/**
* Canonical API to handle WordPress Redirecting
*
* Based on "Permalink Redirect" from Scott Yang and "Enforce www. Preference"
* by Mark Jaquith
*
* @package WordPress
* @since 2.3.0
*/
/**
* Redirects incoming links to the proper URL based on the site url.
*
* Search engines consider www.somedomain.com and somedomain.com to be two
* different URLs when they both go to the same location. This SEO enhancement
* prevents penalty for duplicate content by redirecting all incoming links to
* one or the other.
*
* Prevents redirection for feeds, trackbacks, searches, and
* admin URLs. Does not redirect on non-pretty-permalink-supporting IIS 7+,
* page/post previews, WP admin, Trackbacks, robots.txt, searches, or on POST
* requests.
*
* Will also attempt to find the correct link when a user enters a URL that does
* not exist based on exact WordPress query. Will instead try to parse the URL
* or query in an attempt to figure the correct page to go to.
*
* @since 2.3.0
*
* @global WP_Rewrite $wp_rewrite
* @global bool $is_IIS
* @global WP_Query $wp_query
* @global wpdb $wpdb WordPress database abstraction object.
* @global WP $wp Current WordPress environment instance.
*
* @param string $requested_url Optional. The URL that was requested, used to
* figure if redirect is needed.
* @param bool $do_redirect Optional. Redirect to the new URL.
* @return string|void The string of the URL, if redirect needed.
*/
function redirect_canonical( $requested_url = null, $do_redirect = true ) {
global $wp_rewrite, $is_IIS, $wp_query, $wpdb, $wp;
if ( isset( $_SERVER['REQUEST_METHOD'] ) && ! in_array( strtoupper( $_SERVER['REQUEST_METHOD'] ), array( 'GET', 'HEAD' ) ) ) {
return;
}
// If we're not in wp-admin and the post has been published and preview nonce
// is non-existent or invalid then no need for preview in query
if ( is_preview() && get_query_var( 'p' ) && 'publish' == get_post_status( get_query_var( 'p' ) ) ) {
if ( ! isset( $_GET['preview_id'] )
|| ! isset( $_GET['preview_nonce'] )
|| ! wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . (int) $_GET['preview_id'] ) ) {
$wp_query->is_preview = false;
}
}
if ( is_trackback() || is_search() || is_admin() || is_preview() || is_robots() || ( $is_IIS && !iis7_supports_permalinks() ) ) {
return;
}
if ( ! $requested_url && isset( $_SERVER['HTTP_HOST'] ) ) {
// build the URL in the address bar
$requested_url = is_ssl() ? 'https://' : 'http://';
$requested_url .= $_SERVER['HTTP_HOST'];
$requested_url .= $_SERVER['REQUEST_URI'];
}
$original = @parse_url($requested_url);
if ( false === $original ) {
return;
}
$redirect = $original;
$redirect_url = false;
// Notice fixing
if ( !isset($redirect['path']) )
$redirect['path'] = '';
if ( !isset($redirect['query']) )
$redirect['query'] = '';
// If the original URL ended with non-breaking spaces, they were almost
// certainly inserted by accident. Let's remove them, so the reader doesn't
// see a 404 error with no obvious cause.
