Why does my save_post action not trigger? - php

Question

I'm writing a plug-in for wordpress in classes and I'm adding an action hook to 'save_post' in the constructor of a class. However it does not seem to fire. Am I using it in the right way?
EDIT 25-05-2014 - I wrote a new (tested) minimal example that definitely reproduces the problem for me.
If I use the save_post in a procedural way (like directly in the index.php) it does work, but obviously that's not helpful when I'm structuring everything in classes.
/*
File index.php
This file handles the installation and bootstrapping of the plugin
*/
define("XX_POST_TYPE", 'testposttype');
if( !class_exists('MyPlugin') ):
class MyPlugin {
var $savecontroller;
public function __construct(){
add_action('init', array($this, 'init'), 1);
//include stuff before activation of theme
$this->include_before_theme();
}
//Include these before loading theme
private function include_before_theme(){
include_once("controllers/savecontroller.php");
}
public function init(){
register_post_type( XX_POST_TYPE,
array(
'labels' => array(
'name' => __('Tests'),
'singular_name' => __('Test'),
'add_new' => __('Add new test'),
'add_new_item' => __('Add new test')
),
'public' => true,
'has_archive' => true,
'hierarchical' => true
)
);
add_action('add_meta_boxes', function(){
$this->savecontroller = new SaveController();
});
}
}
function startup(){
global $myPlugin;
if( !isset($myPlugin) ){
$myPlugin = new MyPlugin();
}
return $myPlugin;
}
//Initialize
startup();
endif;
?>
The save actions happen in a different class and file.
<?php
// file savecontroller.php
class SaveController{
public function __construct(){
add_meta_box('xx_field_box', 'Field', array($this, 'setup_field'), XX_POST_TYPE);
}
public function setup_field( $post ){
?>
<input type="text" name="xx_custom_field" id="xx_custom_field" value="">
<?php
add_action('save_post', array($this, 'save_my_post'), 1, 1);
}
public function save_my_post($post_id){
if(isset($_POST['xx_custom_field'])){
update_post_meta($post_id, 'xx_custom_field', $_POST['xx_custom_field']);
}
}
}
?>
It does create my custom posttype and field so I know the classes are working. But the save_post is not triggered. It does not 'die()' and it does not do the 'update_post_meta()'. The custom field does appear in the POST request so the isset() checks out.
It's probably something dumb, but I can't get it to work.

Answer 1

You're trying to add the hook save_post inside the add_meta_box callback, and that's not the place for it.
To solve it, change the init method to
public function init(){
register_post_type( $args );
$this->savecontroller = new SaveController();
}
And modify the SaveController to
class SaveController{
public function __construct(){
add_action( 'add_meta_boxes', array( $this, 'meta_box' ) );
add_action( 'save_post', array( $this, 'save_my_post'), 10, 2 );
}
public function meta_box(){
add_meta_box( 'xx_field_box', 'Field', array($this, 'setup_field'), XX_POST_TYPE );
}
public function setup_field( $post ){
?>
<input type="text" name="xx_custom_field" id="xx_custom_field" value="">
<?php
}
public function save_my_post( $post_id, $post_object ){
wp_die( '<pre>'. print_r( $post_object, true) . '</pre>' );
}
}
Note that the save_post action takes two parameters and the priority can be default (10). You can find lots of examples for meta boxes and save_post here.