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dde266768c
These functions were temporarily ripped out of Shiny and moved to the htmltools package. We've discovered that it's safe to keep including them in shiny; as long as the functions in shiny and the functions in htmltools are identical, the user won't receive a conflict warning.
72 lines
2.3 KiB
R
72 lines
2.3 KiB
R
% Generated by roxygen2 (4.0.1): do not edit by hand
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\name{reactiveFileReader}
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\alias{reactiveFileReader}
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\title{Reactive file reader}
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\usage{
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reactiveFileReader(intervalMillis, session, filePath, readFunc, ...)
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}
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\arguments{
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\item{intervalMillis}{Approximate number of milliseconds to wait between
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checks of the file's last modified time. This can be a numeric value, or a
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function that returns a numeric value.}
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\item{session}{The user session to associate this file reader with, or
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\code{NULL} if none. If non-null, the reader will automatically stop when
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the session ends.}
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\item{filePath}{The file path to poll against and to pass to \code{readFunc}.
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This can either be a single-element character vector, or a function that
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returns one.}
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\item{readFunc}{The function to use to read the file; must expect the first
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argument to be the file path to read. The return value of this function is
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used as the value of the reactive file reader.}
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\item{...}{Any additional arguments to pass to \code{readFunc} whenever it is
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invoked.}
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}
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\value{
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A reactive expression that returns the contents of the file, and
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automatically invalidates when the file changes on disk (as determined by
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last modified time).
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}
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\description{
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Given a file path and read function, returns a reactive data source for the
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contents of the file.
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}
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\details{
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\code{reactiveFileReader} works by periodically checking the file's last
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modified time; if it has changed, then the file is re-read and any reactive
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dependents are invalidated.
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The \code{intervalMillis}, \code{filePath}, and \code{readFunc} functions
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will each be executed in a reactive context; therefore, they may read
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reactive values and reactive expressions.
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}
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\examples{
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\dontrun{
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# Per-session reactive file reader
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shinyServer(function(input, output, session)) {
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fileData <- reactiveFileReader(1000, session, 'data.csv', read.csv)
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output$data <- renderTable({
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fileData()
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})
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}
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# Cross-session reactive file reader. In this example, all sessions share
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# the same reader, so read.csv only gets executed once no matter how many
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# user sessions are connected.
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fileData <- reactiveFileReader(1000, session, 'data.csv', read.csv)
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shinyServer(function(input, output, session)) {
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output$data <- renderTable({
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fileData()
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})
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}
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}
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}
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\seealso{
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\code{\link{reactivePoll}}
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}
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