Cache {fscache}

A cache class for handling caching on the file system.

Description

A cache class for handling caching on the file system.

A cache class for handling caching on the file system.

Details

The purpose of this class is to help managing a user cache folder for an application. Files can be copied or moved into the cache folder. Character values can be saved into files and loaded from files. Sub-folders can be defined. Folders can be listed to see the existing files. Files can be deleted individually or by batch, Whole folders can be deleted, including the main cache folder.

Methods

Public methods

• Cache$new()

• Cache$isReadable()

• Cache$isWritable()

• Cache$setReadable()

• Cache$setWritable()

• Cache$getFolder()

• Cache$hasFolder()

• Cache$getPaths()

• Cache$globPaths()

• Cache$getNbItems()

• Cache$pathsExist()

• Cache$tagExists()

• Cache$writeTag()

• Cache$getTmp()

• Cache$getSubFolders()

• Cache$importFiles()

• Cache$saveContents()

• Cache$loadContents()

• Cache$delPaths()

• Cache$delFolder()

• Cache$listFolder()

• Cache$print()

• Cache$erase()

• Cache$clone()

Method new()

New instance initializer.

Initializes a Cache instance, using a specified folder. Path to the folder can be absolute or relative. When relative, the absolute root folder is either the standard user cache folder or the current working directory, depending on user parameter.

Usage

Cache$new(folder, user = TRUE, force = FALSE, create = TRUE)

Arguments

folder

The path to the wanted cache folder. Either an absolute path, or a relative path that will be resolved immediately into an absolute path.

user

If set to TRUE and the folder path is a relative path, then the path is resolved relatively to the standard user cache folder (i.e.: we call tools::R_user_dir(folder, which = 'cache')). A good and standard practice is to set the folder parameter to your package name, using.

force

If the folder exists, is not empty and is not an fscache folder, fails if force is FALSE, and use folder anyway if force is TRUE.

create

If FALSE, does not create the cache folder if does not exist already. Used for testing purposes only.

Returns

Nothing.

Examples

# Create a new cache instance.
# Note for the sake of the example we use a temporary directory specified
# as an absolute path, however the usual way to use the cache system is
# to provide a relative path, that will be placed inside the standard
# user cache folder defined by the OS.
cache <- Cache$new(tempdir())

# Erase cache
cache$erase()

Method isReadable()

Tests if the cache system is readable.

Cache reading may be disabled and re-enabled with setReadable(), Mainly used for debug purposes.

Usage

Cache$isReadable()

Returns

TRUE if the cache system is readable, FALSE otherwise.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Tests if readable (TRUE by default)
if (cache$isReadable()) {
  print("Cache is readable")
}

# Erase cache
cache$erase()

Method isWritable()

Tests if the cache system is writable.

Cache reading may be disabled and re-enabled with setWritable(). Mainly used for debug purposes.

Usage

Cache$isWritable()

Returns

TRUE if the cache system is writable, FALSE otherwise.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Tests if writeable (TRUE by default)
if (cache$isWritable()) {
  print("Cache is writeable")
}

# Erase cache
cache$erase()

Method setReadable()

Disables or enable cache reading.

Allows or disallows reading to the cache folder.

Usage

Cache$setReadable(readable)

Arguments

readable

Set to FALSE to disallow reading and to TRUE to allow it.

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Disallow reading
cache$setReadable(FALSE)

# Erase cache
cache$erase()

Method setWritable()

Disables or enable cache writing.

Allows or disallows writing to the cache folder.

Usage

Cache$setWritable(writable)

Arguments

writable

Set to FALSE to disallow writing and to TRUE to allow it.

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Disallow writing
cache$setWritable(FALSE)

# Erase cache
cache$erase()

Method getFolder()

Gets the path to the main cache folder or a sub-folder.

Returns the absolute path to the main cache folder or a cache sub-folder. By default, the folder is created if it does not exist.

Usage

Cache$getFolder(
  sub_folder = NULL,
  create = TRUE,
  fail = FALSE,
  sub.folder = NULL
)

Arguments

sub_folder

A sub-folder.

create

If set to TRUE and the folder does not exist, creates it.

fail

If set to TRUE, throws an error if the folder does not exist.

sub.folder

Use sub_folder instead.

