Craft 3 Plugin: Unable to add a new method to EntryQuery

Question

I am developing a Craft 3 plugin and would need to add a new method like {% for item in craft.entries.section('sectionName').birthday('XYZ123').all() %} According to doc https://docs.craftcms.com/v3/element-types.html#element-query-class, I am using following code:

File: /by/prefix/element/Birthdate.php

<?php namespace by\prefix\elements; use craft\base\Element; use craft\elements\db\ElementQueryInterface; use by\prefix\elements\db\BirthdateQuery; class Birthdate extends Element { public $birthdate; public static function find(): ElementQueryInterface {
return new BirthdateQuery(static::class); } }

File: /by/prefix/element/db/BirthdateQuery.php

<?php namespace by\tariffsinfo\elements\db; use craft; use craft\db\Query; use craft\elements\db\ElementQuery; use craft\helpers\Db; use by\tariffsinfo\elements\BirthdateElement; class BirthdateQuery extends ElementQuery { public $birthdate; public function birthdate($value) {
return $value; } }

and I am getting error message: Calling unknown method: craft\elements\db\EntryQuery::birthdate()

Could anyone please help what am I doing wrong.

Thanks

Answer 1

You know you don't add a new function to Crafts EntryQuery you create a custom Element type with a custom Query and add a function to that one. By the way you should probably fix your namespaces

use by\prefix\elements\db\BirthdateQuery;
use by\tariffsinfo\elements\BirthdateElement;

In order to use your function you'll have to do

BirthdateElement::find()->birthdate('whatever');

To search for a custom field in an entries FieldLayout you just need to call the parameter by handle... So when you include a field into the layout with the handle birthday you can do

{% set entries = craft.entries.birthday('whatever').all() %}

When you want to search for your custom element type in your frontend you'll have to include a function to Twig like Craft does

/**
 * Returns a new EntryQuery instance.
 *
 * @param mixed $criteria
 * @return EntryQuery
 */
public function birthdays($criteria = null): BirthdateQuery
{
    $query = BirthdateElement::find();
    if ($criteria) {
        Craft::configure($query, $criteria);
    }

    return $query;
}

So you can access it via

{% set birthdates = craft.pluginName.birthdays.id(2).birthdate('whatever').all() %}