Files
shiny/R/save-state.R
2016-06-20 16:00:25 -05:00

526 lines
16 KiB
R

ShinySaveState <- R6Class("ShinySaveState",
public = list(
input = NULL,
exclude = NULL,
onSave = NULL, # A callback to invoke during the saving process.
# These are set not in initialize(), but by external functions that modify
# the ShinySaveState object.
dir = NULL,
values = NULL,
initialize = function(input = NULL, exclude = NULL, onSave = NULL)
{
self$input <- input
self$exclude <- exclude
self$onSave <- onSave
},
# Persist this state object to disk. Returns a query string which can be
# used to restore the session.
persist = function() {
id <- createUniqueId(8)
persistInterface <- getShinyOption("persist.interface",
default = persistInterfaceLocal)
persistInterface(id, function(stateDir) {
# Directory is provided by the persistInterface function.
self$dir <- stateDir
# Allow user-supplied onSave function to do things like add self$values, or
# save data to state dir.
if (!is.null(self$onSave))
isolate(self$onSave(self))
# Serialize values, possibly saving some extra data to stateDir
inputValues <- serializeReactiveValues(self$input, self$exclude, self$dir)
saveRDS(inputValues, file.path(stateDir, "input.rds"))
# If there values passed in, save them also
if (!is.null(self$values))
saveRDS(self$values, file.path(stateDir, "values.rds"))
})
paste0("__state_id__=", encodeURIComponent(id))
},
# Encode the state to a URL. This does not save to disk.
encode = function() {
inputVals <- serializeReactiveValues(self$input, self$exclude, stateDir = NULL)
# Allow user-supplied onSave function to do things like add self$values.
if (!is.null(self$onSave))
self$onSave(self)
inputVals <- vapply(inputVals,
function(x) toJSON(x, strict_atomic = FALSE),
character(1),
USE.NAMES = TRUE
)
res <- paste0(
encodeURIComponent(names(inputVals)),
"=",
encodeURIComponent(inputVals),
collapse = "&"
)
# If 'values' is present, add them as well.
if (length(self$values) != 0) {
values <- vapply(self$values,
function(x) toJSON(x, strict_atomic = FALSE),
character(1),
USE.NAMES = TRUE
)
res <- paste0(res, "&_values_&",
paste0(
encodeURIComponent(names(values)),
"=",
encodeURIComponent(values),
collapse = "&"
)
)
}
res
}
)
)
RestoreContext <- R6Class("RestoreContext",
public = list(
# This is a RestoreInputSet for input values. This is a key-value store with
# some special handling.
input = NULL,
# Directory for extra files, if restoring from persisted state
dir = NULL,
# For values other than input values. These values don't need the special
# phandling that's needed for input values, because they're only accessed
# from the onRestore function.
values = NULL,
initialize = function(queryString = NULL) {
if (!is.null(queryString)) {
tryCatch(
{
qsValues <- parseQueryString(queryString, nested = TRUE)
if (!is.null(qsValues[["__subapp__"]]) && qsValues[["__subapp__"]] == 1) {
# Ignore subapps in shiny docs
self$reset()
} else if (!is.null(qsValues[["__state_id__"]]) && nzchar(qsValues[["__state_id__"]])) {
# If we have a "__state_id__" key, restore from persisted state and ignore
# other key/value pairs. If not, restore from key/value pairs in the
# query string.
private$loadStateQueryString(queryString)
} else {
# The query string contains the saved keys and values
private$decodeStateQueryString(queryString)
}
},
error = function(e) {
# If there's an error in restoring problem, just reset these values
self$reset()
warning(e$message)
}
)
}
},
reset = function() {
self$input <- RestoreInputSet$new(list())
self$values <- list()
self$dir <- NULL
},
# This should be called before a restore context is popped off the stack.
flushPending = function() {
self$input$flushPending()
},
# Returns a list representation of the RestoreContext object. This is passed
# to the app author's onRestore function. An important difference between
# the RestoreContext object and the list is that the former's `input` field
# is a RestoreInputSet object, while the latter's `input` field is just a
# list.
asList = function() {
list(
input = self$input$asList(),
dir = self$dir,
values = self$values
)
}
),
private = list(
# Given a query string with a __state_id__, load persisted state with that ID.
loadStateQueryString = function(queryString) {
values <- parseQueryString(queryString, nested = TRUE)
id <- values[["__state_id__"]]
# This function is passed to the loadInterface function; given a
# directory, it will load state from that directory
loadFun <- function(stateDir) {
self$dir <- stateDir
inputValues <- readRDS(file.path(stateDir, "input.rds"))
self$input <- RestoreInputSet$new(inputValues)
valuesFile <- file.path(stateDir, "values.rds")
if (file.exists(valuesFile)) {
self$values <- readRDS(valuesFile)
} else {
self$values <- list()
}
}
loadInterface <- getShinyOption("load.interface", default = loadInterfaceLocal)
loadInterface(id, loadFun)
invisible()
},
# Given a query string with values encoded in it, restore persisted state
# from those values.
decodeStateQueryString = function(queryString) {
# Remove leading '?'
if (substr(queryString, 1, 1) == '?')
