Cloudflare Workers™ - 在 Cloudflare Edge 中加入 Script 規則，實現流量過濾與提升網站快取加速能力 - TechMoon 科技月球

Cloudflare Workers™

步驟一

步驟二

在 Cloudflare 後台當中選取 Workers 頁面啟用

步驟三

點擊「Add Script」新增腳本

設定 Workers 當中 Script 的名稱

點選「Edit」編輯剛剛新增的 Script

先將 Script 當中預設的程式碼刪除

// IMPORTANT: Either A Key/Value Namespace must be bound to this worker script // using the variable name EDGE_CACHE. or the API parameters below should be // configured. KV is recommended if possible since it can purge just the HTML // instead of the full cache. // API settings if KV isn't being used const CLOUDFLARE_API = { email: "", // From https://dash.cloudflare.com/profile key: "", // Global API Key from https://dash.cloudflare.com/profile zone: "" // "Zone ID" from the API section of the dashboard overview page https://dash.cloudflare.com/ }; // Default cookie prefixes for bypass const DEFAULT_BYPASS_COOKIES = [ "wp-", "wordpress", "comment_", "woocommerce_" ]; /** * Main worker entry point. */ addEventListener("fetch", event => { const request = event.request; let upstreamCache = request.headers.get('x-HTML-Edge-Cache'); // Only process requests if KV store is set up and there is no // HTML edge cache in front of this worker (only the outermost cache // should handle HTML caching in case there are varying levels of support). let configured = false; if (typeof EDGE_CACHE !== 'undefined') { configured = true; } else if (CLOUDFLARE_API.email.length && CLOUDFLARE_API.key.length && CLOUDFLARE_API.zone.length) { configured = true; } // Bypass processing of image requests (for everything except Firefox which doesn't use image/*) const accept = request.headers.get('Accept'); let isImage = false; if (accept && (accept.indexOf('image/*') !== -1)) { isImage = true; } if (configured && !isImage && upstreamCache === null) { event.passThroughOnException(); event.respondWith(processRequest(request, event)); } }); /** * Process every request coming through to add the edge-cache header, * watch for purge responses and possibly cache HTML GET requests. * * @param {Request} originalRequest – Original request * @param {Event} event – Original event (for additional async waiting) */ async function processRequest(originalRequest, event) { let cfCacheStatus = null; const accept = originalRequest.headers.get('Accept'); const isHTML = (accept && accept.indexOf('text/html') >= 0); let {response, cacheVer, status, bypassCache} = await getCachedResponse(originalRequest); if (response === null) { // Clone the request, add the edge-cache header and send it through. let request = new Request(originalRequest); request.headers.set('x-HTML-Edge-Cache', 'supports=cache|purgeall|bypass-cookies'); response = await fetch(request); if (response) { const options = getResponseOptions(response); if (options && options.purge) { await purgeCache(cacheVer, event); status += ', Purged'; } bypassCache = bypassCache || shouldBypassEdgeCache(request, response); if ((!options || options.cache) && isHTML && originalRequest.method === 'GET' && response.status === 200 && !bypassCache) { status += await cacheResponse(cacheVer, originalRequest, response, event); } } } else { // If the origin didn't send the control header we will send the cached response but update // the cached copy asynchronously (stale-while-revalidate). This commonly happens with // a server-side disk cache that serves the HTML directly from disk. cfCacheStatus = 'HIT'; if (originalRequest.method === 'GET' && response.status === 200 && isHTML) { bypassCache = bypassCache || shouldBypassEdgeCache(originalRequest, response); if (!bypassCache) { const options = getResponseOptions(response); if (!options) { status += ', Refreshed'; event.waitUntil(updateCache(originalRequest, cacheVer, event)); } } } } if (response && status !== null && originalRequest.method === 'GET' && response.status === 200 && isHTML) { response = new Response(response.body, response); response.headers.set('x-HTML-Edge-Cache-Status', status); if (cacheVer !