Initial commit

1 files changed, 436 insertions, 0 deletions

diff --git a/node_modules/cacheable-lookup/source/index.js b/node_modules/cacheable-lookup/source/index.js
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index 0000000..21f731e
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+++ b/node_modules/cacheable-lookup/source/index.js
@@ -0,0 +1,436 @@
+'use strict';
+const {
+	V4MAPPED,
+	ADDRCONFIG,
+	ALL,
+	promises: {
+		Resolver: AsyncResolver
+	},
+	lookup: dnsLookup
+} = require('dns');
+const {promisify} = require('util');
+const os = require('os');
+
+const kCacheableLookupCreateConnection = Symbol('cacheableLookupCreateConnection');
+const kCacheableLookupInstance = Symbol('cacheableLookupInstance');
+const kExpires = Symbol('expires');
+
+const supportsALL = typeof ALL === 'number';
+
+const verifyAgent = agent => {
+	if (!(agent && typeof agent.createConnection === 'function')) {
+		throw new Error('Expected an Agent instance as the first argument');
+	}
+};
+
+const map4to6 = entries => {
+	for (const entry of entries) {
+		if (entry.family === 6) {
+			continue;
+		}
+
+		entry.address = `::ffff:${entry.address}`;
+		entry.family = 6;
+	}
+};
+
+const getIfaceInfo = () => {
+	let has4 = false;
+	let has6 = false;
+
+	for (const device of Object.values(os.networkInterfaces())) {
+		for (const iface of device) {
+			if (iface.internal) {
+				continue;
+			}
+
+			if (iface.family === 'IPv6') {
+				has6 = true;
+			} else {
+				has4 = true;
+			}
+
+			if (has4 && has6) {
+				return {has4, has6};
+			}
+		}
+	}
+
+	return {has4, has6};
+};
+
+const isIterable = map => {
+	return Symbol.iterator in map;
+};
+
+const ttl = {ttl: true};
+const all = {all: true};
+
+class CacheableLookup {
+	constructor({
+		cache = new Map(),
+		maxTtl = Infinity,
+		fallbackDuration = 3600,
+		errorTtl = 0.15,
+		resolver = new AsyncResolver(),
+		lookup = dnsLookup
+	} = {}) {
+		this.maxTtl = maxTtl;
+		this.errorTtl = errorTtl;
+
+		this._cache = cache;
+		this._resolver = resolver;
+		this._dnsLookup = promisify(lookup);
+
+		if (this._resolver instanceof AsyncResolver) {
+			this._resolve4 = this._resolver.resolve4.bind(this._resolver);
+			this._resolve6 = this._resolver.resolve6.bind(this._resolver);
+		} else {
+			this._resolve4 = promisify(this._resolver.resolve4.bind(this._resolver));
+			this._resolve6 = promisify(this._resolver.resolve6.bind(this._resolver));
+		}
+
+		this._iface = getIfaceInfo();
+
+		this._pending = {};
+		this._nextRemovalTime = false;
+		this._hostnamesToFallback = new Set();
+
+		if (fallbackDuration < 1) {
+			this._fallback = false;
+		} else {
+			this._fallback = true;
+
+			const interval = setInterval(() => {
+				this._hostnamesToFallback.clear();
+			}, fallbackDuration * 1000);
+
+			/* istanbul ignore next: There is no `interval.unref()` when running inside an Electron renderer */
+			if (interval.unref) {
+				interval.unref();
+			}
+		}
+
+		this.lookup = this.lookup.bind(this);
+		this.lookupAsync = this.lookupAsync.bind(this);
+	}
+
+	set servers(servers) {
+		this.clear();
+
+		this._resolver.setServers(servers);
+	}
+
+	get servers() {
+		return this._resolver.getServers();
+	}
+
+	lookup(hostname, options, callback) {
+		if (typeof options === 'function') {
+			callback = options;
+			options = {};
+		} else if (typeof options === 'number') {
