Invalid Cookie should point to a recoverable state

[Davst]

So, I know this mainly is a rest product of me having an old cookie left from traefik 1 oauth but as users really can get themselves into odd unexpected situations I believe there should be better error handling for the "Invalid cookie mac" state.

I found myself in a situation after upgrading my server where all my normal browsers just returned Not authenticated whatever I did. The logs showed me this was due to an invalid cookie and thus i had to clear site cookies to recover.

However for many users that aren't that tech savvy this is essentially an unrecoverable state, where simply throwing up a oauth login page would allow them to recover from it. IF not that, at least clearing that cookie or logging them out or such would be resonable as well.

My suggestion is to improve the handling for this or at least provide options for redirection to a recoverable state.

[ljluestc]

package main

import (
    "log"
    "net/http"
    "strings"
)

func clearInvalidCookie(w http.ResponseWriter, r *http.Request) {
    // Check for invalid cookie
    cookie, err := r.Cookie("auth_token")
    if err != nil || !isValidCookie(cookie) {
        // Invalid cookie detected, clear it
        http.SetCookie(w, &http.Cookie{
            Name:   "auth_token",
            Value:  "",
            Path:   "/",
            MaxAge: -1, // expires immediately
        })

        // Redirect the user to the login page
        http.Redirect(w, r, "/login", http.StatusFound)
        return
    }

    // Proceed with normal behavior if cookie is valid
    nextHandler(w, r)
}

func isValidCookie(cookie *http.Cookie) bool {
    // Check the validity of the cookie (example check, can be more complex)
    return strings.HasPrefix(cookie.Value, "valid_token")
}

func nextHandler(w http.ResponseWriter, r *http.Request) {
    // Your normal request handling
    w.Write([]byte("Welcome!"))
}

func main() {
    http.HandleFunc("/", clearInvalidCookie)
    log.Fatal(http.ListenAndServe(":8080", nil))
}