Early proof of concept for media customization support

src/customisations/models/IMediaEventContent.ts

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2021 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.
+ */
+
+// TODO: These types should be elsewhere.
+
+export interface IEncryptedFile {
+    url: string;
+    key: {
+        alg: string;
+        key_ops: string[];
+        kty: string;
+        k: string;
+        ext: boolean;
+    };
+    iv: string;
+    hashes: {[alg: string]: string};
+    v: string;
+}
+
+export interface IMediaEventContent {
+    url?: string; // required on unencrypted media
+    file?: IEncryptedFile; // required for *encrypted* media
+    info?: {
+        thumbnail_url?: string;
+        thumbnail_file?: IEncryptedFile;
+    };
+}
+
+export interface IPreparedMedia extends IMediaObject {
+    thumbnail?: IMediaObject;
+}
+
+export interface IMediaObject {
+    mxc: string;
+    file?: IEncryptedFile;
+}
+
+/**
+ * Parses an event content body into a prepared media object. This prepared media object
+ * can be used with other functions to manipulate the media.
+ * @param {IMediaEventContent} content Unredacted media event content. See interface.
+ * @returns {IPreparedMedia} A prepared media object.
+ * @throws Throws if the given content cannot be packaged into a prepared media object.
+ */
+export function prepEventContentAsMedia(content: IMediaEventContent): IPreparedMedia {
+    let thumbnail: IMediaObject = null;
+    if (content?.info?.thumbnail_url) {
+        thumbnail = {
+            mxc: content.info.thumbnail_url,
+            file: content.info.thumbnail_file,
+        };
+    } else if (content?.info?.thumbnail_file?.url) {
+        thumbnail = {
+            mxc: content.info.thumbnail_file.url,
+            file: content.info.thumbnail_file,
+        };
+    }
+
+    if (content?.url) {
+        return {
+            thumbnail,
+            mxc: content.url,
+            file: content.file,
+        };
+    } else if (content?.file?.url) {
+        return {
+            thumbnail,
+            mxc: content.file.url,
+            file: content.file,
+        };
+    }
+
+    throw new Error("Invalid file provided: cannot determine MXC URI. Has it been redacted?");
+}