title: PHP, Check if URL and a file exists ?
body: <p>I create a plugin for WordPress that requires two files to be exists in order to operate normaly.</p>
  
  <p>The first file is defined as a file system path and the second file is defined as a URL.</p>
  
  <p>Let's say the first file is that:</p>
  
  <pre><code>/home/my_site/public_html/some_folder/required_file.php
  </code></pre>
  
  <p>and the second file is that:</p>
  
  <pre><code>http://www.my_site.com/some_folder/required_url_file.php
  </code></pre>
  
  <p>Note that both files are not the same file into the file system. The required_file.php has other content than the required_url_file.php and they act absolutly diferent</p>
  
  <p>Any idea on how to validate the existance of both files ?</p>