$redirect['path'] = preg_replace( '|(%C2%A0)+$|i', '', $redirect['path'] );
// It's not a preview, so remove it from URL
if ( get_query_var( 'preview' ) ) {
$redirect['query'] = remove_query_arg( 'preview', $redirect['query'] );
}
if ( is_feed() && ( $id = get_query_var( 'p' ) ) ) {
if ( $redirect_url = get_post_comments_feed_link( $id, get_query_var( 'feed' ) ) ) {
$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed'), $redirect_url );
$redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );
}
}
if ( is_singular() && 1 > $wp_query->post_count && ($id = get_query_var('p')) ) {
$vars = $wpdb->get_results( $wpdb->prepare("SELECT post_type, post_parent FROM $wpdb->posts WHERE ID = %d", $id) );
if ( isset($vars[0]) && $vars = $vars[0] ) {
if ( 'revision' == $vars->post_type && $vars->post_parent > 0 )
$id = $vars->post_parent;
if ( $redirect_url = get_permalink($id) )
$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
}
}
// These tests give us a WP-generated permalink
if ( is_404() ) {
// Redirect ?page_id, ?p=, ?attachment_id= to their respective url's
$id = max( get_query_var('p'), get_query_var('page_id'), get_query_var('attachment_id') );
if ( $id && $redirect_post = get_post($id) ) {
$post_type_obj = get_post_type_object($redirect_post->post_type);
if ( $post_type_obj->public && 'auto-draft' != $redirect_post->post_status ) {
$redirect_url = get_permalink($redirect_post);
$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
}
}
if ( get_query_var( 'day' ) && get_query_var( 'monthnum' ) && get_query_var( 'year' ) ) {
$year = get_query_var( 'year' );
$month = get_query_var( 'monthnum' );
$day = get_query_var( 'day' );
$date = sprintf( '%04d-%02d-%02d', $year, $month, $day );
if ( ! wp_checkdate( $month, $day, $year, $date ) ) {
$redirect_url = get_month_link( $year, $month );
$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum', 'day' ), $redirect_url );
}
} elseif ( get_query_var( 'monthnum' ) && get_query_var( 'year' ) && 12 < get_query_var( 'monthnum' ) ) {
$redirect_url = get_year_link( get_query_var( 'year' ) );
$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'year', 'monthnum' ), $redirect_url );
}
if ( ! $redirect_url ) {
if ( $redirect_url = redirect_guess_404_permalink() ) {
$redirect['query'] = _remove_qs_args_if_not_in_url( $redirect['query'], array( 'page', 'feed', 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type' ), $redirect_url );
}
}
if ( get_query_var( 'page' ) && $wp_query->post &&
false !== strpos( $wp_query->post->post_content, '' ) ) {
$redirect['path'] = rtrim( $redirect['path'], (int) get_query_var( 'page' ) . '/' );
$redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
$redirect_url = get_permalink( $wp_query->post->ID );
}
} elseif ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() ) {
// rewriting of old ?p=X, ?m=2004, ?m=200401, ?m=20040101
if ( is_attachment() &&
! array_diff( array_keys( $wp->query_vars ), array( 'attachment', 'attachment_id' ) ) &&
! $redirect_url ) {
if ( ! empty( $_GET['attachment_id'] ) ) {
$redirect_url = get_attachment_link( get_query_var( 'attachment_id' ) );
if ( $redirect_url ) {
$redirect['query'] = remove_query_arg( 'attachment_id', $redirect['query'] );
}
} else {
$redirect_url = get_attachment_link();
}
} elseif ( is_single() && !empty($_GET['p']) && ! $redirect_url ) {
if ( $redirect_url = get_permalink(get_query_var('p')) )
$redirect['query'] = remove_query_arg(array('p', 'post_type'), $redirect['query']);
} elseif ( is_single() && !empty($_GET['name']) && ! $redirect_url ) {
if ( $redirect_url = get_permalink( $wp_query->get_queried_object_id() ) )
$redirect['query'] = remove_query_arg('name', $redirect['query']);
} elseif ( is_page() && !empty($_GET['page_id']) && ! $redirect_url ) {
if ( $redirect_url = get_permalink(get_query_var('page_id')) )
$redirect['query'] = remove_query_arg('page_id', $redirect['query']);
} elseif ( is_page() && !is_feed() && 'page' == get_option('show_on_front') && get_queried_object_id() == get_option('page_on_front') && ! $redirect_url ) {
$redirect_url = home_url('/');
