iCal export of this year's events

ical-export-years-events.php

<?php
/**
 * Description:	This snippet will enable you to have an iCal export of all this year's events
 * when using this url:
 * http://example.com/events/?ical=1&tribe_display=year
 *
 * Paste the code in your (child) theme's functions.php file
 * 
 * Required plugins:  The Events Calendar
 * Last updated:      2017-10-20
 * Author:            Brook Harding
*/

add_action( 'pre_get_posts', 'filter_ical_query' );

function filter_ical_query( $query ) {

	if ( ! isset( $_GET['ical'] ) || ! isset( $query->tribe_is_event_query ) || ! $query->tribe_is_event_query ) return;

	$tribe_display = $_GET[ 'tribe_display' ];

	if( $tribe_display === 'year' ) {

		$start_of_year = date( 'Y' ) . '-01-01';
		
		// Use this line to have the events of the current year
		$end_of_year = date( 'Y' ) . '-12-31';
		
		// Use this line to have the events until the specified date
		// $end_of_year = '2020-12-31';

		$query->set( 'eventDisplay', 'custom' );
		$query->set( 'start_date', $start_of_year );
		$query->set( 'end_date', $end_of_year );
		$query->set( 'posts_per_page', - 1 );
	}

	elseif ( $tribe_display === 'recently-published' ) {

		$query->set( 'order', 'DESC' );
		$query->set( 'orderby', 'modified' );
		$query->set( 'posts_per_page', tribe_get_option( 'postsPerPage', 20 ) );

		// Remove default oderby and wheres, lest they return events sorted by event_date
		remove_filter( 'posts_orderby', array( 'Tribe__Events__Query', 'posts_orderby' ), 10, 2 );
		remove_filter( 'posts_where', array( 'Tribe__Events__Query', 'posts_where' ), 10, 2 );
	}
}