", configTester.Timeout.Duration)
+		mainClient := &client.Client{
+			JID:     configTester.Client.JID,
+			Timeout: configTester.Timeout.Duration,
+			Logging: clientLogger,
+		}
+		err := mainClient.Connect(configTester.Client.Password)
 		if err != nil {
 			log.Fatal("unable to connect with main jabber client: ", err)
 		}

daemon/tester/bot.go

@@ -9,8 +9,13 @@ import (
 )
 
 func (t *Tester) StartBot(status *Status) {
+	logger := log.New()
+	logger.SetLevel(t.LoggingBots)
+	logCTX := logger.WithFields(log.Fields{
+		"type": "bot",
+		"jid":  status.client.JID.Full(),
+	})
 	for {
-		logCTX := log.WithField("jid", status.client.JID.Full())
 
 		element, err := status.client.Read()
 		if err != nil {
@@ -21,7 +26,7 @@ func (t *Tester) StartBot(status *Status) {
 		}
 
 		errMSG := &messages.StreamError{}
-		err = status.client.In.DecodeElement(errMSG, element)
+		err = status.client.Decode(errMSG, element)
 		if err == nil {
 			logCTX.Errorf("recv stream error: %s: %s", errMSG.Text, messages.XMLChildrenString(errMSG.Any))
 			status.client.Close()
@@ -30,14 +35,14 @@ func (t *Tester) StartBot(status *Status) {
 		}
 
 		iq := &messages.IQClient{}
-		err = status.client.In.DecodeElement(iq, element)
+		err = status.client.Decode(iq, element)
 		if err == nil {
 			if iq.Ping != nil {
 				logCTX.Debug("answer ping")
 				iq.Type = messages.IQTypeResult
 				iq.To = iq.From
 				iq.From = status.client.JID
-				status.client.Out.Encode(iq)
+				status.client.Send(iq)
 			} else {
 				logCTX.Warnf("recv iq unsupport: %s", messages.XMLChildrenString(iq))
 			}
@@ -45,7 +50,7 @@ func (t *Tester) StartBot(status *Status) {
 		}
 
 		pres := &messages.PresenceClient{}
-		err = status.client.In.DecodeElement(pres, element)
+		err = status.client.Decode(pres, element)
 		if err == nil {
 			sender := pres.From
 			logPres := logCTX.WithField("from", sender.Full())
@@ -54,12 +59,12 @@ func (t *Tester) StartBot(status *Status) {
 				pres.Type = messages.PresenceTypeSubscribed
 				pres.To = sender
 				pres.From = nil
-				status.client.Out.Encode(pres)
+				status.client.Send(pres)
 				logPres.Debugf("accept new subscribe")
 
 				pres.Type = messages.PresenceTypeSubscribe
 				pres.ID = ""
-				status.client.Out.Encode(pres)
+				status.client.Send(pres)
 				logPres.Info("request also subscribe")
 			} else if pres.Type == messages.PresenceTypeSubscribed {
 				logPres.Info("recv presence accepted subscribe")
@@ -76,7 +81,7 @@ func (t *Tester) StartBot(status *Status) {
 		}
 
 		msg := &messages.MessageClient{}
-		err = status.client.In.DecodeElement(msg, element)
+		err = status.client.Decode(msg, element)
 		if err != nil {
 			logCTX.Warnf("unsupport xml recv: %s <-> %v", err, element)
 			continue
@@ -100,6 +105,30 @@ func (t *Tester) StartBot(status *Status) {
 		case "ping":
 			status.client.Send(messages.MessageClient{Type: msg.Type, To: msg.From, Body: "pong"})
 
+		case "disconnect":
+			first := true
+			allAdmins := ""
+			isAdmin := false
+			for _, jid := range t.Admins {
+				if first {
+					first = false
+				} else {
+					allAdmins += ", "
+				}
+				allAdmins += jid.Bare()
+				if jid.Bare() == msg.From.Bare() {
+					isAdmin = true
+					status.client.Send(messages.MessageClient{Type: msg.Type, To: jid, Body: "last message, disconnect requested by " + msg.From.Bare()})
+
+				}
+			}
+			if isAdmin {
+				status.Login = false
+				status.client.Close()
+				return
+			}
+			status.client.Send(messages.MessageClient{Type: msg.Type, To: msg.From, Body: "not allowed, ask " + allAdmins})
+
 		case "checkmsg":
 			if len(msgText) == 2 {
 				t.UpdateConnectionStatus(msg.From, status.client.JID, msgText[1])