Returns

The path to the cache folder as a character value.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the absolute path to the cache folder
folder <- cache$getFolder()

# Get the absolute path to a cache sub-folder
sub_folder <- cache$getFolder('my_sub_folder')

# Erase cache
cache$erase()

Method hasFolder()

Tests if the cache main folder or a cache sub-folder exists.

Usage

Cache$hasFolder(sub_folder = NULL, sub.folder = NULL)

Arguments

sub_folder

The sub-folder.

sub.folder

Use sub_folder instead.

Returns

TRUE if the folder exists. FALSE otherwise.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Test if a sub-folder exists
if (cache$hasFolder("my_sub_folder")) {
  print("Sub-folder exists.")
}

# Erase cache
cache$erase()

Method getPaths()

Computes paths in the cache folder or a cache sub-folder.

Takes a list of relative paths and resolves them using the cache folder path to a list of absolute paths.

Usage

Cache$getPaths(paths, suffix = NULL, sub_folder = NULL, sub.folder = NULL)

Arguments

paths

A character vector containing paths.

suffix

A suffix to add to all paths.

sub_folder

A sub-folder.

sub.folder

Use sub_folder instead.

Returns

A character vector, the same size as paths, containing the absolute paths.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the paths a list of filenames should have in the cache folder
paths <- cache$getPaths(c("a.csv", "b.txt"))

# Get paths using a common extension for filenames
paths <- cache$getPaths(c("a", "b"), suffix = ".csv")

# Get paths of files inside a sub-folder
paths <- cache$getPaths(c("a.csv", "b.txt"), sub_folder = "foo")

# Erase cache
cache$erase()

Method globPaths()

Search for files inside the cache folder or one of its subfolders.

Usage

Cache$globPaths(
  suffix = NULL,
  sub_folder = NULL,
  tag_files = FALSE,
  folders = FALSE,
  tag.files = NULL,
  sub.folder = NULL
)

Arguments

suffix

The suffix files must have.

sub_folder

A sub-folder where to search.

tag_files

If set to FALSE (default), exclude the tag files. Otherwise include them in the output.

folders

If set to FALSE (default), exclude the folders. Otherwise include them in the output.

tag.files

Use tag_files instead.

sub.folder

Use sub_folder instead.

Returns

A character vector containing paths to existing file matching the criteria.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get all existing files inside sub-folder foo
paths <- cache$globPaths(sub_folder = "foo")

# Get all existing files with extension ".txt" inside main folder
paths <- cache$globPaths(suffix = ".txt")

# Erase cache
cache$erase()

Method getNbItems()

Gets the number of items contained inside a cache folder.

Counts the number of items (files or folders) contained inside a cache folder. This method does not explore the file system recursively, but only look at the files inside the folder.

Usage

Cache$getNbItems(
  sub_folder = NULL,
  tag_files = FALSE,
  folders = FALSE,
  tag.files = NULL,
  sub.folder = NULL
)

Arguments

sub_folder

A sub-folder.

tag_files

If set to FALSE (default), do not count the tag files. Otherwise count them.

folders

If set to FALSE (default), do not count the folders. Otherwise count them.

tag.files

Use tag_files instead.

sub.folder

Use sub_folder instead.

Returns

The number of items.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the number of files inside sub-folder "foo"
n <- cache$getNbItems("foo")

# Erase cache
cache$erase()

Method pathsExist()

Tests if paths exist inside a cache folder.

Takes a list of relative paths and resolves them using the cache folder path to a list of absolute paths. Tests then if each path points to real object on the file system.

Usage

Cache$pathsExist(paths, suffix = NULL, sub_folder = NULL, sub.folder = NULL)

Arguments

paths

A character vector containing paths.

suffix

A suffix to add to all paths.

sub_folder

A sub-folder.

sub.folder

Use sub_folder instead.

