Get_template_part inside filter?

Question

Is it possible to remove gallery from content but in its place do get_template_part('content-gallery'); ?

I have this piece of code which removes gallery from post but I am inserting content-gallery.php which grabs and formats gallery the way I wanted to. This works nice but gallery is inserted at the end of the post what is the problem, it needs to be inserted in whatever position it is in post. I just want a quick fix.

functions.php - removes gallery

add_filter('the_content', 'remove_gallery');
function remove_gallery($content) {
  preg_match_all( '/'. get_shortcode_regex() .'/s', $content, $matches, PREG_SET_ORDER );
  if ( ! empty( $matches ) ) {
    foreach ( $matches as $shortcode ) {
      if ( 'gallery' === $shortcode[2] ) {
        $pos = strpos( $content, $shortcode[0] );
        if ($pos !== false)
          return substr_replace( $content, '', $pos, strlen($shortcode[0]) );
      }
    }
  }
  return $content;
}

content-gallery.php - manual gallery - call images and format them easily

$gallery = get_post_gallery( get_the_ID(), false );
$gallery_attachment_ids = explode( ',', $gallery['ids'] );

$img_attribs = wp_get_attachment_image_src($gallery_attachment_ids[0], 'gallery_main' ); // returns an array
if( $img_attribs ) :

    foreach($gallery_attachment_ids as $id) :  
        $img = wp_get_attachment_image_src($id, 'gallery_thumb' ); 
    $img_full = wp_get_attachment_image_src($id, 'gallery_main' ); 
    $img_alt = get_post_meta(get_the_ID(), '_wp_attachment_image_alt', true); 
    ?>
    <div class="item">
        <img class="thumb img-responsive" data-url="<?php echo $img_full[0]; ?>" id="<?php the_ID(); ?>" src="<?php echo $img[0]; ?>" alt="<?php echo $img_alt; ?>" title="<?php echo $img_alt; ?>" />
    </div>
<?php endforeach; ?>

This is in page.php (I would need to remove manual calling for get_template_part() and call it inside filter function.

    <?php the_content(); ?>
    <?php  get_template_part('content-gallery'); ?>

EDIT

Full filter function

add_filter('the_content', 'remove_gallery');
function remove_gallery($content) {
  preg_match_all( '/'. get_shortcode_regex() .'/s', $content, $matches, PREG_SET_ORDER );
  if ( ! empty( $matches ) ) {
    foreach ( $matches as $shortcode ) {
      if ( 'gallery' === $shortcode[2] ) {
        $pos = strpos( $content, $shortcode[0] );


        if ($pos !== false) {
          ob_start; 
          get_template_part('content-gallery.php');
          $contentgallery = ob_get_contents();
          ob_end_clean();
          return substr_replace( $content, $contentgallery, $pos, strlen($shortcode[0]) );
        }


      }
    }
  }
  return $content;
}

Answer 1

You can use output buffering to get the template output and return it in place of the emptied shortcode content:

if ($pos !== false)
    ob_start; 
    get_template_part('content-gallery.php');
    $contentgallery = ob_get_contents();
    ob_end_clean();
    return substr_replace( $content, $contentgallery, $pos, strlen($shortcode[0]) );` 
}

EDIT It might make it easier to just replace the gallery shortcode?

remove_shortcode('gallery');
add_shortcode('gallery','my_content_gallery');
function my_content_gallery() {
    ob_start; 
    get_template_part('content-gallery.php');
    $contentgallery = ob_get_contents();
    ob_end_clean();
    return $contentgallery;
}