Multiple $_GET through links - php

Question

I'm doing a website. There's a pagination, you click on links and they take you to the page you need, the links pass $_GET variable ( a href="?pn=2" ) and that works fine.
However when i add the category links (also contain $_GET variable
(a href="?sort=english") on the same page, which kind of sort the content on the page, and click it, the system simply overrides the url and deletes all the previous $_GET's.
For example, I'm on page 2 (http://website.com/index.php?pn=2)
and then I click this sorting link and what I'm expecting to get is this (http://website.com/index.php?pn=2&sort=english), but what I get is this:
(http://website.com/index.php?sort=english). It simply overrides the previous $_GET, instead of adding to it!

Answer 1

A relative URI consisting of just a query string will replace the entire existing query string. There is no way to write a URL that will add to an existing query. You have to write the complete query string that you want.
You can maintain the existing string by adding it explicitly:
href="?foo=<?php echo htmlspecialchars($_GET['foo']); ?>&bar=123"

Answer 2

Try using this:
$_SERVER['REQUEST_URI'];
On this link you can see examples. And on this link I have uploaded test document where you can try it yourself, it just prints out this line from above.
EDIT: Although this can help you get the current parameters in URL, I think it's not solution for you. Like Quentin said, you will have to write full link manually and maintain each parameter.

Answer 3

You could create a function that will iterate through your $_GET array and create a query string. Then all you would have to do is change your $_GET array and generate this query string.
Pseudocode (slash I don't really know PHP but here's a good example you should be able to follow):
function create_query_string($array) {
$kvps = array();
for ($key in $array) {
array_push($kvps, "$key=$array[$key]");
}
return "?" . implode("&", $kvps);
}
Usage:
$_GET["sort"] = "english";
$query_string = create_query_string($_GET);

Answer 4

You need to maintain the query parameters when you create the new links. The links on the page should be something like this:
Sort by English
The HTTP protocol is stateless -- it doesn't remember the past. You have to remind it of what the previous HTTP parameters were via PHP or other methods (cookies, etc). In your case, you need to remind it what the current page number is, as in the example above.