How to use TOC with ACF?

Question

I'm using ACF advanced custom fields plugin to create custom fields for my CPT where i replaced the content editor of my CPTs with a custom Wysiwyg Editor field (field name: full_text) from ACF in which i enter the main text of the CPT(I really need that for specific reasons). But, when i tried to use toc+ to generate a table of content from the text in the custom field editor it shows nothing. Actually on the plugin page they wrote that:

Custom post types are supported, however, auto insertion works only when `the_content()` has been used by the custom post type. Each post type will appear in the options panel, so enable the ones you want.

In the plugin toc.php file I noticed that exactly:

        public function extract_headings( &$find, &$replace, $content = '' )
    {
        $matches = array();
        $anchor = '';
        $items = false; 
        // reset the internal collision collection as the_content may have been triggered elsewhere
        // eg by themes or other plugins that need to read in content such as metadata fields in
        // the head html tag, or to provide descriptions to twitter/facebook
        $this->collision_collector = array();
        if ( is_array($find) && is_array($replace) && $content ) {
            // get all headings
            // the html spec allows for a maximum of 6 heading depths
            if ( preg_match_all('/(<h([1-6]{1})[^>]*>).*<\/h\2>/msuU', $content, $matches, PREG_SET_ORDER) ) {
                // remove undesired headings (if any) as defined by heading_levels
                if ( count($this->options['heading_levels']) != 6 ) {
                    $new_matches = array();
                    for ($i = 0; $i < count($matches); $i++) {
                        if ( in_array($matches[$i][2], $this->options['heading_levels']) )
                            $new_matches[] = $matches[$i];
                    }
                    $matches = $new_matches;
                }
                // remove specific headings if provided via the 'exclude' property
                if ( $this->options['exclude'] ) {
                    $excluded_headings = explode('|', $this->options['exclude']);
                    if ( count($excluded_headings) > 0 ) {
                        for ($j = 0; $j < count($excluded_headings); $j++) {
                            // escape some regular expression characters
                            // others: http://www.php.net/manual/en/regexp.reference.meta.php
                            $excluded_headings[$j] = str_replace(
                                array('*'), 
                                array('.*'), 
                                trim($excluded_headings[$j])
                            );
                        }
                        $new_matches = array();
                        for ($i = 0; $i < count($matches); $i++) {
                            $found = false;
                            for ($j = 0; $j < count($excluded_headings); $j++) {
                                if ( @preg_match('/^' . $excluded_headings[$j] . '$/imU', strip_tags($matches[$i][0])) ) {
                                    $found = true;
                                    break;
                                }
                            }
                            if (!$found) $new_matches[] = $matches[$i];
                        }
                        if ( count($matches) != count($new_matches) )
                            $matches = $new_matches;
                    }
                }
                // remove empty headings
                $new_matches = array();
                for ($i = 0; $i < count($matches); $i++) {
                    if ( trim( strip_tags($matches[$i][0]) ) != false )
                        $new_matches[] = $matches[$i];
                }
                if ( count($matches) != count($new_matches) )
                    $matches = $new_matches;
                // check minimum number of headings
                if ( count($matches) >= $this->options['start'] ) {
                    for ($i = 0; $i < count($matches); $i++) {
                        // get anchor and add to find and replace arrays
                        $anchor = $this->url_anchor_target( $matches[$i][0] );
                        $find[] = $matches[$i][0];
                        $replace[] = str_replace(
                            array(
                                $matches[$i][1],                // start of heading
                                '</h' . $matches[$i][2] . '>'   // end of heading
                            ),
                            array(
                                $matches[$i][1] . '<span id="' . $anchor . '">',
                                '</span></h' . $matches[$i][2] . '>'
                            ),
                            $matches[$i][0]
                        );
                        // assemble flat list
                        if ( !$this->options['show_heirarchy'] ) {
                            $items .= '<li><a href="#' . $anchor . '">';
                            if ( $this->options['ordered_list'] ) $items .= count($replace) . ' ';
                            $items .= strip_tags($matches[$i][0]) . '</a></li>';
                        }
                    }
                    // build a hierarchical toc?
                    // we could have tested for $items but that var can be quite large in some cases
                    if ( $this->options['show_heirarchy'] ) $items = $this->build_hierarchy( $matches );
                }
            }
        }
        return $items;
    }

where you can notice that the function works with $content. But is there any way to make it work with the custom field created with ACF? or, have ou any suggestions to solve this problem?

Answer 1

You can use the the acf/save_post action to copy the content from your custom 'full_text' field over to the normal post content field, so it can automatically be accessed by toc+ and other plugins.

add_action( 'acf/save_post', 'wpse199256', 20 );

function wpse199256( $post_ID ) {
    global $wpdb;
    $post = get_post( $post_ID );
    $wpdb->update( $wpdb->posts, array( 'post_content' => get_field( 'full_text', $post_ID ), array( 'ID' => $post_id ) );
}

Depending on how you use your CPT this will lead to some templates etc. having to be adapted, if they were outputting the content field (which was empty until now).