Move various e2e defintions out to yaml files (#1166)

We have code to generate tables, which we should use in the e2e section.

assets/scss/custom.scss

@@ -323,7 +323,6 @@ footer {
   table {
     table-layout: fixed;
     width: 100%;
-    margin: 4rem 0;
 
     caption {
       caption-side: top;

changelogs/client_server/newsfragments/1166.clarification

@@ -0,0 +1 @@
+Clarify the format of some structures in the End-to-end encryption module.

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

@@ -1255,25 +1255,12 @@ When a backup is created with the `algorithm` set to
 `m.megolm_backup.v1.curve25519-aes-sha2`, the `auth_data` should have
 the following format:
 
-`AuthData`
+{{% definition path="api/client-server/definitions/key_backup_auth_data" %}}
-
-| Parameter  | Type       | Description                                                                                      |
-| -----------| -----------|--------------------------------------------------------------------------------------------------|
-| public_key | string     | **Required.** The curve25519 public key used to encrypt the backups, encoded in unpadded base64. |
-| signatures | Signatures | Optional. Signatures of the ``auth_data``, as Signed JSON                                        |
 
 The `session_data` field in the backups is constructed as follows:
 
-1.  Encode the session key to be backed up as a JSON object with the
+1.  Encode the session key to be backed up as a JSON object using the
-    properties:
+    `SessionData` format defined below.
-
-| Parameter                       | Type              | Description                                                                                                                                                                 |
-| --------------------------------|-------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| algorithm                       | string            | **Required.** The end-to-end message encryption algorithm that the key is for.  Must be `m.megolm.v1.aes-sha2`.                                                             |
-| forwarding_curve25519_key_chain | [string]          | **Required.** Chain of Curve25519 keys through which this session was forwarded, via [m.forwarded_room_key](#mforwarded_room_key) events.                                   |
-| sender_key                      | string            | **Required.** Unpadded base64-encoded device curve25519 key.                                                                                                                |
-| sender_claimed_keys             | {string: string}  | **Required.** A map from algorithm name (`ed25519`) to the identity key for the sending device.                                                                             |
-| session_key                     | string            | **Required.** Unpadded base64-encoded session key in [session-sharing format](https://gitlab.matrix.org/matrix-org/olm/blob/master/docs/megolm.md#session-sharing-format).  |
 
 2.  Generate an ephemeral curve25519 key, and perform an ECDH with the
     ephemeral key and the backup's public key to generate a shared
@@ -1295,6 +1282,8 @@ The `session_data` field in the backups is constructed as follows:
     the resulting MAC are base64-encoded, and become the `mac` property
     of the `session_data`.
 
+{{% definition path="api/client-server/definitions/key_backup_session_data" %}}
+
 {{% http-api spec="client-server" api="key_backup" %}}
 
 ##### Key exports
@@ -1344,42 +1333,7 @@ user-supplied passphrase, and is created as follows:
 The exported sessions are formatted as a JSON array of `SessionData`
 objects described as follows:
 
-`SessionData`
+{{% definition path="api/client-server/definitions/megolm_export_session_data" %}}
-
-| Parameter                         | Type             | Description                                                                                                                           |
-|-----------------------------------|------------------|---------------------------------------------------------------------------------------------------------------------------------------|
-| algorithm                         | string           | Required. The encryption algorithm that the session uses. Must be `m.megolm.v1.aes-sha2`.                                             |
-| forwarding_curve25519_key_chain   | [string]         | Required. Chain of Curve25519 keys through which this session was forwarded, via [m.forwarded_room_key](#mforwarded_room_key) events. |
-| room_id                           | string           | Required. The room where the session is used.                                                                                         |
-| sender_key                        | string           | Required. The Curve25519 key of the device which initiated the session originally.                                                    |
-| sender_claimed_keys               | {string: string} | Required. The Ed25519 key of the device which initiated the session originally.                                                       |
-| session_id                        | string           | Required. The ID of the session.                                                                                                      |
-| session_key                       | string           | Required. The key for the session.                                                                                                    |
-
-This is similar to the format before encryption used for the session
-keys in [Server-side key backups](#server-side-key-backups) but adds the
-`room_id` and `session_id` fields.
-
-Example:
-
-```
-[
-    {
-        "algorithm": "m.megolm.v1.aes-sha2",
-        "forwarding_curve25519_key_chain": [
-            "hPQNcabIABgGnx3/ACv/jmMmiQHoeFfuLB17tzWp6Hw"
-        ],
-        "room_id": "!Cuyf34gef24t:localhost",
-        "sender_key": "RF3s+E7RkTQTGF2d8Deol0FkQvgII2aJDf3/Jp5mxVU",
-        "sender_claimed_keys": {
-            "ed25519": "<device ed25519 identity key>",
-        },
-        "session_id": "X3lUlvLELLYxeTx4yOVu6UDpasGEVO0Jbu+QFnm0cKQ",
-        "session_key": "AgAAAADxKHa9uFxcXzwYoNueL5Xqi69IkD4sni8Llf..."
-    },
-    ...
-]
-```
 
