Spec MSC3856: Threads list API

content/client-server-api/_index.md

@@ -2057,6 +2057,7 @@ The endpoints where the server *should* include bundled aggregations are:
 * [`GET /sync`](#get_matrixclientv3sync) when the relevant section has a `limited` value
   of `true`.
 * [`POST /search`](#post_matrixclientv3search) for any matching events under `room_events`.
+* {{< added-in v="1.4" >}} [`GET /rooms/{roomId}/threads`](#get_matrixclientv1roomsroomidthreads)
 
 {{% boxes/note %}}
 The server is **not** required to return bundled aggregations on deprecated endpoints

content/client-server-api/modules/threading.md

@@ -192,16 +192,10 @@ It does not include events sent by [ignored users](#ignoring-users).
 1. The `sender` of the event receiving the bundle (they sent the thread root).
 2. The `sender` of an event which references the thread root with a `rel_type` of `m.thread`.
 
-#### Client behaviour
+#### Querying threads in a room
 
-Client-specific behaviours are described throughout this module and are not repeated here.
+Clients looking to get all the events in a thread can use
+[`GET /relations/{threadRootId}/m.thread`](#get_matrixclientv1roomsroomidrelationseventidreltype),
+however getting all threads in a room is done through a dedicated API:
 
-Clients might wish to read up on the following endpoints to achieve thread-specific functionality,
+{{% http-api spec="client-server" api="threads_list" %}}
-however:
-* [`GET /relations`](#get_matrixclientv1roomsroomidrelationseventidreltype) using the thread root
-  ID to retrieve all events in a thread.
-* ***DEVNOTE***: Normally we'd talk about `related_by_rel_types` and `related_by_senders` filters here,
-  but because MSC3856 literally replaces them we just don't bother speccing them at this point. At the
-  time you're reading this, the commit is targeting MSC3440 specifically and doesn't want to bleed too
-  much into the other MSCs, for reasons of clarity. Then again, here I am leaving a long comment explaining
-  why we aren't including a relatively short MSC in this commit. You're welcome.

data/api/client-server/threads_list.yaml

@@ -0,0 +1,135 @@
+# Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+swagger: '2.0'
+info:
+  title: "Matrix Client-Server Threads List API"
+  version: "1.0.0"
+host: localhost:8008
+schemes:
+  - https
+  - http
+basePath: /_matrix/client/v1
+consumes:
+  - application/json
+produces:
+  - application/json
+securityDefinitions:
+  $ref: definitions/security.yaml
+paths:
+  "/rooms/{roomId}/threads":
+    get:
+      x-addedInMatrixVersion: "1.4"
+      summary: Retrieve a list of threads in a room, with optional filters.
+      description: |-
+        Paginates over the thread roots in a room, ordered by the `latest_event` of each thread root
+        in its bundle.
+      operationId: getThreadRoots
+      security:
+        - accessToken: []
+      parameters:
+        - in: path
+          type: string
+          name: roomId
+          description: The room ID where the thread roots are located.
+          required: true
+          x-example: "!room:example.org"
+        - in: query
+          type: string
+          name: include
+          enum: [all, participated]
+          description: |-
+            Optional (default `all`) flag to denote which thread roots are of interest to the caller.
+            When `all`, all thread roots found in the room are returned. When `participated`, only
+            thread roots for threads the user has [participated in](/client-server-api/#server-side-aggreagtion-of-mthread-relationships)
+            will be returned.
+          x-example: "all"
+        - in: query
+          type: integer
+          name: limit
+          description: |-
+            Optional limit for the maximum number of thread roots to include per response. Must be an integer
+            greater than zero.
+
+            Servers should apply a default value, and impose a maximum value to avoid resource exhaustion.
+          x-example: 20
+        - in: query
+          type: string
+          name: from
+          description: |-
+            A pagination token from a previous result. When not provided, the server starts paginating from
+            the most recent event visible to the user (as per history visibility rules; topologically).
+          x-example: "next_batch_token"
+      responses:
+        200:
+          description: |-
+            A portion of the available thread roots in the room, based on the filter criteria.
+          examples:
+            application/json: {
+              "chunk": [{ "$ref": "../../event-schemas/examples/m.room.message$m.text.yaml" }],
+              "next_batch": "next_batch_token"
+            }
+          schema:
+            type: object
+            properties:
+              chunk:
+                type: array
+                description: |-
+                  The thread roots, ordered by the `latest_event` in each event's aggregation bundle. All events
+                  returned include bundled [aggregations](/client-server-api/#aggregations).
+
+                  If the thread root event was sent by an [ignored user](/client-server-api/#ignoring-users), the
+                  event is returned redacted to the caller. This is to simulate the same behaviour of a client doing
+                  aggregation locally on the thread.
+                items:
+                  $ref: "definitions/client_event.yaml"
+              next_batch:
+                type: string
+                description: |-
+                  A token to supply to `from` to keep paginating the responses. Not present when there are
+                  no further results.
+            required: [chunk]
+        403:
+          description: |-
+            The user cannot view or peek on the room. A meaningful `errcode`
+            and description error text will be returned. Example reasons for rejection are:
+
+            - The room is not set up for peeking.
+            - The user has been banned from the room.
+            - The room does not exist.
+          examples:
+            application/json: {
+              "errcode": "M_FORBIDDEN",
+              "error": "You are not allowed to view this room."
+            }
+          schema:
+            "$ref": "definitions/errors/error.yaml"
+        400:
+          description: |-
+            The request was invalid in some way. A meaningful `errcode`
+            and description error text will be returned. Example reasons for rejection are:
+
+            - The `from` token is unknown to the server.
+          examples:
+            application/json: {
+              "errcode": "M_INVALID_PARAM",
+              "error": "Unknown pagination token"
+            }
+          schema:
+            "$ref": "definitions/errors/error.yaml"
+        429:
+          description: This request was rate-limited.
+          schema:
+            "$ref": "definitions/errors/rate_limited.yaml"
+      tags:
+        - Threads