When I make a XmlHttpRequest (via jQuery's $.ajax) to a particular URL, my Chrome consistently hangs every time with a status on the request of 'Pending'.
After that Chrome must be closed ie. forcibly from Task Manager, and it exhibits general signs of mayhem such as the Cookies and Scripts tabs being empty when they were full of normal looking data immediately prior.
This is odd because (a) my coworkers, running a seemingly identical everything, have no such problems; (b) I have been using Chrome to run this code (our company's JavaScript app) for many months and this just started happening for no apparent reason.
I checked out the Apache logs, they appear to be processing the request normally and to completion, but Chrome never sees the reply, apparently.
A couple of other clarifications: prior to the failure, the same Chrome and Apache return a truckload of JS and image files normally, eg., things seem to be fine right up until they aren't. The request is not particularly large (a few hundred bytes in and out) or complex in any obvious way.
If anybody can give me some hints of where to look, I'd be grateful!
I'm experiencing similar behavior with slightly different symptoms. My ajax requests work fine, every second request up to 6 requests, then they all start failing (same url as when working, same payload, etc), but in my case they're not even hitting the server, just stuck in "Pending" in Inspector.
I dont have an answer for you, but to help debug, have you tried chromes net-internals?
Point your browser at:
chrome://net-internals/#sockets
and/or
chrome://net-internals/#events
I see my requests in #sockets go into "active", but never come back, and in #events I can see that the request stalls after the HOST_RESOLVER_IMPL_REQUEST stage.
I'm thinking it could be a resource issue caused by not properly ending the request, but thats just pure speculation.
Related
Firefox seems to fail on registering a ServiceWorker for Push Notifications, with an error "InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable", but the code works in Chrome and Edge, and appears to be compliant with the examples online and the spec.
I've thrown an example up on one of my test sites, https://wiegandtech.net/ - visiting it in Chrome will prompt for permission and then opt-in successfully, sending the info to the server. But Firefox prompts, doesn't complete the registration, and doesn't fire any error or throw anything into the console. When I try to debug, it seems to never return from navigator.serviceWorker.ready.then call - I debug in and reg is undefined, even though the promise says it shouldn't be. I can find no reason why this is failing. I do see in Fiddler that FF gets the worker file, so it appears to be starting the call, but never finishing? The worker is valid JavaScript, as far as I can tell. Does anyone have any documentation on how Firefox's implementation is different from Chrome's/the spec?
Firefox requires the ServiceWorker's URL to end in .js - I was using an ASP.Net site and returning javascript but through my own controller. When I just give it the URL for the .js file itself, it now works. Would file a bug, but too non-trivial to setup a site given that ServiceWorkers require a real life site to troubleshoot, and their source code doesn't appear to be on github.
I have a page which will send some ajax request to my Jetty7.6.9 server. All of them containing a COOKIE named JSESSIONID so that the server knows the request is logged in.
But sometimes, the method org.eclipse.jetty.server.Request.getCookies() returns an empty Cookie[]. I set a breakpoint and checked the _connection._requestFields and I found the Cookie right there, but Request.getCookies() cannot fetch it or parse it.
The situation can happen in any one or more ajax request in that page, can happen in any time, can happen in both windows and linux. It seems that it's a random case, and even when I dropped the frame at the breakpoint to the pre line, it would run correctly when it ran to the same place, so I think it's an issue about synchronize/concurrent.
I didn't find the same case in jetty bug list.
Is it a bug? What can I do to verify or repeat it? How to fix it?
(For some reason,maybe I cannot update the Jetty version for our system.)
I am currently working on a Django development. There is a problem, which isn't a true problem but very annoying. Often, when I try to debug my Django app by putting down some break points, I get this error at the server end:
error: [Errno 32] Broken pipe
After reading this other post, Django + WebKit = Broken pipe, I have learned that this has nothing to do with the server but the client browser used. Basically, what happened is that the browser has a http request timeout. If it doesn't receive a response within the timeout, it will close down the connection with the server.
I find this timeout isn't really needed, indeed causing headache, during debugging. Is there any way I can lift this timeout or increase it for my browser (Chrome)? Or maybe a substitute browser that doesn't have this constraint?
Note: Although I am using Django and have mentioned about it, this isn't a Django-related question. It's more like a question on how to make my debugging process more effective.
I prefer using linux/unix curl command for debugging web applications. It's good approach, especially if you want to focus on some specific request, for example: POST does not work fine for some set of parameters, or cookies are not set as expected.
Of course it may take some time at the beginning to find out how to use it, but then, you will have a total control about every single piece of request: timeouts, cookies, headers and so on. It's very helpful, because you can be sure that what you wanted to send is actually sent (no additional data is added by the web browser).
