file_get_uri_from_url()

gistfile1.aw

<?php

function file_get_uri_from_url($url, $load_file = TRUE) {
  $base_paths = &drupal_static(__FUNCTION__);

  if (!isset($base_paths)) {
    $base_paths = array();
    foreach (file_get_stream_wrappers() as $scheme => $stream_wrapper) {
      $class = file_stream_wrapper_get_class($scheme);
      if (class_exists($class) && method_exists($class, 'getExternalUrl')) {
        $wrapper = new $class();
        $wrapper->setUri($scheme . '://');
        $base_paths[$scheme] = $wrapper->getExternalUrl();
      }
    }
    $base_paths = array_filter($base_paths);
  }

  foreach ($base_paths as $scheme => $base_path) {
    if (preg_match('/^' . preg_quote($base_path, '/') . '(.+)$/', $url, $matches)) {
      $uri = $scheme . '://' . $matches[1];
      if ($load_file) {
        if ($fid = db_query("SELECT fid FROM {file_managed} WHERE uri = :uri", array(':uri' => $uri))->fetchField()) {
          return file_load($fid);
        }
      }
      else {
        return $uri;
      }
    }
  }

  return FALSE;
}