How to implement asynchronous calling of multi-threads in PHP

In the previous article, we introduced to you the implementation method of PHP multi-threading. So today we will introduce to you in detail the method of PHP to implement asynchronous calling of multi-threading. I hope that through this article, you can further advance your understanding of PHP multi-threading. !

For example, there is a scenario where a recommendation email is sent to 1,000 users. The user enters or imports the email account and submits it to the server for execution.

The first solution:

<?php
$count=count($emailarr);
for($i=0;$i<$count;$i )
{
sendmail(.....);//发送邮件
}
?>

This code has a very poor user experience and cannot be used in practice. First of all, sending so many emails will cause the server to run timeout. In fact, the long user waiting time will make users doubt and lose confidence in the system product. However, the user does not need to wait until all 1,000 emails have been sent before submitting the email successfully. We can directly prompt the user to send successfully after submitting to the background, and then let the background program silently send the emails one by one.

The second solution:

We try to use "asynchronous execution" technology to execute the code. The characteristics of asynchronous execution are Silent execution in the background, users do not need to wait for the execution results of the code. The benefits of using asynchronous execution:

1. Get rid of the application's dependence on a single task

2. Improve the execution efficiency of the program

3. Improved program scalability

4. Improved user experience in certain scenarios

5. Because PHP does not support multi-threading, there are many requests using asynchronous calls The HTTP method achieves the effect of parallel execution of the program, but it should be noted that if too many HTTP requests are made, the system overhead will be greatly increased

User experience: The user waits ->Sending is completed
Then The task of sending letters is transferred to a PHP program that handles sending letters separately. When the user sees "Sent completed", the letter has not been sent yet. At this time, the sending program is working hard in the background, sending each letter one by one. Sealed and sent out

<?php 
$domain="www.***.com"; 
$url="/system_mail.php"; 
$par="email=".implode(&#39;,&#39;,$emailarr)."&........"; 
$header = "POST $url HTTP/1.0rn"; 
$header .= "Content-Type: application/x-www-form-urlencodedrn"; 
$header .= "Content-Length: " . strlen($par) . "rnrn"; 
$fp = @fsockopen ($domain, 80, $errno, $errstr, 30); 
fputs ($fp, $header . $par); 
fclose($fp);
echo &#39;&#39;发送完毕&#39;; 
?> 
system_mail.php 
<?php 
ini_set("ignore_user_abort",true); 
ignore_user_abort(true);//此处的代码需要php.ini开启相关的选项，保证php执行不超时的，不明白，参考我的另一篇文章 “关闭浏览器后,php脚本会不会继续运行” 
//获取email地址，发信，此处为发信代码 
?>

The third method:

1. The simplest way is to embed the AJAX call in the HTML code returned to the client. Alternatively, embed an img tag with src pointing to the time-consuming script to be executed.
This method is the simplest and fastest. The server does not need to make any calls.
But the disadvantage is that generally speaking, Ajax should be triggered after onLoad. That is to say, if the user clicks on the page and then closes it, our background script will not be triggered.
If you use the img tag, this method cannot be called asynchronous execution in the strict sense. The user's browser will wait for a long time for the execution of the php script to be completed, that is, the status column of the user's browser always shows that it is still loading.
Of course, you can also use other methods with similar principles, such as script tags and so on.

The fourth method:

popen()

resource popen ( string command, string mode );

//Open a pipe pointing to the process , the process is spawned by the execution of the given command command. Opens a pipe to the process spawned by execution of the command that spawned the given command.

So you can call it but ignore its output.

pclose(popen("/home/xinchen/backend.php &", 'r'));

This method avoids the shortcomings of the first method and is also fast. But the problem is that this method cannot request another WebService through the HTTP protocol and can only execute local script files. And it can only be opened in one direction, and cannot pass a large number of parameters to the called script.
And if the number of visits is high, a large number of processes will be generated. If you use external resources, you have to consider the competition yourself.

The fifth method:

Use CURL
This method, set CUROPT_TIMEOUT to 1 (the minimum is 1, depressed). That is, the client must wait at least 1 second.

$ch = curl_init();
$curl_opt = array(CURLOPT_URL, 'http://www.example.com/backend.php',
                            CURLOPT_RETURNTRANSFER, 1,
                            CURLOPT_TIMEOUT, 1,);
curl_setopt_array($ch, $curl_opt);
curl_exec($ch);
curl_close($ch);

The sixth method:

Use fsockopen
This method should be the most perfect, but the disadvantage is that you need to spell out the HTTP header part yourself .

$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);
if (!$fp) {
    echo "$errstr ($errno)<br />n";
} else {
    $out = "GET /backend.php / HTTP/1.1rn";
    $out .= "Host: www.example.comrn";
    $out .= "Connection: Closernrn";
    fwrite($fp, $out);
    /*忽略执行结果
while (!feof($fp)) {
echo fgets($fp, 128);
}*/
    fclose($fp);
}

Summary:

The above six methods are examples of asynchronous calling of multi-threads in PHP. Each method has its own characteristics. , you can choose the method that suits you according to your needs!

Related recommendations;

Introduction to three methods of php multi-thread simulation implementation

php multi-threading implementation example

php multi-threading implementation method-shell

PHP multi-threading small case

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