1 files changed, 42 insertions, 14 deletions

diff --git a/resource.c b/resource.c
index 8c67635..c89e188 100644
--- a/resource.c
+++ b/resource.c
@@ -12,23 +12,17 @@ struct resource_object {
 static struct resource_object position_object;
 static struct resource_object signal_object;
 
-static void resource_obj_send(struct client *c, struct resource_object *obj)
+static void resource_obj_send_one(gpointer data, gpointer user_data)
 {
-	GString *string = obj->string;
-
-	if (!string)
-		return;
+	GString *string = user_data;
+	struct client *c = data;
 
 	respond_chunk(c, string);
 }
 
-// Update this client with the new resource object data
-static void resource_obj_update(gpointer data, gpointer user_data)
+static void resource_obj_send_all(struct resource_object *obj, GString *str)
 {
-	struct resource_object *obj = user_data;
-	struct client *c = data;
-
-	resource_obj_send(c, obj);
+	g_list_foreach(obj->client_list, resource_obj_send_one, str);
 }
 
 static void resource_obj_set_string(struct resource_object *obj, GString *str)
@@ -39,7 +33,7 @@ static void resource_obj_set_string(struct resource_object *obj, GString *str)
 	obj->string = str;
 	g_string_free(old, TRUE);
 
-	g_list_foreach(obj->client_list, resource_obj_update, obj);
+	resource_obj_send_all(obj, str);
 }
 
 static void resource_obj_add_client(struct resource_object *obj,
@@ -54,10 +48,23 @@ static void resource_obj_del_client(struct resource_object *obj,
 	obj->client_list = g_list_remove(obj->client_list, c);
 }
 
+static GString *object_backend_status(struct resource *r)
+{
+	GString *str;
+
+	str = g_string_new("event: backend\n");
+	g_string_append_printf(str,
+			"data: {\"status\":\"%s\",\"timestamp\":%ld}\n\n",
+			r->updater ? "connected" : "disconnected",
+			r->updater_time);
+
+	return str;
+}
 
 static int object_v1_get(struct client *c, struct resource *r)
 {
 	struct resource_object *obj = r->data;
+	GString *str;
 
 	respond_header(c, 200, "OK",
 		       "Cache-Control: no-cache\r\n"
@@ -65,7 +72,13 @@ static int object_v1_get(struct client *c, struct resource *r)
 		       "Content-Type: text/event-stream; charset=UTF-8\r\n"
 		       "Transfer-Encoding: chunked\r\n");
 
-	resource_obj_send(c, obj);
+	str = object_backend_status(r);
+	g_string_append(str, "retry: 10000\n");
+	if (obj->string)
+		g_string_append_len(str, obj->string->str,
+				    obj->string->len);
+	respond_chunk(c, str);
+	g_string_free(str, TRUE);
 
 	// Add this client to the object list so it receives updates
 	resource_obj_add_client(obj, c);
@@ -83,8 +96,15 @@ static void object_v1_close(struct client *c, struct resource *r)
 
 static void object_v1_update_open(struct client *c, struct resource *r)
 {
+	GString *str;
+
 	// Keep track of the latest updater
 	r->updater = c;
+	time(&r->updater_time);
+
+	str = object_backend_status(r);
+	resource_obj_send_all(r->data, str);
+	g_string_free(str, TRUE);
 }
 
 // Update all attached clients with the new resource object data
@@ -119,10 +139,18 @@ static int object_v1_update(struct client *c, struct resource *r, const char *m)
 
 static void object_v1_update_close(struct client *c, struct resource *r)
 {
+	GString *str;
+
 	// If the updater goes away, clear the data so we don't serve
 	// stale data.
-	if (r->updater == c)
+	if (r->updater == c) {
 		r->updater = NULL;
+		time(&r->updater_time);
+
+		str = object_backend_status(r);
+		resource_obj_send_all(r->data, str);
+		g_string_free(str, TRUE);
+	}
 }
 
 static const struct resource_ops resource_v1_ops = {