R package to export ICS?

Question

Does anyone know of an R function to export dates and labels to an ics calendar format?

I've googled and searched SO but nothing is obvious, but can't believe someone hasn't already done this...

Possible duplicate of https://stackoverflow.com/questions/43573982/how-to-import-ical-ics-file-in-r — zx8754, Jan 16 '18 at 11:30
Your lack of cut-and-paste-able results is likely due to the iCalendar specification being so non-opaque and quite straightforward to implement (had to be so Microsoft programmers of Outlook & Exchange cld grok it). — hrbrmstr, Jan 16 '18 at 12:33
@hrbrmstr laziness is often a virtue especially when it comes to (re)implementing standards relating to dates and times, so I'm not going to apologise for searching for a library. That said - you're right that the spec is pretty simple! Thanks for the code below. — bjw, Jan 16 '18 at 15:06

score 11 · Accepted Answer · edited Oct 07 '21 at 07:59

The iCalendar specification is pretty straightforward. Extending the following after reading that link and keeping it handy as a reference should be trivial (and I use that word deliberately vs lightly):

#' Create a minimal iCalendar VEVENT
#' 
#' @param start,end start and end times of the event. This will be converted to
#'        GMT from whatever time zone it currently is.
#' @param summary a summary of the event. This is the "title" you see in calendars.
#' @param domain something that will help the generated UUID be even more unique and
#'        is generally good practice to use your org's domain name
#' @return atomic character vector ready for `writeLines()`
create_ical <- function(start, end, summary, domain="example.com") {
  
  require(uuid, quietly = TRUE, warn.conflicts = FALSE)
  
  sprintf(
    "BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//rstats//NONSGML v1.0//EN
BEGIN:VEVENT
UID:%s@%s
DTSTAMP:%s
DTSTART:%s
DTEND:%s
SUMMARY:%s
END:VEVENT
END:VCALENDAR
", uuid::UUIDgenerate(),
    domain, 
    format(Sys.time(), "%Y%m%dT%H%M%SZ", tz="GMT"), 
    format(start, "%Y%m%dT%H%M%SZ", tz="GMT"), 
    format(end, "%Y%m%dT%H%M%SZ", tz="GMT"), 
    summary
)
  
}

Usage:

create_ical(
  as.POSIXct("2018-01-30 13:00:00", origin="1970-01-01 00:00:00"),
  as.POSIXct("2018-01-30 14:00:00", origin="1970-01-01 00:00:00"),
  "A good description of the event",
  "somedom.org"
) -> ics_event

cat(ics_event)
## BEGIN:VCALENDAR
## VERSION:2.0
## PRODID:-//rstats//NONSGML v1.0//EN
## BEGIN:VEVENT
## UID:4ae2435e-7679-495e-9377-b6da17e0090a@somedom.org
## DTSTAMP:20180116T123051Z
## DTSTART:20180130T180000Z
## DTEND:20180130T190000Z
## SUMMARY:A good description of the event
## END:VEVENT
## END:VCALENDAR

writeLines(ics_event, "ics_event.ics")

score 2 · Answer 2 · answered May 10 '18 at 16:17

Thanks a lot for the previous answer. Based on it I write the following function to read "ics" file from disk or web.

read_google_calendar <- function(file_path) {

   # 1. Read data as text lines
   ics_lines <- readLines(file_path, warn = FALSE)

   # 2. Disregarding value fields that have linefeeds for the sake of simplicity 
   stopifnot(!any(grepl("^\\s+", ics_lines)))

   # 3. Parse data
   key_value <- do.call(rbind, regmatches(ics_lines, regexpr(":", ics_lines, fixed = TRUE), invert = TRUE))
   key_value <- key_value[which.max(key_value[ , 1] == "BEGIN" & key_value[ , 2] == "VEVENT"):tail(which(key_value[ , 1] == "END" & key_value[ , 2] == "VEVENT"), 1),]
   key_value <- cbind.data.frame(key_value, id = cumsum(key_value[ , 1] == "BEGIN" & key_value[ , 2] == "VEVENT"))

   # 4. Create data frame
   df <- reshape(key_value, timevar = "1", idvar = "id", direction = "wide")

   # 5. Change features names
   colnames(df) <- c("id", "begin", "date_start", "date_end", "date_stamp",
                "uid", "class", "created", "description", "last_modified",
                "sequence", "status", "summary", "trans", "end")

    # 6. Change features type
    df <- df %>% 
      mutate(
        date_start = as.Date(date_start, format = "%Y%m%d"),
        date_end = as.Date(date_end, format = "%Y%m%d"))

    # 7. Subset features
    df <- df %>% 
      subset(select = c("date_start", "date_end", "summary", "class"))

    # 8. Result
    df

 }

score 2 · Answer 3 · answered Apr 05 '19 at 12:35

Although the solutions posted above work well, another option is the calendar package on CRAN (documentation here). Importing from an ICS file to a data frame takes one line of code, and creating new events then exporting to a new ICS file is also straightforward.

R package to export ICS?

3 Answers3

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