Returns

A logical vector, the same size as paths, with TRUE value if the file exists in the cache, or FALSE otherwise.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Test if some files exist in the cache
exits <- cache$pathsExist(c("a", "b"), suffix = ".txt")

# Erase cache
cache$erase()

Method tagExists()

Tests if a tag exists in the cache.

Tags are empty files, without extension, whose name starts and ends with "__". This method tests if some tag file already exist in a cache folder.

Usage

Cache$tagExists(name, sub_folder = NULL, sub.folder = NULL)

Arguments

name

The name of the tag, without the prefix "__" and the suffix "__". It will be automatically converted in uppercase. It can only contains digits, letters and underscore characters.

sub_folder

A sub-folder.

sub.folder

Use sub_folder instead.

Returns

TRUE if the tag exists in the cache. FALSE otherwise.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Test if tag file "downloaded" exists in sub-folder "hmdb"
if (cache$tagExists("downloaded", sub_folder = "hmdb")) {
  print("Tag exists")
}

# Erase cache
cache$erase()

Method writeTag()

Sets a tag into the cache.

Usage

Cache$writeTag(name, sub_folder = NULL, sub.folder = NULL)

Arguments

name

The name of the tag, without the prefix "__" and the suffix "__". It will be automatically converted in uppercase. It can only contains digits, letters and underscore characters.

sub_folder

A sub-folder.

sub.folder

Use sub_folder instead.

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Create tag file "downloaded" in sub-folder "hmdb"
cache$writeTag("downloaded", sub_folder = "hmdb")

# Erase cache
cache$erase()

Method getTmp()

Gets path to the cache system temporary folder.

This temporary folder located inside the cache folder is needed in order to be able to move/rename files into the right cache location. When creating files in the system temporary folder, which may reside on a different partition, moving a file could fail as in the following error: cannot rename file "/tmp/Rtmpld18y7/10182e3a086e7b8a7.tsv" to "/home/pr228844/dev/biodb/cache/comp.csv.file-58e...c4/2e3...a7.tsv", reason "Invalid cross-device link".

When you download a file directly to the disk using for instance download.file(), write the destination into this destination folder. When downloaded is complete, move the file using the method importFiles().

Usage

Cache$getTmp()

Returns

A string containing the path to the folder.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the cache temporary folder
tmp <- cache$getTmp()

# Erase cache
cache$erase()

Method getSubFolders()

Returns all existing sub-folders.

Usage

Cache$getSubFolders()

Returns

A character vector containing all the sub-folders.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the list of sub-folders
sub.folders <- cache$getSubFolders()

# Erase cache
cache$erase()

Method importFiles()

Imports existing files into the cache.

Usage

Cache$importFiles(
  src,
  dst = NULL,
  suffix = NULL,
  sub_folder = NULL,
  action = c("copy", "move"),
  sub.folder = NULL
)

Arguments

src

A character vector containing paths to files to import.

dst

A character vector containing destination filenames. The vector must have the length as the src vector. If NULL, the filenames in src will be used.

suffix

A suffix to add to all destination paths.

sub_folder

A sub-folder. All files will copied or moved to this sub-folder.

action

Specifies if files have to be moved or copied into the cache.

sub.folder

Use sub_folder instead.

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Create some files for the example
files <- c("k.txt", "u.csv")
file.create(files)

# Move those files into the cache
cache$importFiles(files, sub_folder = "foo", action = "copy")

# Remove original files
unlink(files)

# Erase cache
cache$erase()

Method saveContents()

Saves contents to files into the cache.

Saves character values into files inside a cache folder.

Usage

Cache$saveContents(
  contents,
  dst,
  suffix = NULL,
  sub_folder = NULL,
  sub.folder = NULL
)

Arguments

contents

A character vector containing the contents to write.

dst

A character vector containing destination filenames. The vector must have the length as the contents vector.

suffix

A suffix to add to all destination paths.

sub_folder

A sub-folder. All files will copied or moved to this sub-folder.

sub.folder

Use sub_folder instead.

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Create some contents for the example
contents <- c("a", "b", "c")

# Save contents
cache$saveContents(contents, c("a.txt", "b.txt", "c.txt"))

# Erase cache
cache$erase()

Method loadContents()

Loads contents from files stored into the cache.

