Site editor: preload post and template lookups if needed

[ellatrix]

See:

• Site editor: preload post if needed gutenberg#66631
• Preload: parse post ID from p (path) gutenberg#67465
• Site Editor: Pages: Preload template lookup gutenberg#66654
• Site Editor: speed up load by preloading home and front-page templates gutenberg#66579

Trac ticket:

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[swissspidy]

This is lacking any sort of sanitization.

Also rest_get_route_for_post can return an empty string if no post is found, in which case one wouldn't want do add this to the array.

[ellatrix]

Yes, the empty string check has already been added in GB.

[ellatrix]

Should be fixed. Is get_post enough sanitisation?

[Mamaduka]

Let's verify that postId is an int value.

[ellatrix]

Done

[jorgefilipecosta]

Works well in my tests and the code looks good 👍

[peterwilsoncc]

@ellatrix@youknowriad@Mamaduka Am I correct in assuming that this isn't affected by the switch to path based routing introduced in WordPress/gutenberg#67199?

(I'm pretty sure it isn't but want to avoid making assumptions :)