php curl multi error handler - php

Question

i want to capture curl errors and warnings in my error handler so that they do not get echoed to the user. to prove that all errors have been caught i prepend the $err_start string to the error. currently here is a working (but simplified) snippet of my code (run it in a browser, not cli):
<?php
set_error_handler('handle_errors');
test_curl();
function handle_errors($error_num, $error_str, $error_file, $error_line)
{
$err_start = 'caught error'; //to prove that the error has been properly caught
die("$err_start $error_num, $error_str, $error_file, $error_line<br>");
}
function test_curl()
{
$curl_multi_handle = curl_multi_init();
$curl_handle1 = curl_init('iamdooooooooooown.com');
curl_setopt($curl_handle1, CURLOPT_RETURNTRANSFER, true);
curl_multi_add_handle($curl_multi_handle, $curl_handle1);
$still_running = 1;
while($still_running > 0) $multi_errors = curl_multi_exec($curl_multi_handle, $still_running);
if($multi_errors != CURLM_OK) trigger_error("curl error [$multi_errors]: ".curl_error($curl_multi_handle), E_USER_ERROR);
if(strlen(curl_error($curl_handle1))) trigger_error("curl error: [".curl_error($curl_handle1)."]", E_USER_ERROR);
$curl_info = curl_getinfo($curl_handle1); //info for individual requests
$content = curl_multi_getcontent($curl_handle1);
curl_multi_remove_handle($curl_multi_handle, $curl_handle1);
curl_close($curl_handle1);
curl_multi_close($curl_multi_handle);
}
?>
note that my full code has multiple requests in parallel, however the issue still manifests with a single request as shown here. note also that the error handler shown in this code snippet is very basic - my actual error handler will not die on warnings or notices, so no need to school me on this.
now if i try and curl a host which is currently down then i successfully capture the curl error and my script dies with:
caught error 256, curl error: [Couldn't resolve host 'iamdooooooooooown.com'], /var/www/proj/test_curl.php, 18
however the following warning is not caught by my error handler function, and is being echoed to the page:
Warning: (null)(): 3 is not a valid cURL handle resource in Unknown on line 0
i would like to capture this warning in my error handler so that i can log it for later inspection.
one thing i have noticed is that the warning only manifests when the curl code is inside a function - it does not happen when the code is at the highest scope level. is it possible that one of the curl globals (eg CURLM_OK) is not accessible within the scope of the test_curl() function?
i am using PHP Version 5.3.2-1ubuntu4.19
edits
updated the code snippet to fully demonstrate the error
the uncaptured warning only manifests when inside a function or class method

Answer 1

I don't think i agree with the with the way you are capturing the error ... you can try
$nodes = array(
"http://google.com",
"http://iamdooooooooooown.com",
"https://gokillyourself.com"
);
echo "<pre>";
print_r(multiplePost($nodes));
Output
Array
(
[google.com] => #HTTP-OK 48.52 kb returned
[iamdooooooooooown.com] => #HTTP-ERROR 0 for : http://iamdooooooooooown.com
[gokillyourself.com] => #HTTP-ERROR 0 for : https://gokillyourself.com
)
Function Used
function multiplePost($nodes) {
$mh = curl_multi_init();
$curl_array = array();
foreach ( $nodes as $i => $url ) {
$url = trim($url);
$curl_array[$i] = curl_init($url);
curl_setopt($curl_array[$i], CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl_array[$i], CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)');
curl_setopt($curl_array[$i], CURLOPT_CONNECTTIMEOUT, 5);
curl_setopt($curl_array[$i], CURLOPT_TIMEOUT, 15);
curl_setopt($curl_array[$i], CURLOPT_FOLLOWLOCATION, true);
curl_setopt($curl_array[$i], CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($curl_array[$i], CURLOPT_SSL_VERIFYPEER, 0);
curl_multi_add_handle($mh, $curl_array[$i]);
}
$running = NULL;
do {
usleep(10000);
curl_multi_exec($mh, $running);
} while ( $running > 0 );
$res = array();
foreach ( $nodes as $i => $url ) {
$domain = parse_url($url, PHP_URL_HOST);
$curlErrorCode = curl_errno($curl_array[$i]);
if ($curlErrorCode === 0) {
$info = curl_getinfo($curl_array[$i]);
$info['url'] = trim($info['url']);
if ($info['http_code'] == 200) {
$content = curl_multi_getcontent($curl_array[$i]);
$res[$domain] = sprintf("#HTTP-OK %0.2f kb returned", strlen($content) / 1024);
} else {
$res[$domain] = "#HTTP-ERROR {$info['http_code'] } for : {$info['url']}";
}
} else {
$res[$domain] = sprintf("#CURL-ERROR %d: %s ", $curlErrorCode, curl_error($curl_array[$i]));
}
curl_multi_remove_handle($mh, $curl_array[$i]);
curl_close($curl_array[$i]);
flush();
ob_flush();
}
curl_multi_close($mh);
return $res;
}

Answer 2

it is possible that this is a bug with php-curl. when the following line is removed, then everything behaves ok:
if(strlen(curl_error($curl_handle1))) trigger_error("curl error: [".curl_error($curl_handle1)."]", E_USER_ERROR);
as far as i can tell, curling a host that is down is corrupting $curl_handle1 in some way that the curl_error() function is not prepared for. to get around this problem (until a bug fix is made) just test if the http_code returned by curl_getinfo() is 0. if it is 0 then do not use the curl_error function:
if($multi_errors != CURLM_OK) trigger_error("curl error [$multi_errors]: ".curl_error($curl_multi_handle), E_USER_ERROR);
$curl_info = curl_getinfo($curl_handle1); //info for individual requests
$is_up = ($curl_info['http_code'] == 0) ? 0 : 1;
if($is_up && strlen(curl_error($curl_handle1))) trigger_error("curl error: [".curl_error($curl_handle1)."]", E_USER_ERROR);
its not a very elegant solution, but it may have to do for now.