How to deal with WP_Error?

[kilianso]

Hey folks

I'm struggling a bit catching the WP_Error object in Timber. I have an object oriented custom theme and let logged in users change data with update_user_meta on the author.php page. Since i think i'm missing something on the Timber-side, i try to find an answer here. Any hint would be much appreciated.

Here's my UserMeta.php Class. I'm loading it with autoload in Theme.php.

<?php

namespace SBX\Theme\Package;

class UserMeta
{
   // Instantiate the WP_Error object
   public $error = '';
	
   public function __construct() {
        $this->$error = new \WP_Error();
   }

   public function run() {
        // Update user meta from profile/user/author pages
	add_action( 'template_redirect', [$this, 'updateUserMetaFromFrontend'] );
   }

   // function to update meta fields from auhtor/profile pages
   public function updateUserMetaFromFrontend() {
	
        // Check if the user is authenticated.
        if ( ! is_user_logged_in() ) {
	        return;
        }
        
        // Check if we have all necessary data.
        if ( empty( $_POST['update_meta_nonce'] ) ) {
	        return;
        }
        
        // Verify the nonce.
        if ( ! wp_verify_nonce( $_POST['update_meta_nonce'], 'update-meta' ) ) {
	        return;
        }

        // Update optional user meta
        $this->updateField('nickname', true, 'Please enter a name.');
        $this->updateField('city');
        
        // Redirect back to the previous page.
        wp_safe_redirect( wp_get_referer() );
        exit;
   }

    public function updateField($field, $mandatory = false, $errormsg = null) {
        if (!empty($_POST[$field]) && is_string($_POST[$field])) {
                update_user_meta( get_current_user_id(), $field, htmlspecialchars($_POST[$field]) );
        }else {
            if($mandatory) {
               $this->$error->add('general', '<strong>' . __('ERROR') . '</strong>: ' . $errormsg, array('form-field' => $field));
            }
        }
    }
}

My author.php

<?php

$context = Timber::context();
$context['errors'] = is_wp_error($error);
Timber::render( array( 'author.twig'), $context );

And my author.twig

{% if errors %}
   <pre>
      {{ dump(errors) }}
   </pre>
{% endif %}
<form method="post" action="{{ site.url }}" id="profile-edit-form">
    <fieldset class="ProfileEdit__accounts">
        <label>
            <span>Name<small class="ProfileEdit__required-note">required</small></span>
            <input 
                type="text" 
                name="nickname" 
                placeholder="Enter your name" 
                value="{{user.nickname}}" 
                autocomplete="off" 
                required>
        </label>
        <label>
            <span>City</span>
            <input 
                type="text" 
                name="city" 
                placeholder="Your City" 
                value="{{user.account_city}}" 
                autocomplete="off">
        </label>
    </fieldset>
    {% do function('wp_nonce_field', 'update-meta', 'update_meta_nonce') %}
    <button type="submit" class="submit">Update profile</button>
</form>

So the dump(errors) in my Twig template is always false but i just don't get it why. I thought the WP_Error object is accessible within the same route. What am i missing?

[gchtr]

I see a couple of things. I think the following line in author.php might be the first issue:

$context['errors'] = is_wp_error($error);

I don’t see where the $error variable is coming from. Did you only publish a part of the template file, or is that it?

The errors variable in Twig is always false, because $error is always undefined and is_wp_error() returns only true if $error is an instance of WP_Error.

Also, I don’t see where you actually instantiate the UserMeta class. The template file doesn’t automatically have access to the UserMeta class. You would have to instantiate it there. I’m thinking something like this might work:

author.php

<?php

$user_meta = new UserMeta();

$context = Timber::context();
$context['errors'] = is_wp_error( $user_meta->get_error() );

Timber::render( array( 'author.twig'), $context );

But then, your template_redirect action won’t work anymore, because that function already ran. But you could also directly call the updateUserMetaFromFrontend() method from your template file and remove the template_redirect action.

You then have to make sure that the form loads the same page instead of redirecting to the home page. Check the action attribute in your form tag.

<form method="post" action="{{ user.link }}" id="profile-edit-form">

You could maybe use a get_errors() method in the UserMeta class instead of using is_wp_error().

<?php

$user_meta = new UserMeta();

$user_meta->updateUserMetaFromFrontend();

$context = Timber::context();
$context['errors'] = $user_meta->get_errors();

Timber::render( array( 'author.twig'), $context );

To iterate further, you could also add $user_meta itself to the context:

<?php

$user_meta = new UserMeta();

$user_meta->updateUserMetaFromFrontend();

$context = Timber::context();
$context['user_meta'] = $user_meta;

Timber::render( array( 'author.twig'), $context );

In Twig, you could then use:

{% if user_meta.get_errors is not empty %}
   <pre>
      {{ dump(user_meta.get_errors) }}
   </pre>
{% endif %}

Then, the next problem is when you create an empty WP_Error object in the UserMeta constructor:

public function __construct() {
    $this->$error = new \WP_Error();
}

The $error property will always return true when you use is_wp_error(). You should only create a new WP_Error object if there actually is an error. I wouldn’t actually use a constructor at all.

I hope that helps you to get this working ☺️.

[kilianso]

Hey @gchtr! Thanks for the detailed answer. Checking for errors with get_errors() did the trick. Regarding the whole instantiating of the UserMeta Class: This already happens thanks to an autoloader mechanism in my setup which is based on the helloroots starter.

Thanks and Gruess us Bärn 👋

[gchtr]

Great, I’m glad it helped!

Happy weekend vo Winterthur nach Bern 👋