Uploading many files in Shiny

I am developing an app that helps to organize and visualize many PDF documents by topic/theme. I can upload and read a single PDF but I have difficulty in reading multiple PDF documents.

For single PDF document:

ui.R

  ---
  fileInput('file1', 'Choose PDF File', accept=c('.pdf'))

 ---

server.R

   --------

   library(pdftools)

   -------


 mypdf<-reactive({

   inFile <- input$file1

   if (is.null(inFile)){
  return(NULL)
  }else{
  pdf_text(inFile$datapath)

   }

  })

To upload multiple PDF files, I have to use multiple = TRUE in the ui.R portion of the code, but how can I read in all the uploaded files?