SO 30177053

server.R

library(shiny)
library(tools)
library(XLConnect)

shinyServer(function(input, output){
    
    filedata <- reactive({
        infile <- input$templatedfile
        if(is.null(infile)){
            return(NULL)
        }
        ext <- file_ext(infile$name)
        
        importedfile <- 
            switch(ext,
                   csv = read.csv(infile$datapath, stringsAsFactors=FALSE),
                   xlsx = , xls = readWorksheetFromFile(infile$datapath,
                                                        sheet=1,
                                                        check.names=FALSE),
                   stop("file extension not recognized"))
    })
    
    output$mytable <- renderTable({
        filedata()
    })   
})

ui.R

library(shiny)

shinyUI(
    pageWithSidebar(
        headerPanel("Importing CSV and XLSX files"),
        sidebarPanel(
            p("Demo Page"),
            fileInput("templatedfile", label=h3("Please submit file"))
        ),
        mainPanel(
            tableOutput("mytable")
        )
    )
)