Still on Drupal 7? Security support for Drupal 7 ended on 5 January 2025. Please visit our Drupal 7 End of Life resources page to review all of your options.
Specifically designed to index pdf files, Search PDF in built on PDF Parser, an opensource php library.
PDF Files are parsed and the text is extracted from each page.
The main advantage from this module is that it doesn't required external tool.