Playground Previews

[dd32]

See #14

This is a companion to https://github.com/WordPress/wordpress.org/pull/329 exploring adding Theme Previews using Playground to the new theme.

Notes:

• ~This relies upon the above PR for the rest api endpoint.~ Merged
• ~Some changes in the above PR are irrelevant with the new theme~
• This is assuming that w.org/themes/$theme/preview/ is only used on WordPress.org and is NOT the core previewer
  • WordPress.org shouldn't be loaded within an iframe for core, so the /preview/ endpoint included in the new theme is unlikely to replace wp-themes.com immediately, and it's probably likely that we'd duplicate the previewer offered here onto wp-themes.com.
• ~Took some shortcuts in just deleting some of the previewer code with the overlays to speed up development (I was frustrated with Playground enough, I couldn't determine if playground was at fault or I was using interactivity api wrong)~

This is actually a very small change code-wise, but the user-experience is not at all ideal IMHO, based on the load times.

[dd32]

After this is merged, you'll be able to compare these two urls:

• https://wordpress.org/themes/twentytwenty/preview/ <- wp-themes preview
• https://wordpress.org/themes/twentytwenty/preview/?playground-preview=1 <- editable playground preview

[dd32]

@ryelle This has removed the Invalid URL: The preview could not be loaded. notice and code, but I'm not sure why it exists in the first place.

Is this fine to do? Is there an edge-case that I'm not aware of that we care about?

[ryelle]

This has removed the Invalid URL: The preview could not be loaded. notice and code, but I'm not sure why it exists in the first place.

Is this fine to do? Is there an edge-case that I'm not aware of that we care about?

I added it assuming we would want to avoid showing non-wporg sites in the previewer, but never followed up to see if that was even possible from the plugin code— so no, I was just trying to be extra-cautious.