As defined in RFC2616, http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3, there are three valid formats:
Sun, 06 Nov 1994 08:49:37 GMT ; RFC 822, updated by RFC 1123
Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036
Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format
parse_http_date(x, failure = structure(NA_real_, class = "Date")) http_date(x)
| x | For For |
|---|---|
| failure | What to return on failure? |
A POSIXct object if succesful, otherwise failure
parse_http_date("Sun, 06 Nov 1994 08:49:37 GMT")#> [1] "1994-11-06 08:49:37 GMT"parse_http_date("Sunday, 06-Nov-94 08:49:37 GMT")#> [1] "1994-11-06 08:49:37 GMT"parse_http_date("Sun Nov 6 08:49:37 1994")#> [1] "1994-11-06 08:49:37 GMT"http_date(Sys.time())#> [1] "Wed, 11 Mar 2020 04:10:17 GMT"