cran_archive_cache {pkgcache}

Cache for CRAN archive data

Description

This is an R6 class that implements a cache from older CRAN package versions. For a higher level interface see the functions documented with cran_archive_list().

Details

The cache is similar to cranlike_metadata_cache and has the following layers:

• The data inside the cran_archive_cache object.

• Cached data in the current R session.

• An RDS file in the current session's temporary directory.

• An RDS file in the user's cache directory.

It has a synchronous and an asynchronous API.

Usage

cac <- cran_archive_cache$new(
  primary_path = NULL,
  replica_path = tempfile(),
  cran_mirror = default_cran_mirror(),
  update_after = as.difftime(7, units = "days"),
)

cac$list(packages = NULL, update_after = NULL)
cac$async_list(packages = NULL, update_after = NULL)

cac$update()
cac$async_update()

cac$check_update()
cac$async_check_update()

cac$summary()

cac$cleanup(force = FALSE)

Arguments

• primary_path: Path of the primary, user level cache. Defaults to the user level cache directory of the machine.

• replica_path: Path of the replica. Defaults to a temporary directory within the session temporary directory.

• cran_mirror: CRAN mirror to use, this takes precedence over repos.

• update_after: difftime object. Automatically update the cache if it gets older than this. Set it to Inf to avoid updates. Defaults to seven days.

• packages: Packages to query, character vector.

• force: Whether to force cleanup without asking the user.

Details

Create a new archive cache with cran_archive_cache$new(). Multiple caches are independent, so e.g. if you update one of them, the other existing caches are not affected.

cac$list() lists the versions of the specified packages, or all packages, if none were specified. cac$async_list() is the same, but asynchronous.

cac$update() updates the cache. It always downloads the new metadata. cac$async_update() is the same, but asynchronous.

cac$check_update() updates the cache if there is a newer version available. cac$async_check_update() is the same, but asynchronous.

cac$summary() returns a summary of the archive cache, a list with entries:

• cachepath: path to the directory of the main archive cache,

• current_rds: the RDS file that stores the cache. (This file might not exist, if the cache is not downloaded yet.)

• lockfile: the file used for locking the cache.

• 'timestamp: time stamp for the last update of the cache.

• size: size of the cache file in bytes.

cac$cleanup() cleans up the cache files.

Columns

cac$list() returns a data frame with columns:

• package: package name,

• version: package version. This is a character vector, and not a package_version() object. Some older package versions are not supported by package_version().

• raw: the raw row names from the CRAN metadata.

• mtime: mtime column from the CRAN metadata. This is usually pretty close to the release date and time of the package.

• url: package download URL.

• mirror: CRAN mirror that was used to get this data.

Examples

arch <- cran_archive_cache$new()
arch$update()
arch$list()