Changeset 38427 for main/trunk/greenstone3/web

Timestamp:

2023-11-23T20:19:49+13:00 (7 months ago)

Author:

anupama

Message:

Maintaining a list of running AJAX calls, which get aborted if the user navigates away from the page before they've finished. When any call terminates (either sucessfully, with error or on abort) it gets removed from the list of *running* Ajax calls, so only running ones can be aborted.

File:

• main/trunk/greenstone3/web/interfaces/default/js/javascript-global-functions.js (modified) (5 diffs)

main/trunk/greenstone3/web/interfaces/default/js/javascript-global-functions.js

@@ -5 +5 @@
 var COMPLETED = 11;
 var HALTED = 12;
+
+var runningAjaxCalls = [];
 
 gs.functions = {};
@@ -548 +550 @@
     // ajax calls default to using method GET, we want to do POST operations for get-meta and set-meta requests
     // since get-meta-array and especially set-meta-array can be large, e.g. for user comments.
-    $.ajax({url: url, async: async_setting, type: method, data: data})
+    var ajaxCall = $.ajax({url: url, async: async_setting, type: method, data: data})
         .done(function(response) {
         ajaxResponse = response;
@@ -561 +563 @@
         if(response.indexOf("ERROR: ") !== -1 || response.indexOf("<Error>") !== -1) {
             if(errorResponseFunction != null) {         
-            console.log("(" + callingFunction + ") Failed with gsdlcgi error:\n" + response);
+            console.log("!!!! (" + callingFunction + ") Failed with gsdlcgi error:\n" + response);
             errorResponseFunction(response);
             } else {
-            alert("(" + callingFunction + ") Failed\n" + response);
-            console.log("(" + callingFunction + ") Failed\n" + response);
-            }
-            
+            alert("@@@ (" + callingFunction + ") Failed\n" + response);
+            console.log("@@@ (" + callingFunction + ") Failed\n" + response);
+            }           
         }
         
@@ -575 +576 @@
         }
         })
-        .fail(function(response) {
+        .fail(function(response, textStatus, errorThrown) {
+        // https://stackoverflow.com/questions/13258784/stopping-an-ajax-call-on-page-unload
+        // https://api.jquery.com/jQuery.ajax/
+        if(textStatus == "abort") {
+            console.log ("INFO: Navigating away from page, so aborted running ajax.");
+        } else {
+        
             if(errorResponseFunction != null) { 
-                console.log("(" + callingFunction + ") Failed\n" + response);   
+                console.log("*** (" + callingFunction + ") Failed\n" + response);   
                 errorResponseFunction(response);
             } else {
                     alert("(" + callingFunction + ") Failed\n" + response);
-                console.log("(" + callingFunction + ") Failed\n" + response);
+                console.log("*** (" + callingFunction + ") Failed\n" + response);
             }
+        }
+        })
+        .always(function(data) { // https://api.jquery.com/jQuery.ajax/
+
+        // this call has terminated one way or another, remove it from the list we maintain
+        // of runningAjaxCalls
+        var index_of_call = runningAjaxCalls.indexOf(ajaxCall);
+        if(index_of_call != -1) {
+            // null this ajaxCall in the runningAjaxCalls array if not already nulled
+            //runningAjaxCalls[index_of_call] = null;
+
+            // remove this 1 call from the runningAjaxCalls array
+            runningAjaxCalls.splice(index_of_call, 1);
+        }
+        
         });
+
+    // now we've launched an ajax call, let's add it to our list of runningAjaxCalls
+    runningAjaxCalls.push(ajaxCall);
     }
     else {
@@ -1120 +1145 @@
     }
 }
+
+// When user prematurely navigates away from current page before the page has finished all
+// running ajax calls, abort those still running. Else the error callback is called
+// and error messages are displayed.
+// https://stackoverflow.com/questions/13258784/stopping-an-ajax-call-on-page-unload
+// See also gs.functions._callMetadataServer() which maintains the array of running ajax calls
+// and removes finished calls from the runningAjaxCalls array.
+//window.onbeforeunload = function(event) {
+$(window).on("beforeunload", function(event) {
+    var i = 0;
+    var ajaxCall;
+    for (i = 0; i < runningAjaxCalls.length; i++) { // list of only *running* ajax calls
+    ajaxCall = runningAjaxCalls[i];
+    // abort each still running ajaxCall (gets removed from runningAjaxCalls list elsewhere)
+        ajaxCall.abort();
+    }
+});