} elseif ( is_home() && !empty($_GET['page_id']) && 'page' == get_option('show_on_front') && get_query_var('page_id') == get_option('page_for_posts') && ! $redirect_url ) {
if ( $redirect_url = get_permalink(get_option('page_for_posts')) )
$redirect['query'] = remove_query_arg('page_id', $redirect['query']);
} elseif ( !empty($_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', $redirect['query']);
// now moving on to non ?m=X year/month/day links
} elseif ( is_day() && get_query_var('year') && get_query_var('monthnum') && !empty($_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'), $redirect['query']);
} elseif ( is_month() && get_query_var('year') && !empty($_GET['monthnum']) ) {
if ( $redirect_url = get_month_link(get_query_var('year'), get_query_var('monthnum')) )
$redirect['query'] = remove_query_arg(array('year', 'monthnum'), $redirect['query']);
} elseif ( is_year() && !empty($_GET['year']) ) {
if ( $redirect_url = get_year_link(get_query_var('year')) )
$redirect['query'] = remove_query_arg('year', $redirect['query']);
} elseif ( is_author() && !empty($_GET['author']) && preg_match( '|^[0-9]+$|', $_GET['author'] ) ) {
$author = get_userdata(get_query_var('author'));
if ( ( false !== $author ) && $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE $wpdb->posts.post_author = %d AND $wpdb->posts.post_status = 'publish' LIMIT 1", $author->ID ) ) ) {
if ( $redirect_url = get_author_posts_url($author->ID, $author->user_nicename) )
$redirect['query'] = remove_query_arg('author', $redirect['query']);
}
} elseif ( is_category() || is_tag() || is_tax() ) { // Terms (Tags/categories)
$term_count = 0;
foreach ( $wp_query->tax_query->queried_terms as $tax_query )
$term_count += count( $tax_query['terms'] );
$obj = $wp_query->get_queried_object();
if ( $term_count <= 1 && !empty($obj->term_id) && ( $tax_url = get_term_link((int)$obj->term_id, $obj->taxonomy) ) && !is_wp_error($tax_url) ) {
if ( !empty($redirect['query']) ) {
// Strip taxonomy query vars off the url.
$qv_remove = array( 'term', 'taxonomy');
if ( is_category() ) {
$qv_remove[] = 'category_name';
$qv_remove[] = 'cat';
} elseif ( is_tag() ) {
$qv_remove[] = 'tag';
$qv_remove[] = 'tag_id';
} else { // Custom taxonomies will have a custom query var, remove those too:
$tax_obj = get_taxonomy( $obj->taxonomy );
if ( false !== $tax_obj->query_var )
$qv_remove[] = $tax_obj->query_var;
}
$rewrite_vars = array_diff( array_keys($wp_query->query), array_keys($_GET) );
if ( !array_diff($rewrite_vars, array_keys($_GET)) ) { // Check to see if all the Query vars are coming from the rewrite, none are set via $_GET
$redirect['query'] = remove_query_arg($qv_remove, $redirect['query']); //Remove all of the per-tax qv's
// Create the destination url for this taxonomy
$tax_url = parse_url($tax_url);
if ( ! empty($tax_url['query']) ) { // Taxonomy accessible via ?taxonomy=..&term=.. or any custom qv..
parse_str($tax_url['query'], $query_vars);
$redirect['query'] = add_query_arg($query_vars, $redirect['query']);
} else { // Taxonomy is accessible via a "pretty-URL"
$redirect['path'] = $tax_url['path'];
}
} else { // Some query vars are set via $_GET. Unset those from $_GET that exist via the rewrite
foreach ( $qv_remove as $_qv ) {
if ( isset($rewrite_vars[$_qv]) )
$redirect['query'] = remove_query_arg($_qv, $redirect['query']);
}
}
}
}
} elseif ( is_single() && strpos($wp_rewrite->permalink_structure, '%category%') !== false && $cat = get_query_var( 'category_name' ) ) {
$category = get_category_by_path( $cat );
if ( ( ! $category || is_wp_error( $category ) ) || ! has_term( $category->term_id, 'category', $wp_query->get_queried_object_id() ) ) {
$redirect_url = get_permalink($wp_query->get_queried_object_id());
}
}
// Post Paging
if ( is_singular() && get_query_var('page') ) {
if ( !$redirect_url )
$redirect_url = get_permalink( get_queried_object_id() );
$page = get_query_var( 'page' );
if ( $page > 1 ) {
if ( is_front_page() ) {
$redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( "$wp_rewrite->pagination_base/$page", 'paged' );
} else {
$redirect_url = trailingslashit( $redirect_url ) . user_trailingslashit( $page, 'single_paged' );
}
}
$redirect['query'] = remove_query_arg( 'page', $redirect['query'] );
