zip_file.R

path <- "~/Documents/ingest/readxl/inst/extdata/datasets.xlsx"

zip_file <- function(path) {
  stopifnot(file.exists(path))
  
  path <- normalizePath(path)
  
  contents <- utils::unzip(path, list = TRUE) 
  names(contents) <- c("path", "size", "date")
  contents <- contents[contents$size > 0, , drop = FALSE]
  contents <- tibble::remove_rownames(tibble::as_tibble(contents))
  
  structure(
    contents,
    class = c("zip_file", "tbl_df", "tbl", "data.frame"),
    path = path
  )
}

zip_con <- function(zip_file, path = 1L, open = "rb", ...) {
  
  if (is.numeric(path) && length(path) == 1) {
    path <- zip_file$path[[path]]
  }
  if (!is.character(path) || length(path) != 1) {
    stop("`path` must be a length one character vector or numeric", call. = FALSE)
  }

  if (!path %in% zip_file$path) {
    stop("`path` ", encodeString(path, quote = "'"), " not found", call. = FALSE)
  }
  
  unz(attr(zip_file, "path"), path, open = open, ...)
}