== null) { response.headers.set('x-HTML-Edge-Cache-Version', cacheVer.toString()); } if (cfCacheStatus) { response.headers.set('CF-Cache-Status', cfCacheStatus); } } return response; } /** * Determine if the cache should be bypassed for the given request/response pair. * Specifically, if the request includes a cookie that the response flags for bypass. * Can be used on cache lookups to determine if the request needs to go to the origin and * origin responses to determine if they should be written to cache. * @param {Request} request – Request * @param {Response} response – Response * @returns {bool} true if the cache should be bypassed */ function shouldBypassEdgeCache(request, response) { let bypassCache = false; if (request && response) { const options = getResponseOptions(response); const cookieHeader = request.headers.get('cookie'); let bypassCookies = DEFAULT_BYPASS_COOKIES; if (options) { bypassCookies = options.bypassCookies; } if (cookieHeader && cookieHeader.length && bypassCookies.length) { const cookies = cookieHeader.split(';'); for (let cookie of cookies) { // See if the cookie starts with any of the logged-in user prefixes for (let prefix of bypassCookies) { if (cookie.trim().startsWith(prefix)) { bypassCache = true; break; } } if (bypassCache) { break; } } } } return bypassCache; } const CACHE_HEADERS = ['Cache-Control', 'Expires', 'Pragma']; /** * Check for cached HTML GET requests. * * @param {Request} request – Original request */ async function getCachedResponse(request) { let response = null; let cacheVer = null; let bypassCache = false; let status = 'Miss'; // Only check for HTML GET requests (saves on reading from KV unnecessarily) // and not when there are cache-control headers on the request (refresh) const accept = request.headers.get('Accept'); const cacheControl = request.headers.get('Cache-Control'); let noCache = false; if (cacheControl && cacheControl.indexOf('no-cache') !== -1) { noCache = true; status = 'Bypass for Reload'; } if (!noCache && request.method === 'GET' && accept && accept.indexOf('text/html') >= 0) { // Build the versioned URL for checking the cache cacheVer = await GetCurrentCacheVersion(cacheVer); const cacheKeyRequest = GenerateCacheRequest(request, cacheVer); // See if there is a request match in the cache try { let cache = caches.default; let cachedResponse = await cache.match(cacheKeyRequest); if (cachedResponse) { // Copy Response object so that we can edit headers. cachedResponse = new Response(cachedResponse.body, cachedResponse); // Check to see if the response needs to be bypassed because of a cookie bypassCache = shouldBypassEdgeCache(request, cachedResponse); // Copy the original cache headers back and clean up any control headers if (bypassCache) { status = 'Bypass Cookie'; } else { status = 'Hit'; cachedResponse.headers.delete('Cache-Control'); cachedResponse.headers.delete('x-HTML-Edge-Cache-Status'); for (header of CACHE_HEADERS) { let value = cachedResponse.headers.get('x-HTML-Edge-Cache-Header-' + header); if (value) { cachedResponse.headers.delete('x-HTML-Edge-Cache-Header-' + header); cachedResponse.headers.set(header, value); } } response = cachedResponse; } } else { status = 'Miss'; } } catch (err) { // Send the exception back in the response header for debugging status = "Cache Read Exception: " + err.message; } } return {response, cacheVer, status, bypassCache}; } /** * Asynchronously purge the HTML cache. * @param {Int} cacheVer – Current cache version (if retrieved) * @param {Event} event – Original event */ async function purgeCache(cacheVer, event) { if (typeof EDGE_CACHE !== 'undefined') { // Purge the KV cache by bumping the version number cacheVer = await GetCurrentCacheVersion(cacheVer); cacheVer++; event.waitUntil(EDGE_CACHE.put('html_cache_version', cacheVer.toString())); } else { // Purge everything using the API const url = "https://api.cloudflare.com/client/v4/zones/" + CLOUDFLARE_API.zone + "/purge_cache"; event.waitUntil(fetch(url,{ method: 'POST', headers: {'X-Auth-Email': CLOUDFLARE_API.email, 'X-Auth-Key': CLOUDFLARE_API.key, 'Content-Type': 'application/json'}, body: JSON.stringify({purge_everything: true}) })); } } /** * Update the cached copy of the given page * @param {Request} originalRequest – Original Request * @param {String} cacheVer – Cache Version * @param {EVent} event – Original event */ async function updateCache(originalRequest, cacheVer, event) { // Clone the request, add the edge-cache header and send it through. let request = new Request(originalRequest); request.headers.set('x-HTML-Edge-Cache', 