Product feeds — Google Merchant Center and Meta

A store built on `Osysharp.Shop` serves its catalogue as product feeds: `/feeds/google.xml` for Google Merchant Center and `/feeds/meta.xml` for Meta's catalogue, both RSS 2.0 in Google's `g:` namespace. One item per size or colour, only listed products, generated from the store's rows every time a channel fetches it.

Summary#

A shopping channel lists your products from a feed: a file it fetches from your store on a schedule. A store built on Osysharp.Shop serves two, the way it serves /sitemap.xml (see [Serve]):

Address	For
`/feeds/google.xml`	Google Merchant Center (Shopping ads, free listings)
`/feeds/meta.xml`	Meta's catalogue (Facebook and Instagram shops, dynamic ads)

There is nothing to export and nothing to keep in step. Each fetch is written from the store's rows as they are. Register the address in the channel as a scheduled fetch.

Signature#

[Serve("/feeds/google.xml")] string GoogleProductFeed()
[Serve("/feeds/meta.xml")]   string MetaProductFeed()
string ProductFeed(FeedChannel channel)       // enum FeedChannel { Google, Meta }
Category.GoogleCategory                        // a shelf's place in Google's taxonomy, inherited by its children

Description#

What an item carries#

One item per variant: a customer buys a size or a colour, and a channel shows and prices exactly that. The variants of one product share item_group_id; a product with a single variant is a plain item.

Field	From
`id`	the variant's SKU, else its own id
`title`	the product's name and the variant's options: "Loafer (38)"
`description`	the product's summary, else the start of its description
`link`	the product's page (`ShopSetup.ProductPath`), absolute
`image_link`, `additional_image_link`	its photographs, in order
`availability`	in stock, or out of stock. A sold-out size stays in the feed and says so
`condition`	`new`
`price`, `sale_price`	"165.00 SEK". A markdown shows the regular price as `price` and today's as `sale_price`
`brand`	the product's brand
`mpn`	the SKU
`size`, `color`	the variant's options
`product_type`	the shelf path: "Coffee > Kenya"
`google_product_category`	`Category.GoogleCategory`, from the shelf or the nearest one above it
`shipping_weight`	the variant's packed weight, when known: "250 g"

Only listed products are in a feed, and only those with a price and at least one photograph. Both channels refuse an item without an image. A draft is never listed. Every value is XML-escaped, so a product called Tan & Co <Limited> arrives as text.

Where the two channels differ#

Both channels read the same format: RSS 2.0 with the g: namespace (Google, Meta). They differ in three places, which is why there are two addresses:

	Google	Meta
availability	`in_stock` / `out_of_stock`	`in stock` / `out of stock`
brand	optional. Without one, or without a SKU, the item says `identifier_exists` `no`	required. A product without one gets the shop's own name
extra photographs	up to 10	up to 20

Placing shelves in Google's taxonomy#

Google sorts products by its own product taxonomy. Set a shelf's GoogleCategory to the taxonomy's number ("187") or its path ("Apparel & Accessories > Shoes"). Every product on that shelf and on the shelves under it is sent with it. Staff set it with the rest of the shelf.

Examples#

Placing a shelf in Google's taxonomy from the desk#

app FeedsExample {
  use Osysharp.Shop@1 { egress "api.resend.com"; secret "ResendApiKey"; }
  model "model/**/*.osy";
}

using Osysharp.Shop;

/// Puts a shelf in Google's taxonomy. Its products, and those on the shelves under it, are sent with it.
[Authorize(IsShopStaff)]
public void PlaceShelf(Category shelf, string taxonomy) {
  shelf.GoogleCategory = taxonomy;
  UnitOfWork.Commit();
}

One item, as Google reads it#

<item>
  <g:id>GG-KIAMBU-AA-1000</g:id>
  <g:title>Kiambu AA (1 kg)</g:title>
  <g:description>The product’s summary, as the shop wrote it.</g:description>
  <g:link>https://groundsandgrapes.example/p/kiambu-aa</g:link>
  <g:image_link>https://groundsandgrapes.example/files/products/kiambu-aa.jpg</g:image_link>
  <g:availability>in_stock</g:availability>
  <g:condition>new</g:condition>
  <g:price>560.00 SEK</g:price>
  <g:brand>Grounds &amp; Grapes</g:brand>
  <g:mpn>GG-KIAMBU-AA-1000</g:mpn>
  <g:item_group_id>4b0c…</g:item_group_id>
  <g:size>1 kg</g:size>
  <g:product_type>Coffee</g:product_type>
</item>