preg_match返回通知：未定义的偏移量

Question

I'm making Torrent PHP Crawler and I have problem, here's my code:

// ... the cURL codes (they're working) ...
// Contents of the Page
$contents = curl_exec($crawler->curl);

// Find the Title
$pattern = "/<title>(.*?)<\/title>/s";
preg_match($pattern, $contents, $titlematches);
echo "Title - ".$titlematches[1]."<br/>";

// Find the Category
$pattern = "/Тип<\/td><td(?>[^>]+)>((?>[^<]+))<\/td>/s";
preg_match($pattern, $contents, $categorymatches);
echo "Category - ".$categorymatches[1]."<br/>";

The HTML page ("Тип" means Category and "Филми" means Movies):

<title>The Matrix</title>
<!--Some Codes Here--!>
<tr><td>Тип</td><td valign="top" align=left>Филми</td></tr>
<!--Some Codes Here--!>

The Result:

Title - The Matrix
Notice: Undefined offset: 1 in /var/www/spider.php on line 117

It's showing the title but not the category.. why is that? I've tried to echo $categorymatches[0], $categorymatches[2], $categorymatches[3] without any luck.

Answer 1

You're assuming that preg_match actually finds a match. It's better to test if it did so.

$pattern = "/<title>(.*?)<\/title>/s"; 
$matchCount = preg_match($pattern, $contents, $titlematches); 
if ($matchCount > 0) {
    echo $titlematches[1]."<br/>";
} else {
    // do something else, 'cos no match found
}

Note that you might want to use a switch or two with preg_match: this will only find a result if "title" is used, not "TITLE" or "Title", so using the case-insensitive /i switch might be an idea; or the tag might be on a different line to the value, and to the , so the multiline switch /m could be useful.

And the same principle applies to all your preg_match checks

EDIT

It looks as though your category match is testing for a utf-8 string, so try using the /u switch