Add code to switch backends; not yet used.

[remoteglot] / www / js / remoteglot.js

diff --git a/www/js/remoteglot.js b/www/js/remoteglot.js
index 440419fd0062eb702e5f928655b1e22b0092ef13..f21273edd8a0f4e49bb9f24e6989d99b0a6458d5 100644 (file)
--- a/www/js/remoteglot.js
+++ b/www/js/remoteglot.js
@@ -1,5 +1,22 @@
 (function() {
 
+/**
+ * Version of this script. If the server returns a version larger than
+ * this, it is a sign we should reload to upgrade ourselves.
+ *
+ * @type {Number}
+ * @const
+ * @private */
+var SCRIPT_VERSION = 2015062104;
+
+/**
+ * The current backend URL.
+ *
+ * @type {!string}
+ * @private
+ */
+var backend_url = "/analysis.pl";
+
 /** @type {window.ChessBoard} @private */
 var board = null;
 
@@ -108,6 +125,32 @@ var current_display_line_is_history = false;
 /** @type {?number} @private */
 var current_display_move = null;
 
+/**
+ * The current backend request to get main analysis (not history), if any,
+ * so that we can abort it.
+ *
+ * @type {?jqXHR}
+ * @private
+ */
+var current_analysis_xhr = null;
+
+/**
+ * The current timer to fire off a request to get main analysis (not history),
+ * if any, so that we can abort it.
+ *
+ * @type {?Number}
+ * @private
+ */
+var current_analysis_request_timer = null;
+
+/**
+ * The current backend request to get historic data, if any.
+ *
+ * @type {?jqXHR}
+ * @private
+ */
+var current_historic_xhr = null;
+
 var supports_html5_storage = function() {
        try {
                return 'localStorage' in window && window['localStorage'] !== null;
@@ -131,8 +174,10 @@ var get_unique = function() {
 }
 
 var request_update = function() {
-       $.ajax({
-               url: "/analysis.pl?ims=" + ims + "&unique=" + unique
+       current_analysis_request_timer = null;
+
+       current_analysis_xhr = $.ajax({
+               url: backend_url + "?ims=" + ims + "&unique=" + unique
        }).done(function(data, textstatus, xhr) {
                sync_server_clock(xhr.getResponseHeader('Date'));
                ims = xhr.getResponseHeader('X-RGLM');
@@ -144,16 +189,28 @@ var request_update = function() {
                } else {
                        new_data = data;
                }
+
+               var minimum_version = xhr.getResponseHeader('X-RGMV');
+               if (minimum_version && minimum_version > SCRIPT_VERSION) {
+                       // Upgrade to latest version with a force-reload.
+                       location.reload(true);
+               }
+
                possibly_play_sound(current_analysis_data, new_data);
                current_analysis_data = new_data;
                update_board(current_analysis_data, displayed_analysis_data);
                update_num_viewers(num_viewers);
 
                // Next update.
-               setTimeout(function() { request_update(); }, 100);
-       }).fail(function() {
-               // Wait ten seconds, then try again.
-               setTimeout(function() { request_update(); }, 10000);
+               current_analysis_request_timer = setTimeout(function() { request_update(); }, 100);
+       }).fail(function(jqXHR, textStatus, errorThrown) {
+               if (textStatus === "abort") {
+                       // Aborted because we are switching backends. Abandon and don't retry,
+                       // because another one is already started for us.
+               } else {
+                       // Backend error or similar. Wait ten seconds, then try again.
+                       current_analysis_request_timer = setTimeout(function() { request_update(); }, 10000);
+               }
        });
 }
 
@@ -1193,14 +1250,19 @@ var update_historic_analysis = function() {
        var filename = "/history/move" + (current_display_move + 1) + "-" +
                hiddenboard.fen().replace(/ /g, '_').replace(/\//g, '-') + ".json";
 
-       $.ajax({
+       current_historic_xhr = $.ajax({
                url: filename
        }).done(function(data, textstatus, xhr) {
                displayed_analysis_data = data;
                update_board(current_analysis_data, displayed_analysis_data);
-       }).fail(function() {
-               displayed_analysis_data = {'failed': true};
-               update_board(current_analysis_data, displayed_analysis_data);
+       }).fail(function(jqXHR, textStatus, errorThrown) {
+               if (textStatus === "abort") {
+                       // Aborted because we are switching backends. Don't do anything;
+                       // we will already have been cleared.
+               } else {
+                       displayed_analysis_data = {'failed': true};
+                       update_board(current_analysis_data, displayed_analysis_data);
+               }
        });
 }
 
@@ -1299,6 +1361,37 @@ var set_sound = function(param_enable_sound) {
 }
 window['set_sound'] = set_sound;
 
+/**
+ * @param {string} new_backend_url
+ */
+var switch_backend = function(new_backend_url) {
+       // Stop looking at historic data.
+       current_display_line = null;
+       current_display_move = null;
+       displayed_analysis_data = null;
+       if (current_historic_xhr) {
+               current_historic_xhr.abort();
+       }
+
+       // If we already have a backend response going, abort it.
+       if (current_analysis_xhr) {
+               current_analysis_xhr.abort();
+       }
+
+       // Otherwise, we should have a timer going to start a new one.
+       // Kill that, too.
+       if (current_analysis_request_timer) {
+               clearTimeout(current_analysis_request_timer);
+               current_analysis_request_timer = null;
+       }
+
+       // Request an immediate fetch with the new backend.
+       backend_url = new_backend_url;
+       ims = 0;
+       request_update();
+}
+window['switch_backend'] = switch_backend;
+
 var init = function() {
        unique = get_unique();