preg_replace to change url from relative to absolute - php

Question

My PHP code is:
$string = preg_replace('/(href|src)="([^:"]*)(?:")/i','$1="http://mydomain.com/$2"', $string);
It work with:
- Link 1 => Link 1
- Link 1 => Link 1
But not with:
- <a href='aaa/'>Link 1</a>
- Link 1 (I don't want to change if url start by #).
Please help me!

Answer 1

How about:
$arr = array('Link 1',
'Link 1',
"<a href='aaa/'>Link 1</a>",
'Link 1');
foreach( $arr as $lnk) {
$lnk = preg_replace('~(href|src)=(["\'])(?!#)(?!http://)([^\2]*)\2~i','$1="http://mydomain.com/$3"', $lnk);
echo $lnk,"\n";
}
output:
Link 1
Link 1
Link 1
Link 1
Explanation:
The regular expression:
(?-imsx:(href|src)=(["\'])(?!#)(?!http://)([^\2]*)\2)
matches as follows:
NODE EXPLANATION
----------------------------------------------------------------------
(?-imsx: group, but do not capture (case-sensitive)
(with ^ and $ matching normally) (with . not
matching \n) (matching whitespace and #
normally):
----------------------------------------------------------------------
( group and capture to \1:
----------------------------------------------------------------------
href 'href'
----------------------------------------------------------------------
| OR
----------------------------------------------------------------------
src 'src'
----------------------------------------------------------------------
) end of \1
----------------------------------------------------------------------
= '='
----------------------------------------------------------------------
( group and capture to \2:
----------------------------------------------------------------------
["\'] any character of: '"', '\''
----------------------------------------------------------------------
) end of \2
----------------------------------------------------------------------
(?! look ahead to see if there is not:
----------------------------------------------------------------------
# '#'
----------------------------------------------------------------------
) end of look-ahead
----------------------------------------------------------------------
(?! look ahead to see if there is not:
----------------------------------------------------------------------
http:// 'http://'
----------------------------------------------------------------------
) end of look-ahead
----------------------------------------------------------------------
( group and capture to \3:
----------------------------------------------------------------------
[^\2]* any character except: '\2' (0 or more
times (matching the most amount
possible))
----------------------------------------------------------------------
) end of \3
----------------------------------------------------------------------
\2 what was matched by capture \2
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------

Answer 2

This will work for you
PHP:
function expand_links($link) {
return('href="http://example.com/'.trim($link, '\'"/\\').'"');
}
$textarea = preg_replace('/href\s*=\s*(?<href>"[^\\"]*"|\'[^\\\']*\')/e', 'expand_links("$1")', $textarea);
I also changed the regex to work with either double quotes or apostrophes

Answer 3

try this for your pattern
/(href|src)=['"]([^"']+)['"]/i
the replacement stays as is
EDIT:
wait one...i didn't test on the first 2 link types, just the ones that didn't work...give me a moment
REVISISED:
sorry about the first regex, i forgot about the second example that worked with the domain in it
(href|src)=['"](?:http://.+/)?([^"']+)['"]
that should work