Initial commit

1 files changed, 670 insertions, 0 deletions

diff --git a/node_modules/http2-wrapper/source/agent.js b/node_modules/http2-wrapper/source/agent.js
new file mode 100644
index 0000000..b2b1cff
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+++ b/node_modules/http2-wrapper/source/agent.js
@@ -0,0 +1,670 @@
+'use strict';
+const EventEmitter = require('events');
+const tls = require('tls');
+const http2 = require('http2');
+const QuickLRU = require('quick-lru');
+
+const kCurrentStreamsCount = Symbol('currentStreamsCount');
+const kRequest = Symbol('request');
+const kOriginSet = Symbol('cachedOriginSet');
+const kGracefullyClosing = Symbol('gracefullyClosing');
+
+const nameKeys = [
+	// `http2.connect()` options
+	'maxDeflateDynamicTableSize',
+	'maxSessionMemory',
+	'maxHeaderListPairs',
+	'maxