Debugging https://community.rstudio.com/t/problems-inputfile-and-read-table-in-shiny/34853

app.R

#
# This is a Shiny web application. You can run the application by clicking
# the 'Run App' button above.
#
# Find out more about building applications with Shiny here:
#
#    http://shiny.rstudio.com/
#

library(shiny)

# Define UI for application that draws a histogram
ui <- fluidPage(
    # To rename data
    textInput("data_name", "",  placeholder = "Example : 20190625_Data_Name"),

    # To download file
    fileInput("data_exp","", multiple = TRUE),

    #To launch process
    actionButton("import", "Download")

)


library(shinyWidgets)

# Define server logic required to draw a histogram
server <- function(input, output, session) {

UploadData <- reactive({
    file1 <- input$data_exp
    if(is.null(file1)){return()}
    return(read.table(file=file1$datapath))
})

    observeEvent(input$import, {

        if (is.null(input$data_name) || input$data_name == "") {
            sendSweetAlert(
                session = session,
                title = "Error...",
                text = "Nom des données vide",
                type = "error"
            )

        } else {

            data <- UploadData()
            print(data)

            sendSweetAlert(
                session = session,
                title = "Done !",
                text = "Vos données ont bien été traitées",
                type = "success"
            )
        }

    })

}

# Run the application
shinyApp(ui = ui, server = server)