ljm_j1/modules/RTC/ScreenObtainer.js

/* global chrome, $, alert */

var AdapterJS = require("./adapter.screenshare");
var GlobalOnErrorHandler = require("../util/GlobalOnErrorHandler");
var logger = require("jitsi-meet-logger").getLogger(__filename);
var RTCBrowserType = require("./RTCBrowserType");
import JitsiTrackError from "../../JitsiTrackError";
import * as JitsiTrackErrors from "../../JitsiTrackErrors";

/**
 * Indicates whether the Chrome desktop sharing extension is installed.
 * @type {boolean}
 */
var chromeExtInstalled = false;

/**
 * Indicates whether an update of the Chrome desktop sharing extension is
 * required.
 * @type {boolean}
 */
var chromeExtUpdateRequired = false;

/**
 * Whether the jidesha extension for firefox is installed for the domain on
 * which we are running. Null designates an unknown value.
 * @type {null}
 */
var firefoxExtInstalled = null;

/**
 * If set to true, detection of an installed firefox extension will be started
 * again the next time obtainScreenOnFirefox is called (e.g. next time the
 * user tries to enable screen sharing).
 */
var reDetectFirefoxExtension = false;

var GUM = null;

/**
 * The error returned by chrome when trying to start inline installation from
 * popup.
 */
const CHROME_EXTENSION_POPUP_ERROR
    = "Inline installs can not be initiated from pop-up windows.";

/**
 * The error message returned by chrome when the extension is installed.
 */
const CHROME_NO_EXTENSION_ERROR_MSG // eslint-disable-line no-unused-vars
    = "Could not establish connection. Receiving end does not exist.";

/**
 * Handles obtaining a stream from a screen capture on different browsers.
 */
var ScreenObtainer = {
    obtainStream: null,

    /**
     * Initializes the function used to obtain a screen capture
     * (this.obtainStream).
     *
     * If the browser is Chrome, it uses the value of
     * 'options.desktopSharingChromeMethod' (or 'options.desktopSharing') to
     * decide whether to use the a Chrome extension (if the value is 'ext'),
     * use the "screen" media source (if the value is 'webrtc'),
     * or disable screen capture (if the value is other).
     * Note that for the "screen" media source to work the
     * 'chrome://flags/#enable-usermedia-screen-capture' flag must be set.
     * @param options {object}
     * @param gum {Function} GUM method
     */
    init(options, gum) {
        var obtainDesktopStream = null;
        this.options = options = options || {};
        GUM = gum;

        if (RTCBrowserType.isFirefox())
            initFirefoxExtensionDetection(options);

        // TODO remove this, options.desktopSharing is deprecated.
        var chromeMethod =
            (options.desktopSharingChromeMethod || options.desktopSharing);

        if (RTCBrowserType.isNWJS()) {
            obtainDesktopStream = (options, onSuccess, onFailure) => {
                window.JitsiMeetNW.obtainDesktopStream (
                    onSuccess,
                    (error, constraints) => {
                        var jitsiError;
                        // FIXME:
                        // This is very very durty fix for recognising that the
                        // user have clicked the cancel button from the Desktop
                        // sharing pick window. The proper solution would be to
                        // detect this in the NWJS application by checking the
                        // streamId === "". Even better solution would be to
                        // stop calling GUM from the NWJS app and just pass the
                        // streamId to lib-jitsi-meet. This way the desktop
                        // sharing implementation for NWJS and chrome extension
                        // will be the same and lib-jitsi-meet will be able to
                        // control the constraints, check the streamId, etc.
                        //
                        // I cannot find documentation about "InvalidStateError"
                        // but this is what we are receiving from GUM when the
                        // streamId for the desktop sharing is "".
                        if (error && error.name == "InvalidStateError") {
                            jitsiError = new JitsiTrackError(
                                JitsiTrackErrors.CHROME_EXTENSION_USER_CANCELED
                            );
                        } else {
                            jitsiError = new JitsiTrackError(
                                error, constraints, ["desktop"]);
                        }
                        (typeof(onFailure) === "function") &&
                            onFailure(jitsiError);
                    });
            };
        } else if (RTCBrowserType.isTemasysPluginUsed()) {
            if (!AdapterJS.WebRTCPlugin.plugin.HasScreensharingFeature) {
                logger.info("Screensharing not supported by this plugin " +
                    "version");
            } else if(!AdapterJS.WebRTCPlugin.plugin.isScreensharingAvailable) {
                logger.info(
                    "Screensharing not available with Temasys plugin on" +
                    " this site");
            } else {
                obtainDesktopStream = obtainWebRTCScreen;
                logger.info("Using Temasys plugin for desktop sharing");
            }
        } else if (RTCBrowserType.isChrome()) {
            if (chromeMethod == "ext") {
                if (RTCBrowserType.getChromeVersion() >= 34) {
                    obtainDesktopStream =
                        this.obtainScreenFromExtension;
                    logger.info("Using Chrome extension for desktop sharing");
                    initChromeExtension(options);
                } else {
                    logger.info("Chrome extension not supported until ver 34");
                }
            } else if (chromeMethod == "webrtc") {
                obtainDesktopStream = obtainWebRTCScreen;
                logger.info("Using Chrome WebRTC for desktop sharing");
            }
        } else if (RTCBrowserType.isFirefox()) {
            if (options.desktopSharingFirefoxDisabled) {
                obtainDesktopStream = null;
            } else if (window.location.protocol === "http:"){
                logger.log("Screen sharing is not supported over HTTP. " +
                    "Use of HTTPS is required.");
                obtainDesktopStream = null;
            } else {
                obtainDesktopStream = this.obtainScreenOnFirefox;
            }
        }

