Allow sending ephemeral data to application services (#2018)

As per MSC2409.

Signed-off-by: Kévin Commaille <zecakeh@tedomum.fr>

data/api/application-service/definitions/registration.yaml

@@ -32,6 +32,13 @@ properties:
     description: |-
       The localpart of the user associated with the application service. Events will be sent to the AS if this user is the target of the event, or
       is a joined member of the room where the event occurred.
+  receive_ephemeral:
+    type: boolean
+    x-addedInMatrixVersion: "1.13"
+    description: |-
+      Whether the application service wants to [receive ephemeral data](/application-service-api/#pushing-ephemeral-data).
+      
+      Defaults to `false` if not present.
   namespaces:
     type: object
     title: Namespaces

data/api/application-service/transactions.yaml

@@ -46,6 +46,15 @@ paths:
             schema:
               type: object
               example: {
+                "ephemeral": [
+                  {
+                    "$ref": "../../event-schemas/examples/m.receipt.yaml",
+                    "room_id": "!jEsUZKDJdhlrceRyVU:example.org"
+                  },
+                  {
+                    "$ref": "../../event-schemas/examples/m.presence.yaml"
+                  },
+                ],
                 "events": [
                   {
                     "$ref": "../../event-schemas/examples/m.room.member.yaml"
@@ -61,6 +70,21 @@ paths:
                   description: A list of events, formatted as per the Client-Server API.
                   items:
                     $ref: ../client-server/definitions/client_event.yaml
+                ephemeral:
+                  type: array
+                  x-addedInMatrixVersion: "1.13"
+                  description: |-
+                    A list of ephemeral data, if the `receive_ephemeral` setting was enabled in the
+                    [registration](/application-service-api/#registration) file.
+
+                    There are only three event types that can currently occur in this list: `m.presence`,
+                    `m.typing`, and `m.receipt`. Room-scoped ephemeral data (`m.typing` and
+                    `m.receipt`) MUST include a `room_id` property to identify the room that they
+                    were sent in.
+
+                    This property can be omitted if it would be empty.
+                  items:
+                    $ref: ../../event-schemas/schema/core-event-schema/event.yaml
               required:
                 - events
         description: Transaction information