[FIX] mail: throttle batched `channel_fetched` RPCs

Revision on https://github.com/odoo/odoo/commit/844fb2b51ea7cfa557b19466c0a53dde19433e7a

The commit above added the seen icon on messages in a channel.
However, since this feature, there was a performance issue
when opening the systray messaging menu with several pinned
channels: lots of RPCs are made, almost 1 for each preview
in the messaging menu.

The RPCs comes from the reception of the last message in the
channel, to let the current user notify that he has received
the messages in the channel.
Those RPCs were made for each channel, thus the more pinned
channels the more RPCs were made when opening the messaging
menu.

This commit fixes the issue by throttling and batching the RPCs.
To do so, instead of letting the channel model handle the RPC
`channel_fetched`, the mail service now handles it. This has
the advantage to throttle the RPC globally and to batch the
requests to notify that messages have been received on channels.

closes odoo/odoo#31026

2 files changed, 11 insertions, 60 deletions

diff --git a/addons/mail/static/src/js/models/threads/channel.js b/addons/mail/static/src/js/models/threads/channel.js
index 7db3474ebb2..a2316edb7be 100644
--- a/addons/mail/static/src/js/models/threads/channel.js
+++ b/addons/mail/static/src/js/models/threads/channel.js
@@ -387,24 +387,10 @@ var Channel = SearchableThread.extend(ChannelSeenMixin, ThreadTypingMixin, {
      */
     _markAsRead: function () {
         var superDef = this._super.apply(this, arguments);
-        var seenDef = this._throttleNotifySeen();
+        var seenDef = this._notifySeen();
         return $.when(superDef, seenDef);
     },
     /**
-     * @override {mail.model.ThreadSeenMixin}
-     * @private
-     * @returns {$.Promise}
-     */
-    _notifyFetched: function () {
-        return this._rpc({
-            model: 'mail.channel',
-            method: 'channel_fetched',
-            args: [[this._id]],
-        }, {
-            shadow: true
-        });
-    },
-    /**
      * @override {mail.model.ThreadTypingMixin}
      * @private
      * @param {Object} params
@@ -420,25 +406,6 @@ var Channel = SearchableThread.extend(ChannelSeenMixin, ThreadTypingMixin, {
         }, { shadow: true });
     },
     /**
-     * @override {mail.model.ThreadSeenMixin}
-     * @private
-     * @returns {$.Promise<integer>} resolved with ID of last seen message
-     */
-    _notifySeen: function () {
-        var self = this;
-        this._cancelThrottledNotifyFetched();
-        return this._rpc({
-            model: 'mail.channel',
-            method: 'channel_seen',
-            args: [[this._id]],
-        }, {
-            shadow: true
-        }).then(function (lastSeenMessageID) {
-            self._lastSeenMessageID = lastSeenMessageID;
-            return lastSeenMessageID;
-        });
-    },
-    /**
      * Prepare and send a message to the server on this channel.
      *
      * @override
diff --git a/addons/mail/static/src/js/models/threads/mixins/channel_seen_mixin.js b/addons/mail/static/src/js/models/threads/mixins/channel_seen_mixin.js
index 8a59db70aa2..022994673d2 100644
--- a/addons/mail/static/src/js/models/threads/mixins/channel_seen_mixin.js
+++ b/addons/mail/static/src/js/models/threads/mixins/channel_seen_mixin.js
@@ -1,8 +1,6 @@
 odoo.define('mail.model.ChannelSeenMixin', function (require) {
 "use strict";
 
-var CCThrottleFunction = require('mail.model.CCThrottleFunction');
-
 var session = require('web.session');
 
 /**
@@ -25,12 +23,6 @@ var ChannelSeenMixin = {
     init: function (params) {
         this._seenPartnersInfo = params.data.seen_partners_info || [];
 
-        this._throttleNotifySeen = _.throttle(this._notifySeen.bind(this), 3000);
-        this._throttleNotifyFetched = CCThrottleFunction({
-            duration: 3000,
-            func: this._notifyFetched.bind(this),
-        });
-
         this.on('message_added', this, this._onSeenMessageAdded);
     },
 
@@ -226,26 +218,18 @@ var ChannelSeenMixin = {
 
     /**
      * @private
-     */
-    _cancelThrottledNotifyFetched: function () {
-        this._throttleNotifyFetched.cancel();
-        this._throttleNotifyFetched.clear();
-    },
-    /**
-     * @abstract
-     * @private
-     * @returns {$.Promise}
-     */
-    _notifyFetched: function () {
-        return $.when();
-    },
-    /**
-     * @abstract
-     * @private
      * @returns {$.Promise<integer>} resolved with ID of last seen message
      */
     _notifySeen: function () {
-        return $.when();
+        var self = this;
+        return this._rpc({
+            model: 'mail.channel',
+            method: 'channel_seen',
+            args: [[this._id]],
+        }, { shadow: true }).then(function (lastSeenMessageID) {
+            self._lastSeenMessageID = lastSeenMessageID;
+            return lastSeenMessageID;
+        });
     },
 
     //--------------------------------------------------------------------------
@@ -256,7 +240,7 @@ var ChannelSeenMixin = {
      * @private
      */
     _onSeenMessageAdded: function () {
-        this._throttleNotifyFetched();
+        this.call('mail_service', 'notifyChannelFetched', { channelID: this._id });
     },
 };