从请求的页面提取关键词

它可以从一个给定的URL检索网页提取出一些关键词

例如从代码珠玑的首页可以提取出类似下面图片中的关键词

if(!empty($_REQUEST["url"])){

        include 'class.keywords.php';

        $keywords = new keywordsugest();
        $keywords->_lang = 'es';
        $keywords->_encoding = 'iso-8859-1';
        $keywords->_catego = 'telecom';
        $keywords->_keyCount = 100; // is like the porcent %
        $keywords->file($_REQUEST['url']);

        #$keywords->readMetaKeyWords();

        #$keywords->readHtmlKeyWords();

        $keywords->readAll();

        echo 'Keywords found :';

        $i = 1;

        foreach($keywords->get() as $word) echo $i++.". $word";
}
//url例如：http://www.codepearl.com
echo "

";


?>

  class keywordsugest{

        var $_html        =    FALSE;
        var $_keyCount    =    5;
        var $_keyWords    =    array();
        var $_encoding    =    'UTF-8';
        var $_lang        =    'es';
        var $_catego      =    'telecom';
        var $_url         =    '';

        /**
        * # read meta keywords
        *
        */
        public function readMetaKeyWords()    {

            if (! $this->_html) return;

            preg_match('/"]*)\"?[\s]*[\/]?[\s]*>/is', $this->_html, $match);

            //$tags = get_meta_tags($this->_url);
            //echo $tags['keywords'];


            if (count($match))    {
                $this->_keyWords = array_unique(explode(',', preg_replace('/\s/i', ' ', mb_strtolower($match[1], $this->_encoding))));
            }
        }

       /**
       * strip tags
       *
       * @param mixed $string
       */
       private function rip_tags($string) {

    // ----- remove HTML TAGs -----
    $string = preg_replace ('/]*>/', ' ', $string);

    /* // ----- remove control characters -----
    $string = str_replace("\r", '', $string);    // --- replace with empty space
    $string = str_replace("\n", ' ', $string);   // --- replace with space
    $string = str_replace("\t", ' ', $string);   // --- replace with space
   */
    // ----- remove multiple spaces -----
    $string = trim(preg_replace('/ {2,}/', ' ', $string));

    return $string;

}

        /**
        * # read keywords from page body or string
        *
        */
        public function readHtmlKeyWords()    {

            if (! $this->_html) return;

            if(!empty($this->_keyWords)){
                $implo = implode(' ',$this->_keyWords);
                $this->_html = $this->_html." ".$implo;
                $this->_keyWords = array();
            }

            $this->_html = str_replace(' ',' ', $this->_html);

            # remove unneeded parts
            $toRemove = array('head', 'script', 'style', 'object', 'embed', 'noembed', 'applet', 'noframes', 'noscript');

            foreach ($toRemove as $remove)    $this->_html = preg_replace("/\.*?\/is", ' ', $this->_html);

            # remove comments
            $this->_html = preg_replace("/\/is", ' ', $this->_html);

            # delete html tags
            $this->_html = mb_strtolower($this->rip_tags($this->_html), $this->_encoding);

            $this->_html = htmlspecialchars_decode($this->_html);

            # decode encoded hmtl entities
            $this->_html = html_entity_decode ($this->_html, ENT_COMPAT, $this->_encoding);

            # break into words
            $words = preg_split("/[\s]+|[\t]+|[\.]+|[\,]+|[\:]+|[\;]+|[\!]+|[\?]+|[\|]+/s", $this->_html, -1, PREG_SPLIT_NO_EMPTY);

            if (count($words))    {

                $frequency = array_count_values($words);
                unset($frequency['']);

                if (count($frequency))    {

                    # delete stop words and interpunctions
                    include('stopwords_'.$this->_lang.'.php');
                    include('glodic_'.$this->_catego.'_'.$this->_lang.'.php');

                    $punct = '~!@#$%^&*()_+|}{[];:\'\",<.>/?`-=\\';

                    foreach (array_keys($frequency) as $word)    {
                        if (    (in_array($word, $stopWords)) or (strspn($word, $punct) == strlen($word))  ){ unset($frequency[$word]); }
                    }

                    $max = max($frequency);
                    $count = count($frequency);
                    $tot = round(($max * 100) / $count);
                    $tot2 = round(($this->_keyCount * 100) / $count);
                    if($tot > $count){$tot = $tot / 2;}
                    if($tot2 > $count){$tot = $tot / 2;}
                    $showmax = round(($tot + $tot2) / 2);

                    foreach (array_keys($frequency) as $word)    {
                        if (    in_array($word, $glodic)   ){$frequency[$word] = $frequency[$word] + $showmax; }
                    }

                    # sort by frequency
                    arsort($frequency, SORT_NUMERIC);

                    # add them to keyword array
                    $i = 0;

                    foreach ($frequency as $word=>$count)    {

                       if ( (! in_array($word, $this->_keyWords)) &&
                            (! is_numeric($word)) &&
                            (! empty($word)) ) {
                            $this->_keyWords[] = (string)$word;

                            $i++;

                            if ($i == $showmax) break;
                        }
                   }
                }
            }
        }


        /**
        * change the encoding from default utf-8
        *
        * @param mixed $enc
        */
        private function encoding($enc = FALSE)    {

            if ($enc) $this->_encoding = $enc;
        }


        /**
        * # reads from file or url
        *
        * @param mixed $fileUrl
        */
        public function file($fileUrl = FALSE)    {

            if ($fileUrl){ $this->_html = @file_get_contents($fileUrl);
            $this->_url = $fileUrl;
            }
        }



        /**
        *  # define html as string
        *
        * @param mixed $page
        */
        public function html($page = FALSE)    {

            if ($page) $this->_html = $page;
        }


        /**
        * # reads both meta keywords and from body
        *
        */
        public function readAll()    {

            if ($this->_html !== FALSE)    {

                $this->readMetaKeyWords();

                $this->readHtmlKeyWords();
            }

            $this->_keyWords = array_unique($this->_keyWords);
        }


        /**
        *  # returns keywords as array
        *
        */
        public function get()    {

            return $this->_keyWords;
        }
  }

?>