        if (!obtainDesktopStream) {
            logger.info("Desktop sharing disabled");
        }

        this.obtainStream = obtainDesktopStream;
    },

    /**
     * Checks whether obtaining a screen capture is supported in the current
     * environment.
     * @returns {boolean}
     */
    isSupported() {
        return !!this.obtainStream;
    },

    /**
     * Obtains a screen capture stream on Firefox.
     * @param callback
     * @param errorCallback
     */
    obtainScreenOnFirefox(options, callback, errorCallback) {
        var extensionRequired = false;
        if (this.options.desktopSharingFirefoxMaxVersionExtRequired === -1 ||
            (this.options.desktopSharingFirefoxMaxVersionExtRequired >= 0 &&
                RTCBrowserType.getFirefoxVersion() <=
                    this.options.desktopSharingFirefoxMaxVersionExtRequired)) {
            extensionRequired = true;
            logger.log("Jidesha extension required on firefox version " +
                RTCBrowserType.getFirefoxVersion());
        }

        if (!extensionRequired || firefoxExtInstalled === true) {
            obtainWebRTCScreen(options, callback, errorCallback);
            return;
        }

        if (reDetectFirefoxExtension) {
            reDetectFirefoxExtension = false;
            initFirefoxExtensionDetection(this.options);
        }

        // Give it some (more) time to initialize, and assume lack of
        // extension if it hasn't.
        if (firefoxExtInstalled === null) {
            window.setTimeout(
                () => {
                    if (firefoxExtInstalled === null)
                        firefoxExtInstalled = false;
                    this.obtainScreenOnFirefox(callback, errorCallback);
                },
                300);
            logger.log("Waiting for detection of jidesha on firefox to " +
                "finish.");
            return;
        }

        // We need an extension and it isn't installed.

        // Make sure we check for the extension when the user clicks again.
        firefoxExtInstalled = null;
        reDetectFirefoxExtension = true;

        // Make sure desktopsharing knows that we failed, so that it doesn't get
        // stuck in 'switching' mode.
        errorCallback(
            new JitsiTrackError(JitsiTrackErrors.FIREFOX_EXTENSION_NEEDED));
    },

    /**
     * Asks Chrome extension to call chooseDesktopMedia and gets chrome
     * 'desktop' stream for returned stream token.
     */
    obtainScreenFromExtension(options, streamCallback, failCallback) {
        if (chromeExtInstalled) {
            doGetStreamFromExtension(this.options, streamCallback,
                failCallback);
        } else {
            if (chromeExtUpdateRequired) {
                alert(
                    'Jitsi Desktop Streamer requires update. ' +
                    'Changes will take effect after next Chrome restart.');
            }

            try {
                chrome.webstore.install(
                    getWebStoreInstallUrl(this.options),
                    arg => {
                        logger.log("Extension installed successfully", arg);
                        chromeExtInstalled = true;
                        // We need to give a moment to the endpoint to become
                        // available.
                        waitForExtensionAfterInstall(this.options, 200, 10)
                            .then(() => {
                                doGetStreamFromExtension(this.options,
                                    streamCallback, failCallback);
                            }).catch(reason => {
                                this.handleExtensionInstallationError(options,
                                    streamCallback, failCallback, reason);
                            });
                    },
                    this.handleExtensionInstallationError.bind(this,
                        options, streamCallback, failCallback)
                );
            } catch(e) {
                this.handleExtensionInstallationError(options, streamCallback,
                    failCallback, e);
            }
        }
    },