}
// paging and feeds
if ( get_query_var('paged') || is_feed() || get_query_var('cpage') ) {
while ( preg_match( "#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", $redirect['path'] ) || preg_match( '#/(comments/?)?(feed|rss|rdf|atom|rss2)(/+)?$#', $redirect['path'] ) || preg_match( "#/{$wp_rewrite->comments_pagination_base}-[0-9]+(/+)?$#", $redirect['path'] ) ) {
// Strip off paging and feed
$redirect['path'] = preg_replace("#/$wp_rewrite->pagination_base/?[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing paging
$redirect['path'] = preg_replace('#/(comments/?)?(feed|rss2?|rdf|atom)(/+|$)#', '/', $redirect['path']); // strip off feed endings
$redirect['path'] = preg_replace("#/{$wp_rewrite->comments_pagination_base}-[0-9]+?(/+)?$#", '/', $redirect['path']); // strip off any existing comment paging
}
$addl_path = '';
if ( is_feed() && in_array( get_query_var('feed'), $wp_rewrite->feeds ) ) {
$addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
if ( !is_singular() && get_query_var( 'withcomments' ) )
$addl_path .= 'comments/';
if ( ( 'rss' == get_default_feed() && 'feed' == get_query_var('feed') ) || 'rss' == get_query_var('feed') )
$addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == 'rss2' ) ? '' : 'rss2' ), 'feed' );
else
$addl_path .= user_trailingslashit( 'feed/' . ( ( get_default_feed() == get_query_var('feed') || 'feed' == get_query_var('feed') ) ? '' : get_query_var('feed') ), 'feed' );
$redirect['query'] = remove_query_arg( 'feed', $redirect['query'] );
} elseif ( is_feed() && 'old' == get_query_var('feed') ) {
$old_feed_files = array(
'wp-atom.php' => 'atom',
'wp-commentsrss2.php' => 'comments_rss2',
'wp-feed.php' => get_default_feed(),
'wp-rdf.php' => 'rdf',
'wp-rss.php' => 'rss2',
'wp-rss2.php' => 'rss2',
);
if ( isset( $old_feed_files[ basename( $redirect['path'] ) ] ) ) {
$redirect_url = get_feed_link( $old_feed_files[ basename( $redirect['path'] ) ] );
wp_redirect( $redirect_url, 301 );
die();
}
}
if ( get_query_var('paged') > 0 ) {
$paged = get_query_var('paged');
$redirect['query'] = remove_query_arg( 'paged', $redirect['query'] );
if ( !is_feed() ) {
if ( $paged > 1 && !is_single() ) {
$addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit("$wp_rewrite->pagination_base/$paged", 'paged');
} elseif ( !is_single() ) {
$addl_path = !empty( $addl_path ) ? trailingslashit($addl_path) : '';
}
} elseif ( $paged > 1 ) {
$redirect['query'] = add_query_arg( 'paged', $paged, $redirect['query'] );
}
}
if ( get_option( 'page_comments' ) && (
( 'newest' == get_option( 'default_comments_page' ) && get_query_var( 'cpage' ) > 0 ) ||
( 'newest' != get_option( 'default_comments_page' ) && get_query_var( 'cpage' ) > 1 )
) ) {
$addl_path = ( !empty( $addl_path ) ? trailingslashit($addl_path) : '' ) . user_trailingslashit( $wp_rewrite->comments_pagination_base . '-' . get_query_var('cpage'), 'commentpaged' );
$redirect['query'] = remove_query_arg( 'cpage', $redirect['query'] );
}
$redirect['path'] = user_trailingslashit( preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/?$|', '/', $redirect['path']) ); // strip off trailing /index.php/
if ( !empty( $addl_path ) && $wp_rewrite->using_index_permalinks() && strpos($redirect['path'], '/' . $wp_rewrite->index . '/') === false )
$redirect['path'] = trailingslashit($redirect['path']) . $wp_rewrite->index . '/';
if ( !empty( $addl_path ) )
$redirect['path'] = trailingslashit($redirect['path']) . $addl_path;
$redirect_url = $redirect['scheme'] . '://' . $redirect['host'] . $redirect['path'];
}
if ( 'wp-register.php' == basename( $redirect['path'] ) ) {
if ( is_multisite() ) {
/** This filter is documented in wp-login.php */
$redirect_url = apply_filters( 'wp_signup_location', network_site_url( 'wp-signup.php' ) );
} else {
$redirect_url = wp_registration_url();
}
wp_redirect( $redirect_url, 301 );
die();
}
}
// tack on any additional query vars
$redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
if ( $redirect_url && !empty($redirect['query']) ) {
parse_str( $redirect['query'], $_parsed_query );
$redirect = @parse_url($redirect_url);
if ( ! empty( $_parsed_query['name'] ) && ! empty( $redirect['query'] ) ) {