 #### Messaging Algorithms
 

data/api/client-server/definitions/key_backup_auth_data.yaml

@@ -0,0 +1,36 @@
+# 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.
+
+
+type: object
+title: AuthData
+description: |-
+  The format of the `auth_data` when a key backup is created with the
+  `algorithm` set to `m.megolm_backup.v1.curve25519-aes-sha2`.
+properties:
+  public_key:
+    type: string
+    description: |-
+      The curve25519 public key used to encrypt the backups, encoded in unpadded base64.
+    example: "abcdefg"
+  signatures:
+    type: object
+    description: |-
+      Signatures of the `auth_data`, as Signed JSON
+    example: {
+      "something": {
+        "ed25519:something": "hijklmnop"
+      }
+    }
+required: ['public_key']

data/api/client-server/definitions/key_backup_session_data.yaml

@@ -0,0 +1,62 @@
+# 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.
+
+
+type: object
+title: SessionData
+description: |-
+  The format of a backed-up session key, prior to encryption, when using the
+  `m.megolm_backup.v1.curve25519-aes-sha2` algorithm.
+properties:
+  algorithm:
+    type: string
+    description: |-
+      The end-to-end message encryption algorithm that the key is for. Must be `m.megolm.v1.aes-sha2`.
+  forwarding_curve25519_key_chain:
+    type: array
+    items:
+      type: string
+    description: |-
+      Chain of Curve25519 keys through which this session was forwarded, via [m.forwarded_room_key](#mforwarded_room_key) events.
+  sender_key:
+    type: string
+    description: |-
+      Unpadded base64-encoded device Curve25519 key.
+  sender_claimed_keys:
+    type: object
+    additionalProperties:
+      type: string
+    description: |-
+      A map from algorithm name (`ed25519`) to the Ed25519 signing key of the sending device.
+  session_key:
+    type: string
+    description: |-
+      Unpadded base64-encoded session key in [session-export format](https://gitlab.matrix.org/matrix-org/olm/blob/master/docs/megolm.md#session-export-format).
+example: {
+  "algorithm": "m.megolm.v1.aes-sha2",
+  "forwarding_curve25519_key_chain": [
+    "hPQNcabIABgGnx3/ACv/jmMmiQHoeFfuLB17tzWp6Hw"
+  ],
+  "sender_key": "RF3s+E7RkTQTGF2d8Deol0FkQvgII2aJDf3/Jp5mxVU",
+  "sender_claimed_keys": {
+    "ed25519": "aj40p+aw64yPIdsxoog8jhPu9i7l7NcFRecuOQblE3Y",
+  },
+  "session_key": "AgAAAADxKHa9uFxcXzwYoNueL5Xqi69IkD4sni8Llf..."
+}
+required:
+  - algorithm
+  - forwarding_curve25519_key_chain
+  - sender_key
+  - sender_claimed_keys
+  - session_key

data/api/client-server/definitions/megolm_export_session_data.yaml

@@ -0,0 +1,38 @@
+# 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.
+
+
+allOf:
+  - $ref: key_backup_session_data.yaml
+  - type: object
+    description: |-
+      The format used to encode a Megolm session key for export.
+
+      This is similar to the format before encryption used for the session keys
+      in [Server-side key backups](#server-side-key-backups) but adds the
+      `room_id` and `session_id` fields.
+    properties:
+      room_id:
+        type: string
+        description: |-
+          The room where the session is used.
+        example: "!Cuyf34gef24t:localhost"
+      session_id:
+        type: string
+        description: |-
+          The Megolm session ID.
+        example: "X3lUlvLELLYxeTx4yOVu6UDpasGEVO0Jbu+QFnm0cKQ"
+    required:
+      - room_id
+      - session_id

layouts/shortcodes/definition.html

@@ -18,6 +18,10 @@
 {{/* The definition is referenced by the .path parameter */}}
 {{ $definition := index .Site.Data $pieces }}
 
+{{ if not $definition }}
+  {{ errorf "site data %s not found" $path }}
+{{ end }}
+
 {{/* The base path, which we use to resolve $ref, omits the last component */}}
 {{ $pieces = first (sub (len $pieces) 1) $pieces}}
 {{ $path = delimit $pieces "/" }}