R: Define Server Functionality

shinyServer {shiny} | R Documentation

## Define Server Functionality

### Description

Defines the server-side logic of the Shiny application. This generally involves creating functions that map user inputs to various kinds of output. In older versions of Shiny, it was necessary to call `shinyServer()` in the `server.R` file, but this is no longer required as of Shiny 0.10. Now the `server.R` file may simply return the appropriate server function (as the last expression in the code), without calling `shinyServer()`.

### Usage

    shinyServer(func)

### Arguments

`func` | The server function for this application. See the details section for more information.

### Details

Call `shinyServer` from your application's `server.R` file, passing in a "server function" that provides the server-side logic of your application.

The server function will be called when each client (web browser) first loads the Shiny application's page. It must take an `input` and an `output` parameter. Any return value will be ignored. It also takes an optional `session` parameter, which is used when greater control is needed.

See the tutorial for more on how to write a server function.

### Examples

    ## Not run:
    # A very simple Shiny app that takes a message from the user
    # and outputs an uppercase version of it.
    shinyServer(function(input, output, session) {
      output$uppercase <- renderText({
        toupper(input$message)
      })
    })

    # It is also possible for a server.R file to simply return the function,
    # without calling shinyServer().
    # For example, the server.R file could contain just the following:
    function(input, output, session) {
      output$uppercase <- renderText({
        toupper(input$message)
      })
    }

    ## End(Not run)

[Package shiny version 1.0.5 Index]