Get user timezones using Slack API

slack-user-timezones.php

<?php

$api_token = 'slack-api-token';

if ( file_exists( 'users.json' ) ) {
	$api_users = file_get_contents( 'users.json' );
} else {
	$api_users = file_get_contents( 'https://slack.com/api/users.list?token=' . $api_token );

	if ( false === $api_users ) {
		die( "Failed to retrieve the list of users:\n" . print_r( $http_response_header, true ) );
	}

	file_put_contents( 'users.json', $api_users );
}

$users = json_decode( $api_users );
$user_tz = array();
$users_missing_tx = array();

foreach ( $users->members as $member ) {

	if ( $member->deleted || $member->is_restricted || $member->is_ultra_restricted || $member->is_bot )
		continue;

	if ( isset( $member->tz_label ) ) {
		$user_tz[] = array(
			'username' => $member->name,
			'name' => $member->real_name,
			'email' => $member->profile->email,
			'tz_label' => $member->tz_label,
			'tz_offset' => $member->tz_offset,
		);
	} else {
		$users_missing_tx[] = $member;
	}

}

usort( $user_tz, function( $a, $b ) {
	return $a['tz_offset'] - $b['tz_offset'];
});

file_put_contents( 'user-timezone.json', json_encode( $user_tz ) );