Loads character values from cache files.

Usage

Cache$loadContents(paths, suffix = NULL, sub_folder = NULL, sub.folder = NULL)

Arguments

paths

A character vector containing destination filenames. The vector must have the length as the contents vector.

suffix

A suffix to add to all destination paths.

sub_folder

A sub-folder. All files will copied or moved to this sub-folder.

sub.folder

Use sub_folder instead.

Returns

A character vector , the same size as paths, containing the contents of the files. If some file does not exist, a NA value is returned.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Create some contents for the example
contents <- c("1", "2", "3")

# Save contents
cache$saveContents(contents, c("a", "b", "c"), suffix = ".txt",
                   sub_folder = "ex2")

# Load contents
contents <- cache$loadContents(c("a", "b", "c"), suffix = ".txt",
                               sub_folder = "ex2")

# Erase cache
cache$erase()

Method delPaths()

Deletes a list of paths inside the cache system.

Takes a list of relative paths, resolves them using the cache folder path to a list of absolute paths, and deletes the corresponding files.

Usage

Cache$delPaths(
  paths = NULL,
  suffix = NULL,
  sub_folder = NULL,
  sub.folder = NULL
)

Arguments

paths

A character vector containing paths.

suffix

A suffix to add to all paths.

sub_folder

A sub-folder.

sub.folder

Use sub_folder instead.

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Delete some cache files
cache$delPaths(c("a.txt", "b.txt"))

# Erase cache
cache$erase()

Method delFolder()

Deletes all files in a sub-folder.

Deletes a sub-folder and all its content.

Usage

Cache$delFolder(sub_folder, sub.folder = NULL)

Arguments

sub_folder

A sub-folder.

sub.folder

Use sub_folder instead.

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Delete sub-folder
cache$delFolder("my_sub_folder")

# Erase cache
cache$erase()

Method listFolder()

Lists files present inside a cache folder.

Lists files that exist inside a cache folder. Returns by default the full paths of the found files. It is possible to filter on files suffix, and to extract the basename.

Usage

Cache$listFolder(
  sub_folder = NULL,
  suffix = NULL,
  extract_name = FALSE,
  remove_suffix = FALSE,
  tag_files = FALSE,
  folders = FALSE,
  extract.name = NULL,
  remove.suffix = NULL,
  tag.files = NULL,
  sub.folder = NULL
)

Arguments

sub_folder

A sub-folder, or NULL for the main folder.

suffix

A file suffix on which to filter.

extract_name

If set to TRUE, instead of returning the full paths of the files, returns their basenames.

remove_suffix

When set to TRUE and extract.name is TRUE and suffix is not NULL, remove the suffix from the returned basenames.

tag_files

If set to FALSE (default), exclude the tag files. Otherwise include them in the output.

folders

If set to FALSE (default), exclude the folders. Otherwise include them in the output.

extract.name

Use extract_name instead.

remove.suffix

Use remove_suffix instead.

tag.files

Use tag_files instead.

sub.folder

Use sub_folder instead.

Returns

The paths to the found files, or the names of the files if extract.name is set to TRUE.

Examples

# Create a new cache instance
cache <- Cache$new("my_cache_folder")

# List files in sub-folder
files <- cache$listFolder("my_sub_folder")

# Remove cache folder
cache$erase()

Method print()

Displays information about this object.

Usage

Cache$print()

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Print information
print(cache)

# Erase cache
cache$erase()

Method erase()

Erases the whole cache folder.

Deletes the main cache folder and all its files and sub-folders.

Usage

Cache$erase()

Returns

Nothing.

Examples

# Create a new cache instance
cache <- Cache$new(tempdir())

# Deletes the whole cache content
cache$erase()

# Erase cache
cache$erase()

Method clone()

The objects of this class are cloneable with this method.

