facebook-api: ignore messages which are sequentially duplicated

Sometimes Facebook will sent a batch of duplicated messages over the
MQTT stream. There are occasions where Facebook will send duplicated
messages which are not sequential, however, it does not occur at the
rete of the sequential duplication. This is likely due to the fact that
the plugin is using an older revision of the Messenger protocol.

For now, we should attempt to ignore sequential duplicates from being
from being display. This fix is not bullet proof, but it is simple, and
should cut down on the duplicated message spam.

The proper fix is likely going to be to update the plugin to use a more
recent Messenger protocol revision.

1 files changed, 17 insertions, 5 deletions

diff --git a/facebook/facebook-api.c b/facebook/facebook-api.c
index dc22bea..4344cf8 100644
--- a/facebook/facebook-api.c
+++ b/facebook/facebook-api.c
@@ -60,7 +60,7 @@ struct _FbApiPrivate
     GQueue *msgs;
     gboolean invisible;
     guint unread;
-
+    FbId lastmid;
 };
 
 struct _FbApiData
@@ -1439,6 +1439,8 @@ fb_api_cb_publish_ms(FbApi *api, GByteArray *pload)
 
     values = fb_json_values_new(root);
     fb_json_values_add(values, FB_JSON_TYPE_INT, FALSE,
+                       "$.deltaNewMessage.messageMetadata.offlineThreadingId");
+    fb_json_values_add(values, FB_JSON_TYPE_INT, FALSE,
                        "$.deltaNewMessage.messageMetadata.actorFbId");
     fb_json_values_add(values, FB_JSON_TYPE_INT, FALSE,
                        "$.deltaNewMessage.messageMetadata"
@@ -1457,6 +1459,20 @@ fb_api_cb_publish_ms(FbApi *api, GByteArray *pload)
     fb_json_values_set_array(values, TRUE, "$.deltas");
 
     while (fb_json_values_update(values, &err)) {
+        id = fb_json_values_next_int(values, 0);
+
+        /* Ignore everything but new messages */
+        if (id == 0) {
+            continue;
+        }
+
+        /* Ignore sequential duplicates */
+        if (id == priv->lastmid) {
+            fb_util_debug_info("Ignoring duplicate %" FB_ID_FORMAT, id);
+            continue;
+        }
+
+        priv->lastmid = id;
         fb_api_message_reset(&msg, FALSE);
         msg.uid = fb_json_values_next_int(values, 0);
         oid = fb_json_values_next_int(values, 0);
@@ -1471,10 +1487,6 @@ fb_api_cb_publish_ms(FbApi *api, GByteArray *pload)
             }
         }
 
-        if (msg.uid == 0) {
-            continue;
-        }
-
         body = fb_json_values_next_str(values, NULL);
 
         if (body != NULL) {