3.18 - Exclusions part

[piotrbak]

User Story
As a user, I’d like to be able to exclude fonts from the feature using filter

Acceptance Criteria

• We’ll introduce a filter and backend exclusion possibility
• It’ll be possible to exclude the whole Google Fonts CSS file from being processed
• The exclusion can be based either on argument or on the URL
• The exclusion should be regex compatible
• When excluded, the CSS file will not be processed and will remain in the HTML source
• When excluded, fonts inside the CSS file will not be rewritten/downloaded

[Khadreal]

This is dependent on the completion of #7063

Scope a solution:

We'll create a filter rocket_exclude_locally_host_fonts
Add a new method here

public function get_exclude_host_fonts() : array {
      $lists = $this->providers['defaultlists']->data_manager->get_lists();

       return $lists->host_fonts ?? [];
}

We add our new filter to the subscriber class
'rocket_exclude_locally_host_fonts' => 'add_host_fonts_exclusions'
And add_host_fonts_exclusions method in the same subscriber class

public function add_host_fonts_exclusions( $exclusion ) {
     return array_merge( (array) $exclusions, $this->dynamic_lists->get_exclude_host_fonts() );
}

In Frontend\Controller we would create a private method method which get exclusions and this method will be used in the rewriting process( created here #7063) to check if the rewrite should happen or not.
The exclusion should be compatible with regular expression.

private function get_exclusions(): array {
      return wpm_apply_filters_typed( 'string[]', 'rocket_exclude_locally_host_fonts', [] );
}

Estimation
[S]

[jeawhanlee]

I think it doesn't matter whatever is passed to the filter, be it a full url or a part of it like the name, we should be able to exclude it using regex, we've done something similar in the past with other features, having 2 filters could seem redundant for accomplishing the same thing.

[jeawhanlee]

I have a question, does the backend exclusion mentioned mean having a textarea in our settings page on the admin or rather handling externally, the same way we do with the dynamic lists @piotrbak @Khadreal @MathieuLamiot

[piotrbak]

@jeawhanlee It's only filter + backend for now

[jeawhanlee]

@Khadreal We will not need to introduce a new textarea on the admin for exclusions as it will be backend for now.
CC @piotrbak

[Khadreal]

Thanks for spotting it @jeawhanlee
okay, I'll modify the grooming

[Khadreal]

@jeawhanlee the grooming has been updated.

[jeawhanlee]

LGTM

[remyperona]

The current grooming is missing to consider how should exclusions work when the Google fonts link is composed of multiple fonts?

Does it mean we need to rewrite the google link to keep the excluded font? So splitting the combine into 2 separate links, with only one being processed.

How does the exclusion interacts with the combine google fonts feature?

[piotrbak]

@remyperona What about excluding the font from being combined? Then it'll not be combined and might not be part of the rewrite system.

[remyperona]

What about the case where the fonts are already combined, not by our feature?

[piotrbak]

Then, if our exclusion matches, we'll exclude whole combined (not by us) CSS file