REQUEST_URI return single slash - php

Question

I Use this part of code to print canonical tag:
<?php
if(!empty($_SERVER["REQUEST_URI"])){
$url = strtok($_SERVER["REQUEST_URI"],'?');
?>
<link rel="canonical" href="https://mywebsite.com<?=urldecode($url);?>" />
<?php
} else {
?>
<link rel="canonical" href="https://mywebsite.com" />
<?php
}
?>
But it not going to ready else condition if current URL is https://mywebsite.com. I found out why, because var_dump($_SERVER["REQUEST_URI"]); return string(1) "/". Why when I open this URL REQUEST_URI return / while there is no slash at tail?
Anyway, beside of this question, how can I solve my code to working?

Answer 1

In a HTTP call $_SERVER['REQUEST_URI'] can never be empty unless it is unset($_SERVER['REQUEST_URI']) or $_SERVER['REQUEST_URI] = '' by the script itself.
For a HTTP call to http://mywebsite.com, it will hold / as its value. That's what you are getting. / denotes root of the website, so when HTTP request is made to the root of the website, / is sent as path and will always be present, whether you add it or not into the URL.
I think that clarifies why you are not hitting else condition of your code ever.
Coming to your problem, if you want to append the path to the url without any query parameters, the better approach for this should be:
<link rel="canonical" href="https://mywebsite.com<?php echo parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH); ?>">
This replaces all of your code. You may want to take a look at parse_url function of PHP.
If you don't want the trailing slash intentionally, you can make use of rtrim.
<link rel="canonical" href="https://mywebsite.com<?php echo rtrim(parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH), '/'); ?>">
In case, you are passing any valid URL to parse_url and don't want trailing slash only for root, then:
<?php
$path = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH);
if($path == '/' || !$path) {
$path = '';
} ?>
<link rel="canonical" href="https://mywebsite.com<?php echo $path; ?>">