/** * Finds a pingback server URI based on the given URL. * * Checks the HTML for the rel="pingback" link and x-pingback headers. It does * a check for the x-pingback headers first and returns that, if available. The * check for the rel="pingback" has more overhead than just the header. * * @since 0.0.1 * * @param string $url URL to ping. * @param int $deprecated Not Used. * @return false|string False on failure, string containing URI on success. */ function discover_pingback_server_uri($url, $deprecated = '') { if (!empty($deprecated)) { _deprecated_argument(__FUNCTION__, '2.7'); } $pingback_str_dquote = 'rel="pingback"'; $pingback_str_squote = 'rel=\'pingback\''; /** @todo Should use Filter Extension or custom preg_match instead. */ $parsed_url = parse_url($url); if (!isset($parsed_url['host'])) { // Not an URL. This should never happen. return false; } //Do not search for a pingback server on our own uploads $uploads_dir = hq_upload_dir(); if (0 === strpos($url, $uploads_dir['baseurl'])) { return false; } $response = hq_safe_remote_head($url, array('timeout' => 2, 'httpversion' => '1.0')); if (is_hq_error($response)) { return false; } if (hq_remote_retrieve_header($response, 'x-pingback')) { return hq_remote_retrieve_header($response, 'x-pingback'); } // Not an (x)html, sgml, or xml page, no use going further. if (preg_match('#(image|audio|video|model)/#is', hq_remote_retrieve_header($response, 'content-type'))) { return false; } // Now do a GET since we're going to look in the html headers (and we're sure it's not a binary file) $response = hq_safe_remote_get($url, array('timeout' => 2, 'httpversion' => '1.0')); if (is_hq_error($response)) { return false; } $contents = hq_remote_retrieve_body($response); $pingback_link_offset_dquote = strpos($contents, $pingback_str_dquote); $pingback_link_offset_squote = strpos($contents, $pingback_str_squote); if ($pingback_link_offset_dquote || $pingback_link_offset_squote) { $quote = $pingback_link_offset_dquote ? '"' : '\''; $pingback_link_offset = $quote == '"' ? $pingback_link_offset_dquote : $pingback_link_offset_squote; $pingback_href_pos = @strpos($contents, 'href=', $pingback_link_offset); $pingback_href_start = $pingback_href_pos + 6; $pingback_href_end = @strpos($contents, $quote, $pingback_href_start); $pingback_server_url_len = $pingback_href_end - $pingback_href_start; $pingback_server_url = substr($contents, $pingback_href_start, $pingback_server_url_len); // We may find rel="pingback" but an incomplete pingback URL if ($pingback_server_url_len > 0) { // We got it! return $pingback_server_url; } } return false; }
/** * Retrieve HTTP Headers from URL. * * @since 0.0.1 * * @param string $url URL to retrieve HTTP headers from. * @param bool $deprecated Not Used. * @return bool|string False on failure, headers on success. */ function hq_get_http_headers($url, $deprecated = false) { if (!empty($deprecated)) { _deprecated_argument(__FUNCTION__, '2.7'); } $response = hq_safe_remote_head($url); if (is_hq_error($response)) { return false; } return hq_remote_retrieve_headers($response); }