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Principle of PHP5 scheduled task offline function_PHP tutorial
- WBOYOriginal
- 2016-07-13 17:42:431025browse
In order to update a certain file regularly, the program needs to run automatically. I found two methods from the Internet: ignore_user_abort() and crontab
The ignore_user_abort() function can be used with set_time_limit(0) and sleep($interval) to realize automatic program running and updating. Here is an example
ignore_user_abort(); //Even if the Client is disconnected (such as closing the browser), the PHP script can continue to execute.
set_time_limit(0); // The execution time is unlimited. The default execution time of PHP is 30 seconds. Through set_time_limit(0), the program can be executed without limit
$interval=60*5; // Run every 5 minutes
do{
$fp = fopen(test.txt,a);
fwrite($fp,test);
fclose($fp);
sleep($interval); // Wait 5 minutes
}while(true);
?>
As long as you run the page above and then close it, the program will continue to run.
There is a simpler method under Linux, which is the crontab command
The function of the crontab command is to schedule the execution of some commands at a certain time interval.
How to use crontab: crontab [ -e | -l | -r ] file name -e: edit task -l: display task information -r: delete scheduled execution task information
crontab format:
* * * * * Command
Minute Hour Day Month Weekday Command to run
Example of crontab:
*/5 * * * * lynx http://www.BkJia.com
Visit www.2cto.com every 5 minutes
0 8 * * * lynx http://www.BkJia.com
Visit www.2cto.com at 8am every day
0 10 6 * 1-5 lynx http://www.BkJia.com
Visit www.2cto.com on the 6th of every month and every Monday to Friday at 10am
0 5 7 8 * lynx http://www.BkJia.com
Visit www.2cto.com at 5am on August 7
Special meanings of the above:
"*" represents all numbers within the value range, "/" represents every, "*/5" represents every 5 units, "-" represents from a certain number to a certain number,", "Separate several discrete numbers.
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