Description

When updating products by importing a DFC catalog we never update the image. And we shouldn't update it unless it has changed.

How do we know if it changed or not?

To be completely sure, we would need to download the current image and the given image and compare them. But storing the new image takes just as long.

Most product images are uploaded by users and each version has its own unique id and URL. That is true for OFN and Shopify (our only other known integration at the moment). So if we remember the URL of the image then we can compare that.

What if my other platform keeps the same product image? In that case the referenced image URL needs to contain a version number, hash or timestamp. That can be a query parameter or even a hash anchor. For example:

https://example.net/product5/image.png#hash:abc123

Implementation

ActiveStorage supports metadata.

blob.custom_metadata[:origin] = semantic_id

Then later we can check before assigning:

    image = supplied_product.isVariantOf.first.try(:image) ||
            supplied_product.image

    return if image.blank?
    return if image == spree_product.image.attachment.blob.custom_metadata[:origin]

    spree_product.image = ImageBuilder.import(image)