'supports=cache|purgeall|bypass-cookies'); response = await fetch(request); if (response) { status = ': Fetched'; const options = getResponseOptions(response); if (options && options.purge) { await purgeCache(cacheVer, event); } let bypassCache = shouldBypassEdgeCache(request, response); if ((!options || options.cache) && !bypassCache) { await cacheResponse(cacheVer, originalRequest, response, event); } } } /** * Cache the returned content (but only if it was a successful GET request) * * @param {Int} cacheVer – Current cache version (if already retrieved) * @param {Request} request – Original Request * @param {Response} originalResponse – Response to (maybe) cache * @param {Event} event – Original event * @returns {bool} true if the response was cached */ async function cacheResponse(cacheVer, request, originalResponse, event) { let status = ""; const accept = request.headers.get('Accept'); if (request.method === 'GET' && originalResponse.status === 200 && accept && accept.indexOf('text/html') >= 0) { cacheVer = await GetCurrentCacheVersion(cacheVer); const cacheKeyRequest = GenerateCacheRequest(request, cacheVer); try { // Move the cache headers out of the way so the response can actually be cached. // First clone the response so there is a parallel body stream and then // create a new response object based on the clone that we can edit. let cache = caches.default; let clonedResponse = originalResponse.clone(); let response = new Response(clonedResponse.body, clonedResponse); for (header of CACHE_HEADERS) { let value = response.headers.get(header); if (value) { response.headers.delete(header); response.headers.set('x-HTML-Edge-Cache-Header-' + header, value); } } response.headers.delete('Set-Cookie'); response.headers.set('Cache-Control', 'public; max-age=315360000'); event.waitUntil(cache.put(cacheKeyRequest, response)); status = ", Cached"; } catch (err) { // status = ", Cache Write Exception: " + err.message; } } return status; } /****************************************************************************** * Utility Functions *****************************************************************************/ /** * Parse the commands from the x-HTML-Edge-Cache response header. * @param {Response} response – HTTP response from the origin. * @returns {*} Parsed commands */ function getResponseOptions(response) { let options = null; let header = response.headers.get('x-HTML-Edge-Cache'); if (header) { options = { purge: false, cache: false, bypassCookies: [] }; let commands = header.split(','); for (let command of commands) { if (command.trim() === 'purgeall') { options.purge = true; } else if (command.trim() === 'cache') { options.cache = true; } else if (command.trim().startsWith('bypass-cookies')) { let separator = command.indexOf('='); if (separator >= 0) { let cookies = command.substr(separator + 1).split('|'); for (let cookie of cookies) { cookie = cookie.trim(); if (cookie.length) { options.bypassCookies.push(cookie); } } } } } } return options; } /** * Retrieve the current cache version from KV * @param {Int} cacheVer – Current cache version value if set. * @returns {Int} The current cache version. */ async function GetCurrentCacheVersion(cacheVer) { if (cacheVer === null) { if (typeof EDGE_CACHE !== 'undefined') { cacheVer = await EDGE_CACHE.get('html_cache_version'); if (cacheVer === null) { // Uninitialized – first time through, initialize KV with a value // Blocking but should only happen immediately after worker activation. cacheVer = 0; await EDGE_CACHE.put('html_cache_version', cacheVer.toString()); } else { cacheVer = parseInt(cacheVer); } } else { cacheVer = -1; } } return cacheVer; } /** * Generate the versioned Request object to use for cache operations. * @param {Request} request – Base request * @param {Int} cacheVer – Current Cache version (must be set) * @returns {Request} Versioned request object */ function GenerateCacheRequest(request, cacheVer) { let cacheUrl = request.url; if (cacheUrl.indexOf('?') >= 0) { cacheUrl += '&'; } else { cacheUrl += '?'; } cacheUrl += 'cf_edge_cache_ver=' + cacheVer; return new Request(cacheUrl); }

貼上程式碼之後，需要分別輸入你的 Email、Global API Key 與 Zone ID

儲存 Script 後，需要指定 Route 才能真正的啟用剛剛設定的腳本規則

到「Routes」點擊「Add Route」新增一個 Route

左側填入要應用的網域，右側則是指定剛剛先增的 Script

Cloudflare 快取狀態

html edge 快取狀態