element-web/src/vector/jitsi/index.ts

/*
Copyright 2020 New Vector Ltd.

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 { KJUR } from 'jsrsasign';
import {
    IOpenIDCredentials,
    IWidgetApiRequest,
    VideoConferenceCapabilities,
    WidgetApi,
} from "matrix-widget-api";
import { ElementWidgetActions } from "matrix-react-sdk/src/stores/widgets/ElementWidgetActions";
import { logger } from "matrix-js-sdk/src/logger";
import { IConfigOptions } from "matrix-react-sdk/src/IConfigOptions";
import { SnakedObject } from "matrix-react-sdk/src/utils/SnakedObject";

import { getVectorConfig } from "../getconfig";

// We have to trick webpack into loading our CSS for us.
require("./index.scss");

const JITSI_OPENIDTOKEN_JWT_AUTH = 'openidtoken-jwt';

// Dev note: we use raw JS without many dependencies to reduce bundle size.
// We do not need all of React to render a Jitsi conference.

declare let JitsiMeetExternalAPI: any;

let inConference = false;

// Jitsi params
let jitsiDomain: string;
let conferenceId: string;
let displayName: string;
let avatarUrl: string;
let userId: string;
let jitsiAuth: string;
let roomId: string;
let openIdToken: IOpenIDCredentials;
let roomName: string;
let startAudioOnly: boolean;
let isVideoChannel: boolean;

let widgetApi: WidgetApi;
let meetApi: any; // JitsiMeetExternalAPI
let skipOurWelcomeScreen = false;

const ack = (ev: CustomEvent<IWidgetApiRequest>) => widgetApi.transport.reply(ev.detail, {});

(async function() {
    try {
        // Queue a config.json lookup asap, so we can use it later on. We want this to be concurrent with
        // other setup work and therefore do not block.
        const configPromise = getVectorConfig('..');

        // The widget's options are encoded into the fragment to avoid leaking info to the server.
        const widgetQuery = new URLSearchParams(window.location.hash.substring(1));
        // The widget spec on the other hand requires the widgetId and parentUrl to show up in the regular query string.
        const realQuery = new URLSearchParams(window.location.search.substring(1));
        const qsParam = (name: string, optional = false): string => {
            const vals = widgetQuery.has(name) ? widgetQuery.getAll(name) : realQuery.getAll(name);
            if (!optional && vals.length !== 1) {
                throw new Error(`Expected singular ${name} in query string`);
            }
            return vals[0];
        };

        // If we have these params, expect a widget API to be available (ie. to be in an iframe
        // inside a matrix client). Otherwise, assume we're on our own, eg. have been popped
        // out into a browser.
        const parentUrl = qsParam('parentUrl', true);
        const widgetId = qsParam('widgetId', true);
        const theme = qsParam('theme', true);

        if (theme) {
            document.body.classList.add(`theme-${theme.replace(" ", "_")}`);
        }

        // Set this up as early as possible because Element will be hitting it almost immediately.
        let readyPromise: Promise<[void, void]>;
        if (parentUrl && widgetId) {
            const parentOrigin = new URL(qsParam('parentUrl')).origin;
            widgetApi = new WidgetApi(qsParam("widgetId"), parentOrigin);
            widgetApi.requestCapabilities(VideoConferenceCapabilities);
            readyPromise = Promise.all([
                new Promise<void>(resolve => {
                    widgetApi.once(`action:${ElementWidgetActions.ClientReady}`, ev => {
                        ev.preventDefault();
                        widgetApi.transport.reply(ev.detail, {});
                        resolve();
                    });
                }),
                new Promise<void>(resolve => {
                    widgetApi.once("ready", () => resolve());
                }),
            ]);
            widgetApi.start();
        } else {
            logger.warn("No parent URL or no widget ID - assuming no widget API is available");
        }

