I just spent several hours of my life debugging this problem. I'm documenting it here for others.
Question:
I'm getting the following error when I try to click on an AjaxLink in Internet Explorer:
Wicket: ERROR: Wicket.Ajax.Call.failure: Error while parsing response: Object required
It works fine in all other browsers; just IE is busted.
Check to make sure that your HTML is 100% syntactically correct. Ajax responses are returned to the browser inside a CDATA section, and if the payload is not well-formed, IE will sometimes choke.
In my case I neglected to close a <link> tag in the <head> section. Simply closing that link tag made all the difference.
Aside: if you ever come across a tough-to-solve problem in Wicket, it's a good idea to create a quickstart project that reproduces your issue. It can be a lot of work to boil things down, but in doing so you often find the source of the problem.
I want to note one more potential reason for the issue with Wicket's AJAX in IE. It might help someone, who encounters similar problem.
In my case I had the following error message in IE:
Wicket: ERROR: Wicket.Ajax.Call.failure: Error while parsing response: could not find root <ajax-response> element
The reason was an incorrect Content-Type of AJAX response. I used AbstractTransformerBehavior and there was a bug in Wicket 1.4.x so this behavior was rewriting response Content-Type with text/html. IE does not parse such response as XML.
Related
The site works fine on Chrome/iOS/Safari/Android (you should be able to select and image and proceed to write a message on the next step). Firefox refuses to run my project's main script (you can't select an image or go forward), and gives the following error in the console:
> Content Security Policy: Directive ‘frame-src’ has been deprecated.
> Please use directive ‘child-src’ instead. (3) Unknown
It's very cryptic. I've tried the following:
1) Adding a meta tag for the CSP in the header.
Result: Creates more errors if restrictive, same amount of errors if
left to wildcards on all parameters.
2) Locally serving all scripts.
Result: I still get three unknown CSP errors. It also loads a lot
slower since the dependencies are not being loaded from a CDN.
3) Removing specific scripts.
Result: It reduces the errors by up to one, but it seems all scripts
are equally responsible. Very strange behavior.
Is this a bug in Firefox that is unsolvable? I'm tearing my hair out over this.
I needed to put listeners in $(document).ready as Firefox loads things differently as pointed out to me by Matt Gibson.
Content Security Policy did not cause the script to fail. However, it is a weird error message that gives you no information to where the error is originating, and can potentially break the site, but that is not what happened here.
I am writing a website with Struts and Tomcat as the server.
On a page there's an ajax post request using jQuery (not cross-domain). The returned value is plain html.
The problem is, I sometimes (not always, not even frequent) get 412 (Precondition Failed) error. What could be the cause of this unstable error?
I'm posting an answer because I've just had this issue today. It's obviously an update to Mod Security in my case.
I was sending data to the server via AJAX and some Javascript which was part of this message caused the 412. It turned out to be the word HTML (I was passing element.innerHTML within the code)
ModSecurity treats that as a potential threat by the looks of it. For a quick fix I replaced all HTML strings with H%T%M%L and reversed the process on the server and it's now running.
You've probably long-since solved this but posting in case it's useful for anyone else.
Just today i was facing the same problem "412 Precondition Failed".
It is a Codeigntier app that uploads audio and Image files.
Till now a lot of files uploaded through the Ajax File uploader. But today i file was not uploading and through chrome Inspect > Network i found that error 412 Precondition Failed.
I re-uploaded the file so many file by changing my ajax script multiple times.
Suddenly some special character caught my attention. I renamed the file and tried to re-upload. Trust me it worked.
Before:
AFTER:
I don't have proper explanation but it works for me.
Thanks
I have a web application that crashes on ajax requests with google chrome (it works with every other web browser it was tested it). After debugging I found that the error is caused by response.responseText being undefined. The xhr object looks like this:
argument: undefined
isAbort: false
isTimeout: undefined
status: 0
statusText: "communication failure"
tId: 3
In debugger in the 'network' tab I get "(failed)", however all the headers are there and I can even copy into clipboard the response body (which is a valid JSON).
My question is - how can I debug this problem? Where to find additional information, what causes this request to fail?
