Why str_replace Failing On "action =" ?

Php Experts,

Look at this cURL script and let me know what you think.

The cURL fetches pages just like web proxies do.
The script shows you an html form. It has a field: Url.
You type a url and cURL fecthes that page and proxies all links by preceding:
proxified_page_test.php?url_to_proxify=

So, if the fetched page contains a link on it's page like so:

http://google.com/contactus.html

The script would then string_replace that link with the following before displaying it on you screen:

proxified_page_test.php?url_to_proxify=http://google.com/contactus.html

That way, when you click the link, you don't go direct to the page but to a proxied version of it.

Now, here is the problem ...
When you fetch google homepage then it gets fetched alright. But when you do a keyword search then you should see a proxied page of the google serp (searchengine result page) but you see an invalid or dead page instead.
Keyword search features or forms usually have the "action = url".
The script is supposed to str_replace the "action =" to:

action= "proxified_page_test.php?url_to_proxify=\".$domain\""'

But, for some reason, this replacement is not taking place. That is the problem.
This not doing it's str_replace job:

Code:

---

$pattern = array('action="', 'action = "', 'action= "', 'action ="', "action='", "action = '", "action= '", "action='");
        $replace = array('action="proxified_page_test.php?url_to_proxify=\".$domain\""', 'action = "proxified_page_test.php?url_to_proxify=\".$domain\""', 'action= "proxified_page_test.php?url_to_proxify=\".$domain\""', 'action ="proxified_page_test.php?url_to_proxify=\".$domain\""', "action='proxified_page_test.php?url_to_proxify=\".$domain\"'", "action = 'proxified_page_test.php?url_to_proxify=\".$domain\"'", "action= 'proxified_page_test.php?url_to_proxify=\".$domain\"'", "action ='proxified_page_test.php?url_to_proxify=\".$domain\"'");
        $string_replaced_data = str_replace($pattern, $replace, $curl_result);
        echo var_dump($string_replaced_data);
        print_r($curl_result);

---

cURL full Script:

Code:

---

<?php
//STEP 1: ERROR HANDLING
declare(strict_types=1);
ini_set('display_errors', '1');
ini_set('display_startup_errors', '1');
//For All Error, Warning and Notice
error_reporting(E_ALL);
E_DEPRECATED;
/* STEP 2:
The IF gets triggered as soon as the "submit" button is clicked in the ui text box labeled: Url
Following IF code deals with GET method.
*/
if(isset($_GET["url_to_proxify"]) === TRUE)
  {
        echo "IF got triggered!";
        $url_to_proxify = filter_input(INPUT_GET, 'url_to_proxify', FILTER_VALIDATE_URL);
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, "$url_to_proxify");
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
        curl_setopt($ch, CURLOPT_HEADER, 5);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
        $curl_result = curl_exec($ch);       
        $domain = parse_url($url_to_proxify, PHP_URL_HOST);
        echo var_dump($domain);
        //Add proxy link on all links present on proxified page
        $pattern = array("http://", "https://", "http://www.", "https://www.", "localhost");
        $replace = array("proxified_page_test.php?url_to_proxify=http://\".$domain\"", "proxified_page_test.php?url_to_proxify=https://\".$domain\"", "proxified_page_test.php?url_to_proxify=http://www.\".$domain\"", "proxified_page_test.php?url_to_proxify=https://www.\".$domain\"", "proxified_page_test.php?url_to_proxify=http://www.\".$domain\"");
        $string_replaced_data = str_replace($pattern, $replace, $curl_result);
        echo var_dump($string_replaced_data);
        //Add proxy link on all Image Links (Eg. Google Img File)       
        $pattern = array('src="', 'src = "', 'src= "', 'src ="', "src='", "src = '", "src= '", "src='");
        $replace = array('src="proxified_page_test.php?url_to_proxify=\".$domain\""', 'src = "proxified_page_test.php?url_to_proxify=\".$domain\""', 'src= "proxified_page_test.php?url_to_proxify=\".$domain\""', 'src ="proxified_page_test.php?url_to_proxify=\".$domain\""', "src='proxified_page_test.php?url_to_proxify=\".$domain\"'", "src = 'proxified_page_test.php?url_to_proxify=\".$domain\"'", "src= 'proxified_page_test.php?url_to_proxify=\".$domain\"'", "src ='proxified_page_test.php?url_to_proxify=\".$domain\"'");
        $string_replaced_data = str_replace($pattern, $replace, $curl_result);
        echo var_dump($string_replaced_data);
        //Add proxy link on all links presented by the searchengine result pages (SERPS). Eg. Google Search Pages (SERPs)
        $pattern = array('action="', 'action = "', 'action= "', 'action ="', "action='", "action = '", "action= '", "action='");
        $replace = array('action="proxified_page_test.php?url_to_proxify=\".$domain\""', 'action = "proxified_page_test.php?url_to_proxify=\".$domain\""', 'action= "proxified_page_test.php?url_to_proxify=\".$domain\""', 'action ="proxified_page_test.php?url_to_proxify=\".$domain\""', "action='proxified_page_test.php?url_to_proxify=\".$domain\"'", "action = 'proxified_page_test.php?url_to_proxify=\".$domain\"'", "action= 'proxified_page_test.php?url_to_proxify=\".$domain\"'", "action ='proxified_page_test.php?url_to_proxify=\".$domain\"'");
        $string_replaced_data = str_replace($pattern, $replace, $curl_result);
        echo var_dump($string_replaced_data);
        print_r($curl_result);
    curl_close($ch);
   
           
}
else
    {
        echo "ELSE got triggered!";
        //Html Form
        ?>
        <html>
            <body> 
                <form action = "<?php echo $_SERVER['PHP_SELF']; ?>" method = "GET">
                Url: <input type = "text" name = "url_to_proxify" />
                <input type = "submit" />
      </form>     
  </body>
</html>
<?php
    }
?>

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