        // Populate the Jitsi params now
        jitsiDomain = qsParam('conferenceDomain');
        conferenceId = qsParam('conferenceId');
        displayName = qsParam('displayName', true);
        avatarUrl = qsParam('avatarUrl', true); // http not mxc
        userId = qsParam('userId');
        jitsiAuth = qsParam('auth', true);
        roomId = qsParam('roomId', true);
        roomName = qsParam('roomName', true);
        startAudioOnly = qsParam('isAudioOnly', true) === "true";
        isVideoChannel = qsParam('isVideoChannel', true) === "true";

        // We've reached the point where we have to wait for the config, so do that then parse it.
        const instanceConfig = new SnakedObject<IConfigOptions>((await configPromise) ?? <IConfigOptions>{});
        const jitsiConfig = instanceConfig.get("jitsi_widget") ?? {};
        skipOurWelcomeScreen = (new SnakedObject<IConfigOptions["jitsi_widget"]>(jitsiConfig))
            .get("skip_built_in_welcome_screen") ?? false;

        // Either reveal the prejoin screen, or skip straight to Jitsi depending on the config.
        // We don't set up the call yet though as this might lead to failure without the widget API.
        toggleConferenceVisibility(skipOurWelcomeScreen);

        if (widgetApi) {
            await readyPromise;

            // See https://github.com/matrix-org/prosody-mod-auth-matrix-user-verification
            if (jitsiAuth === JITSI_OPENIDTOKEN_JWT_AUTH) {
                // Request credentials, give callback to continue when received
                openIdToken = await widgetApi.requestOpenIDConnectToken();
                logger.log("Got OpenID Connect token");
            }

            widgetApi.on(`action:${ElementWidgetActions.JoinCall}`,
                (ev: CustomEvent<IWidgetApiRequest>) => {
                    const { audioDevice, videoDevice } = ev.detail.data;
                    joinConference(audioDevice as string, videoDevice as string);
                    ack(ev);
                },
            );
            widgetApi.on(`action:${ElementWidgetActions.HangupCall}`,
                (ev: CustomEvent<IWidgetApiRequest>) => {
                    meetApi?.executeCommand('hangup');
                    ack(ev);
                },
            );
            widgetApi.on(`action:${ElementWidgetActions.MuteAudio}`,
                async (ev: CustomEvent<IWidgetApiRequest>) => {
                    ack(ev);
                    if (meetApi && !await meetApi.isAudioMuted()) {
                        meetApi.executeCommand('toggleAudio');
                    }
                },
            );
            widgetApi.on(`action:${ElementWidgetActions.UnmuteAudio}`,
                async (ev: CustomEvent<IWidgetApiRequest>) => {
                    ack(ev);
                    if (meetApi && await meetApi.isAudioMuted()) {
                        meetApi.executeCommand('toggleAudio');
                    }
                },
            );
            widgetApi.on(`action:${ElementWidgetActions.MuteVideo}`,
                async (ev: CustomEvent<IWidgetApiRequest>) => {
                    ack(ev);
                    if (meetApi && !await meetApi.isVideoMuted()) {
                        meetApi.executeCommand('toggleVideo');
                    }
                },
            );
            widgetApi.on(`action:${ElementWidgetActions.UnmuteVideo}`,
                async (ev: CustomEvent<IWidgetApiRequest>) => {
                    ack(ev);
                    if (meetApi && await meetApi.isVideoMuted()) {
                        meetApi.executeCommand('toggleVideo');
                    }
                },
            );
            widgetApi.on(`action:${ElementWidgetActions.StartLiveStream}`,
                (ev: CustomEvent<IWidgetApiRequest>) => {
                    if (meetApi) {
                        meetApi.executeCommand('startRecording', {
                            mode: 'stream',
                            // this looks like it should be rtmpStreamKey but we may be on too old
                            // a version of jitsi meet
                            //rtmpStreamKey: ev.detail.data.rtmpStreamKey,
                            youtubeStreamKey: ev.detail.data.rtmpStreamKey,
                        });
                        ack(ev);
                    } else {
                        widgetApi.transport.reply(ev.detail, { error: { message: "Conference not joined" } });
                    }
                },
            );
        }

