EU Digital Product Passport in WooCommerce: Implementing ESPR Compliance with Structured Data and QR Codes

<?php
declare(strict_types=1);

class SP_DPP_Data_Model {

    public const FIELDS = [
        // Identity
        'dpp_gtin'                   => 'sanitize_text_field',
        'dpp_manufacturer_name'      => 'sanitize_text_field',
        'dpp_manufacturer_country'   => 'sanitize_text_field',
        'dpp_batch_number'           => 'sanitize_text_field',

        // Materials
        'dpp_main_material'          => 'sanitize_text_field',
        'dpp_recycled_content_pct'   => 'absint',
        'dpp_hazardous_substances'   => 'sanitize_textarea_field',

        // Repairability
        'dpp_repairability_score'    => 'sanitize_text_field',
        'dpp_spare_parts_url'        => 'esc_url_raw',
        'dpp_repair_manual_url'      => 'esc_url_raw',
        'dpp_warranty_years'         => 'absint',

        // Environmental
        'dpp_carbon_footprint_kg'    => 'sanitize_text_field',
        'dpp_energy_class'           => 'sanitize_text_field',
        'dpp_energy_kwh_year'        => 'sanitize_text_field',

        // End of life
        'dpp_recycling_instructions' => 'sanitize_textarea_field',
        'dpp_disassembly_time_min'   => 'absint',
        'dpp_collection_point_url'   => 'esc_url_raw',

        // Compliance
        'dpp_ce_declaration_url'     => 'esc_url_raw',
        'dpp_reach_compliant'        => 'absint',
    ];

    public function save_product_meta( int $product_id ): void {
        if ( ! current_user_can( 'edit_product', $product_id ) ) return;

        if ( ! isset( $_POST['sp_dpp_nonce'] ) || ! wp_verify_nonce(
            sanitize_text_field( wp_unslash( $_POST['sp_dpp_nonce'] ) ),
            'sp_dpp_save_' . $product_id
        ) ) return;

        $product = wc_get_product( $product_id );
        if ( ! $product ) return;

        foreach ( self::FIELDS as $field => $sanitizer ) {
            if ( isset( $_POST[ $field ] ) ) {
                $value = call_user_func( $sanitizer, wp_unslash( $_POST[ $field ] ) );
                $product->update_meta_data( '_' . $field, $value );
            }
        }
        $product->save();
    }

    public function get_passport_data( int $product_id ): array {
        $product = wc_get_product( $product_id );
        if ( ! $product ) return [];

        $data = [];
        foreach ( array_keys( self::FIELDS ) as $field ) {
            $data[ $field ] = $product->get_meta( '_' . $field );
        }
        return $data;
    }
}

<?php
declare(strict_types=1);

class SP_DPP_REST_Controller extends WP_REST_Controller {

    protected $namespace = 'sp-dpp/v1';
    protected $rest_base = 'passport';

    public function register_routes(): void {
        register_rest_route( $this->namespace, '/' . $this->rest_base . '/(?P<product_id>[\d]+)', [
            [
                'methods'             => WP_REST_Server::READABLE,
                'callback'            => [ $this, 'get_passport' ],
                'permission_callback' => '__return_true',  // Public
                'args'                => [
                    'product_id' => [
                        'validate_callback' => fn($v) => is_numeric($v),
                        'sanitize_callback' => 'absint',
                    ],
                ],
            ],
        ] );
    }

    public function get_passport( WP_REST_Request $request ): WP_REST_Response {
        $product_id = $request->get_param( 'product_id' );
        $product    = wc_get_product( $product_id );

        if ( ! $product || ! $product->is_visible() ) {
            return new WP_REST_Response( [ 'error' => 'Product not found' ], 404 );
        }

        $model = new SP_DPP_Data_Model();
        $data  = $model->get_passport_data( $product_id );

        $passport = [
            '@context' => [
                'schema' => 'https://schema.org/',
                'dpp'    => 'https://digital-product-passport.eu/ns#',
            ],
            '@type'       => [ 'schema:Product', 'dpp:DigitalProductPassport' ],
            '@id'         => get_permalink( $product_id ),
            'schema:name' => $product->get_name(),
            'schema:gtin' => $data['dpp_gtin'],
            'dpp:materials' => [
                'dpp:primaryMaterial'    => $data['dpp_main_material'],
                'dpp:recycledContentPct' => (int) $data['dpp_recycled_content_pct'],
                'dpp:hazardousSubstances' => json_decode( $data['dpp_hazardous_substances'] ?: '[]', true ),
            ],
            'dpp:repairability' => [
                'dpp:score'         => $data['dpp_repairability_score'],
                'dpp:sparePartsUrl' => $data['dpp_spare_parts_url'],
                'dpp:repairManual'  => $data['dpp_repair_manual_url'],
                'dpp:warrantyYears' => (int) $data['dpp_warranty_years'],
            ],
            'dpp:environmental' => [
                'dpp:carbonFootprintKg' => (float) $data['dpp_carbon_footprint_kg'],
                'dpp:energyClass'       => $data['dpp_energy_class'],
                'dpp:energyKwhYear'     => (float) $data['dpp_energy_kwh_year'],
            ],
            'dpp:endOfLife' => [
                'dpp:recyclingInstructions' => $data['dpp_recycling_instructions'],
                'dpp:disassemblyTimeMin'    => (int) $data['dpp_disassembly_time_min'],
                'dpp:collectionPointUrl'    => $data['dpp_collection_point_url'],
            ],
            'dpp:compliance' => [
                'dpp:ceDeclarationUrl' => $data['dpp_ce_declaration_url'],
                'dpp:reachCompliant'   => (bool) $data['dpp_reach_compliant'],
            ],
            'dpp:generatedAt' => gmdate( 'c' ),
        ];

