find dead feeds in OPML export (supports Atom and RSS2, will fail to parse on occasions)

opml_dates.r

library(dplyr)
library(httr)
library(readr)
library(rvest)

d <- read_xml("~/Downloads/digg_reader_subscriptions.xml") %>% 
  xml_nodes("outline")
d <- data_frame(
  title = xml_attr(d, "text"),
  url = xml_attr(d, "xmlUrl")
)
d <- filter(d, !is.na(url)) %>% 
  mutate(last = NA_character_)

for (i in rev(d$url)) {
  
  cat(which(d$url == i))
  f <- try(read_html(i), silent = TRUE)
  
  if ("try-error" %in% class(f)) {
    cat(": error\n")
  } else {
    
    # Atom
    j <- html_node(f, "entry published") %>% 
      html_text()
    
    if (is.na(j)) {
      
      # RSS
      j <- html_node(f, "item pubdate") %>%
        html_text()
      
    }
    
    d$last[ d$url == i ] <- j
    cat(":", parse_url(i)$hostname, "last updated", j, "\n")
    
  }
  
}

table(is.na(d$last)) %>% 
  print

filter(d, !is.na(last), !grepl("201[67]", last)) %>% 
  View

write_csv(d, "opml_dates.csv")