LouisLam
3 years ago
6 changed files with 831 additions and 14 deletions
@ -0,0 +1,749 @@ |
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let url = require("url"); |
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let MemoryCache = require("./memory-cache"); |
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|
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let t = { |
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ms: 1, |
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second: 1000, |
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minute: 60000, |
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hour: 3600000, |
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day: 3600000 * 24, |
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week: 3600000 * 24 * 7, |
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month: 3600000 * 24 * 30, |
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}; |
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let instances = []; |
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let matches = function (a) { |
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return function (b) { |
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return a === b; |
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}; |
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}; |
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|
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let doesntMatch = function (a) { |
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return function (b) { |
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return !matches(a)(b); |
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}; |
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}; |
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|
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let logDuration = function (d, prefix) { |
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let str = d > 1000 ? (d / 1000).toFixed(2) + "sec" : d + "ms"; |
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return "\x1b[33m- " + (prefix ? prefix + " " : "") + str + "\x1b[0m"; |
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}; |
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|
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function getSafeHeaders(res) { |
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return res.getHeaders ? res.getHeaders() : res._headers; |
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} |
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|
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function ApiCache() { |
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let memCache = new MemoryCache(); |
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let globalOptions = { |
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debug: false, |
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defaultDuration: 3600000, |
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enabled: true, |
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appendKey: [], |
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jsonp: false, |
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redisClient: false, |
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headerBlacklist: [], |
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statusCodes: { |
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include: [], |
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exclude: [], |
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}, |
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events: { |
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expire: undefined, |
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}, |
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headers: { |
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// 'cache-control': 'no-cache' // example of header overwrite
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}, |
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trackPerformance: false, |
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respectCacheControl: false, |
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}; |
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|
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let middlewareOptions = []; |
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let instance = this; |
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let index = null; |
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let timers = {}; |
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let performanceArray = []; // for tracking cache hit rate
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instances.push(this); |
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this.id = instances.length; |
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function debug(a, b, c, d) { |
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let arr = ["\x1b[36m[apicache]\x1b[0m", a, b, c, d].filter(function (arg) { |
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return arg !== undefined; |
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}); |
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let debugEnv = process.env.DEBUG && process.env.DEBUG.split(",").indexOf("apicache") !== -1; |
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|
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return (globalOptions.debug || debugEnv) && console.log.apply(null, arr); |
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} |
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|
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function shouldCacheResponse(request, response, toggle) { |
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let opt = globalOptions; |
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let codes = opt.statusCodes; |
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if (!response) { |
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return false; |
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} |
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if (toggle && !toggle(request, response)) { |
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return false; |
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} |
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if (codes.exclude && codes.exclude.length && codes.exclude.indexOf(response.statusCode) !== -1) { |
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return false; |
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} |
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if (codes.include && codes.include.length && codes.include.indexOf(response.statusCode) === -1) { |
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return false; |
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} |
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return true; |
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} |
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function addIndexEntries(key, req) { |
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let groupName = req.apicacheGroup; |
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if (groupName) { |
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debug("group detected \"" + groupName + "\""); |
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let group = (index.groups[groupName] = index.groups[groupName] || []); |
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group.unshift(key); |
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} |
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index.all.unshift(key); |
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} |
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function filterBlacklistedHeaders(headers) { |
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return Object.keys(headers) |
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.filter(function (key) { |
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return globalOptions.headerBlacklist.indexOf(key) === -1; |
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}) |
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.reduce(function (acc, header) { |
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acc[header] = headers[header]; |
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return acc; |
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}, {}); |
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} |
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function createCacheObject(status, headers, data, encoding) { |
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return { |
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status: status, |
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headers: filterBlacklistedHeaders(headers), |
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data: data, |
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encoding: encoding, |
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timestamp: new Date().getTime() / 1000, // seconds since epoch. This is used to properly decrement max-age headers in cached responses.