parse_str( $redirect['query'], $_parsed_redirect_query );
if ( empty( $_parsed_redirect_query['name'] ) )
unset( $_parsed_query['name'] );
}
$_parsed_query = rawurlencode_deep( $_parsed_query );
$redirect_url = add_query_arg( $_parsed_query, $redirect_url );
}
if ( $redirect_url )
$redirect = @parse_url($redirect_url);
// www.example.com vs example.com
$user_home = @parse_url(home_url());
if ( !empty($user_home['host']) )
$redirect['host'] = $user_home['host'];
if ( empty($user_home['path']) )
$user_home['path'] = '/';
// Handle ports
if ( !empty($user_home['port']) )
$redirect['port'] = $user_home['port'];
else
unset($redirect['port']);
// trailing /index.php
$redirect['path'] = preg_replace('|/' . preg_quote( $wp_rewrite->index, '|' ) . '/*?$|', '/', $redirect['path']);
$punctuation_pattern = implode( '|', array_map( 'preg_quote', array(
' ', '%20', // space
'!', '%21', // exclamation mark
'"', '%22', // double quote
"'", '%27', // single quote
'(', '%28', // opening bracket
')', '%29', // closing bracket
',', '%2C', // comma
'.', '%2E', // period
';', '%3B', // semicolon
'{', '%7B', // opening curly bracket
'}', '%7D', // closing curly bracket
'%E2%80%9C', // opening curly quote
'%E2%80%9D', // closing curly quote
) ) );
// Remove trailing spaces and end punctuation from the path.
$redirect['path'] = preg_replace( "#($punctuation_pattern)+$#", '', $redirect['path'] );
if ( !empty( $redirect['query'] ) ) {
// Remove trailing spaces and end punctuation from certain terminating query string args.
$redirect['query'] = preg_replace( "#((p|page_id|cat|tag)=[^&]*?)($punctuation_pattern)+$#", '$1', $redirect['query'] );
// Clean up empty query strings
$redirect['query'] = trim(preg_replace( '#(^|&)(p|page_id|cat|tag)=?(&|$)#', '&', $redirect['query']), '&');
// Redirect obsolete feeds
$redirect['query'] = preg_replace( '#(^|&)feed=rss(&|$)#', '$1feed=rss2$2', $redirect['query'] );
// Remove redundant leading ampersands
$redirect['query'] = preg_replace( '#^\??&*?#', '', $redirect['query'] );
}
// strip /index.php/ when we're not using PATHINFO permalinks
if ( !$wp_rewrite->using_index_permalinks() )
$redirect['path'] = str_replace( '/' . $wp_rewrite->index . '/', '/', $redirect['path'] );
// trailing slashes
if ( is_object($wp_rewrite) && $wp_rewrite->using_permalinks() && !is_404() && (!is_front_page() || ( is_front_page() && (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', 'home') 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_front_page() ) {
$redirect['path'] = trailingslashit($redirect['path']);
}
// Strip multiple slashes out of the URL
if ( strpos($redirect['path'], '//') > -1 )
$redirect['path'] = preg_replace('|/+|', '/', $redirect['path']);
// Always trailing slash the Front Page URL
if ( trailingslashit( $redirect['path'] ) == trailingslashit( $user_home['path'] ) )
$redirect['path'] = trailingslashit($redirect['path']);
// Ignore differences in host capitalization, as this can lead to infinite redirects
// Only redirect no-www <=> yes-www
if ( strtolower($original['host']) == strtolower($redirect['host']) ||
( strtolower($original['host']) != 'www.' . strtolower($redirect['host']) && 'www.' . strtolower($original['host']) != strtolower($redirect['host']) ) )
$redirect['host'] = $original['host'];
$compare_original = array( $original['host'], $original['path'] );
if ( !empty( $original['port'] ) )
$compare_original[] = $original['port'];
if ( !empty( $original['query'] ) )
$compare_original[] = $original['query'];
$compare_redirect = array( $redirect['host'], $redirect['path'] );
if ( !empty( $redirect['port'] ) )
$compare_redirect[] = $redirect['port'];
if ( !empty( $redirect['query'] ) )
$compare_redirect[] = $redirect['query'];
if ( $compare_original !== $compare_redirect ) {
$redirect_url = $redirect['scheme'] . '://' . $redirect['host'];
if ( !empty($redirect['port']) )
$redirect_url .= ':' . $redirect['port'];
$redirect_url .= $redirect['path'];
if ( !empty($redirect['query']) )
$redirect_url .= '?' . $redirect['query'];
}
if ( ! $redirect_url || $redirect_url == $requested_url ) {
return;
}
// Hex encoded octets are case-insensitive.
