The key difference between WP Cron and the traditional UNIX Cron is that when scheduled tasks are executed with WP Cron, this takes place within the WordPress website. Whereas traditional UNIX scheduled tasks are executed within the server environment. <\/p>\n\n\n\n
The advantage of traditional Unix Cron is that WP Cron is only executed if a user visits your website. <\/p>\n\n\n\n
Unix Cron uses the system\u2019s clock, so you can schedule a time or how often a scheduled task is executed even if there are not any visits to your website. <\/p>\n\n\n\n
Nevertheless, setting up a scheduled task with WP Cron is relatively easy and doesn\u2019t require knowledge of UNIX to configure a command to execute. <\/p>\n\n\n\n
Some use cases of WP Cron include: <\/p>\n\n\n\n
- \n
- Import new products to your website <\/li>\n\n\n\n
- Automate publishing of posts <\/li>\n\n\n\n
- Send out email notifications for your subscribers or customers <\/li>\n<\/ul>\n\n\n\n
Setting up and managing WordPress Cron jobs with a plugin<\/strong><\/h2>\n\n\n\n
There are various ways to setup and manage WordPress cron jobs. In the following example, I\u2019ll use a WordPress plugin called WP Control<\/a>, which will allow you to view and configure WordPress crons. <\/p>\n\n\n\n
With WP Control, you can: <\/p>\n\n\n\n
- \n
- View all cron events, their arguments, when they\u2019re next due to run, the action the event will take and how often the event will run. <\/li>\n\n\n\n
- Add, Edit, delete, pause, resume, and immediately run cron events. <\/li>\n\n\n\n
- Add and remove custom cron schedules. <\/li>\n<\/ul>\n\n\n\n
For this example, \u2019ll use WP Control to create a custom event using wp_mail. <\/p>\n\n\n\n
- \n
- Install WP Control: <\/strong>You can use the usual method of installing the plugin via wp-admin and then activate it.
![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/WP-Control-install.png\")
<\/li>\n\n\n\n- View Cron Events: <\/strong>When the installation has completed, head over to \u2018Cron Events\u2019 under the \u2018Tools\u2019 section. This is where you can view and manage your current cron events. The event names should be recognisable as they would reference part of your plugin name such as \u201cai1wm_storage_cleanup\u201d
![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/WP-control-events.png\")
<\/li>\n\n\n\n- Head over to Appearance > Theme File Editor > Functions.php <\/strong>This is where you will edit the Functions.php file and add the coding for the custom cron event. The following example will send an email using the wp_mail function when the cron has triggered. <\/li>\n<\/ol>\n\n\n\n
add_action( '20i_demo_cron', 'demo_function' ); \n\nfunction demo_function() { \n\nwp_mail( 'sales@20i-demo.com, '20i Demo Cron', 'Hosted By 20i!' ); \n\n}<\/code><\/pre>\n\n\n\nHere is a breakdown of the above code snippet: <\/p>\n\n\n\n
add_action( '20i_demo_cron', 'demo_function' ); <\/code><\/p>\n\n\n\nThis line of code is adding an action hook in WordPress. In this case, we\u2019re creating a custom action hook named ’20i_demo_cron’ and this is what will be used when adding the cron event using WP Control. <\/p>\n\n\n\n
function demo_function() <\/code><\/p>\n\n\n\nThis code defines a custom PHP function called demo_function. This will be called when ’20i_demo_cron’ is triggered. <\/p>\n\n\n\n
{ <\/code>\nwp_mail( 'sales@20i-demo.com, '20i Demo Cron', 'Hosted By 20i!' );<\/code>\n}<\/code> <\/code><\/pre>\n\n\n\nInside
demo_function<\/code> , we\u2019re using the built in WordPress functionwp_mail<\/code> to send an email to sales@20i-demo.com<\/a> with the subject heading \u201820i Demo Cron\u2019 and a message body of \u2018Hosted By 20i!\u2019 <\/p>\n\n\n\n- \n
- From \u2018Cron Events\u2019 > Click Add New: <\/strong>From here, you can create your new cron event. In the following example, I created an event name called \u201820i_demo_cron\u2019, scheduled this to run immediately and to recur daily. \u00a0
![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/WP-Control-create-event.png\")
<\/li>\n\n\n\n- After clicking \u2018Add Event\u2019 this should trigger the event and if you check your inbox, you should have received the email from WordPress with the subject heading \u201820i Demo Cron\u2019 and message \u2018Hosted By 20i!\u2019\u00a0
![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/message-received.png\")
<\/li>\n<\/ol>\n\n\n\nSetting Up and Managing Basic WordPress Cron Jobs using WP-CLI<\/strong><\/h2>\n\n\n\n
WP-CLI stands for WordPress Command Line Interface. It provides a way to manage your WordPress installation via command line rather than through the WordPress admin area. This is available on our hosting via SSH. <\/p>\n\n\n\n
- \n
- Access your hosting via SSH. If you\u2019re a 20i customer, you can access your hosting via SSH by following this guide<\/a>
<\/li>\n<\/ol>\n\n\n\n- \n
