title: MIME error when uploading with PHP - docx files
body: <p>A website I am building allows file uploads by authorised users.  For any specific category of uploads, a set of file types is allowed, e.g. .pdf and .docx, so that my client can choose what they want to accept.</p>
  
  <p>When uploading, I check the uploaded file's MIME type (using <code>finfo_open(FILEINFO_MIME_TYPE)</code>) against a database table of MIME types for that extension.</p>
  
  <p>In testing, I am uploading a docx file from my PC - it has a docx extension and Windows reports the file type as application/vnd.openxmlformats-officedocument.wordprocessingml.document which is what I expect.  However, <code>finfo_open</code> is giving me a MIME type of application/msword.</p>
  
  <p>Does finfo_open's information come from within the file or from something in the browser or the upload process (in which case I guess I'll need to specify additional MIME types allowed) or is it something within the web server (in which case, can it be modified with php.ini)?</p>