php asynchronous cURL request

Use blow to make async curl call

    curl_setopt($crl, CURLOPT_TIMEOUT, 1);
    curl_setopt($crl, CURLOPT_NOSIGNAL, 1);

PHP SetOpt

If you want to send multiple curl requests parallely, curl_multi will be helpful as below:

// 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);

//execute the multi handle
do {
    $status = curl_multi_exec($mh, $active);
    if ($active) {
        curl_multi_select($mh);
    }
} while ($active && $status == CURLM_OK);

//close the handles
curl_multi_remove_handle($mh, $ch1);
curl_multi_remove_handle($mh, $ch2);
curl_multi_close($mh);

You can customize this code ex. use loop for creating curl requests etc.

Ref : https://www.php.net/manual/en/function.curl-multi-init.php

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.

Add requirements to composer:

"require": {
    ...
    "graceas/php-simple-curl-wrapper": "v1.5.4"
    ...
}

Initiate requests:

$requests = [
    (new \SimpleCurlWrapper\SimpleCurlRequest())
        ->setUrl('http://ip-api.com/json?r=1')
        ->setMethod(\SimpleCurlWrapper\SimpleCurlRequest::METHOD_GET)
        ->setHeaders([
            'Accept: application/json',
            'User-Agent: simple curl wrapper',
        ])
        ->setOptions([
            CURLOPT_FOLLOWLOCATION => false,
        ])
        ->setCallback('loadCallback'),
    (new \SimpleCurlWrapper\SimpleCurlRequest())
        ->setUrl('http://ip-api.com/json?r=2')
        ->setMethod(\SimpleCurlWrapper\SimpleCurlRequest::METHOD_GET)
        ->setHeaders([
            'Accept: application/json',
            'User-Agent: simple curl wrapper',
        ])
        ->setOptions([
            CURLOPT_FOLLOWLOCATION => false,
        ])
        ->setCallback('loadCallback'),
];

Initiate callback:

function loadCallback(\SimpleCurlWrapper\SimpleCurlResponse $response) {
    print_r($response->getRequest()->getUrl());
    print_r($response->getHeadersAsArray());
    print_r($response->getBodyAsJson());
}

Initiate wrapper and execute requests:

$wrapper = new \SimpleCurlWrapper\SimpleCurlWrapper();
$wrapper->setRequests($requests);
$wrapper->execute(2); // how many requests will be executed async

If you wish to send asynchronous cUrl requests then we need to use curl_multi_init().

I share sample code about Simultaneous cURL requests using curl_multi_exec in PHP Foreach loop

<?php
$products = [
    [
        "name" => "test",
        "slug" => "test-product"
    ],
    [
        "name" => "test-data",
        "slug" => "test-data"
    ],
];

$adminToken = "your-api-access-token";
// array of curl handles
$multiCurl = array();
$result = array();

//create the multiple cURL handle
$mh = curl_multi_init();

$headers = ['Content-Type:application/json', 'Authorization:Bearer ' . $adminToken];
$apiUrl = $this->baseUrl . "products/create";

foreach ($products as $key => $product) {
    $productData["product"] = $product;
    $dataString = json_encode($productData);

    $multiCurl[$key] = curl_init();
    curl_setopt($multiCurl[$key], CURLOPT_URL, $apiUrl);
    curl_setopt($multiCurl[$key], CURLOPT_CUSTOMREQUEST, "POST");

    curl_setopt($multiCurl[$key], CURLOPT_POSTFIELDS, $dataString);
    curl_setopt($multiCurl[$key], CURLOPT_RETURNTRANSFER, true);
    curl_setopt($multiCurl[$key], CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($multiCurl[$key], CURLOPT_HTTPHEADER, $headers);
    curl_multi_add_handle($mh, $multiCurl[$key]);
}
$index = null;
do {
    curl_multi_exec($mh,$index);
} while($index > 0);

// get content and remove handles
foreach($multiCurl as $k => $ch) {
    $result[$k] = curl_multi_getcontent($ch);
    curl_multi_remove_handle($mh, $ch);
}
// close
curl_multi_close($mh);
return $result;

I hope this one helps to you...

Use this function

//background excute and wait for response
private function BackgroundsendPostData($url, Array $post) {
    $data = "";
    foreach ($post as $key => $row) {
        $row = urlencode($row); //fix the url encoding
        $key = urlencode($key); //fix the url encoding                
        if ($data == "") {
            $data .="$key=$row";
        } else {
            $data .="&$key=$row";
        }
    }
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_TIMEOUT_MS, 2000);
    $result = curl_exec($ch);
    curl_close($ch);  // Seems like good practice
    return;
}
//usage 
BackgroundsendPostData("http://www.google.co.uk/",array('pram1'=>'value1','pram2'=>'value2'));