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  予約システムを作るなら get_calendar をカスタマイズするのがおすすめ
2020
11
Aug

予約システムを作るなら get_calendar をカスタマイズするのがおすすめ

このページはsql言語についての知識がある程度ある方を対象にしています。ワードプレスで予約システムを作りたい方はsql について学ぶ必要があります。知っているとワードプレスをカスタマイズするうえで何かと便利です。

ワードプレスでsql を自由に使いこなしたい方へ二つのステップ。これだけで充分です。

これから先を読み進めようとする方は私が説明するまでもないと思いますので、私が眺めて気付いたことを参考までに。

  • データベースへの負荷軽減のために cash が使われています。
  • 世界中のワードプレスユーザーのために書かれているため使用場所と用途が決まっている場合は省略して書くことができます。
  • フィルターフックが準備してあります。
  • 投稿記事がある日に印がつけられます。
  • カレンダーを見ている今日の日付にclass が設定されています。
  • 自由にカスタマイズできることがわかります。

 
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get_calendar (wp-includes/general-template.phpより。)


/**
 * Display calendar with days that have posts as links.
 *
 * The calendar is cached, which will be retrieved, if it exists. If there are
 * no posts for the month, then it will not be displayed.
 *
 * @since 1.0.0
 *
 * @global wpdb      $wpdb
 * @global int       $m
 * @global int       $monthnum
 * @global int       $year
 * @global WP_Locale $wp_locale
 * @global array     $posts
 *
 * @param bool $initial Optional, default is true. Use initial calendar names.
 * @param bool $echo    Optional, default is true. Set to false for return.
 * @return string|void String when retrieving.
 */
function get_calendar( $initial = true, $echo = true ) {
	global $wpdb, $m, $monthnum, $year, $wp_locale, $posts;

	$key = md5( $m . $monthnum . $year );
	$cache = wp_cache_get( 'get_calendar', 'calendar' );

	if ( $cache && is_array( $cache ) && isset( $cache[ $key ] ) ) {
		/** This filter is documented in wp-includes/general-template.php */
		$output = apply_filters( 'get_calendar', $cache[ $key ] );

		if ( $echo ) {
			echo $output;
			return;
		}

		return $output;
	}

	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' AND post_status = 'publish' LIMIT 1");
		if ( ! $gotsome ) {
			$cache[ $key ] = '';
			wp_cache_set( 'get_calendar', $cache, 'calendar' );
			return;
		}
	}

	if ( isset( $_GET['w'] ) ) {
		$w = (int) $_GET['w'];
	}
	// week_begins = 0 stands for Sunday
	$week_begins = (int) get_option( 'start_of_week' );
	$ts = current_time( 'timestamp' );

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

	$unixmonth = mktime( 0, 0 , 0, $thismonth, 1, $thisyear );
	$last_day = date( 't', $unixmonth );

	// Get the next and previous month and year with at least one post
	$previous = $wpdb->get_row("SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
		FROM $wpdb->posts
		WHERE post_date <; '$thisyear-$thismonth-01'
		AND post_type = 'post' AND post_status = 'publish'
			ORDER BY post_date DESC
			LIMIT 1");
	$next = $wpdb->get_row("SELECT MONTH(post_date) AS month, YEAR(post_date) AS year
		FROM $wpdb->posts
		WHERE post_date > '$thisyear-$thismonth-{$last_day} 23:59:59'
		AND post_type = 'post' 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">
	<;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 = $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 ) . '">« ' .
			$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"> <;/td>';
	}

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

	if ( $next ) {
		$calendar_output .= "\n\t\t".'<;td colspan="3" id="next"><;a href="' . get_month_link( $next->year, $next->month ) . '">' .
			$wp_locale->get_month_abbrev( $wp_locale->get_month( $next->month ) ) .
		' »<;/a><;/td>';
	} else {
		$calendar_output .= "\n\t\t".'<;td colspan="3" id="next" class="pad"> <;/td>';
	}

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

	<;tbody>
	<;tr>';

	$daywithpost = array();

	// Get days with posts
	$dayswithposts = $wpdb->get_results("SELECT DISTINCT DAYOFMONTH(post_date)
		FROM $wpdb->posts WHERE post_date >= '{$thisyear}-{$thismonth}-01 00:00:00'
		AND post_type = 'post' AND post_status = 'publish'
		AND post_date <;= '{$thisyear}-{$thismonth}-{$last_day} 23:59:59'", ARRAY_N);
	if ( $dayswithposts ) {
		foreach ( (array) $dayswithposts as $daywith ) {
			$daywithpost[] = $daywith[0];
		}
	}

	// 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"> <;/td>';
	}

	$newrow = false;
	$daysinmonth = (int) 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', $ts ) &&
			$thismonth == gmdate( 'm', $ts ) &&
			$thisyear == gmdate( 'Y', $ts ) ) {
			$calendar_output .= '<;td id="today">';
		} else {
			$calendar_output .= '<;td>';
		}

		if ( in_array( $day, $daywithpost ) ) {
			// any posts today?
			$date_format = date( _x( 'F j, Y', 'daily archives date format' ), strtotime( "{$thisyear}-{$thismonth}-{$day}" ) );
			/* translators: Post calendar label. 1: Date */
			$label = sprintf( __( 'Posts published on %s' ), $date_format );
			$calendar_output .= sprintf(
				'<;a href="%s" aria-label="%s">%s<;/a>',
				get_day_link( $thisyear, $thismonth, $day ),
				esc_attr( $label ),
				$day
			);
		} 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 ) .'"> <;/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 ) {
		/**
		 * Filters the HTML calendar output.
		 *
		 * @since 3.0.0
		 *
		 * @param string $calendar_output HTML output of the calendar.
		 */
		echo apply_filters( 'get_calendar', $calendar_output );
		return;
	}
	/** This filter is documented in wp-includes/general-template.php */
	return apply_filters( 'get_calendar', $calendar_output );
}

 

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