+			options = {
+				family: options
+			};
+		}
+
+		if (!callback) {
+			throw new Error('Callback must be a function.');
+		}
+
+		// eslint-disable-next-line promise/prefer-await-to-then
+		this.lookupAsync(hostname, options).then(result => {
+			if (options.all) {
+				callback(null, result);
+			} else {
+				callback(null, result.address, result.family, result.expires, result.ttl);
+			}
+		}, callback);
+	}
+
+	async lookupAsync(hostname, options = {}) {
+		if (typeof options === 'number') {
+			options = {
+				family: options
+			};
+		}
+
+		let cached = await this.query(hostname);
+
+		if (options.family === 6) {
+			const filtered = cached.filter(entry => entry.family === 6);
+
+			if (options.hints & V4MAPPED) {
+				if ((supportsALL && options.hints & ALL) || filtered.length === 0) {
+					map4to6(cached);
+				} else {
+					cached = filtered;
+				}
+			} else {
+				cached = filtered;
+			}
+		} else if (options.family === 4) {
+			cached = cached.filter(entry => entry.family === 4);
+		}
+
+		if (options.hints & ADDRCONFIG) {
+			const {_iface} = this;
+			cached = cached.filter(entry => entry.family === 6 ? _iface.has6 : _iface.has4);
+		}
+
+		if (cached.length === 0) {
+			const error = new Error(`cacheableLookup ENOTFOUND ${hostname}`);
+			error.code = 'ENOTFOUND';
+			error.hostname = hostname;
+
+			throw error;
+		}
+
+		if (options.all) {
+			return cached;
+		}
+
+		return cached[0];
+	}
+
+	async query(hostname) {
+		let cached = await this._cache.get(hostname);
+
+		if (!cached) {
+			const pending = this._pending[hostname];
+
+			if (pending) {
+				cached = await pending;
+			} else {
+				const newPromise = this.queryAndCache(hostname);
+				this._pending[hostname] = newPromise;
+
+				try {
+					cached = await newPromise;
+				} finally {
+					delete this._pending[hostname];
+				}
+			}
+		}
+
+		cached = cached.map(entry => {
+			return {...entry};
+		});
+
+		return cached;
+	}
+
+	async _resolve(hostname) {
+		const wrap = async promise => {
+			try {
+				return await promise;
+			} catch (error) {
+				if (error.code === 'ENODATA' || error.code === 'ENOTFOUND') {
+					return [];
+				}
+
+				throw error;
+			}
+		};
+
+		// ANY is unsafe as it doesn't trigger new queries in the underlying server.
+		const [A, AAAA] = await Promise.all([
+			this._resolve4(hostname, ttl),
+			this._resolve6(hostname, ttl)
+		].map(promise => wrap(promise)));
+
+		let aTtl = 0;
+		let aaaaTtl = 0;
+		let cacheTtl = 0;
+
+		const now = Date.now();
+
+		for (const entry of A) {
+			entry.family = 4;
+			entry.expires = now + (entry.ttl * 1000);
+
+			aTtl = Math.max(aTtl, entry.ttl);
+		}
+
+		for (const entry of AAAA) {
+			entry.family = 6;
+			entry.expires = now + (entry.ttl * 1000);
+
+			aaaaTtl = Math.max(aaaaTtl, entry.ttl);
+		}
+
+		if (A.length > 0) {
+			if (AAAA.length > 0) {
+				cacheTtl = Math.min(aTtl, aaaaTtl);
+			} else {
+				cacheTtl = aTtl;
+			}
+		} else {
+			cacheTtl = aaaaTtl;
+		}
+
+		return {
+			entries: [
+				...A,
+				...AAAA
+			],
+			cacheTtl
+		};
+	}
+
+	async _lookup(hostname) {
+		try {
+			const entries = await this._dnsLookup(hostname, {
+				all: true
+			});
+
+			return {
+				entries,
+				cacheTtl: 0
+			};
+		} catch (_) {
+			return {
+				entries: [],
+				cacheTtl: 0
+			};
+		}
+	}
+
