EmberData find request isRejected, how do I debug this?

Question

I'm having a similar problem as: Find operation (AJAX request) rejected, not seen in the wire

However, in my case, I am making one request. This request works on normal page load. It fails to load silently after a form submit (not through ember), that redirects back to the same page. There is no AJAX request being made.

My main question is: how do I go about debugging issues like this?

What I've Tried

I've added console.log statements in all sorts of places to understand the request lifecycle.

Since I've read that promises can get rejected if something throws an exception within it, I've tried switching the chrome debugger to "Pause on all exceptions" (as opposed to "Pause on uncaught exceptions"). Of course it breaks at a bunch of exceptions like:

            // This should fail with an exception
            // Gecko does not error, returns false instead
            try {
                matches.call( div, "[test!='']:sizzle" );

But since I have a way to get the request to work and a way to get it to not work, I can easily compare the difference. I expected there to be an uncaught exception when my request failed, but no such luck.

I've also added a

Ember.RSVP.configure('onerror', function(error) {
  console.log(error.message);
  console.log(error.stack);
});

block, but it does not get called.

I've also poked around at different objects in the console to try and understand my application state:

store = App.__container__.lookup('store:main')
b = store.find('bundle')
b.isRejected // => true
b.reason.statusText // => "error"

Update: More Details

The project I am working on is backed by rails. I am using:

DEBUG: -------------------------------
DEBUG: Ember.VERSION : 1.0.0
DEBUG: Handlebars.VERSION : 1.0.0 
DEBUG: jQuery.VERSION : 1.8.3
DEBUG: -------------------------------

And it doesn't show up in the debug output, but I'm using ember-data 1.0 beta 3:

// Version: v1.0.0-beta.3
// Last commit: 2259c27 (2013-09-28 19:24:07 -0700)

The app loads all of the bundles to render them and a form, but the form submits directly to rails. Rails processes the post request and redirects back to /, where the ember app lives.

The first request to / loads everything fine, but when I submit the form, and it redirects back, that's when my ajax call my call to store.find('bundle') does nothing.

UPDATE

I've discovered that my issue is related to pusher (websockets).

The issue seems intermittent and I've only seen it in Chrome (I've only tested Firefox).

The issue went away when I disconnected from websockets before a page refresh.

@atsjj Yes, I have the Ember Inspector. How would I use it to help debug this issue? — Amiel Martin
When it comes to an Ember issue and AJAX, I have to break down the process. I look at Chrome's requests first to see if there is a request and if the response is what I expect. Next, I use the Ember Inspector to see if the objects are being setup with the values I expect as well as the data from that object. I know this is heavily simplified, but that's my general workflow with that tool... — atsjj

Marcio Junior Marcio Junior · Accepted Answer · 2013-09-30T17:40:59

In your case the fail handler is receiving the jQuery XMLHttpRequest. Try to see what responseText and status is returning.

App.__container__.lookup('store:main').find('bundle').then(null, function(reason) {
  reason.responseText // response from the server, maybe can show an error page in html
  reason.status // 404 page not found, 500 some server error you will need to chech the logs etc.
});

I hope it helps

EmberData find request isRejected, how do I debug this?

1 Answers