php Asynchronous calling method

The client and server communicate through the HTTP protocol. The client initiates a request and the server receives it. Execute processing after request and return processing results.

Sometimes the server needs to perform a time-consuming operation, and the result of this operation does not need to be returned to the client. But because PHP is executed synchronously, the client needs to wait for the service to be processed before proceeding to the next step.

Therefore, time-consuming operations are suitable for asynchronous execution. After the server receives the request, it returns after processing the data required by the client, and then performs time-consuming operations asynchronously on the server. .

1. Use Ajax and img tag

Principle, the server returns Insert Ajax code or img tag into the html, and the src of img is the program that needs to be executed.

Advantages: Simple implementation, the server does not need to perform any calls

Disadvantages: During execution, the browser will always be in the loading state, so This method is not a true asynchronous call.

$.get("doRequest.php", { name: "fdipzone"} );

2. Use popen

Use popen to execute the command, syntax:

// popen — 打开进程文件指针 
resource popen ( string $command , string $mode )

pclose(popen('php /home/fdipzone/doRequest.php &', 'r'));

Advantages: Fast execution

Disadvantages: 1. Can only be executed on this machine

2. You cannot pass a large number of parameters

3. Many processes will be created when the number of visits is high.

3. Use curl

Set the curl timeoutCURLOPT_TIMEOUT is 1 (minimum is 1), so the client needs to wait for 1 second

##4. Use fsockopen

#fsockopen is the best. The disadvantage is that you need to splice the header part yourself.

'fdipzone',
    'gender'=>'male',
    'age'=>30
);
doRequest($url, $param);
function doRequest($url, $param=array()){
    $urlinfo = parse_url($url);
    $host = $urlinfo['host'];
    $path = $urlinfo['path'];
    $query = isset($param)? http_build_query($param) : '';
    $port = 80;
    $errno = 0;
    $errstr = '';
    $timeout = 10;
    $fp = fsockopen($host, $port, $errno, $errstr, $timeout);
    $out = "POST ".$path." HTTP/1.1\r\n";
    $out .= "host:".$host."\r\n";
    $out .= "content-length:".strlen($query)."\r\n";
    $out .= "content-type:application/x-www-form-urlencoded\r\n";
    $out .= "connection:close\r\n\r\n";
    $out .= $query;
    fputs($fp, $out);
    fclose($fp);
}
?>

Note: During the execution process, the client connection is disconnected or the connection times out, which may cause incomplete execution, so you need to add

ignore_user_abort(true); // 忽略客户端断开
set_time_limit(0);       // 设置执行不超时

Tips: For the introduction and usage of fsockopen, please refer to the "php" I wrote before Use fsockopen GET/POST to submit forms and upload files" and "PHP HTTP request class, support GET, POST, Multipart/form-data"

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