绝对URL的相对+基本URL？

Question

Basically, given a base URL like

file:///path/to/some/file.html

And a relative URL like

another_file.php?id=5

I want to get out

file:///path/to/some/another_file.php?id=5

I found this script (which is the same as this one) but it doesn't seem to work on the file:// scheme. I'm doing some local tests before I go live with my code, so I'd like to work on both file:// and http://.

Any one know of a script/function that will do this?

In C#, I'd use Uri(Uri base, string rel).

---

The above is just an example. It should work on any URL that you could throw into <a href="xxx">.

---

This is the best I've got so far, but it won't handle .. and probably a few other things:

function rel2abs($base, $rel) {
    if (parse_url($rel, PHP_URL_SCHEME) != '') return $rel;
    if ($rel[0]=='#' || $rel[0]=='?') return $base.$rel;
    $parse = parse_url($base);
    $path = preg_replace('#/[^/]*$#', '', $parse['path']);
    if ($rel[0] == '/') $path = '';
    $abs = (isset($path['host'])?$path['host']:'')."$path/$rel";
    $re = array('#(/\.?/)#', '#/(?!\.\.)[^/]+/\.\./#');
    for($n=1; $n>0; $abs=preg_replace($re, '/', $abs, -1, $n)) {}
    return $parse['scheme'].'://'.$abs;
}

Answer 1

You can use parse_url() to get the URL broken into parts, and then split the 'path' portion on the forward-slash character. That should allow you to re-assemble them and replace the last portion.

Something like this (psuedo-code, untested, not sure it's even valid PHP syntax):

$url_parts = parse_url($url_text);
$path_parts = explode('/', $url_parts[path]);

$new_url = $url_parts[scheme] + ":";

if ($url_parts[scheme] == "file") {
    $new_url .= '///';
} else {
    $new_url .= '//';
}

$new_url .= $url_parts[hostname] . '/';
for (int i = 0; i < count($path_parts) - 1; i++) {
    $new_url .= $path_parts[i] . "/";
} 

$new_url .= $REPLACEMENT_FILENAME

If need be, you can append the query string and/or anchor fragment (starts with #) at the end - see that parse_url() manual page for a list of the URL portions in its array.