daemon/tester/config.go

@@ -11,6 +11,8 @@ type Config struct {
 	AccountsPath   string            `toml:"accounts_path"`
 	OutputPath     string            `toml:"output_path"`
 	Logging        log.Level         `toml:"logging"`
+	LoggingClients log.Level         `toml:"logging_clients"`
+	LoggingBots    log.Level         `toml:"logging_bots"`
 	Timeout        duration.Duration `toml:"timeout"`
 	Interval       duration.Duration `toml:"interval"`
 	Admins         []*model.JID      `toml:"admins"`

daemon/tester/status.go

@@ -38,16 +38,26 @@ func (s *Status) Update(timeout time.Duration) {
 		return
 	}
 
-	bareJID := model.NewJID(s.account.JID.Bare())
+	c := &client.Client{
-	if client, err := client.NewClientProtocolDuration(bareJID, s.account.Password, "tcp4", timeout/2); err == nil {
+		JID:      model.NewJID(s.account.JID.Bare()),
+		Protocol: "tcp4",
+		Logging:  s.client.Logging,
+		Timeout:  timeout / 2,
+	}
+
+	if err := c.Connect(s.account.Password); err == nil {
 		s.IPv4 = true
-		client.Close()
+		c.Close()
 	} else {
 		s.IPv4 = false
 	}
-	if client, err := client.NewClientProtocolDuration(bareJID, s.account.Password, "tcp6", timeout/2); err == nil {
+
+	c.JID = model.NewJID(s.account.JID.Bare())
+	c.Protocol = "tcp6"
+
+	if err := c.Connect(s.account.Password); err == nil {
 		s.IPv6 = true
-		client.Close()
+		c.Close()
 	} else {
 		s.IPv6 = false
 	}

daemon/tester/tester.go

@@ -17,6 +17,9 @@ type Tester struct {
 	Accounts       map[string]*Account `json:"accounts"`
 	Status         map[string]*Status  `json:"-"`
 	mux            sync.Mutex
+	LoggingClients *log.Logger  `json:"-"`
+	LoggingBots    log.Level    `json:"-"`
+	Admins         []*model.JID `json:"-"`
 }
 
 func NewTester() *Tester {
@@ -68,7 +71,12 @@ func (t *Tester) Connect(acc *Account) {
 		logCTX.Warn("is already loggedin")
 		return
 	}
-	c, err := client.NewClientProtocolDuration(acc.JID, acc.Password, "tcp", t.Timeout)
+	c := &client.Client{
+		Timeout: t.Timeout,
+		JID:     acc.JID,
+		Logging: t.LoggingClients,
+	}
+	err := c.Connect(acc.Password)
 	if err != nil {
 		logCTX.Warnf("could not connect client: %s", err)
 	} else {
@@ -143,7 +151,7 @@ func (t *Tester) CheckStatus() {
 				logCTXTo = logCTXTo.WithField("msg-old", msg)
 				own.Connections[jid] = false
 				if ok, exists := own.Connections[jid]; !exists || ok {
-					logCTXTo.Warn("could not recv msg")
+					logCTXTo.Info("could not recv msg")
 				} else {
 					logCTXTo.Debug("could not recv msg")
 				}
@@ -157,7 +165,7 @@ func (t *Tester) CheckStatus() {
 				To:   s.JID,
 			})
 			own.MessageForConnection[s.JID.Bare()] = msg
-			logCTXTo.Info("test send")
+			logCTXTo.Debug("test send")
 			send++
 		}
 	}

messages/connection.go

@@ -11,7 +11,7 @@ type StreamFeatures struct {
 	XMLName    xml.Name `xml:"http://etherx.jabber.org/streams features"`
 	StartTLS   *TLSStartTLS
 	Mechanisms SASLMechanisms
-	Bind       Bind
+	Bind       *Bind
 	Session    bool
 }
 

messages/utils.go

@@ -17,6 +17,18 @@ type XMLElement struct {
 	InnerXML string `xml:",innerxml"`
 }
 
+func XMLStartElementToString(element *xml.StartElement) string {
+	if element == nil {
+		return "<nil>"
+	}
+	debug := fmt.Sprintf("<%s xmlns=\"%s\"", element.Name.Local, element.Name.Space)
+	for _, attr := range element.Attr {
+		debug = fmt.Sprintf("%s %s=\"%s\"", debug, attr.Name, attr.Value)
+	}
+	debug += ">"
+	return debug
+}
+
 func XMLChildrenString(o interface{}) (result string) {
 	first := true
 	val := reflect.ValueOf(o)