matrix-react-sdk/src/utils/device/dehydration.ts

SDK for matrix.org using React

/*
Copyright 2024 New Vector Ltd.
Copyright 2024 The Matrix.org Foundation C.I.C.

SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
Please see LICENSE files in the repository root for full details.
*/

import { logger } from "matrix-js-sdk/src/logger";
import { Crypto } from "matrix-js-sdk/src/matrix";

import { MatrixClientPeg } from "../../MatrixClientPeg";

/**
 * Check if device dehydration is enabled.
 *
 * Note that this doesn't necessarily mean that device dehydration has been initialised
 * (yet) on this client; rather, it means that the server supports it, the crypto backend
 * supports it, and the application configuration suggests that it *should* be
 * initialised on this device.
 *
 * Dehydration can currently only be enabled by setting a flag in the .well-known file.
 */
async function deviceDehydrationEnabled(crypto: Crypto.CryptoApi | undefined): Promise<boolean> {
    if (!crypto) {
        return false;
    }
    if (!(await crypto.isDehydrationSupported())) {
        return false;
    }
    const wellknown = await MatrixClientPeg.safeGet().waitForClientWellKnown();
    return !!wellknown?.["org.matrix.msc3814"];
}

/**
 * If dehydration is enabled (i.e., it is supported by the server and enabled in
 * the configuration), rehydrate a device (if available) and create
 * a new dehydrated device.
 *
 * @param createNewKey: force a new dehydration key to be created, even if one
 *   already exists.  This is used when we reset secret storage.
 */
export async function initialiseDehydration(createNewKey: boolean = false): Promise<void> {
    const crypto = MatrixClientPeg.safeGet().getCrypto();
    if (await deviceDehydrationEnabled(crypto)) {
        logger.log("Device dehydration enabled");
        await crypto!.startDehydration(createNewKey);
    }
}