get_calendar() lacks filters on it's database queries

[Viper007Bond]

There's no way to limit the calendar to a specific taxonomy or taxonomy value. Most everything else in WordPress has filters on the WHERE and JOIN parts of the database query (wp_get_archives() for example). get_calendar() does not. It should. :)

[nacin]

Punting pending patch. Might be able to sneak it in if one gets provided soon.

[mrenns]

It would also be nice if the calendar could be set for use with custom post types.

[mrenns]

Replying to mrenns:

It would also be nice if the calendar could be set for use with custom post types.

it works using this syntax: get_calendar(false, 'custom-post-name');

and this patch:

function get_calendar($initial = true, $post_type = 'post', $echo = true) {
	global $wpdb, $m, $monthnum, $year, $wp_locale, $posts;

	$cache = array();
	$key = md5( $m . $monthnum . $year );
	if ( $cache = wp_cache_get( 'get_calendar', 'calendar' ) ) {
		if ( is_array($cache) && isset( $cache[ $key ] ) ) {
			if ( $echo ) {
				echo apply_filters( 'get_calendar',  $cache[$key] );
				return;
			} else {
				return apply_filters( 'get_calendar',  $cache[$key] );
			}
		}
	}

	if ( !is_array($cache) )
		$cache = array();

	// Quick check. If we have no posts at all, abort!
	if ( !$posts ) {
		$gotsome = $wpdb->get_var("SELECT 1 as test FROM $wpdb->posts WHERE post_type = '$post_type' AND post_status = 'publish' LIMIT 1");
		if ( !$gotsome ) {
			$cache[ $key ] = '';
			wp_cache_set( 'get_calendar', $cache, 'calendar' );
			return;
		}
	}

	if ( isset($_GET['w']) )
		$w = ''.intval($_GET['w']);

	// week_begins = 0 stands for Sunday
	$week_begins = intval(get_option('start_of_week'));

	// Let's figure out when we are
	if ( !empty($monthnum) && !empty($year) ) {
		$thismonth = ''.zeroise(intval($monthnum), 2);
		$thisyear = ''.intval($year);
	} elseif ( !empty($w) ) {
		// We need to get the month from MySQL
		$thisyear = ''.intval(substr($m, 0, 4));
		$d = (($w - 1) * 7) + 6; //it seems MySQL's weeks disagree with PHP's
		$thismonth = $wpdb->get_var("SELECT DATE_FORMAT((DATE_ADD('${thisyear}0101', INTERVAL $d DAY) ), '%m')");
	} elseif ( !empty($m) ) {
		$thisyear = ''.intval(substr($m, 0, 4));
		if ( strlen($m) < 6 )
				$thismonth = '01';
		else
				$thismonth = ''.zeroise(intval(substr($m, 4, 2)), 2);
	} else {
		$thisyear = gmdate('Y', current_time('timestamp'));
		$thismonth = gmdate('m', current_time('timestamp'));
	}

	$unixmonth = mktime(0, 0 , 0, $thismonth, 1, $thisyear);

	// Get the next and previous month and year with at least one post
	$previous = $wpdb->get_row("SELECT DISTINCT MONTH(post_date) AS month, YEAR(post_date) AS year
		FROM $wpdb->posts
		WHERE post_date < '$thisyear-$thismonth-01'
		AND post_type = '$post_type' AND post_status = 'publish'
			ORDER BY post_date DESC
			LIMIT 1");
	$next = $wpdb->get_row("SELECT	DISTINCT MONTH(post_date) AS month, YEAR(post_date) AS year
		FROM $wpdb->posts
		WHERE post_date >	'$thisyear-$thismonth-01'
		AND MONTH( post_date ) != MONTH( '$thisyear-$thismonth-01' )
		AND post_type = '$post_type' AND post_status = 'publish'
			ORDER	BY post_date ASC
			LIMIT 1");

