NOTE

直接把下方代码粘贴到 Worker，部署后访问 Worker对应的域名即可。

'use strict'

/**
 * Static files (404.html, sw.js, conf.js)
 */
const ASSET_URL = 'https://hunshcn.github.io/gh-proxy/'
// Prefix, if custom route is example.com/gh/*, change PREFIX to '/gh/' (Ensure trailing slash)
const PREFIX = '/'
// Toggle jsDelivr mirror for branch files, 0 = off (default)
const Config = {
    jsdelivr: 0
}

const whiteList = [] // Whitelist, only allow paths containing specific substrings, e.g., ['/username/']

/** Preflight response for CORS requests */
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',
    }),
}

// Regular expressions for URL matching
const regexPatterns = [
    /^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:releases|archive)\/.*$/i,
    /^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:blob|raw)\/.*$/i,
    /^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:info|git-).*$/i,
    /^(?:https?:\/\/)?raw\.(?:githubusercontent|github)\.com\/.+?\/.+?\/.+?\/.+$/i,
    /^(?:https?:\/\/)?gist\.(?:githubusercontent|github)\.com\/.+?\/.+?\/.+$/i,
    /^(?:https?:\/\/)?github\.com\/.+?\/.+?\/tags.*$/i,
]

/**
 * Helper function to create a Response
 * @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 })
}

/**
 * Safely create a new URL object
 * @param {string} urlStr
 */
function newUrl(urlStr) {
    try {
        return new URL(urlStr)
    } catch (err) {
        return null
    }
}

addEventListener('fetch', e => {
    const ret = fetchHandler(e).catch(err => {
        console.error('Error occurred:', err)
        return makeRes(`cfworker error: ${err.message}\nStack: ${err.stack}`, 502)
    })
    e.respondWith(ret)
})

/**
 * Check if the URL matches allowed patterns
 * @param {string} url
 */
function checkUrl(url) {
    return regexPatterns.some(pattern => pattern.test(url))
}

/**
 * Fetch handler for incoming requests
 * @param {FetchEvent} e
 */
async function fetchHandler(e) {
    const req = e.request
    const urlStr = req.url
    const urlObj = new URL(urlStr)
    let path = urlObj.searchParams.get('q')

    // Redirect if 'q' parameter exists
    if (path) {
        return Response.redirect(`https://${urlObj.host}${PREFIX}${path}`, 301)
    }

    // Normalize path
    path = urlObj.href.substr(urlObj.origin.length + PREFIX.length).replace(/^https?:\/+/, 'https://')

    // Handle requests matching specific patterns
    if (regexPatterns.some(pattern => pattern.test(path))) {
        return httpHandler(req, path)
    } else if (path.match(regexPatterns[1])) { // Handle blob/raw paths
        if (Config.jsdelivr) {
            const newUrl = path.replace('/blob/', '@').replace(/^(?:https?:\/\/)?github\.com/, 'https://cdn.jsdelivr.net/gh')
            return Response.redirect(newUrl, 302)
        } else {
            path = path.replace('/blob/', '/raw/')
            return httpHandler(req, path)
        }
    } else {
        return fetch(ASSET_URL + path)
    }
}

/**
 * Handle HTTP requests to the proxied resource
 * @param {Request} req
 * @param {string} pathname
 */
function httpHandler(req, pathname) {
    const reqHdrRaw = req.headers

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

    const reqHdrNew = new Headers(reqHdrRaw)
    let flag = whiteList.length === 0 // Allow all if whitelist is empty
    for (let item of whiteList) {
        if (pathname.includes(item)) {
            flag = true
            break
        }
    }
    if (!flag) {
        return new Response("blocked", { status: 403 })
    }

    // Normalize GitHub URLs
    if (pathname.startsWith('github')) {
        pathname = 'https://' + pathname
    }
    const urlObj = newUrl(pathname)

    /** Request options */
    const reqInit = {
        method: req.method,
        headers: reqHdrNew,
        redirect: 'manual',
        body: req.body
    }
    return proxy(urlObj, reqInit)
}

/**
 * Proxy the request to the destination URL
 * @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)

    // Handle redirects
    if (resHdrNew.has('location')) {
        const location = resHdrNew.get('location')
        if (checkUrl(location)) {
            resHdrNew.set('location', PREFIX + location)
        } else {
            reqInit.redirect = 'follow'
            return proxy(newUrl(location), reqInit)
        }
    }

    // Adjust headers for response
    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: res.status,
        headers: resHdrNew,
    })
}