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function redirect_canonical($requested_url=null, $do_redirect=true) {	global $wp_rewrite, $is_IIS;	if ( is_feed() || is_trackback() || is_search() || is_comments_popup() || is_admin() || $is_IIS || ( isset($_POST) && count($_POST) ) || is_preview() )		return;	if ( !$requested_url ) {		// build the URL in the address bar		$requested_url  = ( isset($_SERVER['HTTPS'] ) && strtolower($_SERVER['HTTPS']) == 'on' ) ? 'https://' : 'http://';		$requested_url .= $_SERVER['HTTP_HOST'];		$requested_url .= $_SERVER['REQUEST_URI'];	}	$original = @parse_url($requested_url);	if ( false === $original )		return;	// Some PHP setups turn requests for / into /index.php in REQUEST_URI	$original['path'] = preg_replace('|/index\.php$|', '/', $original['path']);	$redirect = $original;	$redirect_url = false;	// These tests give us a WP-generated permalink	if ( is_404() ) {		$redirect_url = redirect_guess_404_permalink();	} elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {		// rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101		if ( is_single() && isset($_GET['p']) ) {			if ( $redirect_url = get_permalink(get_query_var('p')) )				$redirect['query'] = remove_query_arg('p', $redirect['query']);		} elseif ( is_page() && isset($_GET['page_id']) ) {			if ( $redirect_url = get_permalink(get_query_var('page_id')) )				$redirect['query'] = remove_query_arg('page_id', $redirect['query']);		} elseif ( isset($_GET['m']) && ( is_year() || is_month() || is_day() ) ) {			$m = get_query_var('m');			switch ( strlen($m) ) {				case 4: // Yearly					$redirect_url = get_year_link($m);					break;				case 6: // Monthly					$redirect_url = get_month_link( substr($m, 0, 4), substr($m, 4, 2) );					break;				case 8: // Daily					$redirect_url = get_day_link(substr($m, 0, 4), substr($m, 4, 2), substr($m, 6, 2));					break;			}			if ( $redirect_url )				$redirect['query'] = remove_query_arg('m', $redirect['query']);		// now moving on to non ?m=X year/month/day links		} elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && isset($_GET['day']) ) {			if ( $redirect_url = get_day_link(get_query_var('year'), get_query_var('monthnum'), get_query_var('day')) )				$redirect['query'] = remove_query_arg(array('year', 'monthnum', 'day'), $redirect['query']);		} elseif ( is_month() && get_query_var('year') && isset($_GET['monthnum']) ) {			if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )				$redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);		} elseif ( is_year() && isset($_GET['year']) ) {			if ( $redirect_url = get_year_link(get_query_var('year')) )				$redirect['query'] = remove_query_arg('year', $redirect['query']);		} elseif ( is_category() && isset($_GET['cat']) ) {			if ( $redirect_url = get_category_link(get_query_var('cat')) )				$redirect['query'] = remove_query_arg('cat', $redirect['query']);		} elseif ( is_author() && isset($_GET['author']) ) {			$author = get_userdata(get_query_var('author'));			if ( false !== $author && $redirect_url = get_author_link(false, $author->ID, $author->user_nicename) )				$redirect['query'] = remove_query_arg('author', $redirect['author']);		}	// paging		if ( $paged = get_query_var('paged') ) {			if ( $paged > 0 ) {				if ( !$redirect_url )					$redirect_url = $requested_url;				$paged_redirect = @parse_url($redirect_url);				$paged_redirect['path'] = preg_replace('|/page/[0-9]+?(/+)?$|', '/', $paged_redirect['path']); // strip off any existing paging				$paged_redirect['path'] = preg_replace('|/index.php/?$|', '/', $paged_redirect['path']); // strip off trailing /index.php/				if ( $paged > 1 && !is_single() ) {					$paged_redirect['path'] = trailingslashit($paged_redirect['path']);					if ( $wp_rewrite->using_index_permalinks() && strpos($paged_redirect['path'], '/index.php/') === false )						$paged_redirect['path'] .= 'index.php/';					$paged_redirect['path'] .= user_trailingslashit("page/$paged", 'paged');				} elseif ( !is_home() && !is_single() ){					$paged_redirect['path'] = user_trailingslashit($paged_redirect['path'], 'paged');				}				$redirect_url = $paged_redirect['scheme'] . '://' . $paged_redirect['host'] . $paged_redirect['path'];				$redirect['path'] = $paged_redirect['path'];			}			$redirect['query'] = remove_query_arg('paged', $redirect['query']);		}	}	// tack on any additional query vars	if ( $redirect_url && $redirect['query'] ) {		if ( strpos($redirect_url, '?') !== false )			$redirect_url .= '&';		else			$redirect_url .= '?';		$redirect_url .= $redirect['query'];	}	if ( $redirect_url )		$redirect = @parse_url($redirect_url);	// www.example.com vs example.com	$user_home = @parse_url(get_option('home'));	$redirect['host'] = $user_home['host'];	// Handle ports	if ( isset($user_home['port']) )		$redirect['port'] = $user_home['port'];	else		unset($redirect['port']);	// trailing /index.php/	$redirect['path'] = preg_replace('|/index.php/$|', '/', $redirect['path']);	// strip /index.php/ when we're not using PATHINFO permalinks	if ( !$wp_rewrite->using_index_permalinks() )		$redirect['path'] = str_replace('/index.php/', '/', $redirect['path']);	// trailing slashes	if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_home() || ( is_home() && (get_query_var('paged') > 1) ) ) ) {		$user_ts_type = '';		if ( get_query_var('paged') > 0 ) {			$user_ts_type = 'paged';		} else {			foreach ( array('single', 'category', 'page', 'day', 'month', 'year') as $type ) {				$func = 'is_' . $type;				if ( call_user_func($func) )					$user_ts_type = $type;					break;				}			}		$redirect['path'] = user_trailingslashit($redirect['path'], $user_ts_type);	} elseif ( is_home() ) {		$redirect['path'] = trailingslashit($redirect['path']);	}	// Always trailing slash the 'home' URL	if ( $redirect['path'] == $user_home['path'] )		$redirect['path'] = trailingslashit($redirect['path']);	// Ignore differences in host capitalization, as this can lead to infinite redirects	if ( strtolower($original['host']) == strtolower($redirect['host']) )		$redirect['host'] = $original['host'];	if ( array($original['host'], $original['port'], $original['path'], $original['query']) !== array($redirect['host'], $redirect['port'], $redirect['path'], $redirect['query']) ) {		$redirect_url = $redirect['scheme'] . '://' . $redirect['host'];		if ( isset($redirect['port']) )		 	$redirect_url .= ':' . $redirect['port'];		$redirect_url .= $redirect['path'];		if ( $redirect['query'] )			$redirect_url .= '?' . $redirect['query'];	}	if ( !$redirect_url || $redirect_url == $requested_url )	 	return false;	// Note that you can use the "redirect_canonical" filter to cancel a canonical redirect for whatever reason by returning FALSE	$redirect_url = apply_filters('redirect_canonical', $redirect_url, $requested_url);	if ( !$redirect_url || $redirect_url == $requested_url ) // yes, again -- in case the filter aborted the request	 	return false;	if ( $do_redirect ) {		// protect against chained redirects		if ( !redirect_canonical($redirect_url, false) ) {			wp_redirect($redirect_url, 301);			exit();		} else {			return false;		}	} else {		return $redirect_url;	}}