Is it possible to log out user from a web site if he is using basic authentication?
Killing session is not enough, since, once user is authenticated, each request co
Have the user click on a link to https://log:out@example.com/. That will overwrite existing credentials with invalid ones; logging them out.
Based on what I read above I got a simple solution that works on any browser:
1) on you logout page you call an ajax to your login back end. Your login back end must accept logout user. Once the back end accept, the browser clear the current user and assumes the "logout" user.
$.ajax({
async: false,
url: 'http://your_login_backend',
type: 'GET',
username: 'logout'
});
setTimeout(function () {
window.location.href = 'http://normal_index';
}, 200);
2) Now when the user got back to the normal index file it will try to automatic enter in the system with the user "logout", on this second time you must block it by reply with 401 to invoke the login/password dialog.
3) There are many ways to do that, I created two login back ends, one that accepts the logout user and one that doesn't. My normal login page use the one that doesn't accept, my logout page use the one that accepts it.
It's actually pretty simple.
Just visit the following in your browser and use wrong credentials: http://username:password@yourdomain.com
That should "log you out".
All you need is redirect user on some logout URL and return 401 Unauthorized
error on it. On error page (which must be accessible without basic auth) you need to provide a full link to your home page (including scheme and hostname). User will click this link and browser will ask for credentials again.
Example for Nginx:
location /logout {
return 401;
}
error_page 401 /errors/401.html;
location /errors {
auth_basic off;
ssi on;
ssi_types text/html;
alias /home/user/errors;
}
Error page /home/user/errors/401.html
:
<!DOCTYPE html>
<p>You're not authorised. <a href="<!--# echo var="scheme" -->://<!--# echo var="host" -->/">Login</a>.</p>
I've just tested the following in Chrome (79), Firefox (71) and Edge (44) and it works fine. It applies the script solution as others noted above.
Just add a "Logout" link and when clicked return the following html
<div>You have been logged out. Redirecting to home...</div>
<script>
var XHR = new XMLHttpRequest();
XHR.open("GET", "/Home/MyProtectedPage", true, "no user", "no password");
XHR.send();
setTimeout(function () {
window.location.href = "/";
}, 3000);
</script>
I updated mthoring's solution for modern Chrome versions:
function logout(secUrl, redirUrl) {
if (bowser.msie) {
document.execCommand('ClearAuthenticationCache', 'false');
} else if (bowser.gecko) {
$.ajax({
async: false,
url: secUrl,
type: 'GET',
username: 'logout'
});
} else if (bowser.webkit || bowser.chrome) {
var xmlhttp = new XMLHttpRequest();
xmlhttp.open(\"GET\", secUrl, true);
xmlhttp.setRequestHeader(\"Authorization\", \"Basic logout\");\
xmlhttp.send();
} else {
// http://stackoverflow.com/questions/5957822/how-to-clear-basic-authentication-details-in-chrome
redirUrl = url.replace('http://', 'http://' + new Date().getTime() + '@');
}
setTimeout(function () {
window.location.href = redirUrl;
}, 200);
}