Technical Tip: How to redirect request when specified cookies are not present using a LUA script

Requirement:
To redirect the client’s request to a landing or login page when a specific cookie is not present in the initial HTTP request.

Create Scripting: Go under Application Delivery -> Scripting -> Create New, define a name, input a Lua script statement. and select OK.

when HTTP_REQUEST {
  local path = HTTP:path()
  if path == "/index.php" then
    local cookie_tbl = HTTP:header("Cookie")
    local has_cookie = false
    if cookie_tbl then
      for _, v in pairs(cookie_tbl) do
        if string.find(v, "PHPSESSID=", 1, true) then
          has_cookie = true
          break
        end
      end
    else
    end

    if not has_cookie then
      return HTTP:redirect("https://%s/login.php", HTTP:host())
    else
    end
  else
  end
}

Details and comments for the Lua script used in this article:

Assign the server policy with the created script under Policy -> Server Policy > edit respective server policy, enable Scripting and select the created script.

Demonstration:

• Request a non-existing URL.
• Expect the script to redirect to the new Location.

Related document:

HTTP Commands - FortiWeb 7.6.0 documentation

Script Guide - FortiWeb documentation