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# For most types of values, simply return the value unchanged.
serializerDefault <- function(value, stateDir) {
value
}
serializerFileInput <- function(value, stateDir = NULL) {
# File inputs can be serialized only if there's a stateDir
if (is.null(stateDir)) {
return(serializerUnserializable())
}
# value is a data frame. When persisting files, we need to copy the file to
# the persistent dir and then strip the original path before saving.
newpaths <- file.path(stateDir, basename(value$datapath))
file.copy(value$datapath, newpaths, overwrite = TRUE)
value$datapath <- basename(newpaths)
value
}
# Return a sentinel value that represents "unserializable". This is applied to
# for example, passwords and actionButtons.
serializerUnserializable <- function(value, stateDir) {
structure(
list(),
serializable = FALSE
)
}
# Is this an "unserializable" sentinel value?
isUnserializable <- function(x) {
identical(
attr(x, "serializable", exact = TRUE),
FALSE
)
}
# Given a reactiveValues object and optional directory for saving state, apply
# serializer function to each of the values, and return a list of the returned
# values. This function passes stateDir to the serializer functions, so if
# stateDir is non-NULL, it can have a side effect of writing values to disk (in
# stateDir).
serializeReactiveValues <- function(values, exclude, stateDir = NULL) {
impl <- .subset2(values, "impl")
# Get named list where keys and values are the names of inputs; we'll retrieve
# actual values later.
vals <- isolate(impl$names())
vals <- setdiff(vals, exclude)
names(vals) <- vals
# Get values and apply serializer functions
vals <- lapply(vals, function(name) {
val <- impl$get(name)
# Get the serializer function for this input value. If none specified, use
# the default.
serializer <- impl$getMeta(name, "shiny.serializer")
if (is.null(serializer))
serializer <- serializerDefault
# Apply serializer function.
serializer(val, stateDir)
})
# Filter out any values that were marked as unserializable.
vals <- Filter(Negate(isUnserializable), vals)
vals
}
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