WordPress Image Caption Filter

wp_caption.php

<?php
add_filter( 'img_caption_shortcode', 'cleaner_caption', 10, 3 );

function cleaner_caption( $output, $attr, $content ) {

  $output2 = null;
  $output3 = null;
  $pattern  = 'http://';

  /* We're not worried abut captions in feeds, so just return the output here. */
  if ( is_feed() )
    return $output;

  /* Set up the default arguments. */
  $defaults = array(
    'id' => '',
    'align' => 'alignnone',
    'width' => '',
    'caption' => ''
  );

  /* Merge the defaults with user input. */
  $attr = shortcode_atts( $defaults, $attr );

  /* Set up the attributes for the caption <div>. */
  $attributes = ( !empty( $attr['id'] ) ? ' id="' . esc_attr( $attr['id'] ) . '"' : '' );
  $attributes .= ' class="wp-caption ' . esc_attr( $attr['align'] ) . '"';
  $attributes .= ' style="width: ' . esc_attr( $attr['width'] ) . 'px"';

  /* Open the caption <div>. */
  $output = '<div' . $attributes .'>';

  /* Allow shortcodes for the content the caption was created for. */
  $output .= do_shortcode( $content );

  $id = explode("_", $attr['id']);

  if ( get_field('photographer', $id['1']) )
  {
    $photographer_web = get_field('photographer_web', $id['1']);
    $photographer = get_field('photographer', $id['1']);

    if (strpos($photographer_web, $pattern) === false)
    {
        $photographer_web = 'http://'.$photographer_web;
    }

    $output2  = '<span>Photo by </span>';
    $output2 .= '<a class="bmd_photographer" href="';
    $output2 .= $photographer_web;
    $output2 .= '" target="_blank">';
    $output2 .= $photographer;
    $output2 .= '</a>';

  }

  if (get_field('photo_courtesy', $id['1']))
  {
    $courtesy = get_field('photo_courtesy', $id['1']);
    $courtesy_website = get_field('photo_courtesy_website', $id['1']);

    $output3 = '<span class="bmd_photo_courtesy">, courtesy of ';
    if ($courtesy_website)
    {
      if (strpos($courtesy_website, $pattern) === false)
      {
          $courtesy_website = 'http://'.$courtesy_website;
      }
      $output3 .= '<a class="bmd_photographer" href="';
      $output3 .= $courtesy_website;
      $output3 .= '" target="_blank">';
      $output3 .= $courtesy;
      $output3 .= '</a>';
    }
    else
    {
      $output3 .= $courtesy;
    }

    $output3 .= '</span>';
  }

  if ($output2)
  {
    $output .= $output2;
  }

  if ($output3)
  {
    $output .= $output3;
  }

  /* Close the caption </div>. */
  $output .= '</div>';

  /* Return the formatted, clean caption. */
  return $output;
}