	/* translators: Calendar caption: 1: month name, 2: 4-digit year */
	$calendar_caption = _x('%1$s %2$s', 'calendar caption');
	$calendar_output = '<table id="wp-calendar" summary="' . esc_attr__('Calendar') . '">
	<caption>' . sprintf($calendar_caption, $wp_locale->get_month($thismonth), date('Y', $unixmonth)) . '</caption>
	<thead>
	<tr>';

	$myweek = array();

	for ( $wdcount=0; $wdcount<=6; $wdcount++ ) {
		$myweek[] = $wp_locale->get_weekday(($wdcount+$week_begins)%7);
	}

	foreach ( $myweek as $wd ) {
		$day_name = (true == $initial) ? $wp_locale->get_weekday_initial($wd) : $wp_locale->get_weekday_abbrev($wd);
		$wd = esc_attr($wd);
		$calendar_output .= "\n\t\t<th scope=\"col\" title=\"$wd\">$day_name</th>";
	}

	$calendar_output .= '
	</tr>
	</thead>

	<tfoot>
	<tr>';

	if ( $previous ) {
		$calendar_output .= "\n\t\t".'<td colspan="3" id="prev"><a href="' . get_month_link($previous->year, $previous->month) . '" title="' . sprintf(__('View posts for %1$s %2$s'), $wp_locale->get_month($previous->month), date('Y', mktime(0, 0 , 0, $previous->month, 1, $previous->year))) . '">&laquo; ' . $wp_locale->get_month_abbrev($wp_locale->get_month($previous->month)) . '</a></td>';
	} else {
		$calendar_output .= "\n\t\t".'<td colspan="3" id="prev" class="pad">&nbsp;</td>';
	}

	$calendar_output .= "\n\t\t".'<td class="pad">&nbsp;</td>';

	if ( $next ) {
		$calendar_output .= "\n\t\t".'<td colspan="3" id="next"><a href="' . get_month_link($next->year, $next->month) . '" title="' . esc_attr( sprintf(__('View posts for %1$s %2$s'), $wp_locale->get_month($next->month), date('Y', mktime(0, 0 , 0, $next->month, 1, $next->year))) ) . '">' . $wp_locale->get_month_abbrev($wp_locale->get_month($next->month)) . ' &raquo;</a></td>';
	} else {
		$calendar_output .= "\n\t\t".'<td colspan="3" id="next" class="pad">&nbsp;</td>';
	}

	$calendar_output .= '
	</tr>
	</tfoot>

	<tbody>
	<tr>';

	// Get days with posts
	$dayswithposts = $wpdb->get_results("SELECT DISTINCT DAYOFMONTH(post_date)
		FROM $wpdb->posts WHERE MONTH(post_date) = '$thismonth'
		AND YEAR(post_date) = '$thisyear'
		AND post_type = '$post_type' AND post_status = 'publish'
		AND post_date < '" . current_time('mysql') . '\'', ARRAY_N);
	if ( $dayswithposts ) {
		foreach ( (array) $dayswithposts as $daywith ) {
			$daywithpost[] = $daywith[0];
		}
	} else {
		$daywithpost = array();
	}

	if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false || stripos($_SERVER['HTTP_USER_AGENT'], 'camino') !== false || stripos($_SERVER['HTTP_USER_AGENT'], 'safari') !== false)
		$ak_title_separator = "\n";
	else
		$ak_title_separator = ', ';

	$ak_titles_for_day = array();
	$ak_post_titles = $wpdb->get_results("SELECT ID, post_title, DAYOFMONTH(post_date) as dom "
		."FROM $wpdb->posts "
		."WHERE YEAR(post_date) = '$thisyear' "
		."AND MONTH(post_date) = '$thismonth' "
		."AND post_date < '".current_time('mysql')."' "
		."AND post_type = '$post_type' AND post_status = 'publish'"
	);
	if ( $ak_post_titles ) {
		foreach ( (array) $ak_post_titles as $ak_post_title ) {

