Add files via upload

index.js

@@ -0,0 +1,180 @@
+'use strict'
+
+/**
+ * static files (404.html, sw.js, conf.js)
+ */
+const ASSET_URL = 'https://shenyefan.github.io/gh_dl_proxy/'
+    // 前缀，如果自定义路由为example.com/gh/*，将PREFIX改为 '/gh/'，注意，少一个杠都会错！
+const PREFIX = '/'
+    // 分支文件使用jsDelivr镜像的开关，0为关闭，默认关闭
+const Config = {
+    jsdelivr: 0
+}
+
+const whiteList = [] // 白名单，路径里面有包含字符的才会通过，e.g. ['/username/']
+
+/** @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',
+    }),
+}
+
+
+const exp1 = /^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:releases|archive)\/.*$/i
+const exp2 = /^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:blob|raw)\/.*$/i
+const exp3 = /^(?:https?:\/\/)?github\.com\/.+?\/.+?\/(?:info|git-).*$/i
+const exp4 = /^(?:https?:\/\/)?raw\.(?:githubusercontent|github)\.com\/.+?\/.+?\/.+?\/.+$/i
+const exp5 = /^(?:https?:\/\/)?gist\.(?:githubusercontent|github)\.com\/.+?\/.+?\/.+$/i
+const exp6 = /^(?:https?:\/\/)?github\.com\/.+?\/.+?\/tags.*$/i
+
+/**
+ * @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)
+})
+
+
+function checkUrl(u) {
+    for (let i of[exp1, exp2, exp3, exp4, exp5, exp6]) {
+        if (u.search(i) === 0) {
+            return true
+        }
+    }
+    return false
+}
+
+/**
+ * @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')
+    if (path) {
+        return Response.redirect('https://' + urlObj.host + PREFIX + path, 301)
+    }
+    // cfworker 会把路径中的 `//` 合并成 `/`
+    path = urlObj.href.substr(urlObj.origin.length + PREFIX.length).replace(/^https?:\/+/, 'https://')
+    if (path.search(exp1) === 0 || path.search(exp5) === 0 || path.search(exp6) === 0 || path.search(exp3) === 0 || path.search(exp4) === 0) {
+        return httpHandler(req, path)
+    } else if (path.search(exp2) === 0) {
+        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 if (path.search(exp4) === 0) {
+        const newUrl = path.replace(/(?<=com\/.+?\/.+?)\/(.+?\/)/, '@$1').replace(/^(?:https?:\/\/)?raw\.(?:githubusercontent|github)\.com/, 'https://cdn.jsdelivr.net/gh')
+        return Response.redirect(newUrl, 302)
+    } else {
+        return fetch(ASSET_URL + path)
+    }
+}
+
+
+/**
+ * @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)
+    }
+
+    const reqHdrNew = new Headers(reqHdrRaw)
+
+    let urlStr = pathname
+    let flag = !Boolean(whiteList.length)
+    for (let i of whiteList) {
+        if (urlStr.includes(i)) {
+            flag = true
+            break
+        }
+    }
+    if (!flag) {
+        return new Response("blocked", { status: 403 })
+    }
+    if (urlStr.startsWith('github')) {
+        urlStr = 'https://' + urlStr
+    }
+    const urlObj = newUrl(urlStr)
+
+    /** @type {RequestInit} */
+    const reqInit = {
+        method: req.method,
+        headers: reqHdrNew,
+        redirect: 'manual',
+        body: req.body
+    }
+    return 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)
+
+    const status = res.status
+
+    if (resHdrNew.has('location')) {
+        let _location = resHdrNew.get('location')
+        if (checkUrl(_location))
+            resHdrNew.set('location', PREFIX + _location)
+        else {
+            reqInit.redirect = 'follow'
+            return proxy(newUrl(_location), reqInit)
+        }
+    }
+    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,
+    })
+}