Using php preg to find url and replace it with a second url

Question

I've got a large number of webpages stored in an MySQL database.

Most of these pages contain at least one (and occasionally two) entries like this...

<a href="http://first-url-which-always-ends-with-a-slash/">
  <img src="http://second-different-url-which-always-ends-with.jpg" />
</a>

I'd like to just set up a little php loop to go through all the entires replacing the first url with a copy of the second url for that entry.

How can I use preg to:

find the second url from the image tag
replace the first url in the a tag, with a copy of the second url

Is this possible?

Thanks but the "how" bit just as important to me, as knowing that it is possible... — Phil Newby
– Phil Newby, Commented Aug 17, 2012 at 14:25

Community · Accepted Answer · 2017-05-23 10:24:39Z

1

see this url

PHP preg match / replace?

see also:- http://php.net/manual/en/function.preg-replace.php

$qp = qp($html);
foreach ($qp->find("img") as $img) {
    $img->attr("title", $img->attr("alt"));
}
print $qp->writeHTML();

Though it might be feasible in this simple case to resort to an regex:

preg_replace('#(<img\s[^>]*)(\balt=)("[^"]+")#', '$1$2$3 title=$3', $h);

(It would make more sense to use preg_replace_callback to ensure no title= attribute is present yet.)

edited May 23, 2017 at 10:24

CommunityBot

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answered Aug 17, 2012 at 9:51

Abid Hussain

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2 Comments

Phil Newby Over a year ago

Thanks, it took me a while there to work out what qp($html) was all about. I don't understand how the preg_replace can get the src url from the img tag into the a href tag?

Abid Hussain Over a year ago

see this url:- stackoverflow.com/questions/5195337/php-preg-match-replace

Atul Rai · Accepted Answer · 2012-08-17 10:41:14Z

0

You can do following :

$dom = new DOMDocument('1.0', 'UTF-8');
$dom->formatOutput = true;
$source = "<a href=\"http://first-url-which-always-ends-with-a-slash/\">
  <img src=\"http://second-different-url-which-always-ends-with.jpg\" />
</a>";
$dom->loadHTML($source);
$tags = $dom->getElementsByTagName('a');

foreach ($tags as $tag) {
  $atag = $tag->getAttribute('href');  
  $imgTag = $dom->getElementsByTagName('img');
  foreach ($imgTag as $img) {        
    $img->setAttribute('src', $atag);
    echo $img->getAttribute('src');
  }
}

answered Aug 17, 2012 at 10:41

Atul Rai

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1 Comment

Phil Newby Over a year ago

OK now i've found out about the DOMDocument Class, i can see that might do the trick! Cheers

Phil Newby · Accepted Answer · 2012-08-22 11:15:22Z

0

Thanks for the suggestions i can see how they are better than using Preg.

Even so i finally solved my own question like this...

$result = mysql_query($select);
while ($frow = mysql_fetch_array($result)) {
    $page_content = $frow['page_content'];

    preg_match("#<img\s+src\s*=\s*([\"']+http://[^\"']*\.jpg[\"']+)#i", $page_content, $matches1);
    print_r($matches1);
    $imageURL = $matches1[1] ; 

    preg_match("#<a\s+(?:[^\"'>]+|\"[^\"]*\"|'[^']*')*href\s*=\s(\"http://[^\"]+/\"|'http://[^']+/')#i", $page_content, $matches2);
    print_r( $matches2 );  
    $linkURL = $matches2[1] ;

    $finalpage=str_replace($linkURL, $imageURL, $page_content) ;
}

answered Aug 22, 2012 at 11:15

Phil Newby

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