				$post_title = esc_attr( apply_filters( 'the_title', $ak_post_title->post_title, $ak_post_title->ID ) );

				if ( empty($ak_titles_for_day['day_'.$ak_post_title->dom]) )
					$ak_titles_for_day['day_'.$ak_post_title->dom] = '';
				if ( empty($ak_titles_for_day["$ak_post_title->dom"]) ) // first one
					$ak_titles_for_day["$ak_post_title->dom"] = $post_title;
				else
					$ak_titles_for_day["$ak_post_title->dom"] .= $ak_title_separator . $post_title;
		}
	}


	// See how much we should pad in the beginning
	$pad = calendar_week_mod(date('w', $unixmonth)-$week_begins);
	if ( 0 != $pad )
		$calendar_output .= "\n\t\t".'<td colspan="'. esc_attr($pad) .'" class="pad">&nbsp;</td>';

	$daysinmonth = intval(date('t', $unixmonth));
	for ( $day = 1; $day <= $daysinmonth; ++$day ) {
		if ( isset($newrow) && $newrow )
			$calendar_output .= "\n\t</tr>\n\t<tr>\n\t\t";
		$newrow = false;

		if ( $day == gmdate('j', current_time('timestamp')) && $thismonth == gmdate('m', current_time('timestamp')) && $thisyear == gmdate('Y', current_time('timestamp')) )
			$calendar_output .= '<td id="today">';
		else
			$calendar_output .= '<td>';

		if ( in_array($day, $daywithpost) ) // any posts today?
				$calendar_output .= '<a href="' . get_day_link($thisyear, $thismonth, $day) . "\" title=\"" . esc_attr($ak_titles_for_day[$day]) . "\">$day</a>";
		else
			$calendar_output .= $day;
		$calendar_output .= '</td>';

		if ( 6 == calendar_week_mod(date('w', mktime(0, 0 , 0, $thismonth, $day, $thisyear))-$week_begins) )
			$newrow = true;
	}

	$pad = 7 - calendar_week_mod(date('w', mktime(0, 0 , 0, $thismonth, $day, $thisyear))-$week_begins);
	if ( $pad != 0 && $pad != 7 )
		$calendar_output .= "\n\t\t".'<td class="pad" colspan="'. esc_attr($pad) .'">&nbsp;</td>';

	$calendar_output .= "\n\t</tr>\n\t</tbody>\n\t</table>";

	$cache[ $key ] = $calendar_output;
	wp_cache_set( 'get_calendar', $cache, 'calendar' );

	if ( $echo )
		echo apply_filters( 'get_calendar',  $calendar_output );
	else
		return apply_filters( 'get_calendar',  $calendar_output );

}

[Chouby]

I would be interested by this filter too. Today I am obliged to use a quite ugly workaround: copy paste the get_calendar function, modify a few lines to modify the sql queries and finally use the get_calendar filter to output the modified calendar. Since the get_calendar filter is at the end of the function, most of the code (and sql queries) is executed 2 times... Not very efficient.

[Chouby]

The proposed patch adds two filters: getcalendar_join and getcalendar_where (as it is done for wp_get_archives).

My choice was not to include the date in the where filter. The main reason for this is that this way the filter is called only one time for the 4 sql queries included in get_calendar.

[ximm]

I was just about to submit a similar patch when I found this. As far as I understand, this change is fully backwards compatible and even improves code readability by making it more DRY. In that way this ticket has some benefits over #16173 (which would be another way to solve my particular problem).

So I would very much like to see this one commited. If there is anything I can do to help with that, just tell me.

[ximm]

updated patch

[ximm]

I added an updated patch. Changes:

• I included the first query ("Quick check. If we have no posts at all, abort!"). In order to do that I also had to remove the AND from the beginning of getcalender_where

[Chouby]

If you want to include the filter in the first query, then I would rather use the same way it is generally done in WordPress: keep AND in the filter and add WHERE 1=1 $where in the first query.

[ximm]

updated patch with AND at beginning of $where as suggested by Chouby

[SergeyBiryukov]

Per the discussion in #29319, we should switch the calendar over to use get_posts() with a date query instead of introducing new filters for SQL query fragments.