def get_public_docs(documents)
      result = []
      for doc in documents
        file_name = doc["fileName"]
        if file_name.end_with? ".pdf"
          if documents.length < 2 or file_name.end_with? @public_doc_postfix
            result << doc
          end
        end
      end
      return result
    end
def get_public_docs(documents)
      result = []
      for doc in documents
        file_name = doc["fileName"]
        if file_name.end_with? ".pdf"
          if documents.length < 2 or file_name.end_with? @public_doc_postfix
            result << doc
          end
        end
      end
      return result
    end
only show PDF files