'use strict'

/** @type {RequestInit} / const PREFLIGHT_INIT = { status: 204, headers: new Headers({ 'access-control-allow-origin': '', 'access-control-allow-methods': 'GET,POST,PUT,PATCH,TRACE,DELETE,HEAD,OPTIONS', 'access-control-max-age': '1728000', }), }

/**

• @param {any} body
• @param {number} status
• @param {Object<string, string>} headers / function makeRes(body, status = 200, headers = {}) { headers['access-control-allow-origin'] = '' return new Response(body, { status, headers }) }

/**

• @param {string} urlStr */ function newUrl(urlStr) { try { return new URL(urlStr) } catch (err) { return null } }

addEventListener('fetch', e => { const ret = fetchHandler(e) .catch(err => makeRes('cfworker error:\n' + err.stack, 502)) e.respondWith(ret) })

/**

• @param {FetchEvent} e */ async function fetchHandler(e) { const req = e.request const urlStr = req.url const urlObj = new URL(urlStr) const path = urlObj.href.substr(urlObj.origin.length)

  if (path.startsWith('/http/')) { return await httpHandler(req, path.substr(6)) }

  return makeRes('hello!') }

/**

• @param {Request} req

• @param {string} pathname */ async function httpHandler(req, pathname) { const reqHdrRaw = req.headers if (reqHdrRaw.has('x-jsproxy')) { return Response.error() }

  // preflight if (req.method === 'OPTIONS' && reqHdrRaw.has('access-control-request-headers')) { return new Response(null, PREFLIGHT_INIT) }

  const reqHdrNew = new Headers(reqHdrRaw) reqHdrNew.set('x-jsproxy', '1')

  if (!reqHdrRaw.has('user-agent')) { reqHdrRaw.set('user-agent', 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36') } // cfworker 会把路径中的 // 合并成 / const urlStr = pathname.replace(/^(https?):/+/, '$1://') const urlObj = newUrl(urlStr) if (!urlObj) { return makeRes('invalid proxy url: ' + urlStr, 403) }

  /** @type {RequestInit} */ const reqInit = { method: req.method, headers: reqHdrNew, } if (req.method === 'POST') { reqInit.body = await req.arrayBuffer() } return await proxy(urlObj, reqInit) }

/** *

• @param {URL} urlObj

• @param {RequestInit} reqInit */ async function proxy(urlObj, reqInit) { const res = await fetch(urlObj.href, reqInit) const resHdrOld = res.headers const resHdrNew = new Headers(resHdrOld)

  let status = res.status

  resHdrNew.set('access-control-expose-headers', '') resHdrNew.set('access-control-allow-origin', '')

  resHdrNew.delete('content-security-policy') resHdrNew.delete('content-security-policy-report-only') resHdrNew.delete('clear-site-data')

  return new Response(res.body, { status, headers: resHdrNew, }) }