I finally found the solution to my problem : AdBlocks, when it blocks an ajax request, it just says "communication failure".
The first thing I would double-check is that the data coming back from the response is valid JSON. Just pass it through a JSON validator like this online JSONLint: http://jsonlint.com/
I assume that you are using something like jQuery to make your AJAX requests. If so, then make sure that you are using the development version of that library. Now that you are using the development version (uncompressed) of the script, find the particular function that you are using (eg. $.ajax) and then, within the Chrome inspector, insert a breakpoint in the code where the AJAX response is first handled (eg. https://github.com/jquery/jquery/blob/master/src/ajax.js#L579). Then proceed to step through the code, inspecting various return-values to see exactly what is going wrong.
If you are not using something like jQuery to make AJAX calls, then I'd recommend using a framework to avoid possible cross-browser compatibility issues like you might be experiencing right now.
I'm getting some js errors only for some users, and only every once in a while on a page that uses quite a bit of ASP.NET AJAX.
The page also does some intense SQL querying and some string manipulation to highlight text found in the search results.
Could this be a result of performance? Is it always safe to use ASP.NET AJAX in demanding situations or should I be looking to other AJAX techniques?
(By the way the errors I sometime see are):
Message: Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 12031
Message: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.
Details: Error parsing near ' '.
ASP.NET AJAX has been known to not be the most performance intensive approach, but that's what you got i suppose in exchange for how simple it is to implement.
I do know you aren't allowed to do any Response.Writes within an update panel. That will cause your second error.
This particular exception is very
common and can be caused by any one of
the following:
1. Calls to Response.Write():
By calling Response.Write() directly you are bypassing the normal
rendering mechanism of ASP.NET
controls. The bits you write are going
straight out to the client without
further processing (well, mostly...).
This means that UpdatePanel can't
encode the data in its special format.
2. Response filters:
Similar to Response.Write(), response filters can change the
rendering in such a way that the
UpdatePanel won't know.
3. HttpModules:
Again, the same deal as Response.Write() and response filters.
4. Server trace is enabled:
If I were going to implement trace again, I'd do it differently.
Trace is effectively written out using
Response.Write(), and as such messes
up the special format that we use for
UpdatePanel.
5. Calls to Server.Transfer():
Unfortunately, there's no way to detect that Server.Transfer() was
called. This means that UpdatePanel
can't do anything intelligent when
someone calls Server.Transfer(). The
response sent back to the client is
the HTML markup from the page to which
you transferred. Since its HTML and
not the special format, it can't be
parsed, and you get the error.
Complete Post : ASP.NET AJAX and Sys.Webforms.PageRequestManagerServerErrorException
You can grab the code which causes the error by using Visual Studio Debug feature. I don't know much but maybe it can help and also Firebug will help you to see server response and data you submit to the server.
Here is a video where you can see how to use Firebug to debug Ajax.
See how I used Firebug to learn jQuery
But I don't think Asp.NET Ajax should be avoided in heavy loaded pages. That is actually what Ajax stands for right ? I mean it also relieves servers to send small pieces of pages instead of requesting the whole page again.
I have an app that I'm creating with CakePHP, which rewrites the url from something illegible to most users to something a little easier to comprehend. I'm having a problem when I use the FBML canvas.
When I try to access, say, http://apps.facebook.com/myapp/articles, I get the following error:
Received HTTP error code 404 while
loading
http://www.myapp.com/myapparticles/
I did notice that when I try to access http://apps.facebook.com/myapp/articles/posts, it changes the error to show the following url, which is slightly different: http://www.myapp.com/myapparticles/posts
Which lead me to try accessing it with this: http://apps.facebook.com/myapp//articles, which does work most of the time, though for some reason sometimes it will give the previous error. (And it also seems like a hack-y way of getting it to work).
I'm at a loss for how to fix this.
Turns out I was missing the trailing slash (http://www.myapp.com/myapp/) on the url that I specified as my canvas callback, which is in the app settings. Putting it there fixes the problem.
This happens when you are not using semantic markup or you have an error or some code not supported by fb. Also that famous error is generated by fb when it is down or slow too.
I would suggest you checking your code thoroughly and going through fb documentation. That should help you the most. thanks