package xmpp import ( "encoding/xml" "errors" "fmt" "net" "strings" "time" ) //============================================================================= // EventManager // ConnState represents the current connection state. type ConnState = uint8 // This is a the list of events happening on the connection that the // client can be notified about. const ( StateDisconnected ConnState = iota StateConnected StateSessionEstablished StateStreamError ) // Event is a structure use to convey event changes related to client state. This // is for example used to notify the client when the client get disconnected. type Event struct { State ConnState Description string StreamError string } // EventHandler is use to pass events about state of the connection to // client implementation. type EventHandler func(Event) type EventManager struct { // Store current state CurrentState ConnState // Callback used to propagate connection state changes Handler EventHandler } func (em EventManager) updateState(state ConnState) { em.CurrentState = state if em.Handler != nil { em.Handler(Event{State: em.CurrentState}) } } func (em EventManager) streamError(error, desc string) { em.CurrentState = StateStreamError if em.Handler != nil { em.Handler(Event{State: em.CurrentState, StreamError: error, Description: desc}) } } // Client // ============================================================================ // Client is the main structure used to connect as a client on an XMPP // server. type Client struct { // Store user defined options and states config Config // Session gather data that can be accessed by users of this library Session *Session // TCP level connection / can be replaced by a TLS session after starttls conn net.Conn // Router is used to dispatch packets router *Router // Track and broadcast connection state EventManager } /* Setting up the client / Checking the parameters */ // NewClient generates a new XMPP client, based on Config passed as parameters. // If host is not specified, the DNS SRV should be used to find the host from the domainpart of the JID. // Default the port to 5222. // TODO: better config checks func NewClient(config Config, r *Router) (c *Client, err error) { // Parse JID if config.parsedJid, err = NewJid(config.Jid); err != nil { err = errors.New("missing jid") return nil, NewConnError(err, true) } if config.Password == "" { err = errors.New("missing password") return nil, NewConnError(err, true) } // fallback to jid domain if config.Address == "" { config.Address = config.parsedJid.Domain } // if address has no port (behind his ipv6 address) - add default port if strings.LastIndex(config.Address, ":") <= strings.LastIndex(config.Address, "]") { config.Address += ":5222" } c = new(Client) c.config = config c.router = r if c.config.ConnectTimeout == 0 { c.config.ConnectTimeout = 15 // 15 second as default } return } // Connect triggers actual TCP connection, based on previously defined parameters. func (c *Client) Connect() error { var err error c.conn, err = net.DialTimeout("tcp", c.config.Address, time.Duration(c.config.ConnectTimeout)*time.Second) if err != nil { return err } c.updateState(StateConnected) // Client is ok, we now open XMPP session if c.conn, c.Session, err = NewSession(c.conn, c.config); err != nil { return err } c.updateState(StateSessionEstablished) // We're connected and can now receive and send messages. //fmt.Fprintf(client.conn, "%s%s", "chat", "Online") // TODO: Do we always want to send initial presence automatically ? // Do we need an option to avoid that or do we rely on client to send the presence itself ? fmt.Fprintf(c.Session.socketProxy, "") // Start the keepalive go routine keepaliveQuit := make(chan struct{}) go keepalive(c.conn, keepaliveQuit) // Start the receiver go routine go c.recv(keepaliveQuit) return err } func (c *Client) Disconnect() { _ = c.SendRaw("") // TODO: Add a way to wait for stream close acknowledgement from the server for clean disconnect _ = c.conn.Close() } func (c *Client) SetHandler(handler EventHandler) { c.Handler = handler } // Send marshals XMPP stanza and sends it to the server. func (c *Client) Send(packet Packet) error { data, err := xml.Marshal(packet) if err != nil { return errors.New("cannot marshal packet " + err.Error()) } if _, err := fmt.Fprintf(c.conn, string(data)); err != nil { return errors.New("cannot send packet " + err.Error()) } return nil } // SendRaw sends an XMPP stanza as a string to the server. // It can be invalid XML or XMPP content. In that case, the server will // disconnect the client. It is up to the user of this method to // carefully craft the XML content to produce valid XMPP. func (c *Client) SendRaw(packet string) error { var err error _, err = fmt.Fprintf(c.Session.socketProxy, packet) return err } // ============================================================================ // Go routines // Loop: Receive data from server func (c *Client) recv(keepaliveQuit chan<- struct{}) (err error) { for { val, err := nextPacket(c.Session.decoder) if err != nil { close(keepaliveQuit) c.updateState(StateDisconnected) return err } // Handle stream errors switch packet := val.(type) { case StreamError: c.router.route(c, val) close(keepaliveQuit) c.streamError(packet.Error.Local, packet.Text) return errors.New("stream error: " + packet.Error.Local) } c.router.route(c, val) } } // Loop: send whitespace keepalive to server // This is use to keep the connection open, but also to detect connection loss // and trigger proper client connection shutdown. func keepalive(conn net.Conn, quit <-chan struct{}) { // TODO: Make keepalive interval configurable ticker := time.NewTicker(30 * time.Second) for { select { case <-ticker.C: if n, err := fmt.Fprintf(conn, "\n"); err != nil || n != 1 { // When keep alive fails, we force close the connection. In all cases, the recv will also fail. ticker.Stop() _ = conn.Close() return } case <-quit: ticker.Stop() return } } }