我正在为我的网站编写搜索引擎,需要使用给定的关键字提取文本块,并为搜索结果列表提取几个字。 我结束了这样的事情:
/**
* This function return part of the original text with
* the searched term and few words around the searched term
* @param string $text Original text
* @param string $word Searched term
* @param int $maxChunks Number of chunks returned
* @param int $wordsAround Number of words before and after searched term
*/
public static function searchTerm($text, $word=null, $maxChunks=3, $wordsAround=3) {
$word = trim($word);
if(empty($word)) {
return NULL;
}
$words = explode(' ', $word); // extract single words from searched phrase
$text = strip_tags($text); // clean up the text
$whack = array(); // chunk buffer
$cycle = 0; // successful matches counter
foreach($words as $word) {
$match = array();
// there are named parameters 'pre', 'term' and 'pos'
if(preg_match("/(?P\w+){0,$wordsAround} (?P$word) (?P\w+){0,$wordsAround}/", $text, $match)) {
$cycle++;
$whack[] = $match['pre'] . ' ' . $word . ' ' . $match['pos'];
if($cycle == $maxChunks) break;
}
}
return implode(' | ', $whack);
}
此功能不起作用,但您可以看到基本的想法。欢迎任何有关如何改进正则表达式的建议!
答案 0 :(得分:1)
从不从不将用户内容注入RegEx的模式而不使用preg_quote来清理输入:
答案 1 :(得分:1)
为什么在这里重新发明轮子不会谷歌有最好的搜索引擎我会看他们appliance