can I pass arguments to my function through add_ac

Question

can I do something like that? to pass arguments to my function? I already studied add_action doc but did not figure out how to do it. What the exact syntax to pass two arguments would look like. In particular how to pass text & integer arguments.

function recent_post_by_author($author,$number_of_posts) {
  some commands;
}
add_action('thesis_hook_before_post','recent_post_by_author',10,'author,2')

UPDATE

it seems to me that it is done somehow through do_action but how? :-)

Answer 1

I've wrote wordpress plugin long time ago, but I went to Wordpress Codex and I think that's possible: http://codex.wordpress.org/Function_Reference/add_action

<?php add_action( $tag, $function_to_add, $priority, $accepted_args ); ?> 

I think you should pass them as an array. Look under examples "take arguments".

Bye

Answer 2

I use closure for PHP 5.3+. I can then pass the default values and mine without globals. (example for add_filter)

...
$tt="try this";

add_filter( 'the_posts', function($posts,$query=false) use ($tt) {
echo $tt;
print_r($posts);
return  $posts;
} );

Answer 3

Instead of:

add_action('thesis_hook_before_post','recent_post_by_author',10,'author,2')

it should be:

add_action('thesis_hook_before_post','recent_post_by_author',10,2)

...where 2 is the number of arguments and 10 is the priority in which the function will be executed. You don't list your arguments in add_action. This initially tripped me up. Your function then looks like this:

function function_name ( $arg1, $arg2 ) { /* do stuff here */ }

Both the add_action and function go in functions.php and you specify your arguments in the template file (page.php for example) with do_action like so:

do_action( 'name-of-action', $arg1, $arg2 );

Hope this helps.

Answer 4

I have made a code to send parameters and process.

function recibe_data_post() {

$post_data = $_POST;

if (isset($post_data)) {

    if (isset($post_data['lista_negra'])) {

        $args = array (
            'btn'  =>  'lista_negra',
            'estado'=>  $post_data['lista_negra'],
        );

        add_action('template_redirect',
                   function() use ( $args ) {
                       recibe_parametros_btn( $args ); });
    }
    if (isset($post_data['seleccionado'])) {
        $args = array (
            'btn'  =>  'seleccionado',
            'estado'=>  $post_data['seleccionado'],
        );

        add_action('template_redirect',
                   function() use ( $args ) {
                       recibe_parametros_btn( $args ); });

        }
    }
}

    add_action( 'init', 'recibe_data_post' );

function recibe_parametros_btn( $args ) {

$data_enc = json_encode($args);
$data_dec = json_decode($data_enc);

$btn = $data_dec->btn;
$estado = $data_dec->estado;

fdav_procesa_botones($btn, $estado);

}

function fdav_procesa_botones($btn, int $estado) {

$post_id = get_the_ID();
$data = get_post($post_id);

if ( $estado == 1 ) {
    update_field($btn, 0, $post_id);
    } elseif ( $estado == 0 ) {
       update_field($btn, 1, $post_id);
    }

}

Answer 5

I ran into the same issue and solved it by using global variables. Like so:

global $myvar;
$myvar = value;
add_action('hook', 'myfunction');

function myfunction() {
    global $myvar;
}

A bit sloppy but it works.

Answer 6

can I do something like that? to pass arguments to my function?

Yes you can! The trick really is in what type of function you pass to add_action and what you expect from do_action.

• ‘my_function_name’
• array( instance, ‘instance_function_name’)
• ‘StaticClassName::a_function_on_static_class'
• anonymous
• lambda
• closure

---

We can do it with a closure.

