Question

Assume captcha key is invalid, it need to download new captcha image again and re-validate captcha key. How can that be done?

I have include short example, is this the way to do?

while (1) {
    $postData = http_build_query($data);
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_CAINFO, getcwd() . "\**********************.crt");
    curl_setopt($ch, CURLOPT_URL, "https://domain.com/test" . $form_link);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, TRUE);
    curl_setopt($ch, CURLOPT_COOKIESESSION, TRUE);
    curl_setopt($ch, CURLOPT_COOKIEFILE, $cookiesPath . "/cookiefile.txt");
    curl_setopt($ch, CURLOPT_COOKIEJAR, $cookiesPath . "/cookiefile.txt");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $page = curl_exec($ch);

    //Just a quick example
    if ($page == "Sucess") {
       break;
    } else {
        $ch = curl_init();
        //Some curl code here to Re-download Captcha Image (new image)
        $data['captchaText'] = CaptchaToText::Scan("images/captcha.jpg");
    }
}

Answer 1

Yes, you doing it right. But only in the firs part )

You already have cURL resource initiated ($ch).

So you only need to execute cURL request again by curl_exec($ch) and you will get a new page.
All the cURL options set by curl_setopt() are saved in resourse.

Here is the code:

if ($page == "Sucess") {
   break;
} else {
    $page = curl_exec($ch);
    //Some curl code here to Re-download Captcha Image (new image)
    $data['captchaText'] = CaptchaToText::Scan("images/captcha.jpg");
}