filters - Save something to global var in add_filter

I am here again with a strange question.

First, I'm using ACF plugin for adding cistom fields. My code looks somethink like that:

global $testMe;
$testMe = 0;
function my_acf_update_value( $value, $post_id, $field ) {
    global $testMe;
    $testMe = $value;
    return $value;
}
add_filter('acf/update_value/key=field_5308e5e79784b', 'my_acf_update_value', 10, 3);
echo $testMe; // -> print 0, not the $value!?

The problem is that I want, after the filter apply, $testMe to contain the value of $value.

Any ideas where I'm wrong?

I am here again with a strange question.

First, I'm using ACF plugin for adding cistom fields. My code looks somethink like that:

global $testMe;
$testMe = 0;
function my_acf_update_value( $value, $post_id, $field ) {
    global $testMe;
    $testMe = $value;
    return $value;
}
add_filter('acf/update_value/key=field_5308e5e79784b', 'my_acf_update_value', 10, 3);
echo $testMe; // -> print 0, not the $value!?

The problem is that I want, after the filter apply, $testMe to contain the value of $value.

Any ideas where I'm wrong?

• filters
• advanced-custom-fields
• globals

Share Improve this question asked Mar 1, 2014 at 12:10 NoSenseNoSense 17011 silver badge1010 bronze badges

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1 Answer 1

Sorted by: Reset to default 0

I ran a test and the following works:

global $testMe;
$testMe = 0;
function my_acf_update_value( $value, $post_id, $field ) {
    global $testMe;
    $testMe = $value;
    return $value;
}
add_filter('acf/update_value/key=field_5308e5e79784b', 'my_acf_update_value', 10, 3);

// Test: Apply the filter
apply_filters('acf/update_value/key=field_5308e5e79784b','a','b','c');
// end Test

echo $testMe; // prints 'a'

So, in principle, your code is functional. There are a couple of things that I can think that may be going wrong.

1. You are adding the filter after the hook has ran. Place that test apply_filters before the rest of the code and it won't work.
2. You have the hook name wrong.

Other than that, it should work. However, this global variable technique is a bit messy. Might I suggest something like this:

function my_acf_grab_value($value,$echo = false) {
  static $var = 0;
  if (false === $echo) {
    $var = $value;
  } else {
    return $var;
  }
}

function my_acf_update_value( $value, $post_id, $field ) {
  my_acf_grab_value($value);
  return $value;
}
add_filter('acf/update_value/key=field_5308e5e79784b', 'my_acf_update_value', 10, 3);

// Test: Apply the filter
apply_filters('acf/update_value/key=field_5308e5e79784b','Yay','b','c');
// end test

echo my_acf_grab_value('',true); 

Or this:

function my_acf_update_value( $value = '', $post_id = 0, $field = '' ) {
  static $var = 0;
  if (!empty($value)) {
    $var = $value;
  } else {
    return $var;
  }
  return $value;
}
add_filter('acf/update_value/key=field_5308e5e79784b', 'my_acf_update_value', 10, 3);

// Test: Apply the filter
apply_filters('acf/update_value/key=field_5308e5e79784b','Yay','b','c');
// end test

echo my_acf_update_value();