Updated the Survey.

node_modules/cacheable-request/src/index.js

@@ -0,0 +1,251 @@
+'use strict';
+
+const EventEmitter = require('events');
+const urlLib = require('url');
+const normalizeUrl = require('normalize-url');
+const getStream = require('get-stream');
+const CachePolicy = require('http-cache-semantics');
+const Response = require('responselike');
+const lowercaseKeys = require('lowercase-keys');
+const cloneResponse = require('clone-response');
+const Keyv = require('keyv');
+
+class CacheableRequest {
+	constructor(request, cacheAdapter) {
+		if (typeof request !== 'function') {
+			throw new TypeError('Parameter `request` must be a function');
+		}
+
+		this.cache = new Keyv({
+			uri: typeof cacheAdapter === 'string' && cacheAdapter,
+			store: typeof cacheAdapter !== 'string' && cacheAdapter,
+			namespace: 'cacheable-request'
+		});
+
+		return this.createCacheableRequest(request);
+	}
+
+	createCacheableRequest(request) {
+		return (opts, cb) => {
+			let url;
+			if (typeof opts === 'string') {
+				url = normalizeUrlObject(urlLib.parse(opts));
+				opts = {};
+			} else if (opts instanceof urlLib.URL) {
+				url = normalizeUrlObject(urlLib.parse(opts.toString()));
+				opts = {};
+			} else {
+				const [pathname, ...searchParts] = (opts.path || '').split('?');
+				const search = searchParts.length > 0 ?
+					`?${searchParts.join('?')}` :
+					'';
+				url = normalizeUrlObject({ ...opts, pathname, search });
+			}
+
+			opts = {
+				headers: {},
+				method: 'GET',
+				cache: true,
+				strictTtl: false,
+				automaticFailover: false,
+				...opts,
+				...urlObjectToRequestOptions(url)
+			};
+			opts.headers = lowercaseKeys(opts.headers);
+
+			const ee = new EventEmitter();
+			const normalizedUrlString = normalizeUrl(
+				urlLib.format(url),
+				{
+					stripWWW: false,
+					removeTrailingSlash: false,
+					stripAuthentication: false
+				}
+			);
+			const key = `${opts.method}:${normalizedUrlString}`;
+			let revalidate = false;
+			let madeRequest = false;
+
+			const makeRequest = opts => {
+				madeRequest = true;
+				let requestErrored = false;
+				let requestErrorCallback;
+
+				const requestErrorPromise = new Promise(resolve => {
+					requestErrorCallback = () => {
+						if (!requestErrored) {
+							requestErrored = true;
+							resolve();
+						}
+					};
+				});
+
+				const handler = response => {
+					if (revalidate && !opts.forceRefresh) {
+						response.status = response.statusCode;
+						const revalidatedPolicy = CachePolicy.fromObject(revalidate.cachePolicy).revalidatedPolicy(opts, response);
+						if (!revalidatedPolicy.modified) {
+							const headers = revalidatedPolicy.policy.responseHeaders();
+							response = new Response(revalidate.statusCode, headers, revalidate.body, revalidate.url);
+							response.cachePolicy = revalidatedPolicy.policy;
+							response.fromCache = true;
+						}
+					}
+
+					if (!response.fromCache) {
+						response.cachePolicy = new CachePolicy(opts, response, opts);
+						response.fromCache = false;
+					}
+
+					let clonedResponse;
+					if (opts.cache && response.cachePolicy.storable()) {
+						clonedResponse = cloneResponse(response);
+
+						(async () => {
+							try {
+								const bodyPromise = getStream.buffer(response);
+
+								await Promise.race([
+									requestErrorPromise,
+									new Promise(resolve => response.once('end', resolve))
+								]);
+
+								if (requestErrored) {
+									return;
+								}
+
+								const body = await bodyPromise;
+
+								const value = {
+									cachePolicy: response.cachePolicy.toObject(),