// custom args for hook

$args = array (
    'author'        =>  6, // id
    'posts_per_page'=>  1, // max posts
);

// subscribe to the hook w/custom args

add_action('thesis_hook_before_post', 
           function() use ( $args ) { 
               recent_post_by_author( $args ); });


// trigger the hook somewhere

do_action( 'thesis_hook_before_post' );


// renders a list of post tiles by author

function recent_post_by_author( $args ) {

    // merge w/default args
    $args = wp_parse_args( $args, array (
        'author'        =>  -1,
        'orderby'       =>  'post_date',
        'order'         =>  'ASC',
        'posts_per_page'=>  25
    ));

    // pull the user's posts
    $user_posts = get_posts( $args );

    // some commands
    echo '<ul>';
    foreach ( $user_posts as $post ) {
        echo "<li>$post->post_title</li>";
    }
    echo '</ul>';
}

---

Here is a simplified example of a closure working

$total = array();

add_action('count_em_dude', function() use (&$total) { $total[] = count($total); } );

do_action ('count_em_dude' );
do_action ('count_em_dude' );
do_action ('count_em_dude' );
do_action ('count_em_dude' );
do_action ('count_em_dude' );
do_action ('count_em_dude' );
do_action ('count_em_dude' );

echo implode ( ', ', $total ); // 0, 1, 2, 3, 4, 5, 6

---

Anonymous vs. Closure

add_action ('custom_action', function(){ echo 'anonymous functions work without args!'; } ); //

add_action ('custom_action', function($a, $b, $c, $d){ echo 'anonymous functions work but default args num is 1, the rest are null - '; var_dump(array($a,$b,$c,$d)); } ); // a

add_action ('custom_action', function($a, $b, $c, $d){ echo 'anonymous functions work if you specify number of args after priority - '; var_dump(array($a,$b,$c,$d)); }, 10, 4 ); // a,b,c,d

// CLOSURE

$value = 12345;
add_action ('custom_action', function($a, $b, $c, $d) use ($value) { echo 'closures allow you to include values - '; var_dump(array($a,$b,$c,$d, $value)); }, 10, 4 ); // a,b,c,d, 12345

// DO IT!

do_action( 'custom_action', 'aa', 'bb', 'cc', 'dd' ); 

---

Proxy Function Class

class ProxyFunc {
    public $args = null;
    public $func = null;
    public $location = null;
    public $func_args = null;
    function __construct($func, $args, $location='after', $action='', $priority = 10, $accepted_args = 1) {
        $this->func = $func;
        $this->args = is_array($args) ? $args : array($args);
        $this->location = $location;
        if( ! empty($action) ){
            // (optional) pass action in constructor to automatically subscribe
            add_action($action, $this, $priority, $accepted_args );
        }
    }
    function __invoke() {
        // current arguments passed to invoke
        $this->func_args = func_get_args();

        // position of stored arguments
        switch($this->location){
            case 'after':
                $args = array_merge($this->func_args, $this->args );
                break;
            case 'before':
                $args = array_merge($this->args, $this->func_args );
                break;
            case 'replace':
                $args = $this->args;
                break;
            case 'reference':
                // only pass reference to this object
                $args = array($this);
                break;
            default:
                // ignore stored args
                $args = $this->func_args;
        }

        // trigger the callback
        call_user_func_array( $this->func, $args );

        // clear current args
        $this->func_args = null;
    }
}

Example Usage #1

$proxyFunc = new ProxyFunc(
    function() {
        echo "<pre>"; print_r( func_get_args() ); wp_die();
    },
    array(1,2,3), 'after'
);

add_action('TestProxyFunc', $proxyFunc );
do_action('TestProxyFunc', 'Hello World', 'Goodbye'); // Hello World, 1, 2, 3

Example Usage #2

$proxyFunc = new ProxyFunc(
    function() {
        echo "<pre>"; print_r( func_get_args() ); wp_die();
    },                  // callback function
    array(1,2,3),       // stored args
    'after',            // position of stored args
    'TestProxyFunc',    // (optional) action
    10,                 // (optional) priority
    2                   // (optional) increase the action args length.
);
do_action('TestProxyFunc', 'Hello World', 'Goodbye'); // Hello World, Goodbye, 1, 2, 3