- When you\u2019ve accessed your hosting over SSH, you will need to go into your WordPress installation using the \u2018cd\u2019 (change directory) command. In the following example, the WordPress install is in the public_html directory so I just need to run the following command:
cd public_html
<\/code> <\/li>\n<\/ol>\n\n\n\nNow that you\u2019re in the WordPress installation directory, you can now use WP-CLI to manage your cron events. <\/p>\n\n\n\n
Here are some examples of commands you can use to manage your cron events…<\/p>\n\n\n\n
List Cron Events<\/strong><\/h4>\n\n\n\n
You can use the wp cron event list command to list all scheduled cron events on your WordPress site. After running the command, you will see four columns, Hook, next run time, countdown to next run time and recurrence.\u00a0
wp cron event list\u00a0<\/code>![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/wpcronlist.png\")
<\/p>\n\n\n\nRun a Specific Cron Event<\/strong><\/h4>\n\n\n\n
You can manually trigger a specific cron event to run using the wp cron event run command. Replace event-name with the name of the event you want to execute.\u00a0
wp cron event run event-name\u00a0<\/code>![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/wpcronrun.png\")
<\/p>\n\n\n\nSchedule\/Create a new Cron Event<\/strong><\/h4>\n\n\n\n
You can create a new recurring Cron Event using wp-cli. The following command will create a new cron event to run immediately and reoccur daily. \u00a0
\u00a0wp cron event schedule cron_event now daily\u00a0<\/code>![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/wpcron-daily.png\")
By default, WordPress contains the following interval names, and you can use this as part of your command.\u00a0\u00a0<\/p>\n\n\n\n- \n
- hourly:<\/strong> Runs the event once per hour. <\/li>\n\n\n\n
- twicedaily:<\/strong> Runs the event twice per day (every 12 hours). <\/li>\n\n\n\n
- daily: <\/strong>Runs the event once per day (every 24 hours).<\/li>\n<\/ul>\n\n\n\n
Delete a specific Cron Event<\/strong><\/h4>\n\n\n\n
You can manually delete a cron event by running the following command. (replace event_name with the event you want to remove)\u00a0
\u00a0wp cron event delete event_name<\/code>![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/wpcron-delete.png\")
<\/p>\n\n\n\nOptimising WP-Cron with UNIX scheduled task<\/strong> <\/h2>\n\n\n\n
Using a UNIX scheduled task would be more reliable than using WP Cron. Like we mentioned above, wp-cron.php is only triggered when a user visits your website. <\/p>\n\n\n\n
With a UNIX scheduled task, you can schedule the task recur at certain intervals or you specify a time for the cron to run. <\/p>\n\n\n\n
On the other hand, if you have a high traffic website, WP-Cron could be executed multiple times which would put a strain on the server resources and slow down your website. <\/p>\n\n\n\n
If you choose to use the UNIX method, rather than using WP Cron, you will need to add the following line of code to your wp-config.php file to disable WP Cron:
define('DISABLE_WP_CRON', true); <\/code><\/p>\n\n\n\nYou can set up a cron job or ‘scheduled task’ in the Scheduled Tasks section of your hosting packages control panel. <\/p>\n\n\n\n
Manage Hosting -> Manage -> Scheduled Tasks <\/p>\n\n\n\n
You can add a wget command into the command field to call to wp-cron.php which is the function used to trigger your scheduled cron events. Something like the following will work <\/p>\n\n\n\n
- twicedaily:<\/strong> Runs the event twice per day (every 12 hours). <\/li>\n\n\n\n
- hourly:<\/strong> Runs the event once per hour. <\/li>\n\n\n\n
- When you\u2019ve accessed your hosting over SSH, you will need to go into your WordPress installation using the \u2018cd\u2019 (change directory) command. In the following example, the WordPress install is in the public_html directory so I just need to run the following command:
- After clicking \u2018Add Event\u2019 this should trigger the event and if you check your inbox, you should have received the email from WordPress with the subject heading \u201820i Demo Cron\u2019 and message \u2018Hosted By 20i!\u2019\u00a0
- View Cron Events: <\/strong>When the installation has completed, head over to \u2018Cron Events\u2019 under the \u2018Tools\u2019 section. This is where you can view and manage your current cron events. The event names should be recognisable as they would reference part of your plugin name such as \u201cai1wm_storage_cleanup\u201d
- Install WP Control: <\/strong>You can use the usual method of installing the plugin via wp-admin and then activate it.
![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/run-now-wp-control.png\")
<\/p>\n\n\n\n![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/logs-and-stats-20i.png\")
<\/p>\n\n\n\n![\"\"](\"https:\/\/www.20i.com\/blog\/wp-content\/uploads\/2023\/11\/wp-debug.png\")
<\/figure>\n\n\n\n