Replace WooCommerce placeholder image based on product category

Question

I'm trying to change default image placeholder for products with no images to images according to their product category.

I'm using:

add_filter( 'woocommerce_placeholder_img_src', 'my_custom_woocommerce_placeholder', 10 );

    //  Function to return new placeholder image URL. 
    function my_custom_woocommerce_placeholder( $image_url )
     {  
        if ($product_category == 'category1') {
            $image_url = 'http://website.com/imageforCategory.png'; 
        }
        elseif ($product_category == 'category2') {
            $image_url = 'http://website.com/imageforCategory.png'; 
        }
        else
        {
            $image_url = 'http://website.com/defaultImage.png'; 
        }
        
        return $image_url;
     }

---

I'm stuck at getting product category ($product_category) detected in functions.php file of my theme.

In content-single-product.php page I'm just defining

global $product 

and then just using

$product->get_categories();

to get the category of product.

How do I do it in functions.php of my theme?

Answer 1

You could use has_term() - Checks if the current post has any of given terms.

So you get:

// Single product page
function filter_woocommerce_placeholder_img_src( $src ) {
    // Get the global product object
    global $product;

    // Is a WC product
    if ( is_a( $product, 'WC_Product' ) ) {
        // Has term (product category)
        if ( has_term( 'categorie-1', 'product_cat', $product->get_id() ) ) {
            $src = 'http://website.com/imageforCategory1.png';
        } elseif ( has_term( array('categorie-2', 'categorie-3'), 'product_cat', $product->get_id() ) ) {
            $src = 'http://website.com/imageforCategory2.png';
        }
    }
    
    return $src;
}
add_filter( 'woocommerce_placeholder_img_src', 'filter_woocommerce_placeholder_img_src', 10, 1 );

// Archive/Shop page
function filter_woocommerce_placeholder_img ( $image_html, $size, $dimensions ) {
    $dimensions = wc_get_image_size( $size );
    
    $default_attr = array(
        'class' => 'woocommerce-placeholder wp-post-image',
        'alt'   => __( 'Placeholder', 'woocommerce' ),
    );
    
    $attr = wp_parse_args( '', $default_attr );
    
    $image      = wc_placeholder_img_src( $size );
    $hwstring   = image_hwstring( $dimensions['width'], $dimensions['height'] );
    $attributes = array();

    foreach ( $attr as $name => $value ) {
        $attribute[] = esc_attr( $name ) . '="' . esc_attr( $value ) . '"';
    }

    $image_html = '<img src="' . esc_url( $image ) . '" ' . $hwstring . implode( ' ', $attribute ) . '/>';
    
    return $image_html;
}
add_filter( 'woocommerce_placeholder_img', 'filter_woocommerce_placeholder_img', 10, 3 );

---

Note: the woocommerce_placeholder_img hook, used on archive/shop page returns $image_html. That string can be adapted to your needs. Such as image src, class, alt, size, etc ..