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}; |
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} |
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function cacheResponse(key, value, duration) { |
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let redis = globalOptions.redisClient; |
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let expireCallback = globalOptions.events.expire; |
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if (redis && redis.connected) { |
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try { |
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redis.hset(key, "response", JSON.stringify(value)); |
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redis.hset(key, "duration", duration); |
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redis.expire(key, duration / 1000, expireCallback || function () {}); |
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} catch (err) { |
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debug("[apicache] error in redis.hset()"); |
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} |
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} else { |
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memCache.add(key, value, duration, expireCallback); |
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} |
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// add automatic cache clearing from duration, includes max limit on setTimeout
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timers[key] = setTimeout(function () { |
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instance.clear(key, true); |
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}, Math.min(duration, 2147483647)); |
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} |
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function accumulateContent(res, content) { |
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if (content) { |
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if (typeof content == "string") { |
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res._apicache.content = (res._apicache.content || "") + content; |
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} else if (Buffer.isBuffer(content)) { |
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let oldContent = res._apicache.content; |
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if (typeof oldContent === "string") { |
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oldContent = !Buffer.from ? new Buffer(oldContent) : Buffer.from(oldContent); |
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} |
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if (!oldContent) { |
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oldContent = !Buffer.alloc ? new Buffer(0) : Buffer.alloc(0); |
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} |
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res._apicache.content = Buffer.concat( |
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[oldContent, content], |
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oldContent.length + content.length |
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); |
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} else { |
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res._apicache.content = content; |
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} |
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} |
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} |
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function makeResponseCacheable(req, res, next, key, duration, strDuration, toggle) { |
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// monkeypatch res.end to create cache object
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res._apicache = { |
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write: res.write, |
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writeHead: res.writeHead, |
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end: res.end, |
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cacheable: true, |
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content: undefined, |
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}; |
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// append header overwrites if applicable
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Object.keys(globalOptions.headers).forEach(function (name) { |
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res.setHeader(name, globalOptions.headers[name]); |
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}); |
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res.writeHead = function () { |
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// add cache control headers
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if (!globalOptions.headers["cache-control"]) { |
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if (shouldCacheResponse(req, res, toggle)) { |
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res.setHeader("cache-control", "max-age=" + (duration / 1000).toFixed(0)); |
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} else { |
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res.setHeader("cache-control", "no-cache, no-store, must-revalidate"); |
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} |
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} |
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res._apicache.headers = Object.assign({}, getSafeHeaders(res)); |
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return res._apicache.writeHead.apply(this, arguments); |
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}; |
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// patch res.write
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res.write = function (content) { |
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accumulateContent(res, content); |
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return res._apicache.write.apply(this, arguments); |
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}; |
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// patch res.end
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res.end = function (content, encoding) { |
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if (shouldCacheResponse(req, res, toggle)) { |
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accumulateContent(res, content); |
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if (res._apicache.cacheable && res._apicache.content) { |
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addIndexEntries(key, req); |
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let headers = res._apicache.headers || getSafeHeaders(res); |
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let cacheObject = createCacheObject( |
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res.statusCode, |
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headers, |
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res._apicache.content, |
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encoding |
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); |
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cacheResponse(key, cacheObject, duration); |
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// display log entry
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let elapsed = new Date() - req.apicacheTimer; |
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debug("adding cache entry for \"" + key + "\" @ " + strDuration, logDuration(elapsed)); |
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debug("_apicache.headers: ", res._apicache.headers); |
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debug("res.getHeaders(): ", getSafeHeaders(res)); |
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debug("cacheObject: ", cacheObject); |
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} |
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} |
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return res._apicache.end.apply(this, arguments); |
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}; |
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next(); |
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} |
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function sendCachedResponse(request, response, cacheObject, toggle, next, duration) { |
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if (toggle && !toggle(request, response)) { |
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return next(); |
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} |
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let headers = getSafeHeaders(response); |
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// Modified by @louislam, removed Cache-control, since I don't need client side cache!
