Refactor db and local-cache code

Separated cwmp and ui code into distinct files to enhance clarity and
maintainability with varied internal data representations.

lib/ui/local-cache.ts

@@ -0,0 +1,187 @@
+import * as crypto from "crypto";
+import * as config from "../config";
+import { collections } from "../db/db";
+import * as expression from "../common/expression/util";
+import { parse } from "../common/expression/parser";
+import { Expression, Users, Permissions, Config, UiConfig } from "../types";
+import { LocalCache } from "../local-cache";
+
+interface Snapshot {
+  permissions: Permissions;
+  users: Users;
+  config: Config;
+  ui: UiConfig;
+}
+
+async function fetchPermissions(): Promise<[string, Permissions]> {
+  const perms = await collections.permissions.find().toArray();
+  perms.sort((a, b) => (a._id > b._id ? 1 : -1));
+  const h = crypto
+    .createHash("md5")
+    .update(JSON.stringify(perms))
+    .digest("hex");
+  const permissions: Permissions = {};
+
+  for (const p of perms) {
+    if (!permissions[p.role]) permissions[p.role] = {};
+    if (!permissions[p.role][p.access]) permissions[p.role][p.access] = {};
+
+    permissions[p.role][p.access][p.resource] = {
+      access: p.access,
+      filter: parse(p.filter || "true"),
+    };
+    if (p.validate)
+      permissions[p.role][p.access][p.resource].validate = parse(p.validate);
+  }
+
+  return [h, permissions];
+}
+
+async function fetchUsers(): Promise<[string, Users]> {
+  const _users = await collections.users.find().toArray();
+  _users.sort((a, b) => (a._id > b._id ? 1 : -1));
+  const h = crypto
+    .createHash("md5")
+    .update(JSON.stringify(_users))
+    .digest("hex");
+  const users = {};
+
+  for (const user of _users) {
+    users[user._id] = {
+      password: user.password,
+      salt: user.salt,
+      roles: user.roles.split(",").map((s) => s.trim()),
+    };
+  }
+
+  return [h, users];
+}
+
+async function fetchConfig(): Promise<[string, Config, UiConfig]> {
+  const conf = await collections.config.find().toArray();
+  conf.sort((a, b) => (a._id > b._id ? 1 : -1));
+  const h = crypto.createHash("md5").update(JSON.stringify(conf)).digest("hex");
+
+  const ui = {
+    filters: {},
+    device: {},
+    index: {},
+    overview: {},
+    pageSize: null,
+  };
+
+  const _config = {};
+
+  for (const c of conf) {
+    // Evaluate expressions to simplify them
+    const val = expression.evaluate(parse(c.value));
+    _config[c._id] = val;
+    if (c._id.startsWith("ui.")) {
+      const keys = c._id.split(".");
+      if (!(keys[1] in ui)) continue;
+      // remove the first key(ui)
+      keys.shift();
+      let ref = ui;
+      while (keys.length > 1) {
+        const k = keys.shift();
+        if (ref[k] == null || typeof ref[k] !== "object") ref[k] = {};
+        ref = ref[k];
+      }
+      ref[keys[0]] = val;
+    }
+  }
+
+  return [h, _config, ui];
+}
+
+const localCache = new LocalCache<Snapshot>("ui-local-cache-hash", refresh);
+
+async function refresh(): Promise<[string, Snapshot]> {
+  const res = await Promise.all([
+    fetchPermissions(),
+    fetchUsers(),
+    fetchConfig(),
+  ]);
+
+  const h = crypto.createHash("md5");
+  for (const r of res) h.update(r[0]);
+
+  const snapshot = {
+    permissions: res[0][1],
+    users: res[1][1],
+    config: res[2][1],
+    ui: res[2][2],
+  };
+
+  return [h.digest("hex"), snapshot];
+}
+
+export async function getRevision(): Promise<string> {
+  return await localCache.getRevision();
+}
+
+export function getConfig(
+  revision: string,
+  key: string,
+  context: Record<string, unknown>,
+  now: number,
+  cb?: (e: Expression) => Expression
+): string | number | boolean | null {
+  const snapshot = localCache.get(revision);
+  if (!snapshot) throw new Error("Cache snapshot does not exist");
+
+  const oldOpts = {
+    "cwmp.downloadTimeout": "DOWNLOAD_TIMEOUT",
+    "cwmp.debug": "DEBUG",
+    "cwmp.retryDelay": "RETRY_DELAY",
+    "cwmp.sessionTimeout": "SESSION_TIMEOUT",
+    "cwmp.connectionRequestTimeout": "CONNECTION_REQUEST_TIMEOUT",
+    "cwmp.gpnNextLevel": "GPN_NEXT_LEVEL",
+    "cwmp.gpvBatchSize": "GPV_BATCH_SIZE",
+    "cwmp.cookiesPath": "COOKIES_PATH",
+    "cwmp.datetimeMilliseconds": "DATETIME_MILLISECONDS",
+    "cwmp.booleanLiteral": "BOOLEAN_LITERAL",
+    "cwmp.connectionRequestAllowBasicAuth":
+      "CONNECTION_REQUEST_ALLOW_BASIC_AUTH",
+    "cwmp.maxCommitIterations": "MAX_COMMIT_ITERATIONS",
+    "cwmp.deviceOnlineThreshold": "DEVICE_ONLINE_THRESHOLD",
+    "cwmp.udpConnectionRequestPort": "UDP_CONNECTION_REQUEST_PORT",
+  };
+
+  if (!(key in snapshot.config)) {
+    if (key in oldOpts) {
+      let id;
+      if (context?.["id"]) {
+        id = context["id"];
+      } else if (cb) {
+        id = cb(["PARAM", "DeviceID.ID"]);
+        if (Array.isArray(id)) id = null;
+      }
+      return config.get(oldOpts[key], id);
+    }
+    return null;
+  }
+
+  const v = expression.evaluate(snapshot.config[key], context, now, cb);
+  return Array.isArray(v) ? null : v;
+}
+
+export function getConfigExpression(revision: string, key: string): Expression {
+  const snapshot = localCache.get(revision);
+  return snapshot.config[key];
+}
+
+export function getUsers(revision: string): Users {
+  const snapshot = localCache.get(revision);
+  return snapshot.users;
+}
+
+export function getPermissions(revision: string): Permissions {
+  const snapshot = localCache.get(revision);
+  return snapshot.permissions;
+}
+
+export function getUiConfig(revision: string): UiConfig {
+  const snapshot = localCache.get(revision);
+  return snapshot.ui;
+}