How to Impersonate a User
How to Impersonate a User¶
Sometimes, it’s useful to be able to switch from one user to another without having to log out and log in again (for instance when you are debugging or trying to understand a bug a user sees that you can’t reproduce).
Caution
User impersonation is not compatible with
pre authenticated firewalls. The
reason is that impersonation requires the authentication state to be maintained
server-side, but pre-authenticated information (SSL_CLIENT_S_DN_Email
,
REMOTE_USER
or other) is sent in each request.
Impersonating the user can be easily done by activating the switch_user
firewall listener:
- YAML
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# app/config/security.yml security: # ... firewalls: main: # ... switch_user: true
- XML
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<!-- app/config/security.xml --> <?xml version="1.0" encoding="UTF-8"?> <srv:container xmlns="http://symfony.com/schema/dic/security" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:srv="http://symfony.com/schema/dic/services" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd"> <config> <!-- ... --> <firewall name="main"> <!-- ... --> <switch-user /> </firewall> </config> </srv:container>
- PHP
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// app/config/security.php $container->loadFromExtension('security', array( // ... 'firewalls' => array( 'main'=> array( // ... 'switch_user' => true, ), ), ));
To switch to another user, just add a query string with the _switch_user
parameter and the username as the value to the current URL:
1 | http://example.com/somewhere?_switch_user=thomas
|
To switch back to the original user, use the special _exit
username:
1 | http://example.com/somewhere?_switch_user=_exit
|
During impersonation, the user is provided with a special role called
ROLE_PREVIOUS_ADMIN
. In a template, for instance, this role can be used
to show a link to exit impersonation:
- Twig
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{% if is_granted('ROLE_PREVIOUS_ADMIN') %} <a href="{{ path('homepage', {'_switch_user': '_exit'}) }}">Exit impersonation</a> {% endif %}
- PHP
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<?php if ($view['security']->isGranted('ROLE_PREVIOUS_ADMIN')): ?> <a href="<?php echo $view['router']->path('homepage', array( '_switch_user' => '_exit', ) ?>"> Exit impersonation </a> <?php endif ?>
In some cases you may need to get the object that represents the impersonating
user rather than the impersonated user. Use the following snippet to iterate
over the user’s roles until you find one that a SwitchUserRole
object:
use Symfony\Component\Security\Core\Role\SwitchUserRole;
$authChecker = $this->get('security.authorization_checker');
$tokenStorage = $this->get('security.token_storage');
if ($authChecker->isGranted('ROLE_PREVIOUS_ADMIN')) {
foreach ($tokenStorage->getToken()->getRoles() as $role) {
if ($role instanceof SwitchUserRole) {
$impersonatingUser = $role->getSource()->getUser();
break;
}
}
}
Of course, this feature needs to be made available to a small group of users.
By default, access is restricted to users having the ROLE_ALLOWED_TO_SWITCH
role. The name of this role can be modified via the role
setting. For
extra security, you can also change the query parameter name via the parameter
setting:
- YAML
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# app/config/security.yml security: # ... firewalls: main: # ... switch_user: { role: ROLE_ADMIN, parameter: _want_to_be_this_user }
- XML
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<!-- app/config/security.xml --> <?xml version="1.0" encoding="UTF-8"?> <srv:container xmlns="http://symfony.com/schema/dic/security" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:srv="http://symfony.com/schema/dic/services" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd"> <config> <!-- ... --> <firewall name="main"> <!-- ... --> <switch-user role="ROLE_ADMIN" parameter="_want_to_be_this_user" /> </firewall> </config> </srv:container>
- PHP
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// app/config/security.php $container->loadFromExtension('security', array( // ... 'firewalls' => array( 'main'=> array( // ... 'switch_user' => array( 'role' => 'ROLE_ADMIN', 'parameter' => '_want_to_be_this_user', ), ), ), ));
Events¶
The firewall dispatches the security.switch_user
event right after the impersonation
is completed. The Symfony\Component\Security\Http\Event\SwitchUserEvent
is
passed to the listener, and you can use this to get the user that you are now impersonating.
The Making the Locale “Sticky” during a User’s Session article does not update the locale when you impersonate a user. The following code sample will show how to change the sticky locale:
- YAML
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# app/config/services.yml services: app.switch_user_listener: class: AppBundle\EventListener\SwitchUserListener tags: - { name: kernel.event_listener, event: security.switch_user, method: onSwitchUser }
- XML
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<!-- app/config/services.xml --> <?xml version="1.0" encoding="UTF-8" ?> <container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd" > <services> <service id="app.switch_user_listener" class="AppBundle\EventListener\SwitchUserListener" > <tag name="kernel.event_listener" event="security.switch_user" method="onSwitchUser" /> </service> </services> </container>
- PHP
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// app/config/services.php use AppBundle\EventListener\SwitchUserListener; $container ->register('app.switch_user_listener', SwitchUserListener::class) ->addTag('kernel.event_listener', array( 'event' => 'security.switch_user', 'method' => 'onSwitchUser' )) ;
Caution
The listener implementation assumes your User
entity has a getLocale()
method.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | // src/AppBundle/EventListener/SwitchUserListener.php
namespace AppBundle\EventListener;
use Symfony\Component\Security\Http\Event\SwitchUserEvent;
class SwitchUserListener
{
public function onSwitchUser(SwitchUserEvent $event)
{
$event->getRequest()->getSession()->set(
'_locale',
$event->getTargetUser()->getLocale()
);
}
}
|
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.