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// Original Source: https://github.com/kwhitley/apicache/blob/0d5686cc21fad353c6dddee646288c2fca3e4f50/src/apicache.js#L254
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Object.assign(headers, filterBlacklistedHeaders(cacheObject.headers || {})); |
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// only embed apicache headers when not in production environment
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if (process.env.NODE_ENV !== "production") { |
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Object.assign(headers, { |
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"apicache-store": globalOptions.redisClient ? "redis" : "memory", |
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"apicache-version": "1.6.2-modified", |
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}); |
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} |
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// unstringify buffers
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let data = cacheObject.data; |
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if (data && data.type === "Buffer") { |
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data = |
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typeof data.data === "number" ? new Buffer.alloc(data.data) : new Buffer.from(data.data); |
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} |
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// test Etag against If-None-Match for 304
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let cachedEtag = cacheObject.headers.etag; |
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let requestEtag = request.headers["if-none-match"]; |
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if (requestEtag && cachedEtag === requestEtag) { |
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response.writeHead(304, headers); |
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return response.end(); |
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} |
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response.writeHead(cacheObject.status || 200, headers); |
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return response.end(data, cacheObject.encoding); |
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} |
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function syncOptions() { |
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for (let i in middlewareOptions) { |
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Object.assign(middlewareOptions[i].options, globalOptions, middlewareOptions[i].localOptions); |
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} |
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} |
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this.clear = function (target, isAutomatic) { |
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let group = index.groups[target]; |
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let redis = globalOptions.redisClient; |
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if (group) { |
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debug("clearing group \"" + target + "\""); |
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group.forEach(function (key) { |
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debug("clearing cached entry for \"" + key + "\""); |
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clearTimeout(timers[key]); |
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delete timers[key]; |
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if (!globalOptions.redisClient) { |
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memCache.delete(key); |
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} else { |
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try { |
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redis.del(key); |
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} catch (err) { |
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console.log("[apicache] error in redis.del(\"" + key + "\")"); |
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} |
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} |
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index.all = index.all.filter(doesntMatch(key)); |
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}); |
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delete index.groups[target]; |
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} else if (target) { |
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debug("clearing " + (isAutomatic ? "expired" : "cached") + " entry for \"" + target + "\""); |
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clearTimeout(timers[target]); |
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delete timers[target]; |
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// clear actual cached entry
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if (!redis) { |
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memCache.delete(target); |
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} else { |
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try { |
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redis.del(target); |
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} catch (err) { |
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console.log("[apicache] error in redis.del(\"" + target + "\")"); |
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} |
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} |
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// remove from global index
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index.all = index.all.filter(doesntMatch(target)); |
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// remove target from each group that it may exist in
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Object.keys(index.groups).forEach(function (groupName) { |
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index.groups[groupName] = index.groups[groupName].filter(doesntMatch(target)); |
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// delete group if now empty
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if (!index.groups[groupName].length) { |
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delete index.groups[groupName]; |
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} |
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}); |
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} else { |
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debug("clearing entire index"); |
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if (!redis) { |
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memCache.clear(); |
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} else { |
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// clear redis keys one by one from internal index to prevent clearing non-apicache entries
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index.all.forEach(function (key) { |
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clearTimeout(timers[key]); |
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delete timers[key]; |
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try { |
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redis.del(key); |
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} catch (err) { |
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console.log("[apicache] error in redis.del(\"" + key + "\")"); |
