how to make non blocking call in php - php

Question

I am using a php script to upload lot of files. I am using the CURL command . The remote server accepts only POST requests. But when I execute the below script it processes the first request and waits until the first file is uploaded. Is there a way to make it non blocking and run simultaneous 2 curl upload requests .Find the code sample below.
<?php
$arr= array(somefile1.txt,somefile2.txt);
for ( $i=0;$i<2;$i++) {
$cmd = "curl -F name=aaa -F type=yyy FileName=#/xxxxx/xxxx/$arr[$i] http://someurl.com";
print "Executing file ";
shell_exec("nohup $cmd 2> /dev/null & echo $!" );
print "======= done ================";
}
?>

Answer 1

I believe you may want curl_multi_init. Here is an outbound example; it will have to be adapted for your inbound problem. This seems cleaner than you forking multiple threads yourself.
<?php
// create both cURL resources
$ch1 = curl_init();
$ch2 = curl_init();
// set URL and other appropriate options
curl_setopt($ch1, CURLOPT_URL, "http://lxr.php.net/");
curl_setopt($ch1, CURLOPT_HEADER, 0);
curl_setopt($ch2, CURLOPT_URL, "http://www.php.net/");
curl_setopt($ch2, CURLOPT_HEADER, 0);
//create the multiple cURL handle
$mh = curl_multi_init();
//add the two handles
curl_multi_add_handle($mh,$ch1);
curl_multi_add_handle($mh,$ch2);
$active = null;
//execute the handles
do {
$mrc = curl_multi_exec($mh, $active);
} while ($mrc == CURLM_CALL_MULTI_PERFORM);
while ($active && $mrc == CURLM_OK) {
if (curl_multi_select($mh) != -1) {
do {
$mrc = curl_multi_exec($mh, $active);
} while ($mrc == CURLM_CALL_MULTI_PERFORM);
}
}
//close the handles
curl_multi_remove_handle($mh, $ch1);
curl_multi_remove_handle($mh, $ch2);
curl_multi_close($mh);
?>

Answer 2

There is a good article about "multithreading", take a look at it here: Multithreading in PHP with CURL

Answer 3

You can try use PHP Simple Curl Wrapper - https://github.com/Graceas/php-simple-curl-wrapper. This library allows the processing of multiple request's asynchronously.
You can find full answer here: php asynchronous cURL request

Answer 4

No you cannot run simultaneously two curl statements.
Curl is made for working like this. A Curl statement will make the later statements
wait until it finishes its operation.