There are several topics about the problem with cross-domain AJAX. I've been looking at these and the conclusion seems to be this:
Apart from using somthing like JSONP, or a proxy sollution, you should not be able to do a basic jquery $.post() to another domain
My test code looks something like this (running on "http://myTestdomain.tld/path/file.html")
var myData = {datum1 : "datum", datum2: "datum"}
$.post("http://External-Ip:port", myData,function(return){alert(return);});
When I tried this (the reason I started looking), chrome-console told me:
XMLHttpRequest cannot load
http://External-IP:port/page.php. Origin
http://myTestdomain.tld is not allowed
by Access-Control-Allow-Origin.
Now this is, as far as I can tell, expected. I should not be able to do this. The problem is that the POST actually DOES come trough. I've got a simple script running that saves the $_POST to a file, and it is clear the post gets trough. Any real data I return is not delivered to my calling script, which again seems expected because of the Access-control issue. But the fact that the post actually arrived at the server got me confused.
Is it correct that I assume that above code running on "myTestdomain" should not be able to do a simple $.post() to the other domain (External-IP)?
Is it expected that the request would actually arrive at the external-ip's script, even though output is not received? or is this a bug. (I'm using Chrome 11.0.696.60 )
I posted a ticket about this on the WebKit bugtracker earlier, since I thought it was weird behaviour and possibly a security risk.
Since security-related tickets aren't publicly viewable, I'll quote the reply from Justin Schuh here:
This is implemented exactly as required by the spec. For simple cross-origin requests http://www.w3.org/TR/cors/#simple-method> there is no pre-flight check; the request is made and the response cannot be read if the appropriate headers do not authorize the requesting origin. Functionally, this is no different than creating a form and using script to make an off-origin POST (which has always been possible).
So: you're allowed to do the POST since you could have done that anyway by embedding a form and triggering the submit button with javascript, but you can't see the result. Because you wouldn't be able to do that in the form scenario.
A solution would be to add a header to the script running on the target server, e.g.
<?php
header("Access-Control-Allow-Origin: http://your_source_domain");
....
?>
Haven't tested that, but according to the spec, that should work.
Firefox 3.6 seems to handle it differently, by first doing an OPTIONS to see whether or not it can do the actual POST. Firefox 4 does the same thing Chrome does, or at least it did in my quick experiment. More about that is on https://developer.mozilla.org/en/http_access_control
The important thing to note about the JavaScript same-origin policy restriction is that it is something built into modern browsers for security - it is not a limitation of the technology or something enforced by servers.
To answer your question, neither of these are bugs.
Requests are not stopped from reaching the server - this gives the server the option to allow these cross-domain requests by setting the appropriate headers1.
The response is also received back by the browser. Before the use of the access control headers 1, responses to cross-domain requests would be stopped dead in their tracks by a security conscious browser - the browser would receive the response but it would not hand it off to the script. With the access control headers, the server has the option of setting the appropriate headers indicating to a compliant browser that it would like to allow certain origin URLs to make cross domain requests.
The exact behaviour on response might differ between browsers - I can't recall for sure now but I think Chrome calls the success callback function when using jQuery's ajax() but the response is empty. IIRC, Firefox will not invoke the success function.
I get the same thing happening for me. You are able to post across domains but are not able to receive a response. This is what I expected to be able to do and happens for me in Firefox, Chrome, and IE.
One way to kind of get around this caveat is having a local php file with will call the data via curl and respond the response to your javascript. (Kind of restated what you said you knew already.)
Yes, it's correct and you won't be able to do that unless you use any proxy.
No, request won't go to the external IP as soon as there is such limitation.
I'm seeing an odd behavior in WebKit (on Android) where my server process is sending it a response that it needs to handle immediately (rather than wait for readyState 4). In Firefox and Safari this works as expected, but on webkit, not only does it not respond to the readyState but instead it appears to fire off a repeat request to the server!
This only seems to happen when the server takes a little while to react to the request. I'm still poking around to see what the exact circumstances are that bring this about, but am curious if this is a known bug and what, if anything, is a workaround.
[EDIT] This is just getting weirder and weirder. As long as the server responds within about 10 seconds, everything is fine. But if it takes longer than that, then the request is resubmitted. However, the browser appears to not be aware of this re-submission, or if it is, it's not reporting it in any way. I attached a unique ID to the request and when it arrives for the second time on the server the id is the same. But it's definitely spawning off an additional call to the server. I'm sort of at a loss as to how to debug this further.
No one has piped in, so. I have fixed the problem by killing the connection from the server side.
So, my solution:
a) client makes call to server (which is a perl.cgi)
b) server code:
print (some JSON for the broswer);
close(STDOUT); #this sends a readyState 4 to the browser and closes the connection.
&methodThatTakesAWhile();
This doesn't explain WHY the browser is misbehaving, but it does get around this particular bug.