php用条件替换href

Question

I try to replace href by condition:

http://www.sitea.com/vip:  => http://localhost/aaa?search=
http://www.sitea.com/      => http://localhost/bbb/ (without 'vip:')
http://www.siteb.com/      => http://localhost/ccc/

I use strpos for judge:

$str='<a href="http://www.sitea.com/vip:vp_14098">link A</a><a href="http://www.sitea.com/contact">link B</a><a href="http://www.siteb.com/player">link C</a>';
if(strpos($str,'www.sitea.com')!== false){
    if(strpos($str,'vip:')!== false){
        $str = str_replace('http://www.sitea.com/', 'http://localhost/aaa?search=',$str);
    }else{
        $str = str_replace('http://www.sitea.com/', 'http://localhost/bbb/',$str);
    }
}
if(strpos($str,'www.siteb.com')!== false){
    $str = str_replace('http://www.siteb.com/', 'http://localhost/ccc/',$str);
}
echo $str;

But this output:

<a href="http://localhost/aaa?search=vip:vp_14098">link A</a>
<a href="http://localhost/aaa?search=contact">link B</a>
<a href="http://localhost/ccc/player">link C</a>

The second link not replace as I wish.

Answer 1

Oh boy. You're decisions are based on the results of strpos applied to a string containing all the links. Because $str contains a link of the first type, the corresponding if-condition is always true. You can use a regular expression to address that problem, or if this isn't just a simplified example but your real world code, try this:

$str='<a href="http://www.sitea.com/vip:vp_14098">link A</a><a href="http://www.sitea.com/contact">link B</a><a href="http://www.siteb.com/player">link C</a>';
$str = str_replace('http://www.sitea.com/vip:', 'http://localhost/aaa?search=vip:',$str);
$str = str_replace('http://www.sitea.com/', 'http://localhost/bbb/',$str);
$str = str_replace('http://www.siteb.com/', 'http://localhost/ccc/',$str);
echo $str;

Answer 2

This is because all of your urls are in the same string, so as it goes through your code, it matches the "sitea.com" comparison, and then it matches the "vip:" comparison and then it goes into that and replaces all occurrences of "sitea" with your "aaa" replacement. It never gets into the "bbb" replacement line because $str always contains "vip".

What you will need to do is split your $str into an array of urls and process each one individually.

Answer 3

It's because you are trying to parse each url differently, and you are doing them all in the same string. The str_replace is ALWAYS finding :vip, because it's in your entire string.

There will be a post here that will probably give you some regular expressions to use, but that is not my area of expertise. Instead, I will offer you these changes to your code:

<?php
    $str='<a href="http://www.sitea.com/vip:vp_14098">link A</a><a href="http://www.sitea.com/contact">link B</a><a href="http://www.siteb.com/player">link C</a>';
    $str = str_replace('http://www.sitea.com/vip:', 'http://localhost/aaa?search=',$str);
    $str = str_replace('http://www.sitea.com/', 'http://localhost/bbb/',$str);
    $str = str_replace('http://www.siteb.com/', 'http://localhost/ccc/',$str);
    echo $str;
?>