Free Listings + Paid Ads: Update product feed API to return the bestselling product

[ianlin]

Changes proposed in this Pull Request:

This PR implements the backend task 4 📌 Return merchants key product data (e.g. bestselling) from the epic issue #1610. Here are what have changed:

• Extend an existing API mc/product-feed by adding a new condition total_sales to the parameter orderby.
  • total_sales is one of the meta keys of a product.
  • Combining with other parameters we can get the product which has the most sales. E.g.
    • GET mc/product-feed?per_page=1&orderby=total_sales&order=desc
• Extend an existing API mc/product-feed to return price and image url of a product.
• Add siteLogoUrl to glaData for the frontend.

Detailed test instructions:

1. Make a GET request to mc/product-feed API with parameters:
   • per_page=1
   • orderby=total_sales
   • order=desc
   • Full example: GET mc/product-feed?per_page=1&orderby=total_sales&order=desc
2. The response should contain only one product, with new response data price and image_url.
3. To verify if the returned product has the most sales, use this query in your local database:
   • SELECT * FROM wp_postmeta WHERE meta_key = 'total_sales' ORDER BY CAST( meta_value AS unsigned ) DESC;
4. Go to GLA dashboard, open the dev tool console, and type window.glaData
   • You should see there is a new data siteLogoUrl.
   • It would be null if you did not upload a custom site logo.
5. If the siteLogoUrl is null, go to wp-admin/admin.php?page=wc-admin&task=appearance and upload a logo.
6. Open the dev tool console and type window.glaData again, you should see the value of siteLogoUrl.

Changelog entry

[mikkamp]

Thanks for the changes, I'm getting the response as expected.

{
	"products": [
		{
			"id": 1695,
			"title": "Incredible Steel Coat",
			"visible": true,
			"status": "not_synced",
			"errors": []
		}
	],
	"total": 316,
	"page": 1
}

Just double checking if the product status makes a difference? In my case it picks a product that's not synced (excluded).

I just left a few smaller comments but they aren't blocking so I'll go ahead and approve the PR.

[mikkamp]

We should add total_sales as that's an allowed value.

[mikkamp]

I personally think we should just use a constant string of total_sales here. I don't think it really fits within the ProductMetaHandler class as that's to manage product meta fields we add for the extension, also it means we can call update/get/delete for this field, but it won't target the right entry because it will be adding the prefix. So it can be removed from the ProductMetaHandler class.

[ianlin]

@mikkamp

Just double checking if the product status makes a difference? In my case it picks a product that's not synced (excluded).

I think for most new users when they reach that step of the onboarding flow their products haven't been synced to GMC, so filtering only for synced products might have some problems.

[ianlin]

The original base branch this PR was trying to merge into was update/1610-add-api-to-get-sync-ready-products. However due to PR #1667 will be closed so I changed the base branch to feature/1610-streamlined-onboarding.