        // Now that everything should be set up, skip to the Jitsi splash screen if needed
        if (skipOurWelcomeScreen) {
            skipToJitsiSplashScreen();
        }

        enableJoinButton(); // always enable the button

        // Inform the client that we're ready to receive events
        try {
            await widgetApi?.transport.send(ElementWidgetActions.WidgetReady, {});
        } catch (e) {
            logger.error(e);
        }
    } catch (e) {
        logger.error("Error setting up Jitsi widget", e);
        document.getElementById("widgetActionContainer").innerText = "Failed to load Jitsi widget";
    }
})();

function enableJoinButton() {
    document.getElementById("joinButton").onclick = () => joinConference();
}

function switchVisibleContainers() {
    inConference = !inConference;

    // Our welcome screen is managed by other code, so just don't switch to it ever
    // if we're not supposed to.
    if (!skipOurWelcomeScreen) {
        toggleConferenceVisibility(inConference);
    }
}

function toggleConferenceVisibility(inConference: boolean) {
    document.getElementById("jitsiContainer").style.visibility = inConference ? 'unset' : 'hidden';
    // Video rooms have a separate UI for joining, so they should never show our join button
    document.getElementById("joinButtonContainer").style.visibility =
        (inConference || isVideoChannel) ? 'hidden' : 'unset';
}

function skipToJitsiSplashScreen() {
    // really just a function alias for self-documenting code
    joinConference();
}

/**
 * Create a JWT token fot jitsi openidtoken-jwt auth
 *
 * See https://github.com/matrix-org/prosody-mod-auth-matrix-user-verification
 */
function createJWTToken() {
    // Header
    const header = { alg: 'HS256', typ: 'JWT' };
    // Payload
    const payload = {
        // As per Jitsi token auth, `iss` needs to be set to something agreed between
        // JWT generating side and Prosody config. Since we have no configuration for
        // the widgets, we can't set one anywhere. Using the Jitsi domain here probably makes sense.
        iss: jitsiDomain,
        sub: jitsiDomain,
        aud: `https://${jitsiDomain}`,
        room: "*",
        context: {
            matrix: {
                token: openIdToken.access_token,
                room_id: roomId,
                server_name: openIdToken.matrix_server_name,
            },
            user: {
                avatar: avatarUrl,
                name: displayName,
            },
        },
    };
    // Sign JWT
    // The secret string here is irrelevant, we're only using the JWT
    // to transport data to Prosody in the Jitsi stack.
    return KJUR.jws.JWS.sign(
        'HS256',
        JSON.stringify(header),
        JSON.stringify(payload),
        'notused',
    );
}

async function notifyHangup() {
    if (widgetApi) {
        // We send the hangup event before setAlwaysOnScreen, because the latter
        // can cause the receiving side to instantly stop listening.
        try {
            await widgetApi.transport.send(ElementWidgetActions.HangupCall, {});
        } finally {
            await widgetApi.setAlwaysOnScreen(false);
        }
    }
}

function closeConference() {
    switchVisibleContainers();
    document.getElementById("jitsiContainer").innerHTML = "";

    if (skipOurWelcomeScreen) {
        skipToJitsiSplashScreen();
    }
}

// event handler bound in HTML
function joinConference(audioDevice?: string, videoDevice?: string) {
    let jwt;
    if (jitsiAuth === JITSI_OPENIDTOKEN_JWT_AUTH) {
        if (!openIdToken?.access_token) { // eslint-disable-line camelcase
            // We've failing to get a token, don't try to init conference
            logger.warn('Expected to have an OpenID credential, cannot initialize widget.');
            document.getElementById("widgetActionContainer").innerText = "Failed to load Jitsi widget";
            return;
        }
        jwt = createJWTToken();
    }

