Identify the timestamp of the most recently modified file in the file cache

Returns the timestamp of the most recently modified file. If no such file exists, or if the directory basepath/fname doesn't exist, returns NA.

mostRecentTimestamp(fname, basepath = ".")

Arguments

fname	The name of the directory in basepath where various revisions of the file are stored. I.e., file.txt should be a directory, with revisions of the true file.txt stored inside of it.
basepath	A string. The path which stores the fname directory. Default '.'

Value

A POSIXct object specifying the mtime of the most recently modified file in basepath/fname

Examples

library(lubridate)
#> 
#> Attaching package: 'lubridate'
#> The following object is masked from 'package:base':
#> 
#>     date

saveRDS(mtcars, 'cars')
saveRDS(mtcars, 'cars')

# Some time elapses...

# Decide if the latest version of 'mtcars' is "too old"
if (mostRecentTimestamp('mtcars') %--% now() > hours(24)) {
  # Store a "new" version
  saveRDS(mtcars, 'cars')
} else {
  cached_mtcars <- retrieveRDS('mtcars')
}