<?php
/**
* Site Config
*
* Each instance of this class should hold extraction patterns and other directives
* for a website. See ContentExtractor class to see how it's used.
*
* @version 0.8
* @date 2013-04-16
* @author Keyvan Minoukadeh
* @copyright 2013 Keyvan Minoukadeh
* @license http://www.gnu.org/licenses/agpl-3.0.html AGPL v3
*/
class SiteConfig
{
// Use first matching element as title (0 or more xpath expressions)
public $title = array();
// Use first matching element as body (0 or more xpath expressions)
public $body = array();
// Use first matching element as author (0 or more xpath expressions)
public $author = array();
// Use first matching element as date (0 or more xpath expressions)
public $date = array();
// Strip elements matching these xpath expressions (0 or more)
public $strip = array();
// Strip elements which contain these strings (0 or more) in the id or class attribute
public $strip_id_or_class = array();
// Strip images which contain these strings (0 or more) in the src attribute
public $strip_image_src = array();
// Additional HTTP headers to send
// NOT YET USED
public $http_header = array();
// Process HTML with tidy before creating DOM (bool or null if undeclared)
public $tidy = null;
protected $default_tidy = true; // used if undeclared
// Autodetect title/body if xpath expressions fail to produce results.
// Note that this applies to title and body separately, ie.
// * if we get a body match but no title match, this option will determine whether we autodetect title
// * if neither match, this determines whether we autodetect title and body.
// Also note that this only applies when there is at least one xpath expression in title or body, ie.
// * if title and body are both empty (no xpath expressions), this option has no effect (both title and body will be auto-detected)
// * if there's an xpath expression for title and none for body, body will be auto-detected and this option will determine whether we auto-detect title if the xpath expression for it fails to produce results.
// Usage scenario: you want to extract something specific from a set of URLs, e.g. a table, and if the table is not found, you want to ignore the entry completely. Auto-detection is unlikely to succeed here, so you construct your patterns and set this option to false. Another scenario may be a site where auto-detection has proven to fail (or worse, picked up the wrong content).
// bool or null if undeclared
public $autodetect_on_failure = null;
protected $default_autodetect_on_failure = true; // used if undeclared
// Clean up content block - attempt to remove elements that appear to be superfluous
// bool or null if undeclared
public $prune = null;
protected $default_prune = true; // used if undeclared
// Test URL - if present, can be used to test the config above
public $test_url = array();
// Single-page link - should identify a link element or URL pointing to the page holding the entire article
// This is useful for sites which split their articles across multiple pages. Links to such pages tend to
// display the first page with links to the other pages at the bottom. Often there is also a link to a page
// which displays the entire article on one page (e.g. 'print view').
// This should be an XPath expression identifying the link to that page. If present and we find a match,
// we will retrieve that page and the rest of the options in this config will be applied to the new page.
public $single_page_link = array();
public $next_page_link = array();
// Single-page link in feed? - same as above, but patterns applied to item description HTML taken from feed
public $single_page_link_in_feed = array();
// Which parser to use for turning raw HTML into a DOMDocument (either 'libxml' or 'html5lib')
// string or null if undeclared
public $parser = null;
protected $default_parser = 'libxml'; // used if undeclared
// Strings to search for in HTML before processing begins (used with $replace_string)
public $find_string = array();
// Strings to replace those found in $find_string before HTML processing begins
public $replace_string = array();
// the options below cannot be set in the config files which this class represents
//public $cache_in_apc = false; // used to decide if we should cache in apc or not
public $cache_key = null;
public static $debug = false;
protected static $apc = false;
protected static $config_path;
protected static $config_path_fallback;
protected static $config_cache = array();
const HOSTNAME_REGEX = '/^(([a-zA-Z0-9-]*[a-zA-Z0-9])\.)*([A-Za-z0-9-]*[A-Za-z0-9])$/';
protected static function debug($msg) {
if (self::$debug) {
//$mem = round(memory_get_usage()/1024, 2);
//$memPeak = round(memory_get_peak_usage()/1024, 2);
echo '* ',$msg;
//echo ' - mem used: ',$mem," (peak: $memPeak)\n";
echo "\n";
ob_flush();
flush();
}
}
// enable APC caching of certain site config files?
