Module.php

<?php

declare(strict_types=1);

namespace UniqueProperties;

if (!class_exists(\Generic\AbstractModule::class)) {
    require file_exists(dirname(__DIR__) . '/Generic/AbstractModule.php')
        ? dirname(__DIR__) . '/Generic/AbstractModule.php'
        : __DIR__ . '/src/Generic/AbstractModule.php';
}

use Generic\AbstractModule;
use Laminas\EventManager\Event;
use Laminas\EventManager\SharedEventManagerInterface;
use Omeka\Stdlib\Message;
use Omeka\Mvc\Controller\Plugin\Messenger;
use Omeka\Api\Exception\ValidationException;


class Module extends AbstractModule
{
    const NAMESPACE = __NAMESPACE__;

    public function getConfig()
    {
        return include __DIR__ . '/config/module.config.php';
    }

    public function attachListeners(SharedEventManagerInterface $sharedEventManager)
    {
        // add listeners for add/update
        $sharedEventManager->attach(
            \Omeka\Api\Adapter\ItemAdapter::class,
            'api.create.pre',
            [$this, 'dedupAction']
        );
        $sharedEventManager->attach(
            \Omeka\Api\Adapter\ItemAdapter::class,
            'api.update.pre',
            [$this, 'dedupAction'],
        );
    }

    public function dedupAction(Event $event): void
    {
        $request = $event->getParam('request');
        // Ignore other requests
        if ($request->getOperation() != 'create' && $request->getOperation() != 'update') {
            return;
        }

        $serviceLocator = $this->getServiceLocator();
        $settings = $serviceLocator->get('Omeka\Settings');
        $messenger = new Messenger;

        $itemId = (int) $request->getId();
        $data = $request->getContent();
        $propIds = $settings->get('unique_properties');

        $allowedProps = array();
        foreach ($propIds as $propId) {
            $allowedProps[$propId] = true;
        }

        $itemPropIDs = array();
        // Fetch the property values from this request.
        $propValues = array();
        foreach ($data as $key => $value) {
            if (is_array($value)) {
                foreach ($value as $innerKey => $innerValue) {
                    if (isset($innerValue['property_id']) && !empty($innerValue['@value'])) {
                        // ignore property ids that are not matching
                        if (!$allowedProps[$innerValue['property_id']]) {
                            continue;
                        }
                        array_push($propValues, $innerValue['@value']);
                        array_push($itemPropIDs, $innerValue['property_id']);
                    }
                }
            }
        }

        // Convert property-ids, property-values into json
        // This allows us to load this into a derived table in MySQL
        $jsonPairs = json_encode(array_map(function ($value, $property_id) {
            return ['value' => $value, 'property_id' => $property_id];
        }, $propValues, $itemPropIDs), JSON_UNESCAPED_UNICODE);

        $services = $this->getServiceLocator();
        $connection = $services->get('Omeka\Connection');

        // Check if same property-id, property-value exists in any other items.
        $sql = <<<'SQL'
SELECT
    CONCAT(
        `vocabulary`.`label`,
        ' - ',
        `property`.`label`
    ) as `field`,
    `value`.`value` as `data`,
    `value`.`resource_id` as `resource_id`
FROM
    `value`
    LEFT JOIN `resource` ON `resource`.`id` = `value`.`resource_id`
    LEFT JOIN `property` ON `property`.`id` = `value`.`property_id`
    LEFT JOIN `vocabulary` ON `vocabulary`.`id` = `property`.`vocabulary_id`
WHERE
    `value`.`value` IN (:property_values)
    AND `value`.`resource_id` <> :id
    AND `value`.`property_id` IN (:property_ids)
    AND `resource`.`resource_type` = 'Omeka\\Entity\\Item'
    AND EXISTS (
        SELECT 1
        FROM JSON_TABLE(
            :json_pairs,
            "$[*]" COLUMNS (
                value_prop VARCHAR(255) CHARACTER SET 'utf8mb4' COLLATE 'utf8mb4_unicode_ci' PATH "$.value",
                property_id INT PATH "$.property_id"
            )
        ) derived
        WHERE
            derived.value_prop = value.value
            AND derived.property_id = value.property_id
    )
SQL;
        $stmt = $connection->executeQuery($sql, [
            'id' => $itemId,
            'property_ids' => $itemPropIDs,
            'property_values' => $propValues,
            'json_pairs' => $jsonPairs,
        ], [
            'property_ids' => \Doctrine\DBAL\Connection::PARAM_STR_ARRAY,
            'property_values' => \Doctrine\DBAL\Connection::PARAM_STR_ARRAY,
            'json_pairs' => \PDO::PARAM_STR,
        ]);
        $results = $stmt->fetchAll();

        foreach ($results as $result) {
            $messenger->addError(new Message('Duplicate property value `%s` found for `%s` in #%d', $result['data'], $result['field'], $result['resource_id']));
            throw new ValidationException('');
        }
    }
}