how to extract title from a pdf documment with R - r

Question

I need help to extract information from a pdf file in r
(for example https://arxiv.org/pdf/1701.07008.pdf)
I'm using pdftools, but sometimes pdf_info() doesn't work and in that case I can't manage to do it automatically with pdf_text()
NB notice that tabulizer didn't work on my PC.
Here is the treatment I'm doing (Sorry you need to save the pdf and do it with your own path):
info <- pdf_info(paste0(path_folder,"/",pdf_path))
title <- c(title,info$keys$Title)
key <- c(key,info$keys$Keywords)
auth <- c(auth,info$keys$Author)
dom <- c(dom,info$keys$Subject)
metadata <- c(metadata,info$metadata)
I would like to get title and abstract most of the time.

Answer 1

We will need to make some assumptions about the structure of the pdf we wish to scrape. The code below makes the following assumptions:
Title and abstract are on page 1 (fair assumption?)
Title is of height 15
The abstract is between the first occurrence of the word "Abstract" and first occurrence of the word "Introduction"
library(tidyverse)
library(pdftools)
data = pdf_data("~/Desktop/scrape.pdf")
#Get First page
page_1 = data[[1]]
# Get Title, here we assume its of size 15
title = page_1%>%
filter(height == 15)%>%
.$text%>%
paste0(collapse = " ")
#Get Abstract
abstract_start = which(page_1$text == "Abstract.")[1]
introduction_start = which(page_1$text == "Introduction")[1]
abstract = page_1$text[abstract_start:(introduction_start-2)]%>%
paste0(collapse = " ")
You can, of course, work off of this and impose stricter constraints for your scraper.