<?php
/**
* SeekQuarry/Yioop --
* Open Source Pure PHP Search Engine, Crawler, and Indexer
*
* Copyright (C) 2009 - 2023 Chris Pollett chris@pollett.org
*
* LICENSE:
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* END LICENSE
*
* @author Chris Pollett chris@pollett.org
* @license https://www.gnu.org/licenses/ GPL3
* @link https://www.seekquarry.com/
* @copyright 2009 - 2023
* @filesource
*/
namespace seekquarry\yioop\library\archive_bundle_iterators;
use seekquarry\yioop\library\CrawlConstants;
use seekquarry\yioop\library\FetchUrl;
/**
* Used to iterate through the records of a collection of one or more open
* directory RDF files stored in a WebArchiveBundle folder. Open Directory
* file can be found at http://rdf.dmoz.org/ . Iteration would be
* for the purpose making an index of these records
*
* @author Chris Pollett
* @see WebArchiveBundle
*/
class OdpRdfArchiveBundleIterator extends TextArchiveBundleIterator
{
/**
* Associative array containing global properties like base url of the
* current open odp rdf file
* @var array
*/
public $header;
/**
* How many bytes to read into buffer from gzip stream in one go
* @var int
*/
const BLOCK_SIZE = 1024;
/**
* Creates an open directory rdf archive iterator with the given parameters.
*
* @param string $iterate_timestamp timestamp of the arc archive bundle to
* iterate over the pages of
* @param string $iterate_dir folder of files to iterate over
* @param string $result_timestamp timestamp of the arc archive bundle
* results are being stored in
* @param string $result_dir where to write last position checkpoints to
*/
public function __construct($iterate_timestamp, $iterate_dir,
$result_timestamp, $result_dir)
{
$ini = [ 'compression' => 'gzip',
'file_extension' => 'gz',
'encoding' => 'UTF-8',
'start_delimiter' => '@Topic|ExternalPage@',
'end_delimiter' => '@/Topic|/ExternalPage@'];
parent::__construct($iterate_timestamp, $iterate_dir,
$result_timestamp, $result_dir, $ini);
$this->header['base_address'] = "http://www.dmoz.org/";
$url_parts = @parse_url($this->header['base_address']);
$this->header['ip_address'] = gethostbyname($url_parts['host']);
}
/**
* Estimates the important of the site according to the weighting of
* the particular archive iterator
* @param $site an associative array containing info about a web page
* @return int a 4-bit number based on the topic path of the odp entry
* (@see processTopic @see processExternalPage)
*/
public function weight(&$site)
{
return min($site[self::WEIGHT], 15);
}
/**
* Gets the text content of the first dom node satisfying the
* xpath expression $path in the dom document $dom
*
* @param object $dom DOMDocument to get the text from
* @param $path xpath expression to find node with text
*
* @return string text content of the given node if it exists
*/
public function getTextContent($dom, $path)
{
$xpath = new \DOMXPath($dom);
$objects = $xpath->evaluate($path);
if ($objects && is_object($objects) && $objects->item(0) != null) {
return $objects->item(0)->textContent;
}
return "";
}
/**
* Gets the value of the attribute $attribute for each dom node
* satisfying the xpath expression $path in the dom document $dom
*
* @param object $dom DOMDocument to get the text from
* @param $path xpath expression to find node with text
* @param string $attribute name of the attribute to get the values for
*
* @return array of values of the given attribute
*/
public function getAttributeValueAll($dom, $path, $attribute)
{
$values = [];
$xpath = new \DOMXPath($dom);
$objects = $xpath->evaluate($path);
if ($objects && is_object($objects)) {
foreach ($objects as $object) {
$value = $object->getAttribute($attribute);
if ($value) {
$values[] = $value;
}
}
}
return $values;
}
/**
* Gets the value of the attribute $attribute of the first dom node
* satisfying the xpath expression $path in the dom document $dom
*
* @param object $dom DOMDocument to get the text from
* @param $path xpath expression to find node with text
* @param string $attribute name of the attribute to get the value for
*
* @return string value of the given attribute
*/
public function getAttributeValue($dom, $path, $attribute)
{
$xpath = new \DOMXPath($dom);
$objects = $xpath->evaluate($path);
