Feed item filter

[cadic]

Description of the Change

With this PR we introduce new filter simple_podcasting_feed_item to allow modification of each feed item before output to RSS2.

To be able to filter, tenup_podcasting\feed_item() is rerfactored:

• all data is saved into an array
• array is passed through the filter
• output is made as single portion of code

Closes #17

Alternate Designs

n/a

Possible Drawbacks

not discovered

Verification Process

1. Create new Podcast
2. Add new post with Podcast Block and connect it with the Podcast
3. Add filter to simple_podcasting_feed_item (example below)
4. Check Podcast RSS — expected to match filter modifications

Example of filter:

function podcasting_feed_item_filter( $feed_item = array(), $post_id = null, $term_id = null ) {
	$feed_item['keywords'] = 'one,two,three';
	return $feed_item;
}
add_filter( 'simple_podcasting_feed_item', 'podcasting_feed_item_filter', 10, 3 );

Should result in keywords added to each feed item:

<itunes:keywords>one,two,three</itunes:keywords>

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Changelog Entry

Added - Filter 'simple_podcasting_feed_item' to modify RSS feed item data before output

Credits

Props @cadic

[cadic]

Blocked by #145
Cypress test fails on WordPress 5.9

[iamdharmesh]

Thanks for great work @cadic !! LGTM 👍
I am able to verify test steps mentioned in PR description.