cloudflare-workers/dub_proxy.js

161 lines
3.8 KiB
JavaScript

'use strict'
/**
* static files (404.html, sw.js, conf.js)
*/
/** @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 getReqHeader = (key) => e.request.headers.get(key);
let url = new URL(e.request.url);
url.hostname = "code.dlang.org";
let parameter = {
headers: {
'Host': 'code.dlang.org',
'User-Agent': getReqHeader("User-Agent"),
'Accept': getReqHeader("Accept"),
'Accept-Language': getReqHeader("Accept-Language"),
'Accept-Encoding': getReqHeader("Accept-Encoding"),
'Connection': 'keep-alive',
'Cache-Control': 'max-age=0'
},
cacheTtl: 3600
};
if (e.request.headers.has("Referer")) {
parameter.headers.Referer = getReqHeader("Referer");
}
if (e.request.headers.has("Origin")) {
parameter.headers.Origin = getReqHeader("Origin");
}
const exp = /.*\.zip$/
let redirect_url = ""
if (e.request.url.search(exp)===0) {
await fetch(new Request(url, e.request), parameter).then( r => {
redirect_url = r.headers.get("Location")
})
return httpHandler(e.request, redirect_url)
} else {
return fetch(new Request(url, e.request), parameter);
}
}
/**
* @param {Request} req
* @param {string} pathname
*/
function httpHandler(req, pathname) {
const reqHdrRaw = req.headers
// preflight
if (req.method === 'OPTIONS' &&
reqHdrRaw.has('access-control-request-headers')
) {
return new Response(null, PREFLIGHT_INIT)
}
let rawLen = ''
const reqHdrNew = new Headers(reqHdrRaw)
const refer = reqHdrNew.get('referer')
let urlStr = pathname
if (urlStr.startsWith('github')) {
urlStr = 'https://' + urlStr
}
const urlObj = newUrl(urlStr)
/** @type {RequestInit} */
const reqInit = {
method: req.method,
headers: reqHdrNew,
redirect: 'follow',
body: req.body
}
return proxy(urlObj, reqInit, rawLen, 0)
}
/**
*
* @param {URL} urlObj
* @param {RequestInit} reqInit
*/
async function proxy(urlObj, reqInit, rawLen) {
const res = await fetch(urlObj.href, reqInit)
const resHdrOld = res.headers
const resHdrNew = new Headers(resHdrOld)
// verify
if (rawLen) {
const newLen = resHdrOld.get('content-length') || ''
const badLen = (rawLen !== newLen)
if (badLen) {
return makeRes(res.body, 400, {
'--error': `bad len: ${newLen}, except: ${rawLen}`,
'access-control-expose-headers': '--error',
})
}
}
const status = res.status
resHdrNew.set('access-control-expose-headers', '*')
resHdrNew.set('access-control-allow-origin', '*')
resHdrNew.set('Cache-Control', 'max-age=1500')
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
})
}