Change timezone per user in admin

[gebeer]

Hello,

my site has users from different timezones logging in to the backend.

I have a "timezone" field for each user where I store their timezone string.

Now I need to show dates in the backend in the user's timezone.

I know I can set timezone for php date calculations with: date_default_timezone_set("Europe/Berlin") for example.

In config.php I have $config->timezone = 'America/Phoenix'; as a general setting for that site.

Now when a user logs on I want to set the timezone for his session to date_default_timezone_set($user->timezone).

Where would be the best place to set this?

[horst]

Because it depends on login / logout, my first thought is:

$this->pages->addHookAfter('Session::logout', $this, 'yourFunction');
$this->pages->addHookAfter('Session::login', $this, 'yourFunction');

If this doesn't fit well, there is also

$this->pages->addHookBefore('ProcessLogin::execute', $this, 'yourFunction');
$this->pages->addHookBefore('ProcessLogin::executeLogout', $this, 'yourFunction');

// or 

$this->pages->addHookAfter('ProcessLogin::execute', $this, 'yourFunction');
$this->pages->addHookAfter('ProcessLogin::executeLogout', $this, 'yourFunction');

[gebeer]

Thank you Horst,

I will try those hooks.

Do I then have to set the timezone with $config->timezone = $user->timezone

or with

date_default_timezone_set($user->timezone)

Just asking because I'm not sure whether PW will override the date_default_timezone_set($user->timezone) with $config->timezone value from config.php.

[horst]

I'm not very familiar with (user) timezones. A quick search through PWs wire files shows that timezone is used in ProcessWire::config with

ini_set('date.timezone', $config->timezone);

So I would change $config->timezone and PHPs date.timezone. But haven't worked / tested with that!

In regard of getting the original / default value and not a runtime-changed value from $config, there is this possible workaround:

function getDefaultValuefromConfig($key) {
    $config = new stdClass();
    include( wire-config.php );
    include( site-config.php );
    // now we have merged default settings of $config in local scope of this function 
    // and can return the requested one
    return $config->$key;
}

[LostKobrakai]

I'm not sure if setting the timezone for php is really the most sane way to go about it. I'd rather keep php's timezone to be consistent and just use a library like carbon to handle the timezone differences for the frontend.

Edit: Just read that you need it for the backend as well, so that's not so much an option.

[horst]

Yes, best way would be only to dynamically change all date reading, but not to alter date writing.

[clsource]

I would add a field to the user template

and set its timezone for every user page.

as you did.

then

using horst´s example hooks and session

public function init() {
    $this->pages->addHookAfter('Session::logout', $this, 'timezoneLogout');
    $this->pages->addHookAfter('Session::login', $this, 'timezoneLogin');
}

public function timezoneLogin(HookEvent $event) {
    $user = $event->object;
    $session = wire('session');
    $session->timezone = $user->timezone;
}

public function timezoneLogout(HookEvent $event) {
    $session = wire('session');
    $session->remove('timezone');
}

Now you can use the session var across the backend and the frontend without querying the user