queryString <- substr(queryString, 2, nchar(queryString))
if (grepl("(^|&)_values_(&|$)", queryString)) {
splitStr <- strsplit(queryString, "(^|&)_values_(&|$)")[[1]]
inputValueStr <- splitStr[1]
valueStr <- splitStr[2]
if (is.na(valueStr))
valueStr <- ""
} else {
inputValueStr <- queryString
valueStr <- ""
}
inputValues <- parseQueryString(inputValueStr, nested = TRUE)
values <- parseQueryString(valueStr, nested = TRUE)
valuesFromJSON <- function(vals) {
mapply(names(vals), vals, SIMPLIFY = FALSE,
FUN = function(name, value) {
tryCatch(
jsonlite::fromJSON(value),
error = function(e) {
stop("Failed to parse URL parameter \"", name, "\"")
}
)
}
)
}
inputValues <- valuesFromJSON(inputValues)
self$input <- RestoreInputSet$new(inputValues)
self$values <- valuesFromJSON(values)
}
)
)
# Restore input set. This is basically a key-value store, except for one
# important difference: When the user `get()`s a value, the value is marked as
# pending; when `flushPending()` is called, those pending values are marked as
# used. When a value is marked as used, `get()` will not return it, unless
# called with `force=TRUE`. This is to make sure that a particular value can be
# restored only within a single call to `withRestoreContext()`. Without this, if
# a value is restored in a dynamic UI, it could completely prevent any other
# (non- restored) kvalue from being used.
RestoreInputSet <- R6Class("RestoreInputSet",
private = list(
values = NULL,
pending = character(0),
used = character(0) # Names of values which have been used
),
public = list(
initialize = function(values) {
private$values <- new.env(parent = emptyenv())
list2env(values, private$values)
},
exists = function(name) {
exists(name, envir = private$values)
},
# Return TRUE if the value exists and has not been marked as used.
available = function(name) {
self$exists(name) && !self$isUsed(name)
},
isPending = function(name) {
name %in% private$pending
},
isUsed = function(name) {
name %in% private$used
},
# Get a value. If `force` is TRUE, get the value without checking whether
# has been used, and without marking it as pending.
get = function(name, force = FALSE) {
if (force)
return(private$values[[name]])
if (!self$available(name))
return(NULL)
# Mark this name as pending. Use unique so that it's not added twice.
private$pending <- unique(c(private$pending, name))
private$values[[name]]
},
# Take pending names and mark them as used, then clear pending list.
flushPending = function() {
private$used <- unique(c(private$used, private$pending))
private$pending <- character(0)
},
asList = function() {
as.list.environment(private$values)
}
)
)
restoreCtxStack <- Stack$new()
withRestoreContext <- function(ctx, expr) {
restoreCtxStack$push(ctx)
on.exit({
# Mark pending names as used
restoreCtxStack$peek()$flushPending()
restoreCtxStack$pop()
}, add = TRUE)
force(expr)
}
# Is there a current restore context?
hasCurrentRestoreContext <- function() {
restoreCtxStack$size() > 0
}
# Call to access the current restore context
getCurrentRestoreContext <- function() {
ctx <- restoreCtxStack$peek()
if (is.null(ctx)) {
stop("No restore context found")
}
ctx
}
#' Restore an input value
#'
#' This restores an input value from the current restore context..
#'
#' @param id Name of the input value to restore.
#' @param default A default value to use, if there's no value to restore.
#'
#' @export
restoreInput <- function(id, default) {
# Need to evaluate `default` in case it contains reactives like input$x. If we
# don't, then the calling code won't take a reactive dependency on input$x
# when restoring a value.
force(default)
if (identical(getShinyOption("restorable"), FALSE) || !hasCurrentRestoreContext())
return(default)
oldInputs <- getCurrentRestoreContext()$input
if (oldInputs$available(id)) {
oldInputs$get(id)
} else {
default
}
}
#' Update URL in browser's location bar
#'
#' @param queryString The new query string to show in the location bar.
#' @param session A Shiny session object.
#' @export
updateLocationBar <- function(queryString, session = getDefaultReactiveDomain()) {
session$updateLocationBar(queryString)
}
#' Create a button for bookmarking/sharing
#'
#' A \code{bookmarkButton} is a \code{\link{actionButton}} with a default label
#' that consists of a link icon and the text "Share...". It is meant to be used
#' for bookmarking state.
