Long-running form submit spinners

[davecranwell]

First pass at addressing #305

Still to apply this to more forms

[davecranwell]

Will remove

[tomdyson]

Looks good!

[tomdyson]

@JoshBarr do you have time to review this?

[davecranwell]

• wagtailembed modal badly needs this spinner. The round trip to embed.ly seems to take forever.

[JoshBarr]

@tomdyson sure thing, I can take a look at the media embedding modal. Are there any others you can think of while I'm there?

[JoshBarr]

Hey guys,

I was wondering whether we need to use setTimeout to disable the button? I think we can get the parent form from the current node and trigger submit from the click handler. Something like:

// Trigger form submission if it's a submit button
if (this.form && this.getAttribute('type') === 'submit') {
    $(this.form).trigger('submit');
}

// Then carry on and disable the button + bootup the timeout to clear the spinner... 

see it in core.js

Also, I've found an issue with trying to embed multiple media assets into the rich text field (in Chrome at least). If the first element is an embed (no other text nodes at the start of the block), trying to insert a second embed generates an Uncaught HierarchyRequestError: Failed to execute 'insertBefore' on 'Node': Only one element on document allowed. in rangy-core.js:29. I'll take a look at at one next.

[davecranwell]

Cheers for reviewing, @JoshBarr. As far as submitting the form goes, I suppose I don't have many issue with that, but I was trying to avoid having to refer to forms at all purely to keep it all within the scope of the button. I was hoping to avoid having to test the button type too, allowing this to be used for ajax forms, synchronous ones, and ones where true "submit" buttons aren't used.

[davecranwell]

Ready for merge, I believe.

[gasman]

There's a problem with the form submit logic from #1075 (comment) - the form submission won't include the name/value of the submit button, as it would when the submit action is triggered directly from the button. We use this to differentiate between the save/publish/submit actions on the page editor - consequently, with this patch applied, the 'publish' button fails to publish. I think this should be reverted to the original setTimeout-based implementation.

[davecranwell]

Ah yes, that was the main reason I didn't use form.submit() before, now I remember.

[davecranwell]

Reverted to version that supports passing of button names, also rebases on top of all the gulp & linting stuff which was added after this PR.