验证存储在ShinyDashboard数据框中的用户名，密码和角色

Question

所以我有一个dataframe，其中指定了username，password和Roles。我已经创建了一个ShinyDashboard登录页面，用于根据角色创建UI，但是我无法弄清楚如何验证何时将其存储在数据框中。

Server.R

my_usernames <- c("u1","u2")
my_passwords <- c("u10", "u20")
roles<-c("admin","user")
shinyServer(function(input,output,session)
{
  options(digits = 22)
  USER <- reactiveValues(Logged = Logged, role= NULL)

  # Return the UI for a modal dialog with data selection input. If 'failed' 
  # is TRUE, then display a message that the previous value was invalid.
  loginModal <- function(failed = FALSE){

    modalDialog( tags$img(src = "new.gif",width="140", height="50px"),br(),br(),

                h3("Info App") ,br(),br(),br(),
                textInput("userName", "Username"),
                passwordInput("passwd", "Password"),
                if (failed)
                  div(tags$b("Invalid Username / Password", style = "color: red;")),

                size = "s",
                footer = tagList(
                  actionButton("Login", "Log in")
                )
    )
  }

  # Show modal when button is clicked.  
  # This `observe` is suspended only whith right user credential

  loginobs1 <- observe({
    showModal(tags$div(id = "loginmodal1",loginModal()))
  })

  # When OK button is pressed, attempt to authenticate. If successful,
  # remove the modal. 

  loginobs2 <- observe({
    req(input$Login)
    if (USER$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(Username) > 0 && length(Password) > 0)) {
            if(my_passwords[which(my_usernames==Username)]==Password)
            {
              # browser()
              USER$Logged <<- TRUE
              if(Username=="u1")

              {
                loginobs1$suspend()
                removeModal()
                USER$role<-roles[1]
              }
              else{ 
                if(Username=="u2")

                {
                  loginobs1$suspend()
                  removeModal()
                  USER$role<-roles[2]
                }
              }
            }
            else {
              USER$Logged <- FALSE
            }     
          }
          else {
            USER$Logged <- FALSE
          }     
        } 
    }
    }    

  })

  observe({
    if ((USER$Logged == TRUE)){ 
      if(USER$role == "admin"){
        output$side <- renderUI({
          ui2_side
        })
        output$page <- renderUI({
          ui2_main
        }) 
      }
      if(USER$role == "user"){
        output$side <- renderUI({
          ui3_side
        })
        output$page <- renderUI({
          ui3_main
        })
      }
    }

  })

})

UI.R

library(shiny)
library(shinydashboard) 
library(shinyjs)

shinyUI(
  ( 

    dashboardPage(

      dashboardHeader(title = div(img(src="new.gif", height = 40, width = 200),"My_dashboard",width = 300)),
      dashboardSidebar(
        uiOutput("side"),width = 190),
      dashboardBody(
        shinyjs::useShinyjs(),
        shinyjs::extendShinyjs(text = "shinyjs.refresh = function() { location.reload(); }"),

        uiOutput("page",height=1000)
      )
    )

  )
)

#UI for admin
ui2_side=list(

  sidebarMenu(
    actionButton("Logout", "Logout", icon = icon("sign-out")),
    menuItem("Dashboard", tabName = "dashboard", icon = icon("dashboard")),
))

ui2_main<- list(
tabItems(    
    tabItem("dashboard",
            tabsetPanel(

              tabPanel( title = "Plot Info",
                        br(),
                        fluidRow( 
                          box(
                            h3("All Status", align="center"))
                                )
                        )))))
#UI for users
ui3_side=list(

  sidebarMenu(
    actionButton("Logout", "Logout", icon = icon("sign-out")),
        menuItem("Dashboard", tabName = "dashboard", icon = icon("dashboard"))
             ))

   ui3_main<- list(
    tabItems(    
        tabItem("dashboard",
                tabsetPanel(

                  tabPanel( title = "Just an Info",
                            br(),
                            fluidRow( 
                              box(
                                h3("General Status", align="center"))
                                    )
                            )))))

dataframe

Username        Password            Role  
u1               u10                admin  
u2               u20                user  
u3               u30                admin  
u5               u50                user

在我的代码中，我对username，password和role进行了硬编码，而不是如何使它从数据框中检索