I've got a jQuery client making an Ajax post request to a Spring Controller. On the server side, no error has been logged. On the client side, the request is stuck on pending a very long time, minutes, then might fail either with ERR_SPDY_PROTOCOL_ERROR or ERR_CONNECTION_CLOSED.

This problem is reproducible on Chrome, but not on Firefox. Verified affected version is 70.0.3538.77, there may be others too. Also, the problem occurs on a specific deployment of the application and not elsewhere, development or production.

The client sends HTTPS 2 requests on that environment. On the development environment it is HTTP 1.1. On the server, all requests are recorded as 1.1.

For no apparent reason, the requests started going through, but this is a recurring problem and would like to solve it. Since the problem started happening, I can't reproduce it and check if the problem is too many connections to the server (more than 6). I use three DNS servers, the last one of which is Google's 8.8.8.8.

I am looking for a code fix or a hint whether this could be related to server setup. I am almost certain that it is a bination of client code and networking.

What the problem is not:

• Antivirus (Chrome net::ERR_INCOMPLETE_CHUNKED_ENCODING error)

• Prediction service related (Stalled and pending ajax requests by JQuery in Chrome) - the ment about proxy and connections seems more relevant though.

• Ad-blocker extension / plug-in (Failed to load resource under Chrome)

What I've tried unsuccessfully:

• /

• /

• jQuery Ajax requests are getting cancelled without being sent

What doesn't answer the question:

• Ajax request over https hangs for 40 seconds in chrome only

On the client side, I've tried clearing browser data, flushing sockets and private browsing / incognito.

The only thing that sometimes, rarely, bypasses the error is going on incognito and flushing sockets and emptying cache from chrome://net-internals/#events

var formData = new FormData();

formData.append( /* ... */ );

//...

$.ajax({
    type: "POST",
    url: "/somepath/update",
    cache: false,
    data: formData,
    contentType: false,
    processData: false,
    success: function(result) {
        //...
    },
    fail: function(result) {
        //....
    },
    error: function( jqXHR, textStatus, errorThrown ){
        alert(textStatus + ":" + errorThrown);
    }
});

A separate request using $.post was going through:

$.post("someotherpath/update", $("#someForm").serialize())
    .done(function (data) {
        //...
     })
     .fail(function (data) {
         //...
     })
     .always(function () {
         //...
     });

Server side:

@RequestMapping(value="/somepath/update", method = RequestMethod.POST, produces = "application/json;charset=UTF-8")
public @ResponseBody String update(ModelClass model) {
    JSONObject result = new JSONObject();
    //...
    return result.toString();
}

If it's relevant, there are the following filters. I'm afraid I can't post more of them at the moment:

@Configurable
public class Filter1 extends OpenEntityManagerInViewFilter implements Filter{

    public void doFilterInternal(HttpServletRequest httpReq, HttpServletResponse httpResp, FilterChain chain)
        throws ServletException, IOException {
        //...
    }
}


@Configurable
public class Filter2 extends OncePerRequestFilter implements Filter{

    public void doFilterInternal(HttpServletRequest httpReq, HttpServletResponse httpResp, FilterChain chain)
        throws ServletException, IOException {
        //...
    }
}

@Order(/* very small integer */)
public class Filter3 extends OncePerRequestFilter {

}

Expected result is that the code should go through the success callback. Instead the request is stuck on pending for minutes, then enters the error callback.

I've got a jQuery client making an Ajax post request to a Spring Controller. On the server side, no error has been logged. On the client side, the request is stuck on pending a very long time, minutes, then might fail either with ERR_SPDY_PROTOCOL_ERROR or ERR_CONNECTION_CLOSED.

This problem is reproducible on Chrome, but not on Firefox. Verified affected version is 70.0.3538.77, there may be others too. Also, the problem occurs on a specific deployment of the application and not elsewhere, development or production.

The client sends HTTPS 2 requests on that environment. On the development environment it is HTTP 1.1. On the server, all requests are recorded as 1.1.

For no apparent reason, the requests started going through, but this is a recurring problem and would like to solve it. Since the problem started happening, I can't reproduce it and check if the problem is too many connections to the server (more than 6). I use three DNS servers, the last one of which is Google's 8.8.8.8.

I am looking for a code fix or a hint whether this could be related to server setup. I am almost certain that it is a bination of client code and networking.

