Make keepalive interval configurable

This fixes #133

client.go

@@ -108,6 +108,9 @@ Setting up the client / Checking the 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.
 func NewClient(config Config, r *Router) (c *Client, err error) {
+	if config.KeepaliveInterval == 0 {
+		config.KeepaliveInterval = time.Second * 30
+	}
 	// Parse JID
 	if config.parsedJid, err = NewJid(config.Jid); err != nil {
 		err = errors.New("missing jid")
@@ -185,7 +188,7 @@ func (c *Client) Resume(state SMState) error {
 
 	// Start the keepalive go routine
 	keepaliveQuit := make(chan struct{})
-	go keepalive(c.transport, keepaliveQuit)
+	go keepalive(c.transport, c.config.KeepaliveInterval, keepaliveQuit)
 	// Start the receiver go routine
 	state = c.Session.SMState
 	// Leaving this channel here for later. Not used atm. We should return this instead of an error because right
@@ -312,9 +315,8 @@ func (c *Client) recv(state SMState, keepaliveQuit chan<- struct{}, errChan chan
 // 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(transport Transport, quit <-chan struct{}) {
-	// TODO: Make keepalive interval configurable
-	ticker := time.NewTicker(30 * time.Second)
+func keepalive(transport Transport, interval time.Duration, quit <-chan struct{}) {
+	ticker := time.NewTicker(interval)
 	for {
 		select {
 		case <-ticker.C:

config.go

@@ -2,6 +2,7 @@ package xmpp
 
 import (
 	"os"
+	"time"
 )
 
 // Config & TransportConfiguration must not be modified after having been passed to NewClient. Any
@@ -14,6 +15,7 @@ type Config struct {
 	Credential        Credential
 	StreamLogger      *os.File      // Used for debugging
 	Lang              string        // TODO: should default to 'en'
+	KeepaliveInterval time.Duration // Interval between keepalive packets
 	ConnectTimeout    int           // Client timeout in seconds. Default to 15
 	// Insecure can be set to true to allow to open a session without TLS. If TLS
 	// is supported on the server, we will still try to use it.