R Shiny application protected by a password

app.R

rm(list = ls())
library(shiny)

Logged = FALSE;
## put here the credentials
my_username <- "test"
my_password <- "test"

## part of the user interface for login
ui1 <- function(){
  tagList(
    div(id = "login",
        wellPanel(textInput("userName", "Username"),
                  passwordInput("passwd", "Password"),
                  br(),actionButton("Login", "Log in"))),
    tags$style(type="text/css", "#login {font-size:10px;   text-align: left;position:absolute;top: 40%;left: 50%;margin-top: -100px;margin-left: -150px;}")
  )}


## part of user interface after login
ui2 <- function(){
  
  ##-----------------------------------
  ## write what you need, from this line...
  bootstrapPage(
    
    selectInput(inputId = "n_breaks",
                label = "Number of bins in histogram (approximate):",
                choices = c(10, 20, 35, 50),
                selected = 20),
    
    checkboxInput(inputId = "individual_obs",
                  label = strong("Show individual observations"),
                  value = FALSE),
    
    checkboxInput(inputId = "density",
                  label = strong("Show density estimate"),
                  value = FALSE),
    
    plotOutput(outputId = "main_plot", height = "300px"),
    
    conditionalPanel(condition = "input.density == true",
                     sliderInput(inputId = "bw_adjust",
                                 label = "Bandwidth adjustment:",
                                 min = 0.2, max = 2, value = 1, step = 0.2)
    )
    
  )
  ## ...to this line
  ##-----------------------------------
}

ui = (htmlOutput("page"))


server = (function(input, output,session) {

  ## part of the server managing the login
  USER <- reactiveValues(Logged = Logged)
  
  observe({ 
    if (USER$Logged == FALSE) {
      if (!is.null(input$Login)) {
        if (input$Login > 0) {
          Username <- isolate(input$userName)
          Password <- isolate(input$passwd)
          Id.username <- which(my_username == Username)
          Id.password <- which(my_password == Password)
          if (length(Id.username) > 0 & length(Id.password) > 0) {
            if (Id.username == Id.password) {
              USER$Logged <- TRUE
            } 
          }
        } 
      }
    }    
  })
  observe({
    if (USER$Logged == FALSE) {
      
      output$page <- renderUI({
        div(class="outer",do.call(bootstrapPage,c("",ui1())))
      })
    }
    if (USER$Logged == TRUE) 
    {
      output$page <- renderUI({
        ui2()
      })
      print(ui)
    }
  })
  
  
  ## part of the server interacting with user interface after the login
  ##-----------------------------------
  ## write what you need, from this line...
  output$main_plot <- renderPlot({
    
    hist(faithful$eruptions,
         probability = TRUE,
         breaks = as.numeric(input$n_breaks),
         xlab = "Duration (minutes)",
         main = "Geyser eruption duration")
    
    if (input$individual_obs) {
      rug(faithful$eruptions)
    }
    
    if (input$density) {
      dens <- density(faithful$eruptions,
                      adjust = input$bw_adjust)
      lines(dens, col = "blue")
    }
  })
  ## ...to this line
  ##-----------------------------------
  
})

runApp(list(ui = ui, server = server))

Thank you, that was really helpful!