Here is how I've implemented it:
add_action( 'delete_post', array( 'MyClassName', 'delete' ) );
In the delete function I was using a $wpdb->insert command to see whether the function gets called. But I see that the $wpdb->insert command is called twice (inserts two rows in my table). Any ideas as to why something like this might happen?
I've also attempted to use the before_delete_post hook since it doesn't really make a difference to me but I get the same outcome.
EDIT:
It seems as though the delete function is called for each entry in the wp_posts table for some reason. So if the post has 3 revisions, the delete function will be called 4 times (the original post + 3 revisions). This is really weird behavior.
I found my solution.
The function you hook into delete_post (or probably any other similar hook) executes as many times as needed. Considering delete_post needs to delete the post and all of its revisions, it will always run more than once. In order to avoid having your function execute each time WordPress deletes a record from the database you can use did_action( $hook ). This function returns the number of times the hook executed. With this in consideration, we can fix our multiple-executions problem by placing this condition into our function:
if (did_action('delete_post') === 1)
{
// execute code here
}
Related
Using 'AutomateWoo plugin', I would like to trigger a function when the status of an order changes to 'Processing'.
I want the function to give me the variations selected by the shopper, in a key-value style.
I wrote a function based on this article here, but it didn't work. The function ran but the variables didn't output anything.
Is there a way to resolve this?
Right now I am checking the saved post for certain conditions. If the conditions fail the post is set to draft and an admin notice is displayed to let the user know what needs to change.
The timing of the hooks require me to do the same or similar functions twice. Once for each hook. I would like to reduce overhead if possible.
When wp_insert_post_data runs, I check the content and if it doesn't pass the checks, it sets it to draft. When admin_notices runs the post status has already been set and is unchangable. Is there a different hook I should be using? Or is there a better way to do this?
There are many other checks being done in the real code. Here is a basic example of what I'm doing:
add_action( 'admin_notices', 'incorrect_content_notices' );
function notice_of_incorrect_content() {
/**
* Do a bunch of conditional checks. These also get done in another hook.
*/
}
add_filter( 'wp_insert_post_data', 'incorrect_content_set_to_draft', 99 );
function incorrect_content_set_to_draft( $post_data ) {
/**
* Do a bunch of conditional checks that were already done in another hook.
*/
}
Do custom hooks that hook onto wordpress core get executed automatically by wordpress or do we have to call the do_action function on the custom made hook ourselves?
Example:
add_action("action_one","some_process",10);
add_action("action_one","some_different_process",11);
function some_process(){ //... }
function some_different_process(){ //... }
do_action("action_one");
Does some_process get executed first and then some_different_process gets executed after when do_action("action_one") is called?
If you create custom action hooks that exist within your custom theme or plugin, then yes, you have to call them via do_action in the appropriate location where you would want them to be triggered.
WordPress does not automatically find action hooks and trigger them. It has a number of built-in hooks which you can latch onto in order to run custom code, but if you create your own hooks, then you need to also set up the appropriate do_action call in order to run them.
To answer your other question regarding the execution order of some_process and some_different_process, some_process will be run before some_different_process because it had a lower priority number.
If you want an action to run early, give it a low number like 1 or 5, if you don't care where it runs or want it to run last, I usually use a much higher number like 100 or 1000. If two hooks are defined with the same priority, usually the one that got registered first will run before the other one with the same priority.
All functions that are hooked onto an action are automatically executed IF that action is called, but they are not called if the action is not triggered.
For example if you have:
add_action("action_one","some_function",10);
Then some_function will be called if action_one is triggered. If action_one is never triggered, some_function is not called.
do_action is a mechanism to manually trigger the action, though keep in mind it will trigger ANY hooks into that action, not just yours (unless you setup some filters).
Another example: let's say you setup a custom function to run on the action save_post:
add_action( 'save_post', 'top_secret_function' );
Then every time you a save a post your top_secret_function will run.
If you want to trigger save_post manually (without actually saving a post) you can do so with:
do_action( 'save_post' );
and it will trigger your top_secret_function, but this would generally not be recommended because it will also trigger any other function that is hooked into save_post (which many plugins and core files do).
You can setup custom actions using a combination of add_action and do_action.
I found something similar here: http://wordpress.org/support/topic/publish_post-hook-multiple-firing
Basically I am using the edit hook in wordpress to add some data to a table, and the function gets called twice. The first time it goes with its default values, the second time it has the actual data.
Anyone come up with this issue? Is it really an issue or I am missing something?
Action:
add_action('edit_post', 'my_func');
Function:
function my_func() {
if(!wp_is_post_revision($post_ID)) {
// Code to get $_POST data, omitted
// Call to the database here, omitted
}
Thanks.
edit_post is triggered when you edit AND update the post(even when a comment is added to that post) . What you need is the publish_post hook. Read this page for more info.
I have developed wordpress for days,but I have found no way to these like:add_action,add_filter,user_can, I don't know what are the functions they refere to.
worse still,I don't know the parameter,today I want add a column to user list table admin panel,I fortunatelly found a tutorial, here is the code
add_filter( 'manage_users_columns', 'add_user_column');
function add_user_column( $columns){
$columns['available_stickers'] = __('Stickers Available', 'available_stickers');
return $columns;
}
add_filter('manage_users_custom_column', 'add_user_column_value', 10, 3);
function add_user_column_value( $value, $column_name, $user_id ){
if ( 'available_sticker' == $column_name)
$value = get_user_meta($user_id,"available_stickers",true);
return $value;
}
Even thought I made it, but I don't know where the parameter manage_users_columns comes or why I should use manage_users_columns but not other code? Puzzled
and also they have matched code like apply_filter etc.
some one can help me out of the maze,oops!
WordPress is beautifully designed because most of the actions it does are not executed directly, but through what are called actions and filters. This gives you, the developer, a possibility to hook onto any of these operations. Hooking means you can squeeze your own logic right in the middle of WP's logic, in a very clean way, only by declaring that you want things to be done where the corresponding hooks are used. More precisely:
Actions
So, for example, when a post is saved, WordPress does not just save the post, it does it by executing this line:
do_action( 'save_post', $post_ID, $post );
This is a way to give a name to this action (save_post). That means two things :
1) you can execute the exact same action by using the same line of code somewhere else.
2) you can add your own logic to be executed during this action. How? just by "adding" your custom functions to the action, like this :
add_action('save_post', 'name_of_the_function_you_want_to_execute_when_post_is_saved');
So 'save_post' is the name of the hook, add_action gives you the possibility to add your own function to the action for this hook and do_action actually executes the action.
Filters
Filters are similar to actions, but instead of being used when executing a command, they are used to treat a value, an object, a string or some text (when "filtering" it). Again, instead of just manipulating objects and strings in such a way that you would have no other possibility than dive into the core code to access it, WordPress cleverly does many of its "filtering" operations with a special action called apply_filters(). This gives you the possibility, like for actions, to actually add your own filters to the filters already applied. So when showing the content of a post, WP would execute :
apply_filters('the_content', $post->post_content);
The name of the hook is the_content. If you use :
add_filter('the_content', 'your_function_to_execute_to_further_filter_content');
you can have a function named your_function_to_execute_to_further_filter_content()that can take the content as a parameter and return the filtered version of it after whatever treatment you wish to apply to it. Then this treatment will get applied anywhere in WP where the hook the_content is used to execute these filters (including WP default ones, plug-ins filters that were added to the same hook, and your own).
So here, you are using these hooks so you can interfere with WP operations without messing WP core code. You declare the extra operations you wish to execute and you let WP aware of this. WP will then have the courtesy to execute your functions everytime the corresponding hook action or filter is being executed.