R Code Required for reading keywords in websites and pdfs

Hi. I am looking for R code which searches a list of websites dynamically (and all its pages) and 50 pdf documents in my local computer for key words. The attached file has the list of key words to search in websites and respective pdf documents. It should loop through all keywords when searching. When it finds the key words, it must output in excel 5 sentences before the keywords and also five sentences after the key word. Output must be in *.csv file recording the following columns: Website: Key Word, Sentences (5 before & 5 after key words), Url keyword found Pdf documents: Key word, Sentences (5 before & 5 after key words), pdf name, page number