Improve loading of JSON files to avoid implicit behaviours of Node require (#1519)

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

src/electron-main.ts

@@ -41,6 +41,7 @@ import { getProfileFromDeeplink, protocolInit } from "./protocol";
 import { _t, AppLocalization } from "./language-helper";
 import { setDisplayMediaCallback } from "./displayMediaCallback";
 import { setupMacosTitleBar } from "./macos-titlebar";
+import { loadJsonFile } from "./utils";
 
 const argv = minimist(process.argv, {
     alias: { help: "h" },
@@ -143,8 +144,7 @@ async function loadConfig(): Promise<void> {
     const asarPath = await getAsarPath();
 
     try {
-        // eslint-disable-next-line @typescript-eslint/no-var-requires
-        global.vectorConfig = require(asarPath + "config.json");
+        global.vectorConfig = loadJsonFile(asarPath, "config.json");
     } catch (e) {
         // it would be nice to check the error code here and bail if the config
         // is unparsable, but we get MODULE_NOT_FOUND in the case of a missing
@@ -155,8 +155,7 @@ async function loadConfig(): Promise<void> {
 
     try {
         // Load local config and use it to override values from the one baked with the build
-        // eslint-disable-next-line @typescript-eslint/no-var-requires
-        const localConfig = require(path.join(app.getPath("userData"), "config.json"));
+        const localConfig = loadJsonFile(app.getPath("userData"), "config.json");
 
         // If the local config has a homeserver defined, don't use the homeserver from the build
         // config. This is to avoid a problem where Riot thinks there are multiple homeservers

src/language-helper.ts

@@ -19,6 +19,7 @@ import { TranslationKey as TKey } from "matrix-web-i18n";
 
 import type Store from "electron-store";
 import type EN from "./i18n/strings/en_EN.json";
+import { loadJsonFile } from "./utils";
 
 const FALLBACK_LOCALE = "en";
 
@@ -105,7 +106,7 @@ export class AppLocalization {
     public fetchTranslationJson(locale: string): Record<string, string> {
         try {
             console.log("Fetching translation json for locale: " + locale);
-            return require(`./i18n/strings/${this.denormalize(locale)}.json`);
+            return loadJsonFile(`./i18n/strings/${this.denormalize(locale)}.json`);
         } catch (e) {
             console.log(`Could not fetch translation json for locale: '${locale}'`, e);
             return {};

src/utils.ts

@@ -15,6 +15,8 @@ limitations under the License.
 */
 
 import crypto from "crypto";
+import fs from "node:fs";
+import path from "node:path";
 
 export async function randomArray(size: number): Promise<string> {
     return new Promise((resolve, reject) => {
@@ -27,3 +29,20 @@ export async function randomArray(size: number): Promise<string> {
         });
     });
 }
+
+type JsonValue = null | string | number;
+type JsonArray = Array<JsonValue | JsonObject | JsonArray>;
+interface JsonObject {
+    [key: string]: JsonObject | JsonArray | JsonValue;
+}
+type Json = JsonArray | JsonObject;
+
+/**
+ * Synchronously load a JSON file from the local filesystem.
+ * Unlike `require`, will never execute any javascript in a loaded file.
+ * @param paths - An array of path segments which will be joined using the system's path delimiter.
+ */
+export function loadJsonFile<T extends Json>(...paths: string[]): T {
+    const file = fs.readFileSync(path.join(...paths), { encoding: "utf-8" });
+    return JSON.parse(file);
+}