This TYPO3 extension provides a hook/aspect that uses the signal of ext:solrfal during indexing to extract the contents of known text files.
It uses the binary pdftotext for this (when present on the machine) and has a fallback to the standalone apache Tika jar (when present on the system).
There are some additional checks when processing pdf files to determine if the contents is encrypted.
If encrypted it tries the fallback to tika.