Add preload paths for media categories

[ntsekouras]

Trac ticket: https://core.trac.wordpress.org/ticket/57533

This PR adds the new preload paths for the inserter media categories for post and site editors.
Related GB PR: WordPress/gutenberg#46251

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[ntsekouras]

I'm not sure if it's preferred in this format:

add_query_arg(
	array(
		'context'    => 'edit',
		'per_page'   => 1,
		'orderBy'    => 'date',
		'media_type' => 'image',
	),
	rest_get_route_for_post_type_items( 'attachment' )
),

[TimothyBJacobs]

Yeah this would be better.

[spacedmonkey]

This change added three somewhat complex database queries per page. Can please try and avoid this and just load them in the browser.

[felixarntz]

@ntsekouras I see this implemented in Gutenberg, however in terms of performance considerations I would like to understand why these requests are being preloaded. Will they be made anyway as soon as the block editor loads?

We're talking about WP Admin here, so performance is not as critical as for the frontend, but I would still want to ensure we don't add these queries unnecessarily.

Since I don't have the context here, can you outline the use-case for what these endpoints are used? And most importantly: Is this relevant for every block editor page load, or do you have to do something specific in the block editor for that data to become relevant?

[ntsekouras]

@ntsekouras I see this implemented in Gutenberg, however in terms of performance considerations I would like to understand why these requests are being preloaded. Will they be made anyway as soon as the block editor loads?

@felixarntz yes, they need to, and they are part of the inserter media tab. When a user opens the inserter we need to make these requests to check if there is at least one media item per category(audio, image, video). If there is no result we don't need to show the inserter menu item for that category.

If we don't make these requests, the media tab would need to wait for the resolution of these calls, making it display afterwards. This can be a jarring experience and we want to avoid it.

The media inserter tab is implemented for post and site editors.

[TimothyBJacobs]

I agree with @felixarntz and @spacedmonkey.

If we don't make these requests, the media tab would need to wait for the resolution of these calls, making it display afterwards. This can be a jarring experience and we want to avoid it.

I don't think these need to be completed when the editor is initially loaded. Instead, they could be loaded asynchronously when the editor loads, but before the user opens the inserter.

[hellofromtonya]

I don't think these need to be completed when the editor is initially loaded. Instead, they could be loaded asynchronously when the editor loads, but before the user opens the inserter.

Given this feedback, what needs to change in this PR? @ntsekouras is this something being worked on?

[felixarntz]

@hellofromtonya I believe this is currently being discussed further in WordPress/gutenberg#47503.

[ntsekouras]

Given this feedback, what needs to change in this PR? @ntsekouras is this something being worked on?

@hellofromtonya I've opened a GB PR to see if it makes any difference to preload these client side in JS. The discussions there are mostly about whether we can avoid making the requests as soon as the editor loads, but I don't think that's an option.

This is because these requests are needed for a user before opening the inserter, which is something that could be their first actions as soon as the editor loads..

[hellofromtonya]

Thanks @felixarntz and @ntsekouras for the update on where the discussion is happening.

[ntsekouras]

I'm closing this since we'll back port the following changes here: WordPress/gutenberg#47503 which handle this issue client side.

The approach is:

1. If enableOpenverseMediaCategory setting is set to true(which is the default) show the media tab and also init the requests for the media types in library. This ensures that the media tab will be there right after we open the inserter and since it's not the default tab for any editor, it will almost certainly have resolved the requests when a user selects that tab.
2. If enableOpenverseMediaCategory is set to false, the media tab will wait for the resolution of the requests and will be displayed if there are any available media categories. This is not ideal, but it's less common and it's better than showing the media tab where there could be a chance to remove that tab after the requests' resolution.