Save Post Revisions

• NewJenk

• February 1, 2018 at 4:20 am

Hi all,

I’m currently building a WP theme and I’m making extensive use of the flexible content field.

To ensure user content will remain as-is if the user uninstalls ACF or changes their theme, when a post is saved the ACF fields from the flexible content are copied over to ‘the_content()’ using this function:

function save_flex_to_content( $post_id ) {
		
	// Only run this code if we're on a particular post type
	if ( 'page' == get_post_type() ) {

		// If there are any blocks
		if( get_field('acf-flex') ) {

			// Start an output buffer
			ob_start();
			
			// check if the flexible content field has rows of data
			if( have_rows('acf-flex') ):

				// loop through the rows of data
				while ( have_rows('acf-flex') ) : the_row();

					// Get the file /template-parts/content-partials (which contains the relevant block layouts)
					get_template_part( 'template-parts/content', 'partials' );

				endwhile;

			endif;

			// Store output buffer
			$new_post_content = ob_get_clean();

			// Remove post revisions (as there was an issue with 2 revisions being created)
			remove_action( 'post_updated', 'wp_save_post_revision' );

			// Update the post_content 
			wp_update_post( array('ID' => $post_id, 'post_content' => $new_post_content ));

			// Re-add post revisions
			add_action( 'post_updated', 'wp_save_post_revision' );

		} else {

			return;

		}

	}

}
// On 'ACF Save Post', save our blocks to post content
add_action('acf/save_post', 'save_flex_to_content', 20);

The issue I’m having is that every time a post is saved, 2 revisions are also being saved. I can avoid this in part by adding remove_action( 'post_updated', 'wp_save_post_revision' ); and add_action( 'post_updated', 'wp_save_post_revision' ); to the above function, which means the code being copied to ‘the_content()’ won’t save a revision.

What I want though is for the initial ‘save post’ not to create a revision, so the only revision will be from the above function.

Note: I want revisions to continue to act as normal other than the above, so disabling them altogether is not an option.

Thanks all.

Shaun

• John Huebner

• February 2, 2018 at 5:45 am

I just spent some time looking into this because I also have an interest in doing the same thing. I came to the same conclusion that you have as far as removing and adding the filter for the post revision.

I do not see any way to do this on the initial save, only on your second save as you’ve suggested.

The only possibility I can see is to add a pre_post_update https://developer.wordpress.org/reference/hooks/pre_post_update/

In this filter, check the post type, or other data to see if it’s something that you don’t want to save a revision for. If it is then do.

remove_filter( 'post_updated', 'wp_save_post_revision' );

Not that this will happen before ACF has updated the fields. Then, just before you update the post do

add_action( 'post_updated', 'wp_save_post_revision' );

• scooterlord

• November 12, 2020 at 10:55 pm

Hello, I am resurrecting this old post because I am more or less looking for the same thing.

Whenever a post is created the save_post filter immediately creates another revision of the post, so, consecutive posts, don’t have consecutive ids.

However, I do need revisions, so how can I prevent revisions on the save_post function?

• John Huebner

• November 15, 2020 at 2:29 am

I have recently found something new that might help those looking to prevent multiple revisions. Please note that I have not tested this and it is just speculation at this time.

This filter in WP is called just before saving a post revision

$post_has_changed = (bool) apply_filters( 'wp_save_post_revision_post_has_changed', $post_has_changed, $last_revision, $post );

So, using this hook you could

add_filter('wp_save_post_revision_post_has_changed', 'my_prevent_post_revisions', 10, 3);
function my_prevent_post_revisions($post_has_changed, $last_revision, $post) {
  // here you can do some checking
  // for example if you only want to prevent revisions on a specific post type
  // return false to prevent post revision

  return $post_has_changed;
}

Then in your filter or function where you want the revision to be saved

// remove the prevent post revision filter
remove_filter('wp_save_post_revision_post_has_changed', 'my_prevent_post_revisions', 10);

// update the post
wp_update_post($args)

// add the filter again
add_filter('wp_save_post_revision_post_has_changed', 'my_prevent_post_revisions', 10, 3);

If anyone has a chance to test this let us know.