    handleExtensionInstallationError(options, streamCallback, failCallback, e) {
        const webStoreInstallUrl = getWebStoreInstallUrl(this.options);

        if (CHROME_EXTENSION_POPUP_ERROR === e
                && options.interval > 0
                && typeof(options.checkAgain) === "function"
                && typeof(options.listener) === "function") {
            options.listener("waitingForExtension", webStoreInstallUrl);
            this.checkForChromeExtensionOnInterval(options, streamCallback,
                failCallback, e);
            return;
        }

        const msg
            = "Failed to install the extension from " + webStoreInstallUrl;

        logger.log(msg, e);
        failCallback(new JitsiTrackError(
            JitsiTrackErrors.CHROME_EXTENSION_INSTALLATION_ERROR,
            msg));
    },

    checkForChromeExtensionOnInterval(options, streamCallback, failCallback) {
        if (options.checkAgain() === false) {
            failCallback(new JitsiTrackError(
                JitsiTrackErrors.CHROME_EXTENSION_INSTALLATION_ERROR));
            return;
        }
        waitForExtensionAfterInstall(this.options, options.interval, 1)
            .then(() => {
                chromeExtInstalled = true;
                options.listener("extensionFound");
                this.obtainScreenFromExtension(options,
                    streamCallback, failCallback);
            }).catch(() => {
                this.checkForChromeExtensionOnInterval(options,
                    streamCallback, failCallback);
            });
    }
};

/**
 * Obtains a desktop stream using getUserMedia.
 * For this to work on Chrome, the
 * 'chrome://flags/#enable-usermedia-screen-capture' flag must be enabled.
 *
 * On firefox, the document's domain must be white-listed in the
 * 'media.getusermedia.screensharing.allowed_domains' preference in
 * 'about:config'.
 */
function obtainWebRTCScreen(options, streamCallback, failCallback) {
    GUM(['screen'], streamCallback, failCallback);
}

/**
 * Constructs inline install URL for Chrome desktop streaming extension.
 * The 'chromeExtensionId' must be defined in options parameter.
 * @param options supports "desktopSharingChromeExtId" and "chromeExtensionId"
 * @returns {string}
 */
function getWebStoreInstallUrl(options)
{
    //TODO remove chromeExtensionId (deprecated)
    return "https://chrome.google.com/webstore/detail/" +
        (options.desktopSharingChromeExtId || options.chromeExtensionId);
}

/**
 * Checks whether an update of the Chrome extension is required.
 * @param minVersion minimal required version
 * @param extVersion current extension version
 * @returns {boolean}
 */
function isUpdateRequired(minVersion, extVersion) {
    try {
        var s1 = minVersion.split('.');
        var s2 = extVersion.split('.');

        var len = Math.max(s1.length, s2.length);
        for (var i = 0; i < len; i++) {
            var n1 = 0,
                n2 = 0;

            if (i < s1.length)
                n1 = parseInt(s1[i]);
            if (i < s2.length)
                n2 = parseInt(s2[i]);

            if (isNaN(n1) || isNaN(n2)) {
                return true;
            } else if (n1 !== n2) {
                return n1 > n2;
            }
        }

        // will happen if both versions have identical numbers in
        // their components (even if one of them is longer, has more components)
        return false;
    }
    catch (e) {
        GlobalOnErrorHandler.callErrorHandler(e);
        logger.error("Failed to parse extension version", e);
        return true;
    }
}

function checkChromeExtInstalled(callback, options) {
    if (typeof chrome === "undefined" || !chrome || !chrome.runtime) {
        // No API, so no extension for sure
        callback(false, false);
        return;
    }
    chrome.runtime.sendMessage(
        //TODO: remove chromeExtensionId (deprecated)
        (options.desktopSharingChromeExtId || options.chromeExtensionId),
        { getVersion: true },
        response => {
            if (!response || !response.version) {
                // Communication failure - assume that no endpoint exists
                logger.warn(
                    "Extension not installed?: ", chrome.runtime.lastError);
                callback(false, false);
                return;
            }
            // Check installed extension version
            var extVersion = response.version;
            logger.log('Extension version is: ' + extVersion);
            //TODO: remove minChromeExtVersion (deprecated)
            var updateRequired
                = isUpdateRequired(
                    (options.desktopSharingChromeMinExtVersion ||
                        options.minChromeExtVersion),
                    extVersion);
            callback(!updateRequired, updateRequired);
        }
    );
}

