patch-asar/source/patchAsar.js

Patch .asar archives

import isDirectory from "./functions/isDirectory.js";
import isFile from "./functions/isFile.js";
import { promisify } from "util";
import mkdirp from "./functions/mkdirp.js";
import asar from "@electron/asar";
import { cp } from "fs/promises";
import { basename, extname, join } from "path";
import executePatches from "./executePatches.js";
import rimraf from "./functions/rimraf.js";

export default async function patchAsar(
  asarFilePath,
  patchFolderPath,
  options = {}
) {
  if (typeof options != "object")
    throw new Error("Options must be an object or null.");
  let {
    workingDirectory = null,
    keepWorkingDirectory = false,
    beforeFinishPatching = null,
  } = options || {};
  let outputPath = options.outputPath || options.outputFile || null;
  if (
    beforeFinishPatching !== null &&
    typeof beforeFinishPatching != "function"
  )
    throw new Error(
      "beforeFinishPatching must be a function (that returns true or a promise) or null"
    );
  if (typeof keepWorkingDirectory != "boolean")
    throw new Error("keepWorkingDirectory must be a boolean");
  if (
    typeof asarFilePath != "string" ||
    !asarFilePath.endsWith(".asar") ||
    !(await isFile(asarFilePath))
  )
    throw new Error("Invalid Asar File Path");
  if (
    typeof patchFolderPath != "string" ||
    !(await isDirectory(patchFolderPath))
  )
    throw new Error("Invalid Patch Folder Path");
  if (
    outputPath !== null &&
    (typeof outputPath != "string" || (await isDirectory(outputPath)))
  )
    throw new Error("Invalid Output File Path");
  if (workingDirectory !== null && typeof workingDirectory != "string")
    throw new Error("Invalid Working Directory Path");
  if (outputPath === null) outputPath = asarFilePath; // Patch in place
  if (workingDirectory === null)
    workingDirectory = join(import.meta.dirname, "./build/");
  workingDirectory = join(
    workingDirectory,
    basename(asarFilePath, extname(asarFilePath))
  );
  await rimraf(workingDirectory);
  await mkdirp(workingDirectory);
  await asar.extractAll(asarFilePath, workingDirectory);
  await cp(patchFolderPath, workingDirectory, { recursive: true, force: true });
  await executePatches(workingDirectory, patchFolderPath);
  // Allow the user to edit the working directory before completing our patch using an async function
  if (beforeFinishPatching) {
    const prom = beforeFinishPatching(workingDirectory);
    if (!(prom instanceof Promise) && promise !== true) {
      throw new Error(
        "Expected a promise from the beforeFinishPatching function or true to designate a finished sync function"
      );
    }
  }
  await rimraf(outputPath);
  await asar.createPackage(workingDirectory, outputPath);
  if (keepWorkingDirectory === false) await rimraf(workingDirectory);
}