// If enabled the following site config files will be
// cached in APC cache (when requested for first time):
// * anything in site_config/custom/ and its corresponding file in site_config/standard/
// * the site config files associated with HTML fingerprints
// * the global site config file
// returns true if enabled, false otherwise
public static function use_apc($apc=true) {
if (!function_exists('apc_add')) {
if ($apc) self::debug('APC will not be used (function apc_add does not exist)');
return false;
}
self::$apc = $apc;
return $apc;
}
// return bool or null
public function tidy($use_default=true) {
if ($use_default) return (isset($this->tidy)) ? $this->tidy : $this->default_tidy;
return $this->tidy;
}
// return bool or null
public function prune($use_default=true) {
if ($use_default) return (isset($this->prune)) ? $this->prune : $this->default_prune;
return $this->prune;
}
// return string or null
public function parser($use_default=true) {
if ($use_default) return (isset($this->parser)) ? $this->parser : $this->default_parser;
return $this->parser;
}
// return bool or null
public function autodetect_on_failure($use_default=true) {
if ($use_default) return (isset($this->autodetect_on_failure)) ? $this->autodetect_on_failure : $this->default_autodetect_on_failure;
return $this->autodetect_on_failure;
}
public static function set_config_path($path, $fallback=null) {
self::$config_path = $path;
self::$config_path_fallback = $fallback;
}
public static function add_to_cache($key, SiteConfig $config, $use_apc=true) {
$key = strtolower($key);
if (substr($key, 0, 4) == 'www.') $key = substr($key, 4);
if ($config->cache_key) $key = $config->cache_key;
self::$config_cache[$key] = $config;
if (self::$apc && $use_apc) {
self::debug("Adding site config to APC cache with key sc.$key");
apc_add("sc.$key", $config);
}
self::debug("Cached site config with key $key");
}
public static function is_cached($key) {
$key = strtolower($key);
if (substr($key, 0, 4) == 'www.') $key = substr($key, 4);
if (array_key_exists($key, self::$config_cache)) {
return true;
} elseif (self::$apc && (bool)apc_fetch("sc.$key")) {
return true;
}
return false;
}
public function append(SiteConfig $newconfig) {
// check for commands where we accept multiple statements (no test_url)
foreach (array('title', 'body', 'author', 'date', 'strip', 'strip_id_or_class', 'strip_image_src', 'single_page_link', 'single_page_link_in_feed', 'next_page_link', 'http_header') as $var) {
// append array elements for this config variable from $newconfig to this config
//$this->$var = $this->$var + $newconfig->$var;
$this->$var = array_unique(array_merge($this->$var, $newconfig->$var));
}
// check for single statement commands
// we do not overwrite existing non null values
foreach (array('tidy', 'prune', 'parser', 'autodetect_on_failure') as $var) {
if ($this->$var === null) $this->$var = $newconfig->$var;
}
// treat find_string and replace_string separately (don't apply array_unique) (thanks fabrizio!)