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} |
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}); |
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} |
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this.resetIndex(); |
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} |
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return this.getIndex(); |
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}; |
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function parseDuration(duration, defaultDuration) { |
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if (typeof duration === "number") { |
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return duration; |
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} |
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if (typeof duration === "string") { |
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let split = duration.match(/^([\d\.,]+)\s?(\w+)$/); |
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if (split.length === 3) { |
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let len = parseFloat(split[1]); |
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let unit = split[2].replace(/s$/i, "").toLowerCase(); |
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if (unit === "m") { |
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unit = "ms"; |
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} |
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return (len || 1) * (t[unit] || 0); |
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} |
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} |
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return defaultDuration; |
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} |
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this.getDuration = function (duration) { |
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return parseDuration(duration, globalOptions.defaultDuration); |
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}; |
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/** |
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* Return cache performance statistics (hit rate). Suitable for putting into a route: |
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* <code> |
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* app.get('/api/cache/performance', (req, res) => { |
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* res.json(apicache.getPerformance()) |
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* }) |
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* </code> |
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*/ |
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this.getPerformance = function () { |
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return performanceArray.map(function (p) { |
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return p.report(); |
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}); |
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}; |
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this.getIndex = function (group) { |
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if (group) { |
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return index.groups[group]; |
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} else { |
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return index; |
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} |
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}; |
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this.middleware = function cache(strDuration, middlewareToggle, localOptions) { |
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let duration = instance.getDuration(strDuration); |
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let opt = {}; |
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middlewareOptions.push({ |
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options: opt, |
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}); |
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let options = function (localOptions) { |
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if (localOptions) { |
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middlewareOptions.find(function (middleware) { |
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return middleware.options === opt; |
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}).localOptions = localOptions; |
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} |
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syncOptions(); |
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return opt; |
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}; |
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options(localOptions); |
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/** |
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* A Function for non tracking performance |
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*/ |
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function NOOPCachePerformance() { |
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this.report = this.hit = this.miss = function () {}; // noop;
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} |
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/** |
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* A function for tracking and reporting hit rate. These statistics are returned by the getPerformance() call above. |
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*/ |
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function CachePerformance() { |
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/** |
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* Tracks the hit rate for the last 100 requests. |
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* If there have been fewer than 100 requests, the hit rate just considers the requests that have happened. |
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*/ |
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this.hitsLast100 = new Uint8Array(100 / 4); // each hit is 2 bits
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|
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/** |
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* Tracks the hit rate for the last 1000 requests. |
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* If there have been fewer than 1000 requests, the hit rate just considers the requests that have happened. |
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*/ |
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this.hitsLast1000 = new Uint8Array(1000 / 4); // each hit is 2 bits
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/** |
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* Tracks the hit rate for the last 10000 requests. |
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* If there have been fewer than 10000 requests, the hit rate just considers the requests that have happened. |
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*/ |
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this.hitsLast10000 = new Uint8Array(10000 / 4); // each hit is 2 bits
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/** |
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* Tracks the hit rate for the last 100000 requests. |
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* If there have been fewer than 100000 requests, the hit rate just considers the requests that have happened. |
