visual composer to gutenberg converter (only image flex slider - to Guntenberg gallery and text => paragraph)

functions.php

// attach that to everywhere
add_action( 'template_redirect', function (){

	$w = new WP_Query( array( 
		'post__in' => array( 823, 817 ),
		'post_type' => 'any' ,
		// 'posts_per_page' => 100, 
		// 'offset' => 400 
	));

	while ( $w->have_posts() ) {
		$w->the_post(); $post_id = get_the_ID();
		$con = get_post_field('post_content', $post_id) ;
		preg_match('/[vcex_image_flexslider].*?image_ids="(.*)"]/msi', $con, $match );
		$gallery = $match[1] ; // image slider reg
		preg_match('/\[vc_column_text](.*)\[\/vc_column_text]/msi', $con, $mat );
		$info = $mat[1] ; // text regex

		if( $gallery ){
			$h = '<!-- wp:gallery {"ids":[' . $gallery . '],"columns":1,"sizeSlug":"full","className":"slider"} --><figure class="wp-block-gallery columns-1 is-cropped slider"><ul class="blocks-gallery-grid">' ;
			$arr = explode(',', $gallery );
			foreach ($arr as $vall ) {
				$h .= '<li class="blocks-gallery-item"><figure><img src="' . wp_get_attachment_url( $vall ) . '" alt="" /></figure></li>' ;
			}
			$h .= '</ul></figure><!-- /wp:gallery -->' ;
		}
		if( $info ){
			$h .= '<p>' . $info . '</p>' ;
		}
		// REPLACE VisualComposer with Gutenberg
		$post = array(
			'ID'		=> $post_id,
			'post_content' => $h
		);
		wp_update_post( $post );
	}	

} );