Implementing asynchronous calling of multi-threaded program code in PHP

Implementing asynchronous calling of multi-threaded program code in PHP_PHP tutorial

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Release： 2016-07-20 11:11:02

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This article introduces in detail the implementation of asynchronous calling multi-threading methods in PHP. Next, we will send a recommendation email to 1,000 users. The user enters or imports the email account and submits it to the server for execution.

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 sending.

The code is as follows

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代码如下

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$sqlserver/42852.htm target=_blank >count=count($emailarr);

for($i=0;$i<$count;$i )

{

　　sendmail(.....);//发送邮件

}

$sqlserver/42852.htm target=_blank >count=count($emailarr);

for($i=0 ;$i<$count;$i )

{

sendmail(....);//Send mail

}

? >

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

At this time we need "asynchronous execution" technology to execute the code. The characteristic of asynchronous execution is silent execution in the background. The user does not need to wait for the execution result 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

代码如下

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$domain="www.***.com";
$url="/system_mail.php";
$par="email=".implode(',',$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 ''发送完毕';
?>
system_mail.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
?>

3. Improve the scalability of the program4. In certain scenarios Improved user experience5. Because PHP does not support multi-threading, using asynchronous calls to request multiple HTTPs achieves the effect of parallel execution of the program. However, please note that if too many HTTP requests are requested, the time will be greatly increased. The system overhead is increasedUser experience: User waits ->Sending completedFriends will ask, why is the sending link missing? OK, when the user submits the request, the email sending task is transferred to a PHP program that handles the sending of letters separately. When the user sees "Sent Complete", the letter has not been sent yet. At this time, the mail-sending program is working hard in the background, sending out letters one by one sendmail.php

Okay, after changing to asynchronous mode, the user can submit the information and get the result "sent completed" immediately. Letters will be sent one by one in the background until they are sent.

After testing, I have summarized several methods and share them with you:
1. The simplest way is to embed an AJAX call in the HTML code returned to the client, or embed an img tag, src points 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 bar of the user's browser always shows that it is still loading.
Of course, other methods with similar principles can also be used, such as script tags, etc.

2. popen()

resource popen (string command, string mode);
//Open a pipe pointing to the process that is executed by deriving the given command command produce. 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.

The code is as follows

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$domain= "www.***.com";<🎜>$url="/system_mail.php";<🎜>$par="email=".implode(',',$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 ''Sent completed';<🎜>?>system_mail.phpini_set("ignore_user_abort",true);<🎜>ignore_user_abort(true);//The code here requires php.ini to enable relevant options to ensure that PHP execution does not time out. If you don’t understand, please refer to my other article "Will the php script continue to run after closing the browser?" <🎜>//Get the email address and send a message. Here is the sending code <🎜>?>

代码如下	复制代码
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.

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

$curl_opt = array(CURLOPT_URL, 'http://www.example.com/backend.php',

The code is as follows

代码如下

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$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);

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$ch = curl_init();

代码如下

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$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);

if (!$fp) {

echo "$errstr ($errno)
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);

}

CURLOPT_RETURNTRAN SFER , 1, CURLOPT_TIMEOUT, 1,); curl_setopt_array($ch, $curl_opt);curl_exec( $ch); curl_close($ch); 4. Using fsockopen should be the most perfect method Yes, but the disadvantage is that you need to spell out the HTTP header part yourself.

The code is as follows

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$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);if (!$fp) { echo "$errstr ($errno)
n";} else { $out = "GET /backend.php / HTTP/1.1rn"; $out .= "Host: www.example.comrn"; $out .= "Connection: Closernrn"; fwrite($fp , $out); /*Ignore the execution resultwhile (!feof($fp)) {echo fgets($fp, 128); }*/ fclose($fp);}