Replace string before a string? - php

Question

Sorry, I'm bad English. I'm going to post my code now:
$image = 'http://example.com/thisisimage.gif';
$filename = substr($image, strrpos($image, '/') + 1);
echo '<br>';
echo $filename;
echo '<br>';
echo preg_replace('/^[^\/]+/', 'http://mydomain.com', $image);
echo '<br>';
$image is string;
$filename is image name (in example above, it returns 'thisisimage.gif')
Now i want replace all before $filename with 'http://mydomain.com', my code is above but it doesnt work.
Thanks!

Answer 1

$foo = explode($filename, $image);
echo $foo[0];
Explode "splits" one the given paramater ( in your case $filename ). It returns an array with where the keys are split on the string you gave.
And if you just want to change the url. you use a str_replace
$foo = str_replace("http://example.com", "http://localhost", $image);
//This will change "http://example.com" to "http://localhost", like a text replace in notepad.
In your case:
$image = 'http://example.com/thisisimage.gif';
$filename = substr($image, strrpos($image, '/') + 1);
$foo = explode($filename, $image);
echo '<br>';
echo $filename;
echo '<br>';
echo str_replace($foo[0], "http://yourdomain.com/", $url);
echo '<br>';

Answer 2

There's another approach in which you don't need a regular expression:
in Short:
$image = 'http://example.com/thisisimage.gif';
$url = "http://mydomain.com/".basename($image);
Explanation:
If you just want the file name without url's or directory path's, basename() is your friend;
$image = 'http://example.com/thisisimage.gif';
$filename = basename($image);
output: thisisimage.gif
Then you can add whatever domain you want:
$mydomain = "http://mydomain.com/";
$url = $mydomain.$filename;

Answer 3

Try this :
$image = 'http://example.com/thisisimage.gif';
echo preg_replace('/^http:\/\/.*\.com/', 'http://mydomain.com',$image);

Answer 4

This should simply work:
$image = 'http://example.com/thisisimage.gif';
$filename = substr($image, strrpos($image, '/') + 1);
echo '<br>';
echo $filename;
echo '<br>';
echo 'http://mydomain.com/'.$filename;
echo '<br>';

Answer 5

if you just like to add your own domain before the file name, try this:
$filename = array_pop(explode("/", $image));
echo "http://mydomain.com/" . $filename;
if you wanna only replace thedomain, try this:
echo preg_replace('/.*?[^\/]\/(?!\/)/', 'http://mydomain.com/', $image);

Answer 6

The other people here have given good answers about how to do it - regex has its advantages but also drawbacks - its slower, respectively requires more resources and for something simple as this, I would advice you to use the explode approach, but while speaking for regex functions you also may try this, instead your preg_replace:
echo preg_replace('#(?:.*?)/([^/]+)$#i', 'http://localhost/$1', $image);
It seems variable length positve lookbehind is not supported in PHP.