User Authentication

A sample implementation of a login page for an R Shiny app. It uses the bcrypt R package which provides bindings to the 'blowfish' password hashing algorithm. We've used a similar method with database backend and also implemented a user and permission system on top of it. You can log into the demo app using admin / admin.

You can try out the app here

How it works

In this snippet we have a preconfigured username and hashed password that gets compared with the submitted username and password using the bcrypt package in R.

  # The expected username and password are admin/admin
  # The long password string in the following variable is generated by hashpw("admin")
  credentials <- reactiveValues(userIsAuth = FALSE, username = "admin",
                                password = "$2a$12$jxoOXWVRB0XPJzfyViVjY.NkgqZlCcW4UbnOjRPvppH0ENRlH8s3y")

Listen for a click on the login button and compare the result using checkpw()

observeEvent(input$loginbtn, {
    if(input$username == credentials$username)
    {
      credentials$userIsAuth <<- checkpw(input$password, credentials$password)
    }
    else
    {
      showModal(modalDialog(
        title = "Error",
        "Incorrect username or password. please try again! (Hint: admin/admin)"
      ))
    }
  })

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Code created by Epi-interactive

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