function doGetStreamFromExtension(options, streamCallback, failCallback) {
    // Sends 'getStream' msg to the extension.
    // Extension id must be defined in the config.
    chrome.runtime.sendMessage(
        //TODO: remove chromeExtensionId (deprecated)
        (options.desktopSharingChromeExtId || options.chromeExtensionId),
        {
            getStream: true,
            //TODO: remove desktopSharingSources (deprecated).
            sources: (options.desktopSharingChromeSources ||
                options.desktopSharingSources)
        },
        response => {
            if (!response) {
                // possibly re-wraping error message to make code consistent
                var lastError = chrome.runtime.lastError;
                failCallback(lastError instanceof Error
                    ? lastError
                    : new JitsiTrackError(
                        JitsiTrackErrors.CHROME_EXTENSION_GENERIC_ERROR,
                        lastError));
                return;
            }
            logger.log("Response from extension: ", response);
            if (response.streamId) {
                GUM(
                    ['desktop'],
                    stream => streamCallback(stream),
                    failCallback,
                    { desktopStream: response.streamId });
            } else {
                // As noted in Chrome Desktop Capture API:
                // If user didn't select any source (i.e. canceled the prompt)
                // then the callback is called with an empty streamId.
                if(response.streamId === "")
                {
                    failCallback(new JitsiTrackError(
                        JitsiTrackErrors.CHROME_EXTENSION_USER_CANCELED));
                    return;
                }

                failCallback(new JitsiTrackError(
                    JitsiTrackErrors.CHROME_EXTENSION_GENERIC_ERROR,
                    response.error));
            }
        }
    );
}

/**
 * Initializes <link rel=chrome-webstore-item /> with extension id set in
 * config.js to support inline installs. Host site must be selected as main
 * website of published extension.
 * @param options supports "desktopSharingChromeExtId" and "chromeExtensionId"
 */
function initInlineInstalls(options)
{
    if($("link[rel=chrome-webstore-item]").length === 0) {
        $("head").append("<link rel=\"chrome-webstore-item\">");
    }
    $("link[rel=chrome-webstore-item]").attr("href",
        getWebStoreInstallUrl(options));
}

function initChromeExtension(options) {
    // Initialize Chrome extension inline installs
    initInlineInstalls(options);
    // Check if extension is installed
    checkChromeExtInstalled((installed, updateRequired) => {
        chromeExtInstalled = installed;
        chromeExtUpdateRequired = updateRequired;
        logger.info(
            "Chrome extension installed: " + chromeExtInstalled +
            " updateRequired: " + chromeExtUpdateRequired);
    }, options);
}

/**
 * Checks "retries" times on every "waitInterval"ms whether the ext is alive.
 * @param {Object} options the options passed to ScreanObtainer.obtainStream
 * @param {int} waitInterval the number of ms between retries
 * @param {int} retries the number of retries
 * @returns {Promise} returns promise that will be resolved when the extension
 * is alive and rejected if the extension is not alive even after "retries"
 * checks
 */
function waitForExtensionAfterInstall(options, waitInterval, retries) {
    if(retries === 0) {
        return Promise.reject();
    }
    return new Promise((resolve, reject) => {
        let currentRetries = retries;
        let interval = window.setInterval(() => {
            checkChromeExtInstalled( (installed) => {
                if(installed) {
                    window.clearInterval(interval);
                    resolve();
                } else {
                    currentRetries--;
                    if(currentRetries === 0) {
                        reject();
                        window.clearInterval(interval);
                    }
                }
            }, options);
        }, waitInterval);
    });
}

/**
 * Starts the detection of an installed jidesha extension for firefox.
 * @param options supports "desktopSharingFirefoxDisabled",
 * "desktopSharingFirefoxExtId" and "chromeExtensionId"
 */
function initFirefoxExtensionDetection(options) {
    if (options.desktopSharingFirefoxDisabled) {
        return;
    }
    if (firefoxExtInstalled === false || firefoxExtInstalled === true)
        return;
    if (!options.desktopSharingFirefoxExtId) {
        firefoxExtInstalled = false;
        return;
    }

    var img = document.createElement('img');
    img.onload = () => {
        logger.log("Detected firefox screen sharing extension.");
        firefoxExtInstalled = true;
    };
    img.onerror = () => {
        logger.log("Detected lack of firefox screen sharing extension.");
        firefoxExtInstalled = false;
    };

    // The jidesha extension exposes an empty image file under the url:
    // "chrome://EXT_ID/content/DOMAIN.png"
    // Where EXT_ID is the ID of the extension with "@" replaced by ".", and
    // DOMAIN is a domain whitelisted by the extension.
    var src = "chrome://" +
        (options.desktopSharingFirefoxExtId.replace('@', '.')) +
        "/content/" + document.location.hostname + ".png";
    img.setAttribute('src', src);
}

module.exports = ScreenObtainer;