[Spec] Add directFromSellerSignals

spec.bs

@@ -37,6 +37,7 @@ spec: RFC8941; urlPrefix: https://httpwg.org/specs/rfc8941.html
     text: structured header; url: top
     for: structured header
       text: integer; url: integer
+      text: boolean; url: boolean
 spec: WebAssembly; urlPrefix: https://webassembly.github.io/spec/core/
   type: dfn
     urlPrefix: appendix/embedding.html
@@ -473,6 +474,7 @@ bid in the auction for the chance to display their advertisement.
 
 <h3 id="runadauction">runAdAuction()</h3>
 
+TODO: Promise wiring, pass results to worklets.
 <xmp class="idl">
 [SecureContext]
 partial interface Navigator {
@@ -487,6 +489,7 @@ dictionary AuctionAdConfig {
   Promise<any> auctionSignals;
   Promise<any> sellerSignals;
   Promise<USVString> directFromSellerSignals;
+  Promise<DOMString> directFromSellerSignalsHeaderAdSlot;
   unsigned long long sellerTimeout;
   unsigned short sellerExperimentGroupId;
   USVString sellerCurrency;
@@ -2800,6 +2803,143 @@ This specification defines two [=policy-controlled features=] identified by the
 Issue(WICG/turtledove#522): Move from "`*`" to "`self`".
 
