Start integrating end-to-end into the matrix-client. Add a storage class to store end-to-end sessions. Implement the one-time key upload API, and start sketching out the encryption and decryption functions

lib/store/session/webstorage.js

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+"use strict";
+
+var utils = require("../../utils");
+
+var DEBUG = false;  // set true to enable console logging.
+var E2E_PREFIX = "session.e2e.";
+
+/**
+ * Construct a web storage session store, capable of storing account keys,
+ * session keys and access tokens.
+ * @constructor
+ * @param {WebStorage} webStore A web storage implementation, e.g.
+ * 'window.localStorage' or 'window.sessionStorage' or a custom implementation.
+ * @throws if the supplied 'store' does not meet the Storage interface of the
+ * WebStorage API.
+ */
+function WebStorageSessionStore(webStore) {
+    this.store = webStore;
+    if (!utils.isFunction(webStore.getItem)
+            || !utils.isFunction(webStore.setItem)
+            || !utils.isFunction(webStore.removeItem)) {
+        throw new Error(
+            "Supplied webStore does not meet the WebStorage API interface"
+        );
+    }
+}
+
+WebStorageSessionStore.prototype = {
+
+    /**
+     * Store the end to end account for the logged-in user.
+     * @param {string} account Base64 encoded account.
+     */
+    storeEndToEndAccount: function(account) {
+        this.store.setItem(KEY_END_TO_END_ACCOUNT, account);
+    },
+
+    /**
+     * Load the end to end account for the logged-in user.
+     * @return {?string} Base64 encoded account.
+     */
+    getEndToEndAccount: function() {
+        return this.store.getItem(KEY_END_TO_END_ACCOUNT);
+    },
+
+    /**
+     * Stores the known devices for a user.
+     * @param {string} userId The user's ID.
+     * @param {object} devices A map from device ID to keys for the device.
+     */
+    storeEndToEndDevicesForUser : function(userId, devices) {
+        setJsonItem(this.store, keyEndToEndDevicesForUser(userId), devices);
+    },
+
+    /**
+     * Retrieves the known devices for a user.
+     * @param {string} userId The user's ID.
+     * @return {object} A map from device ID to keys for the device.
+     */
+    getEndToEndDevicesForUser: function(userId)  {
+        return getJsonItem(this.store, keyEndToEndDevicesForUser(userId))
+    },
+
+    /**
+     * Store a session between the logged-in user and another device
+     * @param {string} deviceKey The public key of the other device.
+     * @param {string} sessionId The ID for this end-to-end session.
+     * @param {string} session Base64 encoded end-to-end session.
+     */
+    storeEndToEndSession: function(deviceKey, sessionId, session) {
+        sessions = this.getEndToEndSessions(deviceKey);
+        sessions[sessionId] = session;
+        setJsonItem(
+            this.store, keyEndToEndSessions(deviceKey), sessions
+        );
+    },
+
+    /**
+     * Retrieve the end-to-end sessions between the logged-in user and another
+     * device.
+     * @param {string} deviceKey The public key of the other device.
+     * @return {object} A map from sessionId to Base64 end-to-end session.
+     */
+    getEndToEndSessions: function(deviceKey) {
+        return getJsonItem(this.store, keyEndToEndSessions(deviceKey));
+    },
+
+    /**
+     * Store the end-to-end state for a room.
+     * @param {string} roomId The room's ID.
+     * @param {object} roomInfo The end-to-end info for the room.
+     */
+    storeEndToEndRoom: function(roomId, roomInfo) {
+        setJsonItem(this.store, keyEndToEndRoom(roomId), roomInfo);
+    },
+
+    /**
+     * Get the end-to-end state for a room
+     * @param {string} roomId The room's ID.
+     * @return {object} The end-to-end info for the room.
+     */
+    getEndToEndRoom: function(roomId) {
+        return getJsonItem(this.store, keyEndToEndRoom(roomId));
+    }
+}
+
+var KEY_END_TO_END_ACCOUNT = E2E_PREFIX + "account";
+
+function keyEndToEndDevicesForUser(userId) {
+    return E2E_PREFIX + "devices/" + userId;
+}
+
+function keyEndToEndSessions(deviceKey) {
+    return E2E_PREFIX + "sessions/" + deviceKey;
+}
+
+function keyEndToEndRoom(roomId) {
+    return E2E_PREFIX + "rooms/" + roomId;
+}
+
+function getJsonItem(store, key) {
+    try {
+        return JSON.parse(store.getItem(key));
+    }
+    catch (e) {
+        debuglog("Failed to get key %s: %s", key, e);
+        debuglog(e.stack);
+    }
+    return null;
+}
+
+function setJsonItem(store, key, val) {
+    store.setItem(key, JSON.stringify(val));
+}
+
+function debuglog() {
+    if (DEBUG) {
+        console.log.apply(console, arguments);
+    }
+}
+
+module.exports = WebStorageSessionStore;