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*/ |
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this.hitsLast100000 = new Uint8Array(100000 / 4); // each hit is 2 bits
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/** |
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* The number of calls that have passed through the middleware since the server started. |
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*/ |
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this.callCount = 0; |
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/** |
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* The total number of hits since the server started |
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*/ |
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this.hitCount = 0; |
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/** |
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* The key from the last cache hit. This is useful in identifying which route these statistics apply to. |
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*/ |
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this.lastCacheHit = null; |
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/** |
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* The key from the last cache miss. This is useful in identifying which route these statistics apply to. |
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*/ |
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this.lastCacheMiss = null; |
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/** |
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* Return performance statistics |
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*/ |
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this.report = function () { |
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return { |
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lastCacheHit: this.lastCacheHit, |
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lastCacheMiss: this.lastCacheMiss, |
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callCount: this.callCount, |
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hitCount: this.hitCount, |
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missCount: this.callCount - this.hitCount, |
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hitRate: this.callCount == 0 ? null : this.hitCount / this.callCount, |
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hitRateLast100: this.hitRate(this.hitsLast100), |
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hitRateLast1000: this.hitRate(this.hitsLast1000), |
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hitRateLast10000: this.hitRate(this.hitsLast10000), |
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hitRateLast100000: this.hitRate(this.hitsLast100000), |
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}; |
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}; |
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/** |
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* Computes a cache hit rate from an array of hits and misses. |
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* @param {Uint8Array} array An array representing hits and misses. |
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* @returns a number between 0 and 1, or null if the array has no hits or misses |
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*/ |
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this.hitRate = function (array) { |
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let hits = 0; |
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let misses = 0; |
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for (let i = 0; i < array.length; i++) { |
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let n8 = array[i]; |
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for (let j = 0; j < 4; j++) { |
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switch (n8 & 3) { |
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case 1: |
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hits++; |
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break; |
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case 2: |
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misses++; |
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break; |
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} |
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n8 >>= 2; |
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} |
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} |
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let total = hits + misses; |
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if (total == 0) { |
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return null; |
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} |
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return hits / total; |
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}; |
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/** |
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* Record a hit or miss in the given array. It will be recorded at a position determined |
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* by the current value of the callCount variable. |
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* @param {Uint8Array} array An array representing hits and misses. |
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* @param {boolean} hit true for a hit, false for a miss |
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* Each element in the array is 8 bits, and encodes 4 hit/miss records. |
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* Each hit or miss is encoded as to bits as follows: |
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* 00 means no hit or miss has been recorded in these bits |
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* 01 encodes a hit |
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* 10 encodes a miss |
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*/ |
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this.recordHitInArray = function (array, hit) { |
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let arrayIndex = ~~(this.callCount / 4) % array.length; |
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let bitOffset = (this.callCount % 4) * 2; // 2 bits per record, 4 records per uint8 array element
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let clearMask = ~(3 << bitOffset); |
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let record = (hit ? 1 : 2) << bitOffset; |
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array[arrayIndex] = (array[arrayIndex] & clearMask) | record; |
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}; |
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|
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/** |
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* Records the hit or miss in the tracking arrays and increments the call count. |
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* @param {boolean} hit true records a hit, false records a miss |
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*/ |
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this.recordHit = function (hit) { |
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this.recordHitInArray(this.hitsLast100, hit); |