+	async _set(hostname, data, cacheTtl) {
+		if (this.maxTtl > 0 && cacheTtl > 0) {
+			cacheTtl = Math.min(cacheTtl, this.maxTtl) * 1000;
+			data[kExpires] = Date.now() + cacheTtl;
+
+			try {
+				await this._cache.set(hostname, data, cacheTtl);
+			} catch (error) {
+				this.lookupAsync = async () => {
+					const cacheError = new Error('Cache Error. Please recreate the CacheableLookup instance.');
+					cacheError.cause = error;
+
+					throw cacheError;
+				};
+			}
+
+			if (isIterable(this._cache)) {
+				this._tick(cacheTtl);
+			}
+		}
+	}
+
+	async queryAndCache(hostname) {
+		if (this._hostnamesToFallback.has(hostname)) {
+			return this._dnsLookup(hostname, all);
+		}
+
+		let query = await this._resolve(hostname);
+
+		if (query.entries.length === 0 && this._fallback) {
+			query = await this._lookup(hostname);
+
+			if (query.entries.length !== 0) {
+				// Use `dns.lookup(...)` for that particular hostname
+				this._hostnamesToFallback.add(hostname);
+			}
+		}
+
+		const cacheTtl = query.entries.length === 0 ? this.errorTtl : query.cacheTtl;
+		await this._set(hostname, query.entries, cacheTtl);
+
+		return query.entries;
+	}
+
+	_tick(ms) {
+		const nextRemovalTime = this._nextRemovalTime;
+
+		if (!nextRemovalTime || ms < nextRemovalTime) {
+			clearTimeout(this._removalTimeout);
+
+			this._nextRemovalTime = ms;
+
+			this._removalTimeout = setTimeout(() => {
+				this._nextRemovalTime = false;
+
+				let nextExpiry = Infinity;
+
+				const now = Date.now();
+
+				for (const [hostname, entries] of this._cache) {
+					const expires = entries[kExpires];
+
+					if (now >= expires) {
+						this._cache.delete(hostname);
+					} else if (expires < nextExpiry) {
+						nextExpiry = expires;
+					}
+				}
+
+				if (nextExpiry !== Infinity) {
+					this._tick(nextExpiry - now);
+				}
+			}, ms);
+
+			/* istanbul ignore next: There is no `timeout.unref()` when running inside an Electron renderer */
+			if (this._removalTimeout.unref) {
+				this._removalTimeout.unref();
+			}
+		}
+	}
+
+	install(agent) {
+		verifyAgent(agent);
+
+		if (kCacheableLookupCreateConnection in agent) {
+			throw new Error('CacheableLookup has been already installed');
+		}
+
+		agent[kCacheableLookupCreateConnection] = agent.createConnection;
+		agent[kCacheableLookupInstance] = this;
+
+		agent.createConnection = (options, callback) => {
+			if (!('lookup' in options)) {
+				options.lookup = this.lookup;
+			}
+
+			return agent[kCacheableLookupCreateConnection](options, callback);
+		};
+	}
+
+	uninstall(agent) {
+		verifyAgent(agent);
+
+		if (agent[kCacheableLookupCreateConnection]) {
+			if (agent[kCacheableLookupInstance] !== this) {
+				throw new Error('The agent is not owned by this CacheableLookup instance');
+			}
+
+			agent.createConnection = agent[kCacheableLookupCreateConnection];
+
+			delete agent[kCacheableLookupCreateConnection];
+			delete agent[kCacheableLookupInstance];
+		}
+	}
+
+	updateInterfaceInfo() {
+		const {_iface} = this;
+
+		this._iface = getIfaceInfo();
+
+		if ((_iface.has4 && !this._iface.has4) || (_iface.has6 && !this._iface.has6)) {
+			this._cache.clear();
+		}
+	}
+
+	clear(hostname) {
+		if (hostname) {
+			this._cache.delete(hostname);
+			return;
+		}
+
+		this._cache.clear();
+	}
+}
+
+module.exports = CacheableLookup;
+module.exports.default = CacheableLookup;