foreach (array('find_string', 'replace_string') as $var) {
// append array elements for this config variable from $newconfig to this config
//$this->$var = $this->$var + $newconfig->$var;
$this->$var = array_merge($this->$var, $newconfig->$var);
}
}
// returns SiteConfig instance if an appropriate one is found, false otherwise
// if $exact_host_match is true, we will not look for wildcard config matches
// by default if host is 'test.example.org' we will look for and load '.example.org.txt' if it exists
public static function build($host, $exact_host_match=false) {
$host = strtolower($host);
if (substr($host, 0, 4) == 'www.') $host = substr($host, 4);
if (!$host || (strlen($host) > 200) || !preg_match(self::HOSTNAME_REGEX, ltrim($host, '.'))) return false;
// check for site configuration
$try = array($host);
// should we look for wildcard matches
if (!$exact_host_match) {
$split = explode('.', $host);
if (count($split) > 1) {
array_shift($split);
$try[] = '.'.implode('.', $split);
}
}
// look for site config file in primary folder
self::debug(". looking for site config for $host in primary folder");
foreach ($try as $h) {
if (array_key_exists($h, self::$config_cache)) {
self::debug("... site config for $h already loaded in this request");
return self::$config_cache[$h];
} elseif (self::$apc && ($sconfig = apc_fetch("sc.$h"))) {
self::debug("... site config for $h in APC cache");
return $sconfig;
} elseif (file_exists(self::$config_path."/$h.txt")) {
self::debug("... found site config ($h.txt)");
$file_primary = self::$config_path."/$h.txt";
$matched_name = $h;
break;
}
}
// if we found site config, process it
if (isset($file_primary)) {
$config_lines = file($file_primary, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
if (!$config_lines || !is_array($config_lines)) return false;
$config = self::build_from_array($config_lines);
// if APC caching is available and enabled, mark this for cache
//$config->cache_in_apc = true;
$config->cache_key = $matched_name;
// if autodetec on failure is off (on by default) we do not need to look
// in secondary folder
if (!$config->autodetect_on_failure()) {
self::debug('... autodetect on failure is disabled (no other site config files will be loaded)');
return $config;
}
}
// look for site config file in secondary folder
if (isset(self::$config_path_fallback)) {
self::debug(". looking for site config for $host in secondary folder");
foreach ($try as $h) {
if (file_exists(self::$config_path_fallback."/$h.txt")) {
self::debug("... found site config in secondary folder ($h.txt)");
$file_secondary = self::$config_path_fallback."/$h.txt";
$matched_name = $h;
break;
}
}
if (!isset($file_secondary)) {
self::debug("... no site config match in secondary folder");
}
}
// return false if no config file found
if (!isset($file_primary) && !isset($file_secondary)) {
self::debug("... no site config match for $host");
return false;
}
// return primary config if secondary not found
if (!isset($file_secondary) && isset($config)) {
return $config;
}
// process secondary config file
$config_lines = file($file_secondary, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
if (!$config_lines || !is_array($config_lines)) {
// failed to process secondary
if (isset($config)) {
// return primary config
return $config;
} else {
return false;
}
}
// merge with primary and return
if (isset($config)) {
self::debug('. merging config files');
$config->append(self::build_from_array($config_lines));
return $config;
} else {
// return just secondary
$config = self::build_from_array($config_lines);
// if APC caching is available and enabled, mark this for cache
//$config->cache_in_apc = true;
$config->cache_key = $matched_name;
return $config;
}
}
public static function build_from_array(array $lines) {
$config = new SiteConfig();
foreach ($lines as $line) {
$line = trim($line);
// skip comments, empty lines
if ($line == '' || $line[0] == '#') continue;
// get command
$command = explode(':', $line, 2);
// if there's no colon ':', skip this line
if (count($command) != 2) continue;
$val = trim($command[1]);
$command = trim($command[0]);
if ($command == '' || $val == '') continue;
// check for commands where we accept multiple statements
if (in_array($command, array('title', 'body', 'author', 'date', 'strip', 'strip_id_or_class', 'strip_image_src', 'single_page_link', 'single_page_link_in_feed', 'next_page_link', 'http_header', 'test_url', 'find_string', 'replace_string'))) {
array_push($config->$command, $val);
// check for single statement commands that evaluate to true or false
} elseif (in_array($command, array('tidy', 'prune', 'autodetect_on_failure'))) {
$config->$command = ($val == 'yes');
// check for single statement commands stored as strings
} elseif (in_array($command, array('parser'))) {
$config->$command = $val;
// check for replace_string(find): replace
} elseif ((substr($command, -1) == ')') && preg_match('!^([a-z0-9_]+)\((.*?)\)$!i', $command, $match)) {
if (in_array($match[1], array('replace_string'))) {
$command = $match[1];
array_push($config->find_string, $match[2]);
array_push($config->$command, $val);
}
}
}
return $config;
}
}
