Remove specific variable from URI string - php

Question

With $_SERVER['REQUEST_URI'], I get a URL that could be:
index.php
or
index.php?id=x&etc..
I'd like to do two things:
Find if there is a ?something after index.php name with regular expression.
If there is in the url a specific var (id=x) and delete it from the url.
For example:
index.php?id=x => index.php
index.php?a=11&id=x => index.php?a=11
How can I do this?

Answer 1

To check if there is a ?something after index.php, you could use the built-in function parse_url(), like so:
if (parse_url($url, PHP_URL_QUERY)) {
// ?something exists
}
To remove the id, you could use parse_str(), get the query parameters, store them in an array, and unset the particular id.
And since you also want to re-create the URL after the particular element is deleted from the query part of the URL, then you could use http_build_query().
Here's a function for that:
function removeQueryString($url, $toBeRemoved, $match)
{
// check if url has query part
if (parse_url($url, PHP_URL_QUERY)) {
// parse_url and store the values
$parts = parse_url($url);
$scriptname = $parts['path'];
$query_part = $parts['query'];
// parse the query parameters from the url and store it in $arr
$query = parse_str($query_part, $arr);
// if id == x, unset it
if (isset($arr[$toBeRemoved]) && $arr[$toBeRemoved] == $match) {
unset($arr[$toBeRemoved]);
// if there less than 1 query parameter, don't add '?'
if (count($arr) < 1) {
$query = $scriptname . http_build_query($arr);
} else {
$query = $scriptname . '?' . http_build_query($arr);
}
} else {
// no matches found, so return the url
return $url;
}
return $query;
} else {
return $url;
}
}
Test cases:
echo removeQueryString('index.php', 'id', 'x');
echo removeQueryString('index.php?a=11&id=x', 'id', 'x');
echo removeQueryString('index.php?a=11&id=x&qid=51', 'id', 'x');
echo removeQueryString('index.php?a=11&foo=bar&id=x', 'id', 'x');
Output:
index.php
index.php?a=11
index.php?a=11&qid=51
index.php?a=11&foo=bar
Demo!

Answer 2

If it must be a regular expression :
$url='index.php?a=11&id=1234';
$pattern = '#\id=\d+#';
$url = preg_replace($pattern, '', $url);
echo $url;
output
index.php?a=11&
There is a trailing &, but the above removes any id=xxxxxxxx