meteor/packages/dynamic-import/server.js

import assert from "assert";
import { readFileSync } from "fs";
import {
  join as pathJoin,
  normalize as pathNormalize,
} from "path";

import { check } from "meteor/check";

import "./security.js";
import "./client.js";

const hasOwn = Object.prototype.hasOwnProperty;

Object.keys(dynamicImportInfo).forEach(platform => {
  const info = dynamicImportInfo[platform];
  if (info.dynamicRoot) {
    info.dynamicRoot = pathNormalize(info.dynamicRoot);
  }
});

Meteor.methods({
  __dynamicImport(tree) {
    check(tree, Object);
    this.unblock();

    const platform = this.connection ? "web.browser" : "server";
    const pathParts = [];

    function walk(node) {
      if (node && typeof node === "object") {
        Object.keys(node).forEach(name => {
          pathParts.push(name);
          node[name] = walk(node[name]);
          assert.strictEqual(pathParts.pop(), name);
        });
      } else {
        return read(pathParts, platform);
      }
      return node;
    }

    return walk(tree);
  }
});

function read(pathParts, platform) {
  const { dynamicRoot } = dynamicImportInfo[platform];
  const absPath = pathNormalize(pathJoin(dynamicRoot, ...pathParts));

  if (! absPath.startsWith(dynamicRoot)) {
    throw new Meteor.Error("bad dynamic module path");
  }

  const cache = getCache(platform);
  return hasOwn.call(cache, absPath)
    ? cache[absPath]
    : cache[absPath] = readFileSync(absPath, "utf8");
}

const cachesByPlatform = Object.create(null);
function getCache(platform) {
  return hasOwn.call(cachesByPlatform, platform)
    ? cachesByPlatform[platform]
    : cachesByPlatform[platform] = Object.create(null);
}

process.on("message", msg => {
  // The cache for the "web.browser" platform needs to be discarded
  // whenever a client-only refresh occurs, so that new client code does
  // not receive stale module data from __dynamicImport. This code handles
  // the same message listened for by the autoupdate package.
  if (msg && msg.refresh === "client") {
    delete cachesByPlatform["web.browser"];
  }
});