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post_preview()

Saves a draft or manually autosaves for the purpose of showing a post preview.

Return

(string) URL to redirect to show the preview.

Source

File: wp-admin/includes/post.php 

function post_preview() {

	$post_ID     = (int) $_POST['post_ID'];
	$_POST['ID'] = $post_ID;

	$post = get_post( $post_ID );
	if ( ! $post ) {
		wp_die( __( 'Sorry, you are not allowed to edit this post.' ) );
	}

	if ( ! current_user_can( 'edit_post', $post->ID ) ) {
		wp_die( __( 'Sorry, you are not allowed to edit this post.' ) );
	}

	$is_autosave = false;

	if ( ! wp_check_post_lock( $post->ID ) && get_current_user_id() == $post->post_author
		&& ( 'draft' === $post->post_status || 'auto-draft' === $post->post_status )
	) {
		$saved_post_id = edit_post();
	} else {
		$is_autosave = true;

		if ( isset( $_POST['post_status'] ) && 'auto-draft' === $_POST['post_status'] ) {
			$_POST['post_status'] = 'draft';
		}

		$saved_post_id = wp_create_post_autosave( $post->ID );
	}

	if ( is_wp_error( $saved_post_id ) ) {
		wp_die( $saved_post_id->get_error_message() );
	}

	$query_args = array();

	if ( $is_autosave && $saved_post_id ) {
		$query_args['preview_id']    = $post->ID;
		$query_args['preview_nonce'] = wp_create_nonce( 'post_preview_' . $post->ID );

		if ( isset( $_POST['post_format'] ) ) {
			$query_args['post_format'] = empty( $_POST['post_format'] ) ? 'standard' : sanitize_key( $_POST['post_format'] );
		}

		if ( isset( $_POST['_thumbnail_id'] ) ) {
			$query_args['_thumbnail_id'] = ( intval( $_POST['_thumbnail_id'] ) <= 0 ) ? '-1' : intval( $_POST['_thumbnail_id'] );
		}
	}

	return get_preview_post_link( $post, $query_args );
}

Uses

Uses Description
wp-includes/link-template.php: get_preview_post_link()

Retrieves the URL used for the post preview.
wp-admin/includes/post.php: wp_check_post_lock()

Check to see if the post is currently being edited by another user.
wp-admin/includes/post.php: wp_create_post_autosave()

Creates autosave data for the specified post from $_POST data.
wp-admin/includes/post.php: edit_post()

Update an existing post with values provided in $_POST.
wp-includes/capabilities.php: current_user_can()

Returns whether the current user has the specified capability.
wp-includes/l10n.php: __()

Retrieve the translation of $text.
wp-includes/formatting.php: sanitize_key()

Sanitizes a string key.
wp-includes/pluggable.php: wp_create_nonce()

Creates a cryptographic token tied to a specific action, user, user session, and window of time.
wp-includes/functions.php: wp_die()

Kills WordPress execution and displays HTML page with an error message.
wp-includes/user.php: get_current_user_id()

Get the current user’s ID
wp-includes/post.php: get_post()

Retrieves post data given a post ID or post object.
wp-includes/load.php: is_wp_error()

Check whether variable is a WordPress Error.

Changelog

Version Description
2.7.0 Introduced.

© 2003–2019 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/post_preview