PHP using DOM to get anchors and modify them

Question

I have a string of HTML and I need check whether the href attributes of any anchors contain a certain link pattern. If they match a certain pattern I need to modify them.

Here's a sample HTML string:

<p>Disculpa, pero esta entrada está disponible sólo en <a href="http://www.example.com/static/?json=get_page&amp;post_type=page&amp;slug=sample-page&amp;lang=ru">Pусский</a> y <a href="http://www.example.com/static/?json=get_page&amp;post_type=page&amp;sample-page&amp;lang=en">English</a>.</p>

So the URLs in question take the following pattern

http://www.example.com/static/?json=get_page&post_type=page&slug=sample-page&lang=ru

Where the lang query attribute is variable in its value.

If a href matching that pattern is found I need to change it to:

http://www.example.com/ru/sample-page

So I need to remove 'static' and replace it with the value of the lang attribute, and I need to append the value of the 'slug' attribute to the end of the URL.

Sadly I'm getting confounded at the first step so I haven't even been able to test out methods of parsing the URLs and replacing them with the new value.

    $html = '<p>Disculpa, pero esta entrada está disponible sólo en <a href="http://www.example.com/static/?json=get_page&amp;post_type=page&amp;slug=sample-page&amp;lang=ru">Pусский</a> y <a href="http://www.example.com/static/?json=get_page&amp;post_type=page&amp;sample-page&amp;lang=en">English</a>.</p>';
$dom = new DOMDocument;
    // The UTF-8 encoding is necessary
$dom->loadHTML(mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8'));
$anchors = $dom->getElementsByTagName('a');

In theory from this point on I'd loop through the anchors found and do stuff, but if I var_dump the $anchors variable I just get:

object(DOMNodeList)#66 (0) { }

So I can't even proceed further!

Any idea what's causing the DOM to fail to collect the anchors?

After that any suggestions on how to best identify if the anchor contains the URL pattern, change it and return the new modified HTML?

Update 1

So it turns out that there's a PHP bug pre 5.4.1 which prevents var_dump from displaying the contents of the DOMNodeList. I can find values with

foreach ($anchors as $anchors) {
    echo $anchors->nodeValue, PHP_EOL;
}

However I have no idea what the $anchors object really looks like so am running blind. If anyone has any suggestions on how to parse the $anchors and modify them as originally mentioned that would be hugely appreciated (whilst I try to sort out a PHP5.4.1 instance)

Oddly, count($anchors) returns 1, but the var_dump is: object(DOMNodeList)#66 (0) { } — alexleonard, Jul 16 '13 at 04:38
I've updated the question to show the $html variable and var_dump($anchors) instead of print_r — alexleonard, Jul 16 '13 at 04:40
works fine at my end, i get `DOMNodeList Object ( [length] => 2 )`. Did you check passing html without calling `mb_convert_encoding`. my guess is file encoding or data encoding is creating some problem for you. — user1402647, Jul 16 '13 at 04:42
That's super weird. I have absolutely no idea why it's not working. Hmm. I've dropped the encoding and still get var_dump($anchors) = object(DOMNodeList)#66 (0) { } — alexleonard, Jul 16 '13 at 04:46
Right, I've discovered the issue thanks to a friend's explanation. I can't var_dump the DOM object. I have to do foreach ($anchors as $anchors) { echo $anchors->nodeValue, PHP_EOL; } and then it gives values. Which is weird. I've tested this on our server running php5.2 and locally on xampp on php5.3.8 — alexleonard, Jul 16 '13 at 05:04
http://stackoverflow.com/questions/4776093/why-doesnt-var-dump-work-with-domdocument-objects-while-printdom-savehtml - that's what was throwing me on that one...! — alexleonard, Jul 16 '13 at 05:08

score 6 · Accepted Answer · answered Jul 16 '13 at 05:27

6

I have done a similar thing not long ago. You can iterate over a DOMNodeList and then get the href attribute of the anchor.

$dom = new DOMDocument;
$dom->loadHTML($content);
foreach ($dom->getElementsByTagName('a') as $node) {
    $original_url = $node->getAttribute('href');
    // Do something here
    $node->setAttribute('href', $var);
}
$html = $dom->saveHtml();

answered Jul 16 '13 at 05:27

Hayden

164
1
6

Thanks, I'll look into that after lunch :) – alexleonard Jul 16 '13 at 05:39
Hey Hayden! You totally set me on the right path :) I've updated your answer with the code that worked for me (I hope that's ok?) NB: http_build_url requires PECL. – alexleonard Jul 16 '13 at 07:57

score 0 · Answer 2 · answered Jul 16 '13 at 04:40

0

Maybe try to echo the html first? Maybe you're passing an empty html or something.

answered Jul 16 '13 at 04:40

Wassim Gr

568
2
8
16

I've just updated the question to show the HTML variable I'm passing to it. – alexleonard Jul 16 '13 at 04:40

score 0 · Answer 3 · answered Jul 16 '13 at 04:45

0

Try this you will get the href value

$anchors = $dom->getElementsByTagName('a');
echo $anchors->item(0)->attributes->getNamedItem('href');

answered Jul 16 '13 at 04:45

DevZer0

13,433
7
27
51

1

empty `$anchors` will not give anything! – user1402647 Jul 16 '13 at 04:52

score 0 · Answer 4 · edited Dec 11 '13 at 07:45

0

function getLinks($link)
{
$ret=array();

$dom=new DOMDocument;

@$dom->loadHTML(file_get_contents($link));

$dom->preserveWhiteSpace=false;

$links=$dom->getElementsByTagName('a');
 $html=$dom->saveHTML();
foreach($links as $tag)
{
    @$ret[$tag->getAttribute('href')]=$tag->childNodes->item(0)->nodeValue;
}

return $ret;
}
$link="http://php.net";

 $url=getLinks($link);

edited Dec 11 '13 at 07:45

Tobia Zambon

7,479
3
37
69

answered Dec 11 '13 at 07:26

Ravi Singh

1

score 0 · Answer 5 · answered Nov 27 '17 at 08:08

I do agree with Hyden's answers. But I want to make the solution more independent. Because sometimes while we manipulate with DOM document, we face with encoding issues. Here is the advanced solution given below...........

$dom = new DOMDocument;
$dom->loadHTML(mb_convert_encoding($content, 'HTML-ENTITIES', 'UTF-8'));
foreach ($dom->getElementsByTagName('a') as $node) {
    $original_url = $node->getAttribute('href');
    // Do something here
    $node->setAttribute('href', $var);
}
$html = $dom->saveHtml();

PHP using DOM to get anchors and modify them

Update 1

5 Answers5