You can search and do textmining with the content of many PDF documents, since the content of PDF files is extracted and text in images were recognized by optical character recognition (OCR) automatically.
Therefore you have to index the PDF documents or file directories or file shares that contain PDF documents to the Solr or Elastic Search server index:
If you use Open Semantic Desktop Search, just copy the PDF files to a directory that is indexed automatically or add the directory with the PDF files to shared folders for indexing and restart the virtual machine or press the "Index" button within the VM.
If you use an file share where file monitoring is active, just copy the PDF files to an monitored folder or file directory and wait, until they are indexed automatically.
Using the web admin interface * Open the page Files * Enter filename of the PDF file to the form * Press button "crawl"
Using the command line interface (CLI): opensemanticsearch-index-file *filename*
Using the REST-API within your tools, script or within your browser: http://127.0.0.1/search-apps/api/index-file?uri=*/home/opensemanticsearch/document.pdf*
You can index whole folders with PDF documents to Apache Solr or Elastic Search the same way. Just use the name of the file directory or folder instead of a single file name.
Config file for indexing files: */etc/opensemanticsearch/connector-files*