Use Custom Field as Timezone Parameter in Date Field

Question

I have a custom field where the publisher can choose what time zone they want the entry date to display as, but I'm having trouble when trying to use it in the template:

{exp:channel:entries
    channel='events'
}
    {entry_date format='%g:%i%a %T' timezone='{events_tz}'}
{/exp:channel:entries}

Since both tags are parsed at the same time, the {events_tz} field doesn't get parsed in time to be applied as a parameter to the date field.

How would I accomplish this? I'm willing to use Stash, if necessary.

Answer 1

If I'm inferring correctly, there are events in multiple time zones and they want each to show in the time that is local to the location of the event. If so, I think what you want is Fixed instead of Localized, and just output the time zone next to the date.

If you must use entry date, which will always be localized, you could create a simple plugin that accepts the UTC timestamp and the timezone and return a formatted date, e.g.:

{exp:your_date_plugin timestamp='{entry_date}' timezone='{events_tz}'}

Answer 2

Following Derek's advice above, I wrote a quick plugin to handle the conversion. Here's the plugin method code (note: I used the EE Add-On Builder for Sublime Text to generate the plugin file and boilerplate code):

public function convert_timezone() {
    $timestamp = ee()->TMPL->fetch_param('timestamp');
    $timezone = ee()->TMPL->fetch_param('timezone');
    $format = ee()->TMPL->fetch_param('format');

    return ee()->localize->format_date($format, $timestamp, $timezone);
}

And the tag it uses:

{exp:site_utilities:convert_timezone 
    timestamp='{entry_date}' 
    timezone='{events_tz}' 
    format='%g:%i%a %T'
 }