vector-im-hydrogen-web/src/matrix/net/MediaRepository.ts

/*
Copyright 2020 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.
*/

import {encodeQueryParams} from "./common";
import {decryptAttachment} from "../e2ee/attachment.js";
import {Platform} from "../../platform/web/Platform.js";
import {BlobHandle} from "../../platform/web/dom/BlobHandle.js";
import type {Attachment, EncryptedFile} from "./types/response";

export class MediaRepository {
    private readonly _homeserver: string;
    private readonly _platform: Platform;

    constructor({homeserver, platform}: {homeserver:string, platform: Platform}) {
        this._homeserver = homeserver;
        this._platform = platform;
    }

    mxcUrlThumbnail(url: string, width: number, height: number, method: "crop" | "scale"): string | undefined {
        const parts = this._parseMxcUrl(url);
        if (parts) {
            const [serverName, mediaId] = parts;
            const httpUrl = `${this._homeserver}/_matrix/media/r0/thumbnail/${encodeURIComponent(serverName)}/${encodeURIComponent(mediaId)}`;
            return httpUrl + "?" + encodeQueryParams({width: Math.round(width), height: Math.round(height), method});
        }
        return undefined;
    }

    mxcUrl(url: string): string | undefined {
        const parts = this._parseMxcUrl(url);
        if (parts) {
            const [serverName, mediaId] = parts;
            return `${this._homeserver}/_matrix/media/r0/download/${encodeURIComponent(serverName)}/${encodeURIComponent(mediaId)}`;
        }
        return undefined;
    }

    private _parseMxcUrl(url: string): string[] | undefined {
        const prefix = "mxc://";
        if (url.startsWith(prefix)) {
            return url.substr(prefix.length).split("/", 2);
        } else {
            return undefined;
        }
    }

    async downloadEncryptedFile(fileEntry: EncryptedFile, cache: boolean = false): Promise<BlobHandle> {
        const url = this.mxcUrl(fileEntry.url);
        const {body: encryptedBuffer} = await this._platform.request(url, {method: "GET", format: "buffer", cache}).response();
        const decryptedBuffer = await decryptAttachment(this._platform, encryptedBuffer, fileEntry);
        return this._platform.createBlob(decryptedBuffer, fileEntry.mimetype);
    }

    async downloadPlaintextFile(mxcUrl: string, mimetype: string, cache: boolean = false): Promise<BlobHandle> {
        const url = this.mxcUrl(mxcUrl);
        const {body: buffer} = await this._platform.request(url, {method: "GET", format: "buffer", cache}).response();
        return this._platform.createBlob(buffer, mimetype);
    }

    async downloadAttachment(content: Attachment, cache: boolean = false): Promise<BlobHandle> {
        if (content.file) {
            return this.downloadEncryptedFile(content.file, cache);
        } else {
            return this.downloadPlaintextFile(content.url!, content.info?.mimetype, cache);
        }
    }
}