title: Reading PDF metadata in PHP
body: <p>I'm trying to read metadata attached to arbitrary PDFs: title, author, subject, and keywords.</p>
  
  <p>Is there a PHP library, preferably open-source, that can read PDF metadata? If so, or if there isn't, how would one use the library (or lack thereof) to extract the metadata?</p>
  
  <p>To be clear, I'm not interested in creating or modifying PDFs or their metadata, and I don't care about the PDF bodies. I've looked at a number of libraries, including FPDF (which everyone seems to recommend), but it appears only to be for PDF creation, not metadata extraction.</p>