        $response = new WP_REST_Response( $passport, 200 );
        $response->header( 'Content-Type', 'application/ld+json' );
        $response->header( 'Cache-Control', 'public, max-age=3600' );
        return $response;
    }
}

<?php
declare(strict_types=1);

class SP_DPP_QR_Generator {

    public function generate_qr( int $product_id, int $size = 300 ): string {
        $passport_url = rest_url( 'sp-dpp/v1/passport/' . $product_id );

        $cache_key = 'sp_dpp_qr_' . $product_id . '_' . $size;
        $cached    = get_transient( $cache_key );
        if ( $cached ) return $cached;

        require_once SP_DPP_PATH . 'vendor/phpqrcode/qrlib.php';

        ob_start();
        QRcode::png( $passport_url, false, QR_ECLEVEL_M, 10, 2 );
        $raw_png = ob_get_clean();

        $data_uri = 'data:image/png;base64,' . base64_encode( $raw_png );
        set_transient( $cache_key, $data_uri, WEEK_IN_SECONDS );

        return $data_uri;
    }

    public function save_qr_file( int $product_id ): string {
        $upload_dir = wp_upload_dir();
        $dpp_dir    = trailingslashit( $upload_dir['basedir'] ) . 'sp-dpp-qr/';

        if ( ! file_exists( $dpp_dir ) ) {
            wp_mkdir_p( $dpp_dir );
            file_put_contents( $dpp_dir . 'index.php', '<?php // Silence is golden.' );
        }

        $filename = 'dpp-qr-' . $product_id . '.png';
        require_once SP_DPP_PATH . 'vendor/phpqrcode/qrlib.php';
        QRcode::png( rest_url( 'sp-dpp/v1/passport/' . $product_id ), $dpp_dir . $filename, QR_ECLEVEL_M, 10, 2 );

        return trailingslashit( $upload_dir['baseurl'] ) . 'sp-dpp-qr/' . $filename;
    }
}

<?php
add_filter( 'woocommerce_product_data_tabs', function( array $tabs ): array {
    $tabs['sp_dpp'] = [
        'label'    => __( 'Digital Passport', 'sp-dpp' ),
        'target'   => 'sp_dpp_product_data',
        'priority' => 85,
    ];
    return $tabs;
} );

add_action( 'woocommerce_product_data_panels', function(): void {
    global $post;
    wp_nonce_field( 'sp_dpp_save_' . $post->ID, 'sp_dpp_nonce' );
    echo '<div id="sp_dpp_product_data" class="panel woocommerce_options_panel">';

    echo '<div class="options_group">';
    woocommerce_wp_text_input([
        'id'          => 'dpp_gtin',
        'label'       => __( 'GTIN / EAN', 'sp-dpp' ),
        'description' => __( 'Global Trade Item Number', 'sp-dpp' ),
        'desc_tip'    => true,
        'value'       => get_post_meta( $post->ID, '_dpp_gtin', true ),
    ]);
    woocommerce_wp_text_input([
        'id'    => 'dpp_repairability_score',
        'label' => __( 'Repairability Score (e.g. 7.5/10)', 'sp-dpp' ),
        'value' => get_post_meta( $post->ID, '_dpp_repairability_score', true ),
    ]);
    woocommerce_wp_text_input([
        'id'    => 'dpp_carbon_footprint_kg',
        'label' => __( 'Carbon Footprint (kg CO₂e)', 'sp-dpp' ),
        'value' => get_post_meta( $post->ID, '_dpp_carbon_footprint_kg', true ),
    ]);
    echo '</div>';

    // QR preview
    $qr  = new SP_DPP_QR_Generator();
    $src = $qr->generate_qr( $post->ID, 200 );
    echo '<div class="options_group">';
    echo '<p><strong>' . esc_html__( 'DPP QR Code', 'sp-dpp' ) . '</strong></p>';
    echo '<img src="' . esc_attr( $src ) . '" width="150" />';
    echo '<p><a href="' . esc_url( rest_url( 'sp-dpp/v1/passport/' . $post->ID ) ) . '" target="_blank">'
        . esc_html__( 'View Passport JSON-LD', 'sp-dpp' ) . '</a></p>';
    echo '</div>';
    echo '</div>';
} );

<?php
add_filter( 'woocommerce_csv_product_import_mapping_default_columns', function( array $columns ): array {
    return array_merge( $columns, [
        'GTIN'                => 'dpp_gtin',
        'Manufacturer'        => 'dpp_manufacturer_name',
        'Carbon Footprint kg' => 'dpp_carbon_footprint_kg',
        'Recycled Content %'  => 'dpp_recycled_content_pct',
        'Repairability Score' => 'dpp_repairability_score',
        'Energy Class'        => 'dpp_energy_class',
    ] );
} );

add_filter( 'woocommerce_product_import_pre_insert_product_object',
function( WC_Product $product, array $data ): WC_Product {
    foreach ( array_keys( SP_DPP_Data_Model::FIELDS ) as $field ) {
        if ( isset( $data[ $field ] ) ) {
            $product->update_meta_data( '_' . $field, sanitize_text_field( $data[ $field ] ) );
        }
    }
    return $product;
}, 10, 2 );