Reduces the gcal description size *after* it has been filtered by the_content (applies to TEC 3.9.x)

fix-long-gcal-descriptions.php

<?php
// ---------------------------------------------------------------------------------------
// When inserting this into a theme's functions.php file you can copy and paste everything
// below this comment (no need to include the opening "<?php" tag, etc!)
// ---------------------------------------------------------------------------------------


/**
 * Shortens the event description used within Google Calendar links.
 *
 * The Events Calendar already truncates the event description before using it in Google
 * Calendar links - however some themes/other plugins may add additional markup/content
 * after this, expanding it back to too big a size to make for a valid request.
 *
 * @param  array $properties
 * @return array
 */
function truncate_gcal_description_late( array $properties ) {
	$details = $properties['details'];

	if ( strlen( $details ) > 996 ) {
		//Strip tags
		$details = strip_tags( $details );

		$url     = get_permalink();
		$details = substr( $details, 0, 996 );

		//Only add the permalink if it's shorter than 900 characters, so we don't exceed the browser's URL limits
		if ( strlen( $url ) < 900 ) {
			$details .= ' (View Full Event Description Here: ' . $url . ')';
		}
	}

	$properties['details'] = $details;
	return $properties;
}

add_filter( 'tribe_google_calendar_parameters', 'truncate_gcal_description_late' );