I had the same problem.
My solution -- a little bit uncomfortable, but it works.
* Create a DokuWiki on Your local computer.
* Run it with a XAMPP installation
* Install Antiword and pdftotext and configure as described
https://www.dokuwiki.org/plugin:docsearch
* Run the cronjob via cli
* Upload the directories and files (index, pages) from /data/docsearch on Your local computer to the corresponding directories of Your server.
* search if a new term in Your files is shown in search results.
Dependent on the number of added new files:
* Sync Your local DokuWiki with the server DokuWiki.
* Erase the the directories and files (index, pages) from /data/docsearch local computer
* and again as described.
HTH
Regards
Karl