readr wrapper that also checks md5 sums

readr-write-check.R

readr_write <- function(x, file, ..., .fun = "csv", .check = TRUE) {
  if (is.function(.fun)) {
    .fun <- match.fun(fun)
  } else {
    if (requireNamespace("readr", quietly = TRUE)) {
      .fun <- paste0("write_", .fun)
      .fun <- getFromNamespace(.fun, asNamespace("readr"))
    } else {
      .fun <- switch(
        tolower(.fun),
        csv = utils::write.csv,
        csv2 = utils::write.csv2,
        delim = utils::write.table,
        table = utils::write.table,
        rds = function(x, file, ...) saveRDS(object = x, file = file, ...),
        tsv = function(x, file, sep = "\t", ...) utils::write.table(x = x, file = file, sep = sep, ...),
        lines = function(x, file, ...) writeLines(text = x, con = file, ...)
      )
    }
  }
  
  if (!fs::file_exists(file) || !.check) {
    # if file does not exist or we don't need to check
    return(.fun(x, file = file, ...))
  }
  
  tmp <- fs::file_temp()
  on.exit(fs::file_delete(tmp))
  
  .fun(x, file = tmp, ...)
  if (tools::md5sum(tmp) == tools::md5sum(file)) {
    message("md5sums are the same")
    return(invisible(x))
  }
  
  message("md5sums are different")
  fs::file_copy(tmp, file, overwrite = TRUE)
  return(invisible(x))
}