    switchVisibleContainers();

    logger.warn(
        "[Jitsi Widget] The next few errors about failing to parse URL parameters are fine if " +
        "they mention 'external_api' or 'jitsi' in the stack. They're just Jitsi Meet trying to parse " +
        "our fragment values and not recognizing the options.",
    );

    const options = {
        width: "100%",
        height: "100%",
        parentNode: document.querySelector("#jitsiContainer"),
        roomName: conferenceId,
        devices: {
            audioInput: audioDevice,
            videoInput: videoDevice,
        },
        userInfo: {
            displayName,
            email: userId,
        },
        interfaceConfigOverwrite: {
            SHOW_JITSI_WATERMARK: false,
            SHOW_WATERMARK_FOR_GUESTS: false,
            MAIN_TOOLBAR_BUTTONS: [],
            VIDEO_LAYOUT_FIT: "height",
        },
        configOverwrite: {
            subject: roomName,
            startAudioOnly,
            startWithAudioMuted: audioDevice == null,
            startWithVideoMuted: videoDevice == null,
        } as any,
        jwt: jwt,
    };

    // Video channel widgets need some more tailored config options
    if (isVideoChannel) {
        // Ensure that we skip Jitsi Meet's native prejoin screen, for
        // deployments that have it enabled
        options.configOverwrite.prejoinConfig = { enabled: false };
        // Use a simplified set of toolbar buttons
        options.configOverwrite.toolbarButtons = [
            "microphone", "camera", "desktop", "tileview", "hangup",
        ];
        // Hide all top bar elements
        options.configOverwrite.conferenceInfo = { autoHide: [] };
    }

    meetApi = new JitsiMeetExternalAPI(jitsiDomain, options);

    // fires once when user joins the conference
    // (regardless of video on or off)
    meetApi.on("videoConferenceJoined", () => {
        if (avatarUrl) meetApi.executeCommand("avatarUrl", avatarUrl);

        if (widgetApi) {
            // ignored promise because we don't care if it works
            // noinspection JSIgnoredPromiseFromCall
            widgetApi.setAlwaysOnScreen(true);
            widgetApi.transport.send(ElementWidgetActions.JoinCall, {});
        }

        // Video rooms should start in tile mode
        if (isVideoChannel) meetApi.executeCommand("setTileView", true);
    });

    meetApi.on("videoConferenceLeft", () => {
        notifyHangup();
        meetApi = null;
    });

    meetApi.on("readyToClose", closeConference);

    meetApi.on("errorOccurred", ({ error }) => {
        if (error.isFatal) {
            // We got disconnected. Since Jitsi Meet might send us back to the
            // prejoin screen, we're forced to act as if we hung up entirely.
            notifyHangup();
            meetApi = null;
            closeConference();
        }
    });

    meetApi.on("audioMuteStatusChanged", ({ muted }) => {
        const action = muted ? ElementWidgetActions.MuteAudio : ElementWidgetActions.UnmuteAudio;
        widgetApi.transport.send(action, {});
    });

    meetApi.on("videoMuteStatusChanged", ({ muted }) => {
        if (muted) {
            // Jitsi Meet always sends a "video muted" event directly before
            // hanging up, which we need to ignore by padding the timeout here,
            // otherwise the React SDK will mistakenly think the user turned off
            // their video by hand
            setTimeout(() => {
                if (meetApi) widgetApi.transport.send(ElementWidgetActions.MuteVideo, {});
            }, 200);
        } else {
            widgetApi.transport.send(ElementWidgetActions.UnmuteVideo, {});
        }
    });

    ["videoConferenceJoined", "participantJoined", "participantLeft"].forEach(event => {
        meetApi.on(event, () => {
            widgetApi?.transport.send(ElementWidgetActions.CallParticipants, {
                participants: meetApi.getParticipantsInfo(),
            });
        });
    });
}