HTTPS 加载器


在当前的 Node.js 中,不支持以 https:// 开头的说明符。 下面的加载器注册钩子以启用对此类说明符的基本支持。 虽然这似乎是对 Node.js 核心功能的重大改进,但实际使用这个加载器有很大的缺点:性能比从磁盘加载文件慢得多,没有缓存,也没有安全性。

// https-loader.mjs
import { get } from 'node:https';

export function resolve(specifier, context, defaultResolve) {
  const { parentURL = null } = context;

  // 通常,Node.js 会在以 'https://' 开头的说明符上出错,
  // 因此此钩子会拦截它们并将它们转换为绝对 URL,
  // 以便传给下面的后面的钩子。
  if (specifier.startsWith('https://')) {
    return {
      url: specifier
    };
  } else if (parentURL && parentURL.startsWith('https://')) {
    return {
      url: new URL(specifier, parentURL).href
    };
  }

  // 让 Node.js 处理所有其他说明符。
  return defaultResolve(specifier, context, defaultResolve);
}

export function load(url, context, defaultLoad) {
  // 要通过网络加载 JavaScript,
  // 则需要获取并返回它。
  if (url.startsWith('https://')) {
    return new Promise((resolve, reject) => {
      get(url, (res) => {
        let data = '';
        res.on('data', (chunk) => data += chunk);
        res.on('end', () => resolve({
          // 本示例假设所有网络提供的 JavaScript 
          // 都是 ES 模块代码。
          format: 'module',
          source: data,
        }));
      }).on('error', (err) => reject(err));
    });
  }

  // 让 Node.js 处理所有其他 URL。
  return defaultLoad(url, context, defaultLoad);
}
// main.mjs
import { VERSION } from 'https://coffeescript.org/browser-compiler-modern/coffeescript.js';

console.log(VERSION);

使用前面的加载器,运行 node --experimental-loader ./https-loader.mjs ./main.mjs 会在 main.mjs 中的 URL 处按照模块打印当前版本的 CoffeeScript。

In current Node.js, specifiers starting with https:// are unsupported. The loader below registers hooks to enable rudimentary support for such specifiers. While this may seem like a significant improvement to Node.js core functionality, there are substantial downsides to actually using this loader: performance is much slower than loading files from disk, there is no caching, and there is no security.

// https-loader.mjs
import { get } from 'node:https';

export function resolve(specifier, context, defaultResolve) {
  const { parentURL = null } = context;

  // Normally Node.js would error on specifiers starting with 'https://', so
  // this hook intercepts them and converts them into absolute URLs to be
  // passed along to the later hooks below.
  if (specifier.startsWith('https://')) {
    return {
      url: specifier
    };
  } else if (parentURL && parentURL.startsWith('https://')) {
    return {
      url: new URL(specifier, parentURL).href
    };
  }

  // Let Node.js handle all other specifiers.
  return defaultResolve(specifier, context, defaultResolve);
}

export function load(url, context, defaultLoad) {
  // For JavaScript to be loaded over the network, we need to fetch and
  // return it.
  if (url.startsWith('https://')) {
    return new Promise((resolve, reject) => {
      get(url, (res) => {
        let data = '';
        res.on('data', (chunk) => data += chunk);
        res.on('end', () => resolve({
          // This example assumes all network-provided JavaScript is ES module
          // code.
          format: 'module',
          source: data,
        }));
      }).on('error', (err) => reject(err));
    });
  }

  // Let Node.js handle all other URLs.
  return defaultLoad(url, context, defaultLoad);
}
// main.mjs
import { VERSION } from 'https://coffeescript.org/browser-compiler-modern/coffeescript.js';

console.log(VERSION);

With the preceding loader, running node --experimental-loader ./https-loader.mjs ./main.mjs prints the current version of CoffeeScript per the module at the URL in main.mjs.