update: wp_trim_words function to allow specific html tags

[up1512001]

Trac ticket:

https://core.trac.wordpress.org/ticket/59270

---

As wp_strip_all_tags function strips all HTML tags this won't allow doing any formatting to excerpt. I have used wp_kses() here with specific allowed HTML tags.

Allowed tag list

$allowed_tags = array(
		'a'      => array(
			'class' => array(),
			'style' => array(),
			'href'  => array(),
			'id'    => array(),
		),
		'strong' => array(),
		'b'      => array(),
		'em'     => array(),
		'img'    => array(
			'class'  => array(),
			'style'  => array(),
			'src'    => array(),
			'alt'    => array(),
			'width'  => array(),
			'height' => array(),
		),
		'mark'   => array(
			'class' => array(),
			'style' => array(),
		),
		'code'   => array(
			'class' => array(),
			'style' => array(),
		),
		'kbd'    => array(
			'class' => array(),
			'style' => array(),
		),
		'bdo'    => array(
			'class' => array(),
			'style' => array(),
			'dir'   => array(),
			'lang'  => array(),

		),
		'span'   => array(
			'class' => array(),
			'style' => array(),
		),
		'sup'    => array(
			'class' => array(),
			'style' => array(),
		),
		'sub'    => array(
			'class' => array(),
			'style' => array(),
		),
		's'      => array(
			'class' => array(),
			'style' => array(),
		),
	);

Example output

Screen.Recording.2024-06-13.at.12.28.18.mov

[github-actions]

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[up1512001]

Hi @swissspidy can you please review this PR?

[github-actions]

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[audrasjb]

Hi, thanks for the PR!

I think we should consider passing $allowed_tags as an argument of wp_trim_words() so we can 1) make it optional (and maybe disabled by default?); 2) allow extenders to customize it their way.

What do you think?

[up1512001]

@audrasjb we can definitely do that.

[audrasjb]

Thanks for the update. We also need a since mention in the docblock :)

[up1512001]

@mukeshpanchal27 @audrasjb any update for this PR?

[up1512001]

@swissspidy can you please review this PR?

[swissspidy]

Why me specifically? 😅 I am on vacation

[up1512001]

@swissspidy Sorry for disturbing you.

[up1512001]

added all possible tags & styles to support excerpt styling.

[peterwilsoncc]

This will need some additional unit tests to ensure the code behaves as expected.

Instead of defining the allowed tags in this function, I recommend using an existing value from the existing kses functions. This will allow developers to modify the list of allowed tags according to their needs.

This will also need to ensure that the tags are balanced after the string has been trimmed to protect against HTML errors. See balanceTags()