Usage

Cache$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

# Create a new cache instance inside a custom folder
cache <- Cache$new(tempdir())

# Create some contents for the example
contents <- c("a", "b", "c")

# Save contents
cache$saveContents(contents, c("a.txt", "b.txt", "c.txt"),
                   sub_folder = "sub1")

# Get list of files inside folder
files <- cache$listFolder("sub1")

# Delete files
cache$delPaths(c("a.txt", "c.txt"), sub_folder = "sub1")

# Delete whole sub-folder
cache$delFolder("sub1")

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$new`
## ------------------------------------------------

# Create a new cache instance.
# Note for the sake of the example we use a temporary directory specified
# as an absolute path, however the usual way to use the cache system is
# to provide a relative path, that will be placed inside the standard
# user cache folder defined by the OS.
cache <- Cache$new(tempdir())

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$isReadable`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Tests if readable (TRUE by default)
if (cache$isReadable()) {
  print("Cache is readable")
}

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$isWritable`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Tests if writeable (TRUE by default)
if (cache$isWritable()) {
  print("Cache is writeable")
}

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$setReadable`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Disallow reading
cache$setReadable(FALSE)

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$setWritable`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Disallow writing
cache$setWritable(FALSE)

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$getFolder`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the absolute path to the cache folder
folder <- cache$getFolder()

# Get the absolute path to a cache sub-folder
sub_folder <- cache$getFolder('my_sub_folder')

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$hasFolder`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Test if a sub-folder exists
if (cache$hasFolder("my_sub_folder")) {
  print("Sub-folder exists.")
}

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$getPaths`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the paths a list of filenames should have in the cache folder
paths <- cache$getPaths(c("a.csv", "b.txt"))

# Get paths using a common extension for filenames
paths <- cache$getPaths(c("a", "b"), suffix = ".csv")

# Get paths of files inside a sub-folder
paths <- cache$getPaths(c("a.csv", "b.txt"), sub_folder = "foo")

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$globPaths`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get all existing files inside sub-folder foo
paths <- cache$globPaths(sub_folder = "foo")

# Get all existing files with extension ".txt" inside main folder
paths <- cache$globPaths(suffix = ".txt")

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$getNbItems`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the number of files inside sub-folder "foo"
n <- cache$getNbItems("foo")

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$pathsExist`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Test if some files exist in the cache
exits <- cache$pathsExist(c("a", "b"), suffix = ".txt")

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$tagExists`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Test if tag file "downloaded" exists in sub-folder "hmdb"
if (cache$tagExists("downloaded", sub_folder = "hmdb")) {
  print("Tag exists")
}

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$writeTag`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Create tag file "downloaded" in sub-folder "hmdb"
cache$writeTag("downloaded", sub_folder = "hmdb")

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$getTmp`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the cache temporary folder
tmp <- cache$getTmp()

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$getSubFolders`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Get the list of sub-folders
sub.folders <- cache$getSubFolders()

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$importFiles`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Create some files for the example
files <- c("k.txt", "u.csv")
file.create(files)

# Move those files into the cache
cache$importFiles(files, sub_folder = "foo", action = "copy")

# Remove original files
unlink(files)

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$saveContents`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Create some contents for the example
contents <- c("a", "b", "c")

# Save contents
cache$saveContents(contents, c("a.txt", "b.txt", "c.txt"))

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$loadContents`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Create some contents for the example
contents <- c("1", "2", "3")

# Save contents
cache$saveContents(contents, c("a", "b", "c"), suffix = ".txt",
                   sub_folder = "ex2")

# Load contents
contents <- cache$loadContents(c("a", "b", "c"), suffix = ".txt",
                               sub_folder = "ex2")

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$delPaths`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Delete some cache files
cache$delPaths(c("a.txt", "b.txt"))

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$delFolder`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Delete sub-folder
cache$delFolder("my_sub_folder")

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$listFolder`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new("my_cache_folder")

# List files in sub-folder
files <- cache$listFolder("my_sub_folder")

# Remove cache folder
cache$erase()


## ------------------------------------------------
## Method `Cache$print`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Print information
print(cache)

# Erase cache
cache$erase()


## ------------------------------------------------
## Method `Cache$erase`
## ------------------------------------------------

# Create a new cache instance
cache <- Cache$new(tempdir())

# Deletes the whole cache content
cache$erase()

# Erase cache
cache$erase()