R/convert.R

In Epsian/ics2csv: Converts ICS Files to a Flat CSV

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# Github: https://www.github.com/Epsian               #
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#' @export

ics2csv = function(ics_file_path){

  #### Convert ####
  # Read in ical
  cal = readLines(ics_file_path)

  # Trim out metadata
  meta = cal[1:match("BEGIN:VEVENT", cal)-1]
  cal = cal[match("BEGIN:VEVENT", cal):length(cal)]

  # Convert each event to list element
  chunks = data.frame(starts = stringr::str_which(cal, "BEGIN:VEVENT"), ends = stringr::str_which(cal, "END:VEVENT"))
  entries = apply(chunks, 1, FUN = function(x) (x[1]+1):(x[2]-1))

  entries = lapply(entries, FUN = function(x){
    event = cal[x]

    # What do the valid entries start with?
    .starters = c("DTSTART:", "DTEND:", "DTSTAMP:", "UID:", "CREATED:", "DESCRIPTION:", "LAST-MODIFIED:", "LOCATION:", "SEQUENCE:", "STATUS:", "SUMMARY:", "TRANSP:", "RRULE:", "EXDATE;")

    # Find those that are fragments, past with prior entry
    info_fragment = !stringr::str_detect(event, paste(.starters, collapse = "|"))
    event[info_fragment] = trimws(event)[info_fragment]

    while(any(info_fragment)){
      event[which(info_fragment)[1]-1] = paste(event[which(info_fragment == TRUE)-1][1], event[info_fragment][1], sep = "")
      event = event[-which(info_fragment)[1]]
      info_fragment = !str_detect(event, paste(.starters, collapse = "|"))
    }

    # Turn each event into data frame
    event = data.frame(t(stringr::str_split(event, ":", n = 2, simplify = TRUE)), stringsAsFactors = FALSE)
    colnames(event) = event[1,]
    event = event[-1,]
  })

  # Convert list to DF
  entries = plyr::rbind.fill(entries)

  # Convert dates to lubridate
  entries$DTSTART = lubridate::as_datetime(entries$DTSTART)
  entries$DTEND = lubridate::as_datetime(entries$DTEND)
  entries$DTSTAMP = lubridate::as_datetime(entries$DTSTAMP)
  entries$CREATED = lubridate::as_datetime(entries$CREATED)
  entries$`LAST-MODIFIED` = lubridate::as_datetime(entries$`LAST-MODIFIED`)

  return(entries)
}