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67 lines
2.2 KiB
R
67 lines
2.2 KiB
R
\name{registerInputHandler}
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\alias{registerInputHandler}
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\title{Register an Input Handler}
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\usage{
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registerInputHandler(type, fun, force = FALSE)
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}
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\arguments{
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\item{type}{The type for which the handler should be
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added -- should be a single-element character vector.}
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\item{fun}{The handler function. This is the function
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that will be used to parse the data delivered from the
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client before it is available in the \code{input}
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variable. The function will be called with the following
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three parameters: \enumerate{ \item{The value of this
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input as provided by the client, deserialized using
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RJSONIO.} \item{The \code{shinysession} in which the
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input exists.} \item{The name of the input.} }}
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\item{force}{If \code{TRUE}, will overwrite any existing
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handler without warning. If \code{FALSE}, will throw an
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error if this class already has a handler defined.}
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}
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\description{
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Adds an input handler for data of this type. When called,
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Shiny will use the function provided to refine the data
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passed back from the client (after being deserialized by
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RJSONIO) before making it available in the \code{input}
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variable of the \code{server.R} file.
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}
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\details{
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This function will register the handler for the duration
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of the R process (unless Shiny is explicitly reloaded).
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For that reason, the \code{type} used should be very
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specific to this package to minimize the risk of
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colliding with another Shiny package which might use this
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data type name. We recommend the format of
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"packageName.widgetName".
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Currently Shiny registers the following handlers:
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\code{shiny.matrix}, \code{shiny.number}, and
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\code{shiny.date}.
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The \code{type} of a custom Shiny Input widget will be
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deduced using the \code{getType()} JavaScript function on
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the registered Shiny inputBinding.
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}
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\examples{
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\dontrun{
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# Register an input handler which rounds a input number to the nearest integer
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registerInputHandler("mypackage.validint", function(x, shinysession, name) {
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if (is.null(x)) return(NA)
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round(x)
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})
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## On the Javascript side, the associated input binding must have a corresponding getType method:
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getType: function(el) {
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return "mypackage.validint";
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}
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}
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}
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\seealso{
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\code{\link{removeInputHandler}}
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}
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