PHP code to read a web page's source and get attribute from a tag

Question

I am reading a source code of a page in PHP. There is an hidden input field <input type="hidden" name="session_id" value= in that page.

$url = 'URL HERE';
$needle = '<input type="hidden" name="session_id" value=';
$contents = file_get_contents($url);
if(strpos($contents, $needle)!== false) {
echo 'found';
} else {
echo 'not found';
}

I want to read that hidden field value.

score 8 · Accepted Answer · answered Jan 03 '12 at 17:35

8

By far the best way to do this is with the DOM extension to PHP.

$dom = new DOMDocument;
$dom->loadHtmlFile('your URL');

$xpath = new DOMXPath($dom);

$elements = $xpath->query('//input[@name="session_id"]');
if ($elements->length) {
    echo "found: ", $elements->item(0)->getAttribute('value');
} else {
    echo "not found";
}

answered Jan 03 '12 at 17:35

lonesomeday

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+1 just deleted my own answer in favor of the xpath solution :-) – favo Jan 03 '12 at 17:44
@imi That is not a valid HTML document. You need to suppress warnings with the same technique I describe [in this answer](http://stackoverflow.com/a/6090728/417562). – lonesomeday Jan 03 '12 at 17:53
Its unable to find input[@name="session_id"] – Muhammad Imran Tariq Jan 03 '12 at 18:14
@imi Are you sure it's present? – lonesomeday Jan 03 '12 at 18:16

score 3 · Answer 2 · answered Jan 03 '12 at 17:34

3

I'd look into PHP's native DOMDocument extension:

http://www.php.net/manual/en/domdocument.getelementbyid.php#example-4867

answered Jan 03 '12 at 17:34

Martin Bean

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ID? Does that work for the `name` attribute as well in DOMDocument? – hakre Jan 03 '12 at 17:38

PHP code to read a web page's source and get attribute from a tag

2 Answers2