PHP curl exec fail on php script same domain

Question

I use php curl to get content from a php script in the same domain url. But I get curl_exec error. The curl error code is 28 or operation timed out. After days of debugging, I found that it works on non script page like htm, but not php, it also works if the url is a script on different domain. I have been debugging for days and found no solutions. Helps appreciated.

$url = 'http://...';
$agent = '';
$ch = curl_init();
curl_setopt ($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 8);
curl_setopt($ch, CURLOPT_TIMEOUT, 8);
$result = curl_exec ($ch);
print "<pre>\n";
print_r(curl_getinfo($ch));
// get error info echo "\n\ncURL error number:" .curl_errno($ch);
// print error info echo "\n\ncURL error:" . curl_error($ch);
print "</pre>\n";
curl_close ($ch);
echo $result;

cURL error number:28 cURL error:

Operation timed out after 8000 milliseconds with 0 bytes received

Okay: $url = http://.../page.htm Fail: $url = http://.../page.php

Answer 1

You're not setting the User Agent. Some servers actually do not even respond to such requests (thus the client doesn't know the connection dropped).

Add the following to your code:

curl_setopt($ch, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);

Additionally, I use the following in my CURL functionality:

curl_setopt($ch,CURLOPT_FOLLOWLOCATION,true);
curl_setopt($ch,CURLOPT_MAXREDIRS,50);
if(substr($url,0,8)=='https://'){
    // The following ensures SSL always works. A little detail:
    // SSL does two things at once:
    //  1. it encrypts communication
    //  2. it ensures the target party is who it claims to be.
    // In short, if the following code is allowed, CURL won't check if the 
    // certificate is known and valid, however, it still encrypts communication.
    curl_setopt($ch,CURLOPT_HTTPAUTH,CURLAUTH_ANY);
    curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,false);
}

Answer 2

Maybe because of session locks
Try to drop session_start() from page which you try to get using cURL

Also see this session.auto-start

Answer 3

Set into CURL setting

curl_setopt($ch, CURLOPT_TIMEOUT, 300); // 300 seconds

If still have issue so run the script with following location disable.

curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);