/**
* Sets the headers to prevent caching for the different browsers.
*
* Different browsers support different nocache headers, so several headers must
* be sent so that all of them get the point that no caching should occur.
*
* @since 2.0.0
* @uses nxt_get_nocache_headers()
*/
function nocache_headers()
{
$headers = nxt_get_nocache_headers();
foreach ($headers as $name => $field_value) {
@header("{$name}: {$field_value}");
}
}
/**
* Send additional HTTP headers for caching, content type, etc.
*
* Sets the X-Pingback header, 404 status (if 404), Content-type. If showing
* a feed, it will also send last-modified, etag, and 304 status if needed.
*
* @since 2.0.0
*/
function send_headers()
{
$headers = array('X-Pingback' => get_bloginfo('pingback_url'));
$status = null;
$exit_required = false;
if (is_user_logged_in()) {
$headers = array_merge($headers, nxt_get_nocache_headers());
}
if (!empty($this->query_vars['error']) && '404' == $this->query_vars['error']) {
$status = 404;
if (!is_user_logged_in()) {
$headers = array_merge($headers, nxt_get_nocache_headers());
}
$headers['Content-Type'] = get_option('html_type') . '; charset=' . get_option('blog_charset');
} else {
if (empty($this->query_vars['feed'])) {
$headers['Content-Type'] = get_option('html_type') . '; charset=' . get_option('blog_charset');
} else {
// We're showing a feed, so nxt is indeed the only thing that last changed
if (!empty($this->query_vars['withcomments']) || empty($this->query_vars['withoutcomments']) && (!empty($this->query_vars['p']) || !empty($this->query_vars['name']) || !empty($this->query_vars['page_id']) || !empty($this->query_vars['pagename']) || !empty($this->query_vars['attachment']) || !empty($this->query_vars['attachment_id']))) {
$nxt_last_modified = mysql2date('D, d M Y H:i:s', get_lastcommentmodified('GMT'), 0) . ' GMT';
} else {
$nxt_last_modified = mysql2date('D, d M Y H:i:s', get_lastpostmodified('GMT'), 0) . ' GMT';
}
$nxt_etag = '"' . md5($nxt_last_modified) . '"';
$headers['Last-Modified'] = $nxt_last_modified;
$headers['ETag'] = $nxt_etag;
// Support for Conditional GET
if (isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
$client_etag = stripslashes(stripslashes($_SERVER['HTTP_IF_NONE_MATCH']));
} else {
$client_etag = false;
}
$client_last_modified = empty($_SERVER['HTTP_IF_MODIFIED_SINCE']) ? '' : trim($_SERVER['HTTP_IF_MODIFIED_SINCE']);
// If string is empty, return 0. If not, attempt to parse into a timestamp
$client_modified_timestamp = $client_last_modified ? strtotime($client_last_modified) : 0;
// Make a timestamp for our most recent modification...
$nxt_modified_timestamp = strtotime($nxt_last_modified);
if ($client_last_modified && $client_etag ? $client_modified_timestamp >= $nxt_modified_timestamp && $client_etag == $nxt_etag : $client_modified_timestamp >= $nxt_modified_timestamp || $client_etag == $nxt_etag) {
$status = 304;
$exit_required = true;
}
}
}
$headers = apply_filters('nxt_headers', $headers, $this);
if (!empty($status)) {
status_header($status);
}
foreach ((array) $headers as $name => $field_value) {
@header("{$name}: {$field_value}");
}
if ($exit_required) {
exit;
}
do_action_ref_array('send_headers', array(&$this));
}