Need to do on the server using PHP / MySQL. Creating an index.
The first thing that came to mind was, through the libraries, for example, to open the noname.doc file, to receive all readable text without images and other garbage and to write it into MySQL with the appropriate file name. Further, when searching, you should do a classic search - text_index LIKE '% words words%' It seems to me that this is very cumbersome and maybe there are easier options? It is cumbersome in terms of what may be there are options for how to write more compactly instead of the entire text of the document.
What do you recommend for indexing the contents of files? Libraries or their theories.