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StorageClass R6 class

Source: R/storageclass.R
StorageClass.Rd

This class provides a set of methods to create and manage Shiny bookmarkable state files.

Public fields

local_storage_dir

file path to use for storing bookmarkable state files. If not specified, a temporary directory on the host system will be used.

board_sessions

Optional pre-created board object created with the pins package. If missing, a folder-based pin board will be created using the local_storage_dir path.

Methods

Public methods

Method new()

Initialize a StorageClass object

Usage

StorageClass$new(local_storage_dir = NULL, board_sessions = NULL)

Arguments

local_storage_dir

file path to use for storing bookmarkable state files. If not specified, a temporary directory on the host system will be used.

board_sessions

Optional pre-created board object created with the pins package. If missing, a folder-based pin board will be created using the local_storage_dir path.

Returns

An object with class StorageClass and the methods described in this documentation

Examples

## Only run examples in interactive R sessions
if (interactive()) {

# beginning of application
library(shiny)
library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# Use a pre-specified directory to store state files
# For purposes of this example, use a temporary directory
storage <- StorageClass$new(local_storage_dir = tempdir())

# use a custom pins board to store bookmarkable state data
# For purposes of this example, use a temporary directory
library(pins)
board <- board_temp()
storage <- StorageClass$new(board_sessions = board)
}

Method get_sessions()

Obtain saved bookmarkable state session metadata

Calls $get_sessions() on the StorageClass object to extract the bookmarkable state session metadata. You can leverage this data frame in your Shiny application to let the user manage their existing bookmarkable state sessions, for example.

Usage

StorageClass$get_sessions()

Returns

data frame of bookmarkable session metadata if at least one bookmarkable state session has been saved. Otherwise, the return object will be NULL.

Examples

## Only run examples in interactive R sessions
if (interactive()) {

library(shiny)
library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# obtain session data
storage$get_sessions()
}

Method restore()

Restore a previous bookmarkable state session

Usage

StorageClass$restore(url, session = shiny::getDefaultReactiveDomain())

Arguments

url

character with the unique URL assigned to the bookmarkable state session.

session

The Shiny session to associate with the restore operation

Examples

## Only run examples in interactive R sessions
if (interactive()) {

library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# obtain session data
session_df <- storage$get_sessions()

# restore state
# typically run inside a shiny observe or observeEvent call
storage$restore(tail(session_df$url, n = 1))
}

Method snapshot()

Create a snapshot of bookmarkable state

Usage

StorageClass$snapshot(
  session_metadata = NULL,
  session = shiny::getDefaultReactiveDomain()
)

Arguments

session_metadata

Optional named list of additional variables to include with the default bookmarkable state attributes when creating the snapshot. Each element of the list must be a single-length item

session

The Shiny session to associate with the snapshot operation

Examples

## Only run examples in interactive R sessions
if (interactive()) {

library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# save state with timestamp as metadata
# typically run inside a shiny observe or observeEvent call
storage$snapshot(session_metadata = list(time = Sys.time()))
}

Method delete()

Delete a previous snapshot of bookmarkable state

Usage

StorageClass$delete(url)

Arguments

url

character with the unique URL assigned to the bookmarkable state session.

Examples

## Only run examples in interactive R sessions
if (interactive()) {

library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# obtain session data
session_df <- storage$get_sessions()

# delete a session
# typically run inside a shiny observe or observeEvent call
storage$delete(session_df$url[1])
}

Method register_metadata()

Register bookmarkable state storage data collection

This method must be called in the application server function to perform the necessary customizations to bookmarkable state methods. This function is meant to be called near the beginning of the Shiny application server function.

Usage

StorageClass$register_metadata()

Examples

## Only run examples in interactive R sessions
if (interactive()) {

library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# application server code
server <- function(input, output, session) {
  storage$register_metadata()
}
}

Method clone()

The objects of this class are cloneable with this method.

Usage

StorageClass$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples


## ------------------------------------------------
## Method `StorageClass$new`
## ------------------------------------------------

## Only run examples in interactive R sessions
if (interactive()) {

# beginning of application
library(shiny)
library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# Use a pre-specified directory to store state files
# For purposes of this example, use a temporary directory
storage <- StorageClass$new(local_storage_dir = tempdir())

# use a custom pins board to store bookmarkable state data
# For purposes of this example, use a temporary directory
library(pins)
board <- board_temp()
storage <- StorageClass$new(board_sessions = board)
}

## ------------------------------------------------
## Method `StorageClass$get_sessions`
## ------------------------------------------------

## Only run examples in interactive R sessions
if (interactive()) {

library(shiny)
library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# obtain session data
storage$get_sessions()
}

## ------------------------------------------------
## Method `StorageClass$restore`
## ------------------------------------------------

## Only run examples in interactive R sessions
if (interactive()) {

library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# obtain session data
session_df <- storage$get_sessions()

# restore state
# typically run inside a shiny observe or observeEvent call
storage$restore(tail(session_df$url, n = 1))
}

## ------------------------------------------------
## Method `StorageClass$snapshot`
## ------------------------------------------------

## Only run examples in interactive R sessions
if (interactive()) {

library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# save state with timestamp as metadata
# typically run inside a shiny observe or observeEvent call
storage$snapshot(session_metadata = list(time = Sys.time()))
}

## ------------------------------------------------
## Method `StorageClass$delete`
## ------------------------------------------------

## Only run examples in interactive R sessions
if (interactive()) {

library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# obtain session data
session_df <- storage$get_sessions()

# delete a session
# typically run inside a shiny observe or observeEvent call
storage$delete(session_df$url[1])
}

## ------------------------------------------------
## Method `StorageClass$register_metadata`
## ------------------------------------------------

## Only run examples in interactive R sessions
if (interactive()) {

library(shinystate)

# Create a StorageClass object with default settings
storage <- StorageClass$new()

# application server code
server <- function(input, output, session) {
  storage$register_metadata()
}
}