HTML5App preview broken on develop

[ivanistheone]

So on current production preview loads the HTML content correctly:
https://studio.learningequality.org/channels/faf284a5469d54b8b06881491196888e/edit/38f9ecd/0312595 (Go to Preview tab of modal)

On develop it doesn't:
https://develop.studio.learningequality.org/channels/faf284a5469d54b8b06881491196888e/edit/38f9ecd/0312595 (Go to Preview tab of modal)

The HTML that loads the iframe for HTML5App preview on prod is:

<iframe src="/zipcontent/43a7016005a9aaec4855d3dfc509d307.zip" data-src="/zipcontent/43a7016005a9aaec4855d3dfc509d307.zip" class="html_preview" sandbox="allow-scripts"></iframe>

in develop it says:

<iframe src="about:blank" data-src="/zipcontent/43a7016005a9aaec4855d3dfc509d307.zip" class="html_preview" sandbox="allow-scripts"></iframe>

SUSPECTED CAUSE: For some reason this doesn't run:
https://github.com/learningequality/studio/blob/develop/contentcuration/contentcuration/static/js/edit_channel/preview/views.js#L92-L94

[kollivier]

Strange, I'm not seeing this when I click the develop link, it has src defined properly for me. I wonder if this code is sensitive to async loading issues?

[kollivier]

It does give an error loading one of the scripts in the zip, though. Not sure if that's related or expected.

[ivanistheone]

@kollivier can you confirm you see the preview iframe loading on develop without selecting the HTML5 Zip option from the dropdown. (It works for me too if I choose HTML5 Zip)

Note on PROD the preview content loads automatically (without having to choose HTML5 Zip).

[kollivier]

@ivanistheone Sorry, I do see the same behavior. I clicked on the HTML5 Zip item instinctively the first time around! When you checked the code, is the code in this area the same for master and develop?

[jamalex]

I think I saw a commit title saying the deferred loading via data-src was to keep the iframe from loading before the preview tab was loaded. But I think we now already delay rendering the tab content entirely until it's clicked? (it used to start playing videos in the background when you opened the metadata modal)

So this sounds like it can (and definitely should) be simplified now, just directly using src="/zipcontent/...
and then removing that deferred loading JS?

[jayoshih]

Looking into a fix today!