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https://issues.apache.org/jira/browse/CB-4873?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14008116#comment-14008116
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Maris Seimanovs edited comment on CB-4873 at 5/24/14 1:05 PM:
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I found that in the attached project I have to add the
window.__onXHRLocalCallback[resolvedUrl] fix to be able to run this project on
WP8.1 without any exceptions, and then also the AJAX issue disappears.
In the Corodva 3.4.0 we didn't have such exceptions even with the AJAX issue.
It seems, there are some other changes also affecting this - maybe changes from
Cordova 3.4.0 to the version used in the attached project, or maybe the project
itself has something particular that causes exceptions without the
window.__onXHRLocalCallback[resolvedUrl] fix.
Here is my version of XHRHelper.cs:
https://gist.github.com/anonymous/5bf4d9ba9cdb5d0f3f3e
I took the file from the attached project and added some changes, and now it
runs without exceptions and 'nativeReady' message also is gone on both WP8 and
WP8.1 emulators, and AJAX results are correct. No other changes were necessary
in the attached project, just the ones in XHRHelper.cs.
Still out of curiosity, I'll try to create a simple test project based on
Cordova 3.4.0 to demonstrate the issue because with the attached
CordovaWP8_3.6.0-dev1.zip project those WP8.1 exceptions mess things up
completely.
was (Author: midix):
I found that in the attached project I have to add the
window.__onXHRLocalCallback[resolvedUrl] fix to be able to run this project on
WP8.1 without any exceptions, and then also the AJAX issue disappears.
In the Corodva 3.4.0 we didn't have such exceptions even with the AJAX issue.
It seems, there are some other changes also affecting this - maybe changes from
Cordova 3.4.0 to the version used in the attached project, or maybe the project
itself has something particular that causes exceptions without the
window.__onXHRLocalCallback[resolvedUrl] fix.
Here is my version of XHRHelper.cs:
https://gist.github.com/anonymous/5bf4d9ba9cdb5d0f3f3e
I took the file from the attached project and added some changes, and now it
runs without exceptions and 'nativeReady' message also is gone on both WP8 and
WP8.1 emulators, and AJAX results are correct.
Still out of curiosity, I'll try to create a simple test project based on
Cordova 3.4.0 to demonstrate the issue because with the attached
CordovaWP8_3.6.0-dev1.zip project those WP8.1 exceptions mess things up
completely.
> XHRHelper is failing with simultaneous asynchronous requests
> ------------------------------------------------------------
>
> Key: CB-4873
> URL: https://issues.apache.org/jira/browse/CB-4873
> Project: Apache Cordova
> Issue Type: Bug
> Components: WP7, WP8
> Affects Versions: 3.0.0
> Environment: Any
> Reporter: Jonathan Naguin
> Assignee: Jesse MacFadyen
> Priority: Critical
> Labels: WP8, WP8.1, ajax, asynchronous, multiple, xhrhelper
> Attachments: CordovaWP8_3.6.0-dev1.zip
>
>
> XHRHelper is failing in processing mutiple simultaneous asynchronous AJAX
> requests. I am using the latest code from
> https://github.com/apache/cordova-wp8/blob/master/wp8/template/cordovalib/XHRHelper.cs
> The problem is related with {{_onXHRLocalCallback}} which is save into the
> {{window}} object as a unique function. When, for example, two Ajax requests
> are evaluated at same time, the last {{funk}} function overrides the first
> {{_onXHRLocalCallback}} without receive the data from the C# code to that
> particular request.
> To demostrate this I put {{console.log("XHR: " + resolvedUrl);}} inside
> {{__onXHRLocalCallback}} and
> {{System.Diagnostics.Debug.WriteLine("HandleCommand: " + url);}} in
> {{HandleCommand}} method (my code uses *Require JS* to load this resources).
> The output is this:
> {code}
> HandleCommand: x-wmapp0:www/src/modules/home/HomeView.html
> HandleCommand: x-wmapp0:www/src/modules/orders/OrdersView.html
> XHR: x-wmapp0:www/src/modules/orders/OrdersView.html
> XHR: x-wmapp0:www/src/modules/orders/OrdersView.html
> XHR: HandleCommand: x-wmapp0:www/src/modules/order/OrderDetailView.html
> XHR: x-wmapp0:www/src/modules/order/OrderDetailView.html
> {code}
> As you can see, one request is missing: "HomeView.html".
> h6. NOTES
> - If I set {{false}} the {{this.isAsync}} variable it works (this way it is
> executed without using setTimeout).
> - If I put a console.log before launch {{funk}} it works.
> - It works on the simulator, but it fails on a real device.
> h6. Possible solution
> In conclusion, I assumed that it's a timing problem. To resolve it I decided
> to save a onXHRLocalCallback function per each request:
> {code}
> var funk = function () {
> if (! window.__onXHRLocalCallback){
> window.__onXHRLocalCallback = {}; //Object to store the functions
> }
>
> window.__onXHRLocalCallback[resolvedUrl] = function (responseCode,
> responseText) {
> alias.status = responseCode;
> if (responseCode == '200') {
> alias.responseText = responseText;
> }
> else {
> alias.onerror && alias.onerror(responseCode);
> }
> alias.changeReadyState(XHRShim.DONE);
> delete window.__onXHRLocalCallback[resolvedUrl]; //Delete the function
> }
> alias.changeReadyState(XHRShim.LOADING);
> window.external.Notify('XHRLOCAL/' + resolvedUrl);
> }
> {code}
> So I had to change in {{HandleCommand}} method the way of invoking this
> callback. I decided to create a helper function to be called in each case:
> {code}
> /// <summary>
> /// Invoke a XHR callback
> /// </summary>
> /// <param name="url">The URL of the request</param>
> /// <param name="code">The response code</param>
> /// <param name="text">The response text</param>
> private void InvokeCallback(string url, int code, string text)
> {
> string args = string.Format("('{0}', {1}, {2});", code,
> WPCordovaClassLib.Cordova.JSON.JsonHelper.Serialize(text),
> WPCordovaClassLib.Cordova.JSON.JsonHelper.Serialize(url));
> string callback = @"(function(code, text, url){
> try {
> window.__onXHRLocalCallback[ url ].call(null, code, text);
> }
> catch(e) {
> console.log('Error calling method from XHRHelper :: ' + e);
> }
> })" + args;
> Browser.InvokeScript("eval", new string[] { callback });
> }
> {code}
> To be called as {{InvokeCallback(url, 200, text);}} or {{InvokeCallback(url,
> 404, null);}}
> Thanks.
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