PHP scheduled tasks and fsockopen continuous process examples_PHP tutorial

The web server executes a PHP script, and sometimes it takes a long time to return the execution results, and subsequent scripts need to wait for a long time before they can continue to execute.
If you want to simply trigger the execution of a time-consuming script without waiting for the execution result and directly perform the next operation, you can use the fscokopen function to achieve this.

PHP supports socket programming. The fscokopen function returns a handle to the remote host connection. You can perform fwrite, fgets, fread and other operations on it just like using the handle returned by fopen.
Use fsockopen to connect to the local server, trigger script execution, and then return immediately without waiting for the script execution to complete, thereby achieving the effect of asynchronous PHP execution.

Example:

Copy code The code is as follows:

function triggerRequest($url, $post_data = array() , $cookie = array()){
$method = "GET"; //Pass some parameters to the script to be triggered via POST or GET
$url_array = parse_url($url); //Get URL information
$port = isset($url_array['port'])? $url_array['port'] : 80;
$fp = fsockopen($url_array['host'], $port, $errno, $ errstr, 30);
if (!$fp) {
return FALSE;
}
$getPath = $url_array['path'] ."?". $url_array['query'] ;
if(!empty($post_data)){
$method = "POST";
}
$header = $method . " " . $getPath;
$header .= " HTTP/1.1rn";
$header .= "Host: ". $url_array['host'] . "rn "; //HTTP 1.1 Host field cannot be omitted
/*The following header information fields can be omitted
$header .= "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13 rn";
$header .= "Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,q=0.5 rn";
$header .= "Accept-Language: en-us,en;q=0.5 ";
$header .= "Accept-Encoding: gzip,deflatern";
*/

$header .= "Connection:Closern";
if(!empty($cookie)){
$_cookie = strval(NULL);
foreach($cookie as $k => $v){
$_cookie .= $k."=".$v."; ";
}
$cookie_str = "Cookie: " . base64_encode($_cookie) ." rn"; // Pass Cookie
$header .= $cookie_str;
}
if(!empty($post_data)){
$_post = strval(NULL);
foreach($post_data as $k => $v ){
$_post .= $k."=".$v."&";
}
$post_str = "Content-Type: application/x-www-form-urlencodedrn";
$post_str .= "Content-Length: ". strlen($_post) ." rn"; //The length of POST data
$post_str .= $_post."rnrn "; //Transfer POST data
$header .= $post_str;
}
fwrite($fp, $header);
//echo fread($fp, 1024); //The server returns
fclose($fp) ;
return true;
}

In this way, the execution of a PHP script can be triggered through the fsockopen() function, and then the function will return. Then proceed to the next step.
There is a problem now: when the client disconnects, that is, after triggerRequest sends the request, the connection is closed immediately, which may cause the script being executed on the server to exit

Inside PHP, the system maintains the connection status, and its status has three possible situations:

* 0 - NORMAL (normal)
* 1 - ABORTED (abnormal exit)
* 2 - TIMEOUT (timeout)

When the PHP script runs NORMAL normally status, the connection is valid. When the client disconnects, the ABORTED status flag will be turned on. The interruption of the remote client connection is usually caused by the user clicking the STOP button. When the connection time exceeds PHP's time limit (see set_time_limit() function), the TIMEOUT status flag will be turned on.

You can decide whether the script needs to exit when the client disconnects. Sometimes it is convenient to have a script run completely, even if no remote browser accepts the script's output. The default is that the script will exit when the remote client connection is interrupted. This processing can be controlled by ignore_user_abort in php.ini or by the corresponding "php_value ignore_user_abort" and ignore_user_abort() functions in the Apache .conf settings. If PHP is not told to ignore user interruptions, the script will be interrupted, unless register_shutdown_function() allows us to set another function that can be called when execution is shut down. This means that when our script completes execution or dies unexpectedly When the PHP execution is about to be shut down, our function will be called. When the remote user clicks the STOP button and the script tries to output data again, PHP will detect that the connection has been interrupted and call the shutdown trigger function.

Scripts may also be interrupted by the built-in script timer. The default timeout limit is 30 seconds. This value can be changed by setting max_execution_time in php.ini or the corresponding "php_value max_execution_time" parameter in the Apache .conf settings or the set_time_limit() function. When the counter times out, the script will exit similar to the above connection interruption situation, and the previously registered shutdown trigger function will also be executed at this time. In the shutdown trigger function, you can check whether the timeout caused the shutdown trigger function to be called by calling the connection_status() function. If a timeout results in a call to the shutdown triggering function, the function will return 2.

Note that the ABORTED and TIMEOUT states can be valid at the same time. This is possible when telling PHP to ignore user exit actions. PHP will still notice that the user has disconnected but the script is still running. If the running time limit is reached, the script will be exited and the set shutdown trigger function will also be executed. At this point you will find that the function connection_status() returns 3.

So also specify in the script to be triggered:

Copy code The code is as follows:

ignore_user_abort(TRUE); //If the client is disconnected Opening a connection will not cause the script to abort
set_time_limit(0); //Cancel the upper limit of script execution delay
or use:
register_shutdown_function(callback function[, parameters]); //Function executed when the registration script exits

http://www.bkjia.com/PHPjc/774992.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/774992.htmlTechArticleThe web server executes a PHP script. Sometimes it takes a long time to return the execution results, and subsequent scripts need to wait for a long time. It will take some time to continue execution. If you want to achieve a simple trigger that takes time...