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this.recordHitInArray(this.hitsLast1000, hit); |
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this.recordHitInArray(this.hitsLast10000, hit); |
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this.recordHitInArray(this.hitsLast100000, hit); |
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if (hit) { |
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this.hitCount++; |
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} |
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this.callCount++; |
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}; |
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|
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/** |
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* Records a hit event, setting lastCacheMiss to the given key |
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* @param {string} key The key that had the cache hit |
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*/ |
|||
this.hit = function (key) { |
|||
this.recordHit(true); |
|||
this.lastCacheHit = key; |
|||
}; |
|||
|
|||
/** |
|||
* Records a miss event, setting lastCacheMiss to the given key |
|||
* @param {string} key The key that had the cache miss |
|||
*/ |
|||
this.miss = function (key) { |
|||
this.recordHit(false); |
|||
this.lastCacheMiss = key; |
|||
}; |
|||
} |
|||
|
|||
let perf = globalOptions.trackPerformance ? new CachePerformance() : new NOOPCachePerformance(); |
|||
|
|||
performanceArray.push(perf); |
|||
|
|||
let cache = function (req, res, next) { |
|||
function bypass() { |
|||
debug("bypass detected, skipping cache."); |
|||
return next(); |
|||
} |
|||
|
|||
// initial bypass chances
|
|||
if (!opt.enabled) { |
|||
return bypass(); |
|||
} |
|||
if ( |
|||
req.headers["x-apicache-bypass"] || |
|||
req.headers["x-apicache-force-fetch"] || |
|||
(opt.respectCacheControl && req.headers["cache-control"] == "no-cache") |
|||
) { |
|||
return bypass(); |
|||
} |
|||
|
|||
// REMOVED IN 0.11.1 TO CORRECT MIDDLEWARE TOGGLE EXECUTE ORDER
|
|||
// if (typeof middlewareToggle === 'function') {
|
|||
// if (!middlewareToggle(req, res)) return bypass()
|
|||
// } else if (middlewareToggle !== undefined && !middlewareToggle) {
|
|||
// return bypass()
|
|||
// }
|
|||
|
|||
// embed timer
|
|||
req.apicacheTimer = new Date(); |
|||
|
|||
// In Express 4.x the url is ambigious based on where a router is mounted. originalUrl will give the full Url
|
|||
let key = req.originalUrl || req.url; |
|||
|
|||
// Remove querystring from key if jsonp option is enabled
|
|||
if (opt.jsonp) { |
|||
key = url.parse(key).pathname; |
|||
} |
|||
|
|||
// add appendKey (either custom function or response path)
|
|||
if (typeof opt.appendKey === "function") { |
|||
key += "$$appendKey=" + opt.appendKey(req, res); |
|||
} else if (opt.appendKey.length > 0) { |
|||
let appendKey = req; |
|||
|
|||
for (let i = 0; i < opt.appendKey.length; i++) { |
|||
appendKey = appendKey[opt.appendKey[i]]; |
|||
} |
|||
key += "$$appendKey=" + appendKey; |
|||
} |
|||
|
|||
// attempt cache hit
|
|||
let redis = opt.redisClient; |
|||
let cached = !redis ? memCache.getValue(key) : null; |
|||
|
|||
// send if cache hit from memory-cache
|
|||
if (cached) { |
|||
let elapsed = new Date() - req.apicacheTimer; |
|||
debug("sending cached (memory-cache) version of", key, logDuration(elapsed)); |
|||
|
|||
perf.hit(key); |
|||
return sendCachedResponse(req, res, cached, middlewareToggle, next, duration); |
|||
} |
|||
|
|||
// send if cache hit from redis
|
|||
if (redis && redis.connected) { |
|||
try { |
|||
redis.hgetall(key, function (err, obj) { |
|||
if (!err && obj && obj.response) { |
|||
let elapsed = new Date() - req.apicacheTimer; |
|||
debug("sending cached (redis) version of", key, logDuration(elapsed)); |
|||
|
|||
perf.hit(key); |
|||
return sendCachedResponse( |
|||
req, |
|||
res, |
|||
JSON.parse(obj.response), |
|||
middlewareToggle, |
|||
next, |
|||
duration |
|||
); |
|||
} else { |
|||
perf.miss(key); |
|||
return makeResponseCacheable( |
|||
req, |
|||
res, |
|||
next, |
|||
key, |
|||
duration, |
|||
strDuration, |
|||
middlewareToggle |
|||
); |
|||
} |
|||
}); |
|||
} catch (err) { |
|||
// bypass redis on error
|
|||
perf.miss(key); |
|||
return makeResponseCacheable(req, res, next, key, duration, strDuration, middlewareToggle); |
|||
} |
|||
} else { |
|||
perf.miss(key); |
|||
return makeResponseCacheable(req, res, next, key, duration, strDuration, middlewareToggle); |
|||
} |
|||
}; |
|||
|
|||
cache.options = options; |
|||
|
|||
return cache; |
|||
}; |
|||
|
|||
this.options = function (options) { |
|||
if (options) { |
|||
Object.assign(globalOptions, options); |
|||
syncOptions(); |
|||
|
|||
if ("defaultDuration" in options) { |
|||
// Convert the default duration to a number in milliseconds (if needed)
|
|||
globalOptions.defaultDuration = parseDuration(globalOptions.defaultDuration, 3600000); |
|||
} |
|||
|
|||
if (globalOptions.trackPerformance) { |
|||
debug("WARNING: using trackPerformance flag can cause high memory usage!"); |
|||
} |
|||
|
|||
return this; |
|||
} else { |
|||
return globalOptions; |
|||
} |
|||
}; |
|||
|
|||
this.resetIndex = function () { |
|||
index = { |
|||
all: [], |
|||
groups: {}, |
|||
}; |
|||
}; |
|||
|
|||
this.newInstance = function (config) { |
|||
let instance = new ApiCache(); |
|||
|
|||
if (config) { |
|||
instance.options(config); |
|||
} |
|||
|
|||
return instance; |
|||
}; |
|||
|
|||
this.clone = function () { |
|||
return this.newInstance(this.options()); |
|||
}; |
|||
|
|||
// initialize index
|
|||
this.resetIndex(); |
|||
} |
|||
|
|||
module.exports = new ApiCache(); |
|||
@ -0,0 +1,14 @@ |
|||
const apicache = require("./apicache"); |
|||
|
|||
apicache.options({ |
|||
headerBlacklist: [ |
|||
"cache-control" |
|||
], |
|||
headers: { |
|||
// Disable client side cache, only server side cache.
|
|||
// BUG! Not working for the second request
|
|||
"cache-control": "no-cache", |
|||
}, |
|||
}); |
|||
|
|||
module.exports = apicache; |
|||
@ -0,0 +1,59 @@ |
|||
function MemoryCache() { |
|||
this.cache = {}; |
|||
this.size = 0; |
|||
} |
|||
|
|||
MemoryCache.prototype.add = function (key, value, time, timeoutCallback) { |
|||
let old = this.cache[key]; |
|||
let instance = this; |
|||
|
|||
let entry = { |
|||
value: value, |
|||
expire: time + Date.now(), |
|||
timeout: setTimeout(function () { |
|||
instance.delete(key); |
|||
return timeoutCallback && typeof timeoutCallback === "function" && timeoutCallback(value, key); |
|||
}, time) |
|||
}; |
|||
|
|||
this.cache[key] = entry; |
|||
this.size = Object.keys(this.cache).length; |
|||
|
|||
return entry; |
|||
}; |
|||
|
|||
MemoryCache.prototype.delete = function (key) { |
|||
let entry = this.cache[key]; |
|||
|
|||
if (entry) { |
|||
clearTimeout(entry.timeout); |
|||
} |
|||
|
|||
delete this.cache[key]; |
|||
|
|||
this.size = Object.keys(this.cache).length; |
|||
|
|||
return null; |
|||
}; |
|||
|
|||
MemoryCache.prototype.get = function (key) { |
|||
let entry = this.cache[key]; |
|||
|
|||
return entry; |
|||
}; |
|||
|
|||
MemoryCache.prototype.getValue = function (key) { |
|||
let entry = this.get(key); |
|||
|
|||
return entry && entry.value; |
|||
}; |
|||
|
|||
MemoryCache.prototype.clear = function () { |
|||
Object.keys(this.cache).forEach(function (key) { |
|||
this.delete(key); |
|||
}, this); |
|||
|
|||
return true; |
|||
}; |
|||
|
|||
module.exports = MemoryCache; |
|||
Loading…
Reference in new issue