使用CURL访问带路径参数页面返回空白页问题求助

I've been using CURL to make requests lately, but I've noticed it returns a blank page when I add a text parameter to the path (e.g., /kenteken/TF172H). Accessing the main page /kenteken/ works without any issues. I need technical help figuring this out. Here's my implementation code:

$ktk = $_GET['kenteken']; 
// create curl resource 
$ch = curl_init(); 
// set url 
curl_setopt($ch, CURLOPT_URL, "https://finnik.nl/kenteken/" . $ktk); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"); 
curl_setopt($ch, CURLOPT_REFERER, "http://www.google.com"); 
curl_setopt($ch, CURLOPT_AUTOREFERER, true); 
// $output contains the output string 
$output = curl_exec($ch); 
// close curl resource to free up system resources 
curl_close($ch); 
print_r($output);

Troubleshooting & Fixes #

Blank CURL responses almost always mean silent failures—let's break down how to diagnose and fix this step by step:

1. First, Enable CURL Error Reporting #

Your code doesn't check for CURL-specific errors right now, which is the fastest way to get clarity. Add these lines immediately after curl_exec($ch):

if(curl_errno($ch)) {
    echo 'Curl error: ' . curl_error($ch);
}

This will tell you exactly what's going wrong—whether it's an SSL issue, connection timeout, or something else.

2. Check the HTTP Response Code #

Even if CURL doesn't throw an error, the server might be returning a 403 Forbidden, 404 Not Found, or 500 Internal Server Error. Add this line to get the status code:

$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
echo 'HTTP Status Code: ' . $httpCode;

A 403 is a common sign the server is blocking your request (anti-scraping measures are likely the culprit here).

3. Update Your Request Headers #

Your current User-Agent is extremely outdated (MSIE 6.0)—modern servers block these because they're linked to scrapers or obsolete browsers. Swap it for a recent, standard one:

curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36");

Also, add headers that real browsers send to blend in:

curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
    'Accept-Language: en-US,en;q=0.5'
));

And change your referrer to the actual site's root path instead of Google—this looks more natural:

curl_setopt($ch, CURLOPT_REFERER, "https://finnik.nl/kenteken/");

4. Handle SSL Correctly #

Silent failures can happen if CURL hits an SSL certificate issue. Add these options to ensure proper SSL handling:

curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);

If you get SSL errors during testing, you can temporarily disable verification (not recommended for production):

// curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
// curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);

5. URL-Encode Your Parameter #

While your license plate example doesn't have special characters, it's a good practice to URL-encode the parameter to avoid formatting issues:

$ktk = urlencode($_GET['kenteken']);

6. Simulate a Browser Session #

Some servers require cookies to serve dynamic content. Add these lines to handle cookie storage/reuse:

curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookies.txt');
curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookies.txt');

Full Updated Code #

Here's all the fixes rolled into one working snippet:

$ktk = urlencode($_GET['kenteken']); 
$ch = curl_init(); 

curl_setopt($ch, CURLOPT_URL, "https://finnik.nl/kenteken/" . $ktk); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36"); 
curl_setopt($ch, CURLOPT_REFERER, "https://finnik.nl/kenteken/"); 
curl_setopt($ch, CURLOPT_AUTOREFERER, true); 
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
    'Accept-Language: en-US,en;q=0.5'
));
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookies.txt');
curl_setopt($ch, CURLOPT_COOKIEFILE, 'cookies.txt');

$output = curl_exec($ch); 

// Debug checks
if(curl_errno($ch)) {
    echo 'Curl error: ' . curl_error($ch);
}
$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
echo 'HTTP Status Code: ' . $httpCode;

curl_close($ch); 
print_r($output);

Start with enabling error reporting first—that will give you the most direct insight into what's blocking your request. Odds are, the outdated User-Agent was the main issue here.

内容的提问来源于stack exchange，提问作者Daxter112