What the problem is not:

• Antivirus (Chrome net::ERR_INCOMPLETE_CHUNKED_ENCODING error)

• Prediction service related (Stalled and pending ajax requests by JQuery in Chrome) - the ment about proxy and connections seems more relevant though.

• Ad-blocker extension / plug-in (Failed to load resource under Chrome)

What I've tried unsuccessfully:

• https://www.reddit./r/chrome/ments/3ej5ua/err_spdy_protocol_error/

• https://www.itechgyan./err_spdy_protocol_error/

• jQuery Ajax requests are getting cancelled without being sent

What doesn't answer the question:

• Ajax request over https hangs for 40 seconds in chrome only

On the client side, I've tried clearing browser data, flushing sockets and private browsing / incognito.

The only thing that sometimes, rarely, bypasses the error is going on incognito and flushing sockets and emptying cache from chrome://net-internals/#events

var formData = new FormData();

formData.append( /* ... */ );

//...

$.ajax({
    type: "POST",
    url: "/somepath/update",
    cache: false,
    data: formData,
    contentType: false,
    processData: false,
    success: function(result) {
        //...
    },
    fail: function(result) {
        //....
    },
    error: function( jqXHR, textStatus, errorThrown ){
        alert(textStatus + ":" + errorThrown);
    }
});

A separate request using $.post was going through:

$.post("someotherpath/update", $("#someForm").serialize())
    .done(function (data) {
        //...
     })
     .fail(function (data) {
         //...
     })
     .always(function () {
         //...
     });

Server side:

@RequestMapping(value="/somepath/update", method = RequestMethod.POST, produces = "application/json;charset=UTF-8")
public @ResponseBody String update(ModelClass model) {
    JSONObject result = new JSONObject();
    //...
    return result.toString();
}

If it's relevant, there are the following filters. I'm afraid I can't post more of them at the moment:

@Configurable
public class Filter1 extends OpenEntityManagerInViewFilter implements Filter{

    public void doFilterInternal(HttpServletRequest httpReq, HttpServletResponse httpResp, FilterChain chain)
        throws ServletException, IOException {
        //...
    }
}


@Configurable
public class Filter2 extends OncePerRequestFilter implements Filter{

    public void doFilterInternal(HttpServletRequest httpReq, HttpServletResponse httpResp, FilterChain chain)
        throws ServletException, IOException {
        //...
    }
}

@Order(/* very small integer */)
public class Filter3 extends OncePerRequestFilter {

}

Expected result is that the code should go through the success callback. Instead the request is stuck on pending for minutes, then enters the error callback.

• javascript
• jquery
• ajax
• google-chrome

Share Improve this question Follow edited Jan 17, 2019 at 9:21 N Sarj asked Dec 21, 2018 at 10:26 N SarjN Sarj 43444 silver badges1313 bronze badges 19

• 2 And your jquery version is...? :D And have you tried using postman or curl to send a basic request to confirm the server is responding OK to the same type of request? – Cody Geisler Commented Jan 7, 2019 at 14:25
• Thanks for your ment @CodyG. Version is 1.7.2. I haven't tried postman, but I would guess that trying with Firefox is enough. – N Sarj Commented Jan 8, 2019 at 15:42
• 1 Something to consider: I've had various problems because I turned on a flag in chrome://flags/. The flag experimental web platform features turns on some new headers some web servers can't deal with. Try to reset those flags when testing as well. – Sandro Commented Jan 13, 2019 at 10:00
• 2 Could you please have a look at chrome developer tools (press F12 on Win) then Network tab, and try to run your code. It should display the data you're sending and any errors that would e up, and let us know what's the result. Also try to pare the output on Chrome/Firefox/Chrome incognito – Ivan Satsiuk Commented Jan 15, 2019 at 7:44
• 1 Check the protocol. if the page url is "https" then the backend code which you are trying to access also should be secured. i have faced similar issue. – Jackson Commented Jan 16, 2019 at 22:04

 |  Show 14 more ments

1 Answer 1

Sorted by: Reset to default 2

$.post is calling $.ajax under the covers just defaulting several of the options.

$.post defaults contentType to "application/x-www-form-urlencoded; charset=UTF-8" which would be consistent with your serialized form data payload.

Your call to $.ajax sets contentType to false -- which may cause the browser to send a pre-flight OPTIONS request to the server, which may be causing the difference in behavior you're experiencing.

I would suggest reading the details on jQuery.ajax() and the various behaviors based on options passed here