Remove old PR preview HTML files and add redirects to new preview modals

[brandonpayton]

Motivation for the change, related issues

This PR removes old PR preview pages, adds relevant redirects, and updates old PR preview redirects.

Fixes #1969

Implementation details

In addition to the removals and redirects, this PR:

• Removes some more complicated redirect-related logic because it is awkward and no longer needed.
• Adjust old UI links to wordpress.html to link to the new modal instead

Testing Instructions (or ideally a Blueprint)

• Tested manually on a staging site.
• Use php -l to ensure there are no syntax errors in custom-redirects-lib.php
• Deploy and confirm the following paths redirect to the new PR preview modals
  • /wordpress
  • /wordpress.html
  • /gutenberg
  • /gutenberg.html

[brandonpayton]

This PR accidentally contained some export exploration work. Will fix.

[brandonpayton]

This PR accidentally contained some export exploration work. Will fix.

Fixed.

[brandonpayton]

Tests fine after deployment:

% curl -i https://playground.wordpress.net/{wordpress,wordpress.html,gutenberg,gutenberg.html} HTTP/2 301 server: nginx date: Sat, 14 Dec 2024 02:15:29 GMT content-type: text/html; charset=utf-8 strict-transport-security: max-age=31536000 location: /?modal=preview-pr-wordpress x-ac: 2.mdw _atomic_dca HIT alt-svc: h3=":443"; ma=86400 HTTP/2 301 server: nginx date: Sat, 14 Dec 2024 02:15:29 GMT content-type: text/html; charset=utf-8 strict-transport-security: max-age=31536000 location: /?modal=preview-pr-wordpress x-ac: 2.mdw _atomic_dca HIT alt-svc: h3=":443"; ma=86400 HTTP/2 301 server: nginx date: Sat, 14 Dec 2024 02:15:29 GMT content-type: text/html; charset=utf-8 strict-transport-security: max-age=31536000 location: /?modal=preview-pr-gutenberg x-ac: 2.mdw _atomic_dca HIT alt-svc: h3=":443"; ma=86400 HTTP/2 301 server: nginx date: Sat, 14 Dec 2024 02:15:29 GMT content-type: text/html; charset=utf-8 strict-transport-security: max-age=31536000 location: /?modal=preview-pr-gutenberg x-ac: 2.mdw _atomic_dca HIT alt-svc: h3=":443"; ma=86400 

[adamziel]

Did you test this? When I click on a preview link in wordpress-develop repository, this is what I get instead of a preview:

I'll revert this one until we have a fix

[brandonpayton]

Did you test this? When I click on a preview link in wordpress-develop repository, this is what I get instead of a preview:
...
I'll revert this one until we have a fix

@adamziel, I did not know about those links from the wordpress-develop repo and thought this was simply replacing a UI that required user interaction. I'm sorry for the oversight. And thank you for the revert!

[brandonpayton]

Instead of getting rid of the standalone pages, maybe we should just change the pages to share lookup logic with the preview modals and otherwise leave the pages as-is. cc @ajotka

[brandonpayton]

Instead of getting rid of the standalone pages, maybe we should just change the pages to share lookup logic with the preview modals and otherwise leave the pages as-is. cc @ajotka

Ah, I see the Playground web app also has core-pr and gutenberg-pr query params, so we could conceivably just make the redirects from this PR use those. I'll reopen #1969, and we can address this as there is time.