if ( false !== strpos($requested_url, '%') ) {
if ( !function_exists('lowercase_octets') ) {
/**
* Converts the first hex-encoded octet match to lowercase.
*
* @since 3.1.0
* @ignore
*
* @param array $matches Hex-encoded octet matches for the requested URL.
* @return string Lowercased version of the first match.
*/
function lowercase_octets($matches) {
return strtolower( $matches[0] );
}
}
$requested_url = preg_replace_callback('|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url);
}
/**
* Filters the canonical redirect URL.
*
* Returning false to this filter will cancel the redirect.
*
* @since 2.3.0
*
* @param string $redirect_url The redirect URL.
* @param string $requested_url The requested URL.
*/
$redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );
// yes, again -- in case the filter aborted the request
if ( ! $redirect_url || strip_fragment_from_url( $redirect_url ) == strip_fragment_from_url( $requested_url ) ) {
return;
}
if ( $do_redirect ) {
// protect against chained redirects
if ( !redirect_canonical($redirect_url, false) ) {
wp_redirect($redirect_url, 301);
exit();
} else {
// Debug
// die("1: $redirect_url 2: " . redirect_canonical( $redirect_url, false ) );
return;
}
} else {
return $redirect_url;
}
}
/**
* Removes arguments from a query string if they are not present in a URL
* DO NOT use this in plugin code.
*
* @since 3.4.0
* @access private
*
* @param string $query_string
* @param array $args_to_check
* @param string $url
* @return string The altered query string
*/
function _remove_qs_args_if_not_in_url( $query_string, Array $args_to_check, $url ) {
$parsed_url = @parse_url( $url );
if ( ! empty( $parsed_url['query'] ) ) {
parse_str( $parsed_url['query'], $parsed_query );
foreach ( $args_to_check as $qv ) {
if ( !isset( $parsed_query[$qv] ) )
$query_string = remove_query_arg( $qv, $query_string );
}
} else {
$query_string = remove_query_arg( $args_to_check, $query_string );
}
return $query_string;
}
/**
* Strips the #fragment from a URL, if one is present.
*
* @since 4.4.0
*
* @param string $url The URL to strip.
* @return string The altered URL.
*/
function strip_fragment_from_url( $url ) {
$parsed_url = @parse_url( $url );
if ( ! empty( $parsed_url['host'] ) ) {
// This mirrors code in redirect_canonical(). It does not handle every case.
$url = $parsed_url['scheme'] . '://' . $parsed_url['host'];
if ( ! empty( $parsed_url['port'] ) ) {
$url .= ':' . $parsed_url['port'];
}
if ( ! empty( $parsed_url['path'] ) ) {
$url .= $parsed_url['path'];
}
if ( ! empty( $parsed_url['query'] ) ) {
$url .= '?' . $parsed_url['query'];
}
}
return $url;
}
/**
* Attempts to guess the correct URL based on query vars
*
* @since 2.3.0
*
* @global wpdb $wpdb WordPress database abstraction object.
*
* @return false|string The correct URL if one is found. False on failure.
