How to identify the page number of a . pdf by something written on it?

Question

I have a . pdf with 120 pages, each page is a certificate and the only difference between them is the name of the participant.

I also have a . csv with the list of participants' names and e-mail address (I used this list to generate the . pdf and I will try to use the e-mail to send by R)

How I can separate each page (certificate) into a new . pdf and save with attendee name?

I saw functions like pdf_subset of library(pdftools), but how I can identify the page number by something written on it?

library(pdftools)

# extair paginas de 1 
pdf_subset('certificados.pdf',
           pages = 1, output = "Carlos dos Santos.pdf")

It’s a pretty repetitive job, I wouldn’t want to do it manually.

I also thought of separating page by page and then searching for the name in . pdf and changing the name of the file. But I also don’t know how to do this yet.

Follows model of certificate: https://drive.google.com/file/d/1iwgW6kMT7C9Xee5SM65vz-D8B26bpavz/view?usp=sharing

Example of . csv:

nome,email
Prof. Dr. Thiado Souza,[email protected]
Prof. Dr. Marcelo José,mjose@gmail
Ricado Augusto,[email protected]
Carlos José,[email protected]

Answer 1

Since the certificates follow the same order as the csv file:

library(pdftools)

arq <- read.csv('./rxt.csv')
nomes <- as.character(arq$nome)

cria_pdf <- function(n, i){
  pdf_subset('certificado-teste.pdf',
             pages = i, output = paste(n[i],'.pdf'))
}

lapply(seq_along(nomes),cria_pdf, n = nomes)

This creates separate files in the directory based on the list of csv names.

Answer 2

I believe that the following function divides the input pdf into pages, storing each page in a file and renaming those files with the names of the csv file. The function input is

1. file - the name of the pdf file;
2. nomes - the date.frame with a column 'nome'

Needs the package pdftools to process pdf and package files stringi to remove accents and special letters, such as etá in this answer.

library(pdftools)

rename_file <- function(from, to){
  out <- tryCatch(file.rename(from, to),
                  error = function(e) e
  )
  if(inherits(out, "error")){
    out <- tryCatch(file.copy(from, to),
                    error = function(e) e,
                    warning = function(w) w
    )
    if(inherits(out, "error")){
      stop(e)
    }
    if(inherits(out, "warning")){
      warning(out)
      out <- FALSE
    }
    if(file.exists(to)) {
      if(file.exists(from)) unlink(from)
      out <- TRUE
    } else out <- FALSE
  }
  out
}

fun_split_pdf <- function(file, nomes){
  # ler os dados do pdf para uma lista de data.frames
  data_list <- pdf_data(file)
  # ficar com a coluna 'text' de cada data.frame da lista
  # e convertê-la em um único vetor com paste()
  Text <- unlist(lapply(data_list, function(x) paste(x[['text']], collapse = ' ')))
  # se tiver acentos, removê-los
  Text <- stringi::stri_trans_general(Text, "Latin-ASCII")
  # agora ver quais nomes do csv estão em qual página do pdf
  i <- sapply(nomes[['nome']], function(x){
    x <- stringi::stri_trans_general(x, "Latin-ASCII")
    j <- grep(x, Text)
    if(length(j) > 1) j[1] else j
  })
  # ordenar a coluna 'nome' do csv pela ordem do grep
  nms <- nomes[['nome']][i]
  # nomes finais dos ficheiros de saída
  nms <- paste0(nms, '.pdf')

  # fazer o split para um diretório temporário
  tmp <- tempfile()
  pdf_split(file, output = tmp)

  # renomear os ficheiros temporários
  pattern <- paste0(basename(tmp), "_.*\\.pdf")
  tmp_fls <- list.files(path = dirname(tmp), pattern = pattern)
  tmp_fls <- file.path(dirname(tmp), tmp_fls)
  sapply(seq_along(tmp_fls), function(i){
    rename_file(tmp_fls[[i]], nms[[i]])
  })
}

fl <- list.files(pattern = '\\.pdf')
fl
#[1] "certificado-teste.pdf"

nomes <- read.csv("pdf_teste.csv")

fun_split_pdf(fl, nomes)
#[1] TRUE TRUE TRUE TRUE