all: cast ip address to use to be specified via flags.

Add an 'addr' command line flag to accept the address of the chromecast
device to use. This may be required if the multicast DNS doesn't work
because of networking setup. This will allow the user to specify the ip
address of the device to use. This does require the user to know the ip
address, but that can be found trivially.

Fix panic when no connection available.

Clean up error messages.

Updates: #24

Author: vishen

README.md

@@ -49,6 +49,10 @@ Idle (Backdrop), volume=1.00 muted=false
 $ go-chromecast status -n "Living Room Speaker"
 Idle, volume=0.17 muted=false
 
+# Specify a cat device by ip address.
+$ go-chromecast status -a 192.168.0.52
+Idle, volume=0.17 muted=false
+
 # Specify a cast device uuid.
 $ go-chromecast status -u b87d86bed423a6feb8b91a7d2778b55c
 Idle (Default Media Receiver), volume=0.17 muted=false
@@ -205,11 +209,13 @@ Available Commands:
   watch       Watch all events sent from a chromecaset device
 
 Flags:
+  -a, --addr string          Address of the chromecast device
       --debug                debug logging
   -d, --device string        chromecast device, ie: 'Chromecast' or 'Google Home Mini'
   -n, --device-name string   chromecast device name
       --disable-cache        disable the cache
   -h, --help                 help for go-chromecast
+  -p, --port string          Port of the chromecast device if 'addr' is specified (default "8009")
   -u, --uuid string          chromecast device uuid
       --with-ui              run with a UI
 

application/application.go

@@ -157,7 +157,7 @@ func (a *Application) Start(entry castdns.CastDNSEntry) error {
 	}
 
 	if err := a.conn.Start(entry.GetAddr(), entry.GetPort()); err != nil {
-		return errors.Wrap(err, "unable to start connection")
+		return err
 	}
 	if err := a.sendDefaultConn(&cast.ConnectHeader); err != nil {
 		return errors.Wrap(err, "unable to connect to chromecast")

cast/connection.go

@@ -109,6 +109,9 @@ func (c *Connection) Send(requestID int, payload Payload, sourceID, destinationI
 func (c *Connection) receiveLoop() {
 	for {
 		var length uint32
+		if c.conn == nil {
+			continue
+		}
 		if err := binary.Read(c.conn, binary.BigEndian, &length); err != nil {
 			c.log("failed to binary read payload: %v", err)
 			break

cmd/root.go

@@ -45,4 +45,6 @@ func init() {
 	rootCmd.PersistentFlags().StringP("device", "d", "", "chromecast device, ie: 'Chromecast' or 'Google Home Mini'")
 	rootCmd.PersistentFlags().StringP("device-name", "n", "", "chromecast device name")
 	rootCmd.PersistentFlags().StringP("uuid", "u", "", "chromecast device uuid")
+	rootCmd.PersistentFlags().StringP("addr", "a", "", "Address of the chromecast device")
+	rootCmd.PersistentFlags().StringP("port", "p", "8009", "Port of the chromecast device if 'addr' is specified")
 }

cmd/utils.go

@@ -48,33 +48,48 @@ func castApplication(cmd *cobra.Command, args []string) (*application.Applicatio
 	device, _ := cmd.Flags().GetString("device")
 	debug, _ := cmd.Flags().GetBool("debug")
 	disableCache, _ := cmd.Flags().GetBool("disable-cache")
+	addr, _ := cmd.Flags().GetString("addr")
+	port, _ := cmd.Flags().GetString("port")
 
-	// If a device name or uuid was specified, check the cache for the ip+port
 	var entry castdns.CastDNSEntry
-	found := false
-	if !disableCache && (deviceName != "" || deviceUuid != "") {
-		entry = findCachedCastDNS(deviceName, deviceUuid)
-		found = entry.GetAddr() != ""
-	}
-	if !found {
-		var err error
-		if entry, err = findCastDNS(device, deviceName, deviceUuid); err != nil {
-			return nil, errors.Wrap(err, "unable to find cast dns entry")
+	// If no address was specified, attempt to determine the address of any
+	// local chromecast devices.
+	if addr == "" {
+		// If a device name or uuid was specified, check the cache for the ip+port
+		found := false
+		if !disableCache && (deviceName != "" || deviceUuid != "") {
+			entry = findCachedCastDNS(deviceName, deviceUuid)
+			found = entry.GetAddr() != ""
 		}
-	}
-	if !disableCache {
-		cachedEntry := CachedDNSEntry{
-			UUID: entry.GetUUID(),
-			Name: entry.GetName(),
-			Addr: entry.GetAddr(),
-			Port: entry.GetPort(),
+		if !found {
+			var err error
+			if entry, err = findCastDNS(device, deviceName, deviceUuid); err != nil {
+				return nil, errors.Wrap(err, "unable to find cast dns entry")
+			}
+		}
+		if !disableCache {
+			cachedEntry := CachedDNSEntry{
+				UUID: entry.GetUUID(),
+				Name: entry.GetName(),
+				Addr: entry.GetAddr(),
+				Port: entry.GetPort(),
+			}
+			cachedEntryJson, _ := json.Marshal(cachedEntry)
+			cache.Save(getCacheKey(cachedEntry.UUID), cachedEntryJson)
+			cache.Save(getCacheKey(cachedEntry.Name), cachedEntryJson)
+		}
+		if debug {
+			fmt.Printf("using device name=%s addr=%s port=%d uuid=%s\n", entry.GetName(), entry.GetAddr(), entry.GetPort(), entry.GetUUID())
+		}
+	} else {
+		p, err := strconv.Atoi(port)
+		if err != nil {
+			return nil, errors.Wrap(err, "port needs to be a number")
+		}
+		entry = CachedDNSEntry{
+			Addr: addr,
+			Port: p,
 		}
-		cachedEntryJson, _ := json.Marshal(cachedEntry)
-		cache.Save(getCacheKey(cachedEntry.UUID), cachedEntryJson)
-		cache.Save(getCacheKey(cachedEntry.Name), cachedEntryJson)
-	}
-	if debug {
-		fmt.Printf("using device name=%s addr=%s port=%d uuid=%s\n", entry.GetName(), entry.GetAddr(), entry.GetPort(), entry.GetUUID())
 	}
 	app := application.NewApplication(debug, disableCache)
 	if err := app.Start(entry); err != nil {

dns/dns.go

@@ -58,9 +58,11 @@ func FindCastDNSEntries() []CastEntry {
 	entriesCh := make(chan *mdns.ServiceEntry, 20)
 	go func() {
 		// This will find any and all google products, including chromecast, home mini, etc.
+		fmt.Println("WERD")
 		mdns.Query(&mdns.QueryParam{
 			Service: "_googlecast._tcp",
-			Domain:  "local",
+			// Domain:  "local",
+			Domain:  "192.168.0.1",
 			Timeout: time.Second * 3,
 			Entries: entriesCh,
 		})