*/
function redirect_guess_404_permalink() {
global $wpdb;
if ( get_query_var('name') ) {
$where = $wpdb->prepare("post_name LIKE %s", $wpdb->esc_like( get_query_var('name') ) . '%');
// if any of post_type, year, monthnum, or day are set, use them to refine the query
if ( get_query_var('post_type') )
$where .= $wpdb->prepare(" AND post_type = %s", get_query_var('post_type'));
else
$where .= " AND post_type IN ('" . implode( "', '", get_post_types( array( 'public' => true ) ) ) . "')";
if ( get_query_var('year') )
$where .= $wpdb->prepare(" AND YEAR(post_date) = %d", get_query_var('year'));
if ( get_query_var('monthnum') )
$where .= $wpdb->prepare(" AND MONTH(post_date) = %d", get_query_var('monthnum'));
if ( get_query_var('day') )
$where .= $wpdb->prepare(" AND DAYOFMONTH(post_date) = %d", get_query_var('day'));
$post_id = $wpdb->get_var("SELECT ID FROM $wpdb->posts WHERE $where AND post_status = 'publish'");
if ( ! $post_id )
return false;
if ( get_query_var( 'feed' ) )
return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
elseif ( get_query_var( 'page' ) && 1 < get_query_var( 'page' ) )
return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
else
return get_permalink( $post_id );
}
return false;
}
/**
* Redirects a variety of shorthand URLs to the admin.
*
* If a user visits example.com/admin, they'll be redirected to /wp-admin.
* Visiting /login redirects to /wp-login.php, and so on.
*
* @since 3.4.0
*
* @global WP_Rewrite $wp_rewrite
*/
function wp_redirect_admin_locations() {
global $wp_rewrite;
if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) )
return;
$admins = array(
home_url( 'wp-admin', 'relative' ),
home_url( 'dashboard', 'relative' ),
home_url( 'admin', 'relative' ),
site_url( 'dashboard', 'relative' ),
site_url( 'admin', 'relative' ),
);
if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins ) ) {
wp_redirect( admin_url() );
exit;
}
$logins = array(
home_url( 'wp-login.php', 'relative' ),
home_url( 'login', 'relative' ),
site_url( 'login', 'relative' ),
);
if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins ) ) {
wp_redirect( wp_login_url() );
exit;
}
}
Health Care Financing Administration Archives - Reverse Medicare and Medicaid Audits
The HCFA Ruling 86-1 is one of the most frequently-quoted pieces of law. For example, it is one of the key rulings in Chaves County Home Health Service, Inc., et al., v. Louis W. Sullivan, M.D . 931 F.2d 914 (April 26, 1991).
So we thought we would reproduce the ruling here, but with only the portions that deal specifically with statistical sampling and extrapolation.
HCFAR 86-1-1
MEDICARE PROGRAM
Hospital Insurance and Supplementary Medical Insurance Benefits (Parts A and B) Use of Statistical Sampling to Project Overpayments to Providers and Suppliers
HCFAR 86-1
Purpose: HCFA and its Medicare contractors may use statistical sampling to project overpayments to providers and suppliers when claims are voluminous and reflect a pattern of erroneous billing or overutilization and when a case-by-case review is not administratively feasible .
. . . As result of a subsequent audit of the provider’s Medicare claims, the intermediary discovered a large number of bills for medically unnecessary services. . . . The cost of identifying and calculating each individual overpayment itself would constitute a substantial portion of the amount the intermediary might reasonably be expected to recover. . . .
The intermediary notified the provider that, because of the volume of records and the costs of retrieving and reviewing all records for the period as discussed above, it intended to project the overpayment by reviewing a statistically valid sample of beneficiary records and that if it were determined that the provider had been overpaid for the sample cases, it would project the results (again using statistically valid methods) to the entire population of cases from which the sample had been drawn. This would result in a statistically accurate estimate of the total amount the provider had been overpaid for services to these beneficiaries.
[Next are the complaint items filed by the health care provider.]
The provider objected to the intermediary’s use of sampling to project the overpayment on the following grounds:
1. There is no legal authority in the Medicare statute or regulations for HCFA or its intermediaries to determine overpayments by projecting the findings of a sample of specific claims onto a universe of unspecified beneficiaries and claims.
2. Section 1879 of the Social Security Act, 42 U.S.C. 1395pp, contemplates that medical necessity and custodial care coverage determinations will be made only by means of a case-by-case review.
3. When sampling is used, providers are not able to bill individual beneficiaries not in the sample group for the services determined to be noncovered.
4. Use of a sampling procedure violates the rights of providers to appeal adverse determinations.
5. The use of sampling and extrapolation to determine overpayments deprives the provider of due process.
(The succeeding presentation of our decision and supporting facts is applicable also to the use of sampling to project overpayments to suppliers (including physicians) whose claims are processed by Medicare carriers when 100 percent readjudication would be excessively costly or impractical.)
The Supreme Court has long recognized that the Federal Government possesses an inherent right to recover monies illegally or erroneously paid out. . . . The Government’s common law right of recoupment, and its corollary power of recovery by offset, are based on strong considerations of public policy. . . . The common law right to recover Federal funds has been specifically recognized as being fully applicable to the Medicare program. . . . Congress has affirmed the Government’s right to recover Medicare Trust Funds by reasonable means from those who have no right to retain them. . . .
[Next, the ruling makes the “administrative burden” argument.]
Since HCFA’s contractors process vast numbers of Medicare claims . . . A case-by-case review could require a significant diversion of staff from the ongoing claims process , and the cost of determining the amount of an overpayment would be prohibitively high unless a sampling method were used. . . .
We also do not believe that the statutory provisions limiting provider or beneficiary liability preclude the use of sampling.. . .
The use of sampling to determine overpayments for medically unnecessary services or custodial care does not deprive a provider of its right to bill those beneficiaries who knew or should have known that they were receiving these services. . . .
[There are also “public policy” used to justify sampling.]
As between the provider and the Government, strong considerations of public policy favor recovery.. . .
[Next, the famous shifting of the burden of proof is explained.]
Sampling does not deprive a provider of its rights to challenge the sample, nor of its rights to procedural due process. Sampling only creates a presumption of validity as to the amount of an overpayment which may be used as the basis for recoupment. The burden then shifts to the provider to take the next step. The provider could attack the statistical validity of the sample, or it could challenge the correctness of the determination in specific cases identified by the sample (including waiver of liability where medical necessity or custodial care is at issue). . . . If certain individual cases within the sample are determined to be decided erroneously, the amount of overpayment projected to the universe of claims can be modified. If the statistical basis upon which the projection was based is successfully challenged, the overpayment determination can be corrected.
The provisions of the statutes and regulations provide a constitutionally sufficient means by which the provider may challenge an overpayment determination . In cases of denials made through sampling which are based on medical necessity or custodial care, section 1879 of the Act, 42 U.S.C. 1395pp, permits the provider to assert the same appeal rights that an individual has under the statute when the individual does not exercise his rights to appeal. Under Part A, these rights include an opportunity for reconsideration (42 CFR 405.710- 405.716), an oral evidentiary hearing by an administrative law judge (42 CFR 405.720-405.722), Appeals Council review (42 CFR 405.701(c) and 405.724), and finally judicial review if the amount in controversy is $1,000 or more (42 CFR 405.730; 42 U.S.C. 139 5ff (b)(2)). In cases that do not involve medical necessity or custodial care, 42 CFR 405.370, et seq. sets out the applicable procedures through which current payments may be suspended (offset) to recover an overpayment under the Medicare program. . . .
In summary, the use of sampling is a reasonable and cost effective method of projecting overpayments under Medicare . It is not unfair to a provider or supplier to hold it accountable for the receipt of Medicare funds to which it is not entitled under the statute. . . .
Ruling: Accordingly, it is held that the use of statistical sampling to project an overpayment is consistent with the Government’s common law right to recover overpayments, the Medicare statute, and the Department’s regulations, and does not deny a provider or supplier due process. Neither the statute nor regulations require that a case-by-case review be conducted in order to determine that a provider or supplier has been overpaid and to determine the amount of overpayment.
Effective date: This Ruling is effective February 20, 1986.
Litigation Support for Statistical Analysis