logout • tabler

logout {tabler}

R Documentation

Log Out The Current Session

Description

Forces the browser to drop its session cookie and return to the login page. For use inside a tabler_app server function (e.g. in an observe_event() on a "Log out" button) when check_credentials was supplied to tabler_app.

Usage

logout(session = get_default_reactive_domain())

Arguments

session The session object passed by tabler_app to the server function. Defaults to get_default_reactive_domain().

Details

Why this can't be done by just hiding a DOM element

Unlike show_progress/hide_progress, which only toggle a cosmetic overlay, a login gate has to withhold the actual page content from the browser until the server has verified the visitor - anything already sent to the browser (HTML, JS, JSON) can always be revealed again with the browser's DevTools, no matter how it is hidden client-side. tabler_app therefore checks a signed session cookie before it ever renders the page, serves cached outputs, or accepts a WebSocket connection: an unauthenticated request gets nothing but the login form, both for the initial page load and for the WebSocket handshake that carries reactive output.

logout() sends a small message over the WebSocket telling the browser-side JS (tabler-login.js) to navigate to /logout, which is a real server-side endpoint that clears the session cookie and redirects back to /login. This is the same show/hide message mechanism as show_progress, but logout can only actually take effect through the server, not through anything client-side.

Value

Invisibly, NULL.

Examples

if (interactive()) {
  ui <- page(
    title = "Login Example",
    body = body(action_button("logout_btn", "Log out"))
  )

  server <- function(input, output, session) {
    observe_event(input$logout_btn, {
      logout(session)
    })
  }

  tabler_app(
    ui, server,
    check_credentials = function(username, password) {
      username == "admin" && password == "hunter2"
    }
  )
}

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