How to get rid of `?` in URL when no parameters exist? - php

Question

I have the following rule which checks if the url contains any parameters that start with p2:
function unparse_url($parsed_url) {
$scheme = isset($parsed_url['scheme']) ? $parsed_url['scheme'] . '://' : '';
$host = isset($parsed_url['host']) ? $parsed_url['host'] : '';
$port = isset($parsed_url['port']) ? ':' . $parsed_url['port'] : '';
$user = isset($parsed_url['user']) ? $parsed_url['user'] : '';
$pass = isset($parsed_url['pass']) ? ':' . $parsed_url['pass'] : '';
$pass = ($user || $pass) ? "$pass#" : '';
$path = isset($parsed_url['path']) ? $parsed_url['path'] : '';
$query = isset($parsed_url['query']) ? '?' . trim($parsed_url['query'], '&') : '';
$fragment = isset($parsed_url['fragment']) ? '#' . $parsed_url['fragment'] : '';
return "$scheme$user$pass$host$port$path$query$fragment";
}
function strip_query($url, $query_to_strip) {
$parsed = parse_url($url);
$parsed['query'] = preg_replace('/(^|&)'.$query_to_strip.'[^&]*/', '', $parsed['query']);
return unparse_url($parsed);
}
$url = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
$new_url = (strip_query($url, 'p2'));
# redirect if url contains anything that starts with p2
$filtered = array_filter(array_keys($_GET), function($k) {
return strpos($k, 'p2') === 0;
});
if ( !empty($filtered) ) {
header ("Location: $new_url");
}
else {
}
If a url contain any p2* parameters, a redirect will be made to the same page without these parameters.
Example:
domain.com/?a=3&p2=1
will redirect to
domain.com/?a=3
However, with the current rule, if the original URL is:
domain.com/?p2=1
Then it will redirect to:
domain.com/?
But since it is meaningless, I want that in this case it will redirect to:
domain.com/
How can it be done?

Answer 1

Like #dontfight i would suggest to use mod_rewrite but if you prefer PHP you could use rtrim before you do the redirect
rtrim($url, '?');
With your code you could use like this
$filtered = array_filter(array_keys($_GET), function($k) {
return strpos($k, 'p2') === 0;
});
$new_url_trim = rtrim($new_url, '?');
if ( !empty($filtered) ) {
header ("Location: $new_url_trim");
}
else {
}

Answer 2

Here's another way to remove query parameters:
Parse the URL to separate it into the scheme, path, and query
Parse the query string into an array
Unset the parameter within the array
Recreate the URL
Example:
<?php
function removeQuery($url, $param) {
$parsed = parse_url($url);
parse_str($parsed['query'], $query);
unset($query[$param]);
$parsed['scheme'] .= '://';
$parsed['query'] = http_build_query($query);
if (!empty($parsed['query']))
$parsed['path'] .= '?';
return implode($parsed);
}
echo removeQuery('http://domain.com/?a=3&p2=1', 'a') . "\n";
echo removeQuery('http://domain.com/?a=3&p2=1', 'p2') . "\n";
echo removeQuery('http://domain.com/?p2=1', 'p2');
Output:
http://domain.com/?p2=1
http://domain.com/?a=3
http://domain.com/
Also I noticed that you wanted to remove p2 if it occurs anywhere in the string, so here's another version designed to do just that:
<?php
function removeP2($url) {
$parsed = parse_url($url);
parse_str($parsed['query'], $query);
foreach ($query as $key => $value)
if (strpos($key, 'p2') === 0)
unset($query[$key]);
$parsed['scheme'] .= '://';
$parsed['query'] = http_build_query($query);
if (!empty($parsed['query']))
$parsed['path'] .= '?';
return implode($parsed);
}
echo removeP2('http://domain.com/?a=3&p2=1') . "\n";
echo removeP2('http://domain.com/?a=3&p2sks=1') . "\n";
echo removeP2('http://domain.com/?p2=1');
Output:
http://domain.com/?a=3
http://domain.com/?a=3
http://domain.com/
Now to get it to redirect, you already know how to redirect:
header("Location: " . removeP2('http://' . $_SERVER[HTTP_HOST] . $_SERVER[REQUEST_URI]));

Answer 3

Since nobody has bothered to tell you what's wrong...
Your problem is that your strip_query() function always sets $url["query"] to a value, even if that value is an empty string:
$parsed['query'] = preg_replace('/(^|&)'.$query_to_strip.'[^&]*/', '', $parsed['query']);
When your unparse_url() function gets the URL, it's checking that array index using isset() which always passes:
$query = isset($parsed_url['query']) ? '?' . trim($parsed_url['query'], '&') : '';
Instead of checking with isset() you could use empty(), which will return false if the value is unset or if it's an empty string:
$query = !empty($parsed_url['query']) ? '?' . trim($parsed_url['query'], '&') : '';

Answer 4

if mod_rewrite is available, this can be done without php code.

Answer 5

This is not an answer, its a comment, but its a bit long.
Why are you so keen to strip this variable from the URL? What harm has it ever done to you that you must go to such lengths to eradicate its existence? And why not just...
unset($_GET['p2']);
But since it is meaningless,
In what way?
I can see some merit in the unparse_url($parsed_url) function and if you fix the bugs (hint: try some test cases with usernames and/or passwords) then it's reasonably well structured - but the subsequent code for manipulating the data is a messy mix of regular expression string splicing - which is not the right way to deal with such structured data - PHP has functions for that.
But the worst bit is then injecting another complete RTT to resolve the URL.
You are better than this rockyraw!