Get or set the nhanesR local cache directory

nhanesR stores downloaded and parsed NHANES files in a local cache to avoid redundant downloads. By default the cache is placed in the standard user data directory for your operating system (see below). Use this function to view or change the location for the current session, or set it permanently in your .Rprofile.

Usage

nhanes_cache_dir(path = NULL, create = TRUE)

Arguments

path: Optional character. New path to use as the cache directory for the current session. If NULL, returns the current setting without changing it.
create: Logical. If TRUE (default), create the directory if it does not exist.

Value

The current (or newly set) cache directory path, invisibly.

Details

Package options

Three options control nhanesR behavior. Set any of them in your .Rprofile to make the change permanent across sessions; changes made during a session (via nhanes_cache_dir() or options() directly) last only until the session ends.

Option	Default	Purpose
`nhanesR.cache_dir`	`file.path(tempdir(), "nhanesR")`	Root directory for all cached files
`nhanesR.verbose`	`TRUE`	Print progress messages during downloads
`nhanesR.timeout`	`120L`	HTTP request timeout in seconds

Default cache location

By default the cache lives inside R's session-temporary directory (tempdir()), so nhanesR never writes to your home directory without your consent. Downloaded files are re-fetched in each new R session. To keep a persistent cache, set nhanesR.cache_dir in your ~/.Rprofile.

Setting options permanently

Add lines like these to your ~/.Rprofile:

options(
  nhanesR.cache_dir = "/data/nhanes_cache",  # shared lab server path
  nhanesR.verbose   = FALSE,                  # suppress progress messages
  nhanesR.timeout   = 300L                    # 5-minute timeout for slow connections
)

Options set in .Rprofile take precedence over package defaults: nhanesR only sets an option at load time if it is not already defined.

Examples

# View current cache location (defaults to a subdirectory of tempdir())
nhanes_cache_dir()
#> [1] "/var/folders/68/vh2f8kzn09j8954r6q9100yh0000gn/T//Rtmp7zLR2U/nhanesR"

# Change to a persistent location for this session only
# \donttest{
nhanes_cache_dir("~/my_nhanes_cache")
#> [1] "/Users/dwinsemius/my_nhanes_cache"
# }

# Suppress download messages for this session
options(nhanesR.verbose = FALSE)

# View all current nhanesR option values
Filter(function(x) startsWith(x, "nhanesR."), names(options()))
#> [1] "nhanesR.cache_dir" "nhanesR.timeout"   "nhanesR.verbose"