Modify code to change timestamp timezone in sitemap - php

Question

Below is the code from a plugin I use for sitemaps.
I would like to know if there's a way to "enforce" a different timezone on all date variable and functions in it.
If not, how do I modify the code to change the timestamp to reflect a different timezone? Say for example, to America/New_York timezone.
Please look for date to quickly get to the appropriate code blocks. Code on Pastebin.
<?php
/**
* #package XML_Sitemaps
*/
class WPSEO_Sitemaps {
.....
/**
* Build the root sitemap -- example.com/sitemap_index.xml -- which lists sub-sitemaps
* for other content types.
*
* #todo lastmod for sitemaps?
*/
function build_root_map() {
global $wpdb;
$options = get_wpseo_options();
$this->sitemap = '<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' . "\n";
$base = $GLOBALS['wp_rewrite']->using_index_permalinks() ? 'index.php/' : '';
// reference post type specific sitemaps
foreach ( get_post_types( array( 'public' => true ) ) as $post_type ) {
if ( $post_type == 'attachment' )
continue;
if ( isset( $options['post_types-' . $post_type . '-not_in_sitemap'] ) && $options['post_types-' . $post_type . '-not_in_sitemap'] )
continue;
$count = $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(ID) FROM $wpdb->posts WHERE post_type = %s AND post_status = 'publish' LIMIT 1", $post_type ) );
// don't include post types with no posts
if ( !$count )
continue;
$n = ( $count > 1000 ) ? (int) ceil( $count / 1000 ) : 1;
for ( $i = 0; $i < $n; $i++ ) {
$count = ( $n > 1 ) ? $i + 1 : '';
if ( empty( $count ) || $count == $n ) {
$date = $this->get_last_modified( $post_type );
} else {
$date = $wpdb->get_var( $wpdb->prepare( "SELECT post_modified_gmt FROM $wpdb->posts WHERE post_status = 'publish' AND post_type = %s ORDER BY post_modified_gmt ASC LIMIT 1 OFFSET %d", $post_type, $i * 1000 + 999 ) );
$date = date( 'c', strtotime( $date ) );
}
$this->sitemap .= '<sitemap>' . "\n";
$this->sitemap .= '<loc>' . home_url( $base . $post_type . '-sitemap' . $count . '.xml' ) . '</loc>' . "\n";
$this->sitemap .= '<lastmod>' . htmlspecialchars( $date ) . '</lastmod>' . "\n";
$this->sitemap .= '</sitemap>' . "\n";
}
}
// reference taxonomy specific sitemaps
foreach ( get_taxonomies( array( 'public' => true ) ) as $tax ) {
if ( in_array( $tax, array( 'link_category', 'nav_menu', 'post_format' ) ) )
continue;
if ( isset( $options['taxonomies-' . $tax . '-not_in_sitemap'] ) && $options['taxonomies-' . $tax . '-not_in_sitemap'] )
continue;
// don't include taxonomies with no terms
if ( !$wpdb->get_var( $wpdb->prepare( "SELECT term_id FROM $wpdb->term_taxonomy WHERE taxonomy = %s AND count != 0 LIMIT 1", $tax ) ) )
continue;
// Retrieve the post_types that are registered to this taxonomy and then retrieve last modified date for all of those combined.
$taxobj = get_taxonomy( $tax );
$date = $this->get_last_modified( $taxobj->object_type );
$this->sitemap .= '<sitemap>' . "\n";
$this->sitemap .= '<loc>' . home_url( $base . $tax . '-sitemap.xml' ) . '</loc>' . "\n";
$this->sitemap .= '<lastmod>' . htmlspecialchars( $date ) . '</lastmod>' . "\n";
$this->sitemap .= '</sitemap>' . "\n";
}
// allow other plugins to add their sitemaps to the index
$this->sitemap .= apply_filters( 'wpseo_sitemap_index', '' );
$this->sitemap .= '</sitemapindex>';
}
/**
* Build a sub-sitemap for a specific post type -- example.com/post_type-sitemap.xml
*
* #param string $post_type Registered post type's slug
*/
function build_post_type_map( $post_type ) {
$options = get_wpseo_options();
............
// We grab post_date, post_name, post_author and post_status too so we can throw these objects into get_permalink, which saves a get_post call for each permalink.
while ( $total > $offset ) {
$join_filter = apply_filters( 'wpseo_posts_join', '', $post_type );
$where_filter = apply_filters( 'wpseo_posts_where', '', $post_type );
// Optimized query per this thread: http://wordpress.org/support/topic/plugin-wordpress-seo-by-yoast-performance-suggestion
// Also see http://explainextended.com/2009/10/23/mysql-order-by-limit-performance-late-row-lookups/
$posts = $wpdb->get_results( "SELECT l.ID, post_content, post_name, post_author, post_parent, post_modified_gmt, post_date, post_date_gmt
FROM (
SELECT ID FROM $wpdb->posts {$join_filter}
WHERE post_status = 'publish'
AND post_password = ''
AND post_type = '$post_type'
{$where_filter}
ORDER BY post_modified ASC
LIMIT $steps OFFSET $offset ) o
JOIN $wpdb->posts l
ON l.ID = o.ID
ORDER BY l.ID" );
/* $posts = $wpdb->get_results("SELECT ID, post_content, post_name, post_author, post_parent, post_modified_gmt, post_date, post_date_gmt