#'
#' @seealso configureBookmarking
#' @inheritParams actionButton
#' @export
saveStateButton <- function(inputId, label = "Save and share...",
icon = shiny::icon("link", lib = "glyphicon"),
title = "Save this application's current state and get a URL for sharing.",
...)
{
actionButton(inputId, label, icon, title = title, ...)
}
#' Generate a modal dialog that displays a URL
#'
#' The modal dialog generated by \code{urlModal} will display the URL in a
#' textarea input, and the URL text will be selected so that it can be easily
#' copied. The result from \code{urlModal} should be passed to the
#' \code{\link{showModal}} function to display it in the browser.
#'
#' @param url A URL to display in the dialog box.
#' @param title A title for the dialog box.
#' @param subtitle Text to display underneath URL.
#' @export
urlModal <- function(url, title = "Saved application link", subtitle = NULL) {
subtitleTag <- NULL
if (!is.null(subtitle)) {
subtitleTag <- tagList(
br(),
span(class = "text-muted", subtitle)
)
}
modalDialog(
title = title,
easyClose = TRUE,
footer = NULL,
tags$textarea(class = "form-control", rows = "1", style = "resize: none;",
readonly = "readonly",
url
),
subtitleTag,
# Need separate show and shown listeners. The show listener sizes the
# textarea just as the modal starts to fade in. The 200ms delay is needed
# because if we try to resize earlier, it can't calculate the text height
# (scrollHeight will be reported as zero). The shown listener selects the
# text; it's needed because because selection has to be done after the fade-
# in is completed.
tags$script(
"$('#shiny-modal').
one('show.bs.modal', function() {
setTimeout(function() {
var $textarea = $('#shiny-modal textarea');
$textarea.innerHeight($textarea[0].scrollHeight);
}, 200);
});
$('#shiny-modal')
.one('shown.bs.modal', function() {
$('#shiny-modal textarea').select().focus();
});"
)
)
}
#' Configure bookmarking for the current session
#'
#' There are two types of bookmarking: saving state, and encoding state.
#'
#' @param eventExpr An expression to listen for, similar to
#' \code{\link{observeEvent}}.
#' @param type Either \code{"encode"}, which encodes all of the relevant values
#' in a URL, \code{"persist"}, which saves to disk, or \code{"disable"}, which
#' disables any previously-enabled bookmarking.
#' @param exclude Input values to exclude from bookmarking.
#' @param onBookmark A function to call before saving state. This function
#' should return a list, which will be saved as \code{values}.
#' @param onRestore A function to call when a session is restored. It will be
#' passed one argument, a restoreContext object.
#' @param onBookmarked A callback function to invoke after the bookmarking has
#' been done.
#' @param session A Shiny session object.
#' @export
configureBookmarking <- function(eventExpr,
type = c("encode", "persist", "disable"), exclude = NULL,
onBookmark = NULL, onRestore = NULL, onBookmarked = NULL,
session = getDefaultReactiveDomain())
{
eventExpr <- substitute(eventExpr)
type <- match.arg(type)
# If there's an existing onBookmarked observer, destroy it before creating a
# new one.
if (!is.null(session$bookmarkObserver)) {
session$bookmarkObserver$destroy()
session$bookmarkObserver <- NULL
}
if (type == "disable") {
return(invisible())
}
# If no onBookmarked function is provided, use one of these defaults.
if (is.null(onBookmarked)) {
if (type == "persist") {
onBookmarked <- function(url) {
showModal(urlModal(
url,
subtitle = "The current state of this application has been persisted."
))
}
} else if (type == "encode") {
onBookmarked <- function(url) {
showModal(urlModal(
url,
subtitle = "This link encodes the current state of this application."
))
}
}
} else if (!is.function(onBookmarked)) {
stop("onBookmarked must be a function.")
}
session$bookmarkObserver <- observeEvent(
eventExpr,
event.env = parent.frame(),
event.quoted = TRUE,
{
saveState <- ShinySaveState$new(session$input, exclude, onBookmark)
if (type == "persist") {
url <- saveState$persist()
} else {
url <- saveState$encode()
}
clientData <- session$clientData
url <- paste0(
clientData$url_protocol, "//",
clientData$url_hostname,
if (nzchar(clientData$url_port)) paste0(":", clientData$url_port),
clientData$url_pathname,
"?", url
)
onBookmarked(url)
}
)
# Run the onRestore function immediately
if (!is.null(onRestore)) {
restoreState <- getCurrentRestoreContext()$asList()
onRestore(restoreState)
}
invisible()
}