function coupon_get_code(){
$codeid = $_POST['codeid'];
$response = array();

$code = get_post( $codeid );
if( !empty( $code ) ){
coupon_register_click( $codeid );
$code_meta = get_post_custom( $codeid );
$code_couponcode = coupon_get_smeta( 'code_couponcode', $code_meta, '' );
$shop_id = coupon_get_smeta( 'code_shop_id', $code_meta, '' );
$thumb_id = get_post_thumbnail_id( $shop_id );
$image = wp_get_attachment_image_src( $thumb_id, 'top20' );
$response['image'] = !empty( $image ) ? $image[0] : '';
$response['title'] = $code->post_title;
$response['text'] = $code->post_content;
$response['code'] = $code_couponcode;
}
else{
$response['error'] = __( 'Coupon does not exists', 'coupon' );
}

echo json_encode( $response );
die();
}

Aynı fonksiyondan birtanede categori için oluştur. db field larınıda ona göre gir