Some servers and CDNs (like Cloudflare or Amazon S3) block requests that don’t have a User-Agent header, viewing them as "headless" bot traffic. If the server denies the request with a 403 Forbidden , your script might still create the local file but fail to write any data to it. Mimic a standard browser:
To see if SSL is the problem, temporarily disable verification: curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); Use code with caution. php curl download file 0 bytes
: Use CURLOPT_CONNECTTIMEOUT and CURLOPT_TIMEOUT for large files. Some servers and CDNs (like Cloudflare or Amazon
The most frequent cause of a 0-byte download is a . If the source site has an expired certificate,
In modern web environments, SSL issues are a leading cause of silent failures. If the source site has an expired certificate, an untrusted CA, or a configuration error, cURL might abort the data transfer.
By following these steps, you can transform those empty files into successful downloads.
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows NT 10.0; Win64; x64) Chrome/115.0.0.0 Safari/537.36"); Use code with caution. 5. Proper Debugging (The "Safety Net")