if ($objects && is_object($objects) && $objects->item(0) != null) {
return $objects->item(0)->getAttribute($attribute);
}
return "";
}
/**
* Gets the next doc from the iterator
* @param bool $no_process do not do any processing on page data
* @return array associative array for doc or string if no_process true
*/
public function nextPage($no_process = false)
{
if (!$this->checkFileHandle()) return null;
$tag_data = $this->getNextTagsData(
["Topic","ExternalPage"]);
if (!$tag_data) {
return false;
}
list($page_info, $tag) = $tag_data;
if ($no_process) {
return $page_info;
}
$page_info = strtr($page_info, ["r:id" => "id",
"r:resource" => "resource", "d:Title" => "Title",
"d:Description" => "Description"] );
$dom = new \DOMDocument();
@$dom->loadXML($page_info);
$processMethod = "process".$tag;
$site[self::IP_ADDRESSES] = [$this->header['ip_address']];
$site[self::MODIFIED] = time();
$site[self::TIMESTAMP] = time();
$site[self::TYPE] = "text/html";
$site[self::HEADER] = "odp_rdf_bundle_iterator extractor";
$site[self::HTTP_CODE] = 200;
$site[self::ENCODING] = "UTF-8";
$site[self::SERVER] = "unknown";
$site[self::SERVER_VERSION] = "unknown";
$site[self::OPERATING_SYSTEM] = "unknown";
$this->$processMethod($dom, $site);
$site[self::HASH] = FetchUrl::computePageHash($site[self::PAGE],
"text");
return $site;
}
/**
* Computes an HTML page for a Topic tag parsed from the ODP RDF
* document
*
* @param object $dom document object for one Topic tag tag
* @param array &$site a reference to an array of header and page info
* for an html page
*/
public function processTopic($dom, &$site)
{
$topic_path = $this->getAttributeValue($dom, "/Topic", "id");
$site[self::URL] = $this->header['base_address'].$topic_path;
$site[self::WEIGHT] = max(15 - substr_count($topic_path, "/"), 1);
$title = str_replace("/", " ", $topic_path);
$links = $this->computeTopicLinks($topic_path);
$topic_link1 = $this->getAttributeValue($dom, "/Topic/link1",
"resource");
if ($topic_link1) {
$links[$topic_link1] = $topic_link1." - ".$title;
}
$topic_links = $this->getAttributeValueAll($dom, "/Topic/link",
"resource");
if ($topic_links != null) {
foreach ($topic_links as $topic_link) {
$links[$topic_link] = $topic_link." - ".$title;
}
}
$site[self::PAGE] = "<html>\n".
"<head><title>$title</title></head>\n"
."<body><h1>$title</h1>\n";
$site[self::PAGE] .= $this->linksToHtml($links);
$site[self::PAGE] .= "</body></html>";
}
/**
* Computes an HTML page for an ExternalPage tag parsed from the ODP RDF
* document
*
* @param object $dom document object for one Topic tag tag
* @param array &$site a reference to an array of header and page info
* for an html page
*/
public function processExternalPage($dom, &$site)
{
$site[self::URL] = $this->getAttributeValue($dom,
"/ExternalPage", "about");
$topic_path = $this->getTextContent($dom, "/ExternalPage/topic");
$site[self::WEIGHT] = max(14 - substr_count($topic_path, "/"), 1);
$site[self::DOC_DEPTH] = 1;
$links = $this->computeTopicLinks($topic_path);
$title = $this->getTextContent($dom, "/ExternalPage/Title");
$title = "$title - ".str_replace("/", " ", $topic_path);
$description = $this->getTextContent(
$dom, "/ExternalPage/Description");
$site[self::PAGE] = "<html>\n".
"<head><title>$title</title></head>\n"
."<body><h1>$title</h1>\n";
$site[self::PAGE] .= $this->linksToHtml($links);
$site[self::PAGE] .= "<div>$description</div></body></html>";
}
/**
* Computes links for prefix topics of an ODP topic path
*
* @param string $topic_path to compute links for
* @return array url => text pairs for each prefix of path
*/
public function computeTopicLinks($topic_path)
{
$links = [];
$topic_parts = explode("/", $topic_path);
$path = "";
foreach ($topic_parts as $part){
$path .= "/$part";
$links[$this->header['base_address'].$path] = $part;
}
return $links;
}
/**
* Makes an unordered HTML list out of an associative array of
* url => link_text pairs.
*
* @param array $links url=>link_text pairs
* @return string containing html for unorderlisted list of links
*/
public function linksToHtml($links)
{
$html = "";
if (count($links) > 0) {
$html .= "<ul>\n";
foreach ($links as $url => $text) {
$html .= '<li><a href="'.
$url.'">'.$text.'</a></li>';
}
$html .= "</ul>\n";
}
return $html;
}
}