 
+# Handling Direct from Seller Signals # {#handling-direct-from-seller-signals}
+
+This section specifies a manner by which signals may be provided to auctions such that the signals
+are only used within their intended auction.
+
+Scripts running on the page may peform a `fetch()` call using the `{adAuctionHeaders: true}`
+option, which causes the value of the `Ad-Auction-Signals` response header on that request to
+be used to provide signals in auctions running on the page whose seller matches the origin of the
+`fetch()` destination.
+
+<div algorithm="fetch adAuctionHeaders patch">
+Modify [[FETCH]]'s [[FETCH#requests]] to add: 
+
+A [=request=] has an associated <dfn for=request>capture ad auction headers boolean</dfn>.
+Unless stated otherwise it is false.
+
+Modify [[FETCH]]'s <a href="https://fetch.spec.whatwg.org/#requestinit">RequestInit</a> dictionary to add
+an adAuctionHeaders attribute:
+
+<pre class=idl>
+partial dictionary RequestInit {
+  boolean adAuctionHeaders;
+};
+</pre>
+
+The following step will be added to the <a href="https://fetch.spec.whatwg.org/#dom-request">new Request(input, init) constructor steps</a>,
+before step "Set this's [=Request/request=] to |request|":
+
+1. If <var ignore=''>init</var>["{{RequestInit/adAuctionHeaders}}"] <a for=map>exists</a>, then set |request|'s
+  [=request/capture ad auction headers boolean=] to it.
+
+The following step will be added to the <a href="https://fetch.spec.whatwg.org/#concept-http-network-or-cache-fetch">HTTP-network-or-cache fetch</a>
+algorithm, before step "Modify |httpRequest|'s [=request/header list=] per HTTP. ...":
+
+1. If [=request=]'s [=request/capture ad auction headers boolean=] is true, then
+  [=header list/set a structured field value=] given «`Sec-Ad-Auction-Fetch`, the [=structured header/boolean=] ?1» in
+  |httpRequest|'s [=header list=].
+
+Modify [[FETCH]]'s [[FETCH#infrastructure]] to add a new section called "Per Traversable Navigable Structures",
+with the following content:
+
+<h3 dfn-type=dfn>Direct from seller signals key</h3>
+A direct from seller signals key is a [=struct=] with the following [=struct/items=]:
+
+<dl dfn-for="direct from seller signals key">
+: <dfn>owner</dfn>
+:: An [=origin=]. Matches the origin that served the captured `Ad-Auction-Signals` header.
+: <dfn>ad slot</dfn>
+:: A [=string=]. Matches the `adSlot` key of the JSON dictionaries in the top level array of the
+  `Ad-Auction-Signals` value.
+
+</dl>
+
+<h3 dfn-type=dfn>Direct from seller signals</h3>
+A direct from seller signals is a [=struct=] with the following [=struct/items=]:
+
+<dl dfn-for="direct from seller signals">
+: <dfn>seller signals</dfn>
+:: Null or a [=string=].
+  Opaque JSON data passed to both buyers' and the seller's [=script runners=].
+: <dfn>auction signals</dfn>
+:: Null or a [=string=].
+  Opaque JSON data passed to the seller's [=script runner=].
+: <dfn>per buyer signals</dfn>
+:: A [=map=] whose [=map/keys=] are [=origins=] and whose [=map/values=] are [=strings=].
+  [=map/Keys=] are buyers and must be valid HTTPS origins. [=map/Values=] are opaque JSON data
+  passed to corresponding buyer's [=script runner=].
+
+</dl>
+
+Each [=traversable navigable=] has a <dfn>captured ad auction headers</dfn>, which is a [=map=]
+whose [=map/keys=] are [=direct from seller signals keys=] and whose values are [=direct from seller signals=].
+
+The following step will be added to the <a href="https://fetch.spec.whatwg.org/#concept-http-network-or-cache-fetch">HTTP-network-or-cache fetch</a>
+algorithm, before step "Return |response|.":
+
+1. If |response| is not null, then run [=update captured headers=] with [=this=]'s
+  [=relevant global object=]'s [=associated Document's=] [=node navigable's=]
+  [=traversable navigable's=] [=captured ad auction headers=], |response|'s
+  [=response/header list=], and |request|'s [=request/URL=]'s [=url/origin=].
+
+<div algorithm>
+  To <dfn>update captured headers</dfn> with a [=captured ad auction headers=] |storedHeaders|,
+  [=header list=] |responseHeaders|, and [=origin=] |requestOrigin|:
+  1. Let |adAuctionSignals| be the result of [=header list/get=] with "`Ad-Auction-Signals`",
+    |responseHeaders|.
+  1. If |adAuctionSignals| is null, return.
+  1. [=header list/delete=] "`Ad-Auction-Signals`" from |responseHeaders|.
+
+    NOTE: This step prevents the header value from being used outside the intended auctions.
+  1. Let |parsedSignals| be the result of [=parsing JSON bytes to an Infra value=], given
+    |adAuctionSignals|.
+  1. If |parsedSignals| is failure, return.
+  1. If |parsedSignals| is not a [=list=], return.
+  1. [=list/For each=] |signal| in |parsedSignals|:
+    1. If |signal| is not an [=ordered map=], [=iteration/continue=].
+    1. If |signal|["`adSlot`"] doesn't exist, [=iteration/continue=].
+    1. Create a new [=direct from seller signals key=] |signalsKey|, with its
+      [=direct from seller signals key/owner=] set to |requestOrigin| and its
+      [=direct from seller signals key/ad slot=] set to |signal|["`adSlot`"].
+    1. Create a new [=direct from seller signals=] |processedSignals|.
+    1. [=map/Remove=] |signal|["`adSlot`"].
+    1. [=map/For each=] |key| → |value| of |signal|:
+      1. Switch on |key|:
+        <dl class=switch>
+        <dt>"`sellerSignals`"
+        <dd>
+        1. Set |processedSignals|'s [=direct from seller signals/seller signals=] to the result
+          of [=serializing an Infra value to a JSON string=], given |value|. If this
+          [=exception/throws=], [=iteration/continue=].
+
+        <dt>"`auctionSignals`"
+        <dd>
+        1. Set |processedSignals|'s [=direct from seller signals/auction signals=] to the result
+          of [=serializing an Infra value to a JSON string=], given |value|. If this
+          [=exception/throws=], [=iteration/continue=].
+
+        <dt>"`perBuyerSignals`"
+        <dd>
+        1. If |value| is not an [=ordered map=], [=iteration/continue=].
+        1. For each |buyer| → |buyerSignals| of |value|:
+          1. Let |buyerOrigin| be the result of [=parsing an origin=] on |buyer|. If this
+            [=exception/throws=], [=iteration/continue=].
+          1. Let |buyerSignalsString| be the result of
+            [=serializing an Infra value to a JSON string=], given |buyerSignals|. If this
+            [=exception/throws=], [=iteration/continue=].
+          1. Set |processedSignals|'s [=direct from seller signals/per buyer signals=][|buyerOrigin|]
+            to |buyerSignalsString|.
+
+        </dl>
+
+    1. Set |storedHeaders|[|signalsKey|] to |processedSignals|.
+</div>
+
+</div>
+
+
 # Structures # {#structures}
 
 <xmp class="idl">