+									url: response.url,
+									statusCode: response.fromCache ? revalidate.statusCode : response.statusCode,
+									body
+								};
+
+								let ttl = opts.strictTtl ? response.cachePolicy.timeToLive() : undefined;
+								if (opts.maxTtl) {
+									ttl = ttl ? Math.min(ttl, opts.maxTtl) : opts.maxTtl;
+								}
+
+								await this.cache.set(key, value, ttl);
+							} catch (error) {
+								ee.emit('error', new CacheableRequest.CacheError(error));
+							}
+						})();
+					} else if (opts.cache && revalidate) {
+						(async () => {
+							try {
+								await this.cache.delete(key);
+							} catch (error) {
+								ee.emit('error', new CacheableRequest.CacheError(error));
+							}
+						})();
+					}
+
+					ee.emit('response', clonedResponse || response);
+					if (typeof cb === 'function') {
+						cb(clonedResponse || response);
+					}
+				};
+
+				try {
+					const req = request(opts, handler);
+					req.once('error', requestErrorCallback);
+					req.once('abort', requestErrorCallback);
+					ee.emit('request', req);
+				} catch (error) {
+					ee.emit('error', new CacheableRequest.RequestError(error));
+				}
+			};
+
+			(async () => {
+				const get = async opts => {
+					await Promise.resolve();
+
+					const cacheEntry = opts.cache ? await this.cache.get(key) : undefined;
+					if (typeof cacheEntry === 'undefined') {
+						return makeRequest(opts);
+					}
+
+					const policy = CachePolicy.fromObject(cacheEntry.cachePolicy);
+					if (policy.satisfiesWithoutRevalidation(opts) && !opts.forceRefresh) {
+						const headers = policy.responseHeaders();
+						const response = new Response(cacheEntry.statusCode, headers, cacheEntry.body, cacheEntry.url);
+						response.cachePolicy = policy;
+						response.fromCache = true;
+
+						ee.emit('response', response);
+						if (typeof cb === 'function') {
+							cb(response);
+						}
+					} else {
+						revalidate = cacheEntry;
+						opts.headers = policy.revalidationHeaders(opts);
+						makeRequest(opts);
+					}
+				};
+
+				const errorHandler = error => ee.emit('error', new CacheableRequest.CacheError(error));
+				this.cache.once('error', errorHandler);
+				ee.on('response', () => this.cache.removeListener('error', errorHandler));
+
+				try {
+					await get(opts);
+				} catch (error) {
+					if (opts.automaticFailover && !madeRequest) {
+						makeRequest(opts);
+					}
+
+					ee.emit('error', new CacheableRequest.CacheError(error));
+				}
+			})();
+
+			return ee;
+		};
+	}
+}
+
+function urlObjectToRequestOptions(url) {
+	const options = { ...url };
+	options.path = `${url.pathname || '/'}${url.search || ''}`;
+	delete options.pathname;
+	delete options.search;
+	return options;
+}
+
+function normalizeUrlObject(url) {
+	// If url was parsed by url.parse or new URL:
+	// - hostname will be set
+	// - host will be hostname[:port]
+	// - port will be set if it was explicit in the parsed string
+	// Otherwise, url was from request options:
+	// - hostname or host may be set
+	// - host shall not have port encoded
+	return {
+		protocol: url.protocol,
+		auth: url.auth,
+		hostname: url.hostname || url.host || 'localhost',
+		port: url.port,
+		pathname: url.pathname,
+		search: url.search
+	};
+}
+
+CacheableRequest.RequestError = class extends Error {
+	constructor(error) {
+		super(error.message);
+		this.name = 'RequestError';
+		Object.assign(this, error);
+	}
+};
+
+CacheableRequest.CacheError = class extends Error {
+	constructor(error) {
+		super(error.message);
+		this.name = 'CacheError';
+		Object.assign(this, error);
+	}
+};
+
+module.exports = CacheableRequest;