FROM $wpdb->posts {$join_filter}
WHERE post_status = 'publish'
AND post_password = ''
AND post_type = '$post_type'
{$where_filter}
ORDER BY post_modified ASC
LIMIT $steps OFFSET $offset"); */
$offset = $offset + $steps;
foreach ( $posts as $p ) {
$p->post_type = $post_type;
$p->post_status = 'publish';
$p->filter = 'sample';
if ( wpseo_get_value( 'meta-robots-noindex', $p->ID ) && wpseo_get_value( 'sitemap-include', $p->ID ) != 'always' )
continue;
if ( wpseo_get_value( 'sitemap-include', $p->ID ) == 'never' )
continue;
if ( wpseo_get_value( 'redirect', $p->ID ) && strlen( wpseo_get_value( 'redirect', $p->ID ) ) > 0 )
continue;
$url = array();
$url['mod'] = ( isset( $p->post_modified_gmt ) && $p->post_modified_gmt != '0000-00-00 00:00:00' ) ? $p->post_modified_gmt : $p->post_date_gmt;
$url['chf'] = 'weekly';
$url['loc'] = get_permalink( $p );
.............
}
/**
* Build a sub-sitemap for a specific taxonomy -- example.com/tax-sitemap.xml
*
* #param string $taxonomy Registered taxonomy's slug
*/
function build_tax_map( $taxonomy ) {
$options = get_wpseo_options();
..........
// Grab last modified date
$sql = "SELECT MAX(p.post_date) AS lastmod
FROM $wpdb->posts AS p
INNER JOIN $wpdb->term_relationships AS term_rel
ON term_rel.object_id = p.ID
INNER JOIN $wpdb->term_taxonomy AS term_tax
ON term_tax.term_taxonomy_id = term_rel.term_taxonomy_id
AND term_tax.taxonomy = '$c->taxonomy'
AND term_tax.term_id = $c->term_id
WHERE p.post_status = 'publish'
AND p.post_password = ''";
$url['mod'] = $wpdb->get_var( $sql );
$url['chf'] = 'weekly';
$output .= $this->sitemap_url( $url );
}
}
/**
* Build the <url> tag for a given URL.
*
* #param array $url Array of parts that make up this entry
* #return string
*/
function sitemap_url( $url ) {
if ( isset( $url['mod'] ) )
$date = mysql2date( "Y-m-d\TH:i:s+00:00", $url['mod'] );
else
$date = date( 'c' );
$output = "\t<url>\n";
$output .= "\t\t<loc>" . $url['loc'] . "</loc>\n";
$output .= "\t\t<lastmod>" . $date . "</lastmod>\n";
$output .= "\t\t<changefreq>" . $url['chf'] . "</changefreq>\n";
$output .= "\t\t<priority>" . str_replace( ',', '.', $url['pri'] ) . "</priority>\n";
if ( isset( $url['images'] ) && count( $url['images'] ) > 0 ) {
foreach ( $url['images'] as $img ) {
$output .= "\t\t<image:image>\n";
$output .= "\t\t\t<image:loc>" . esc_html( $img['src'] ) . "</image:loc>\n";
if ( isset( $img['title'] ) )
$output .= "\t\t\t<image:title>" . _wp_specialchars( html_entity_decode( $img['title'], ENT_QUOTES, get_bloginfo('charset') ) ) . "</image:title>\n";
if ( isset( $img['alt'] ) )
$output .= "\t\t\t<image:caption>" . _wp_specialchars( html_entity_decode( $img['alt'], ENT_QUOTES, get_bloginfo('charset') ) ) . "</image:caption>\n";
$output .= "\t\t</image:image>\n";
}
}
$output .= "\t</url>\n";
return $output;
}
/**
* Get the modification date for the last modified post in the post type:
*
* #param array $post_types Post types to get the last modification date for
* #return string
*/
function get_last_modified( $post_types ) {
global $wpdb;
if ( !is_array( $post_types ) )
$post_types = array( $post_types );
$result = 0;
foreach ( $post_types as $post_type ) {
$key = 'lastpostmodified:gmt:' . $post_type;
$date = wp_cache_get( $key, 'timeinfo' );
if ( !$date ) {
$date = $wpdb->get_var( $wpdb->prepare( "SELECT post_modified_gmt FROM $wpdb->posts WHERE post_status = 'publish' AND post_type = %s ORDER BY post_modified_gmt DESC LIMIT 1", $post_type ) );
if ( $date )
wp_cache_set( $key, $date, 'timeinfo' );
}
if ( strtotime( $date ) > $result )
$result = strtotime( $date );
}
// Transform to W3C Date format.
$result = date( 'c', $result );
return $result;
}
}
global $wpseo_sitemaps;
$wpseo_sitemaps = new WPSEO_Sitemaps();

Answer 1

I believe you're looking for the date_default_timezone_set() function, which will force all date functions, including date(), to use the specified time zone.
date_default_timezone_set( 'America/New_York');
For your specific case to only have changes apply to the plugin, you should save the current timezone with date_default_timezone_get(), then set your own timezone, and revert it when you're done. So, you could do something like this:
class WPSEO_Sitemaps {
private $old_timezone = '';
private $new_timezone = 'America/New_York';
function setTimezone() {
$this->old_timezone = date_default_timezone_get();
date_default_timezone_set( $this->new_timezone);
}
function revertTimezone() {
date_default_timezone_set( $this->old_timezone);
}
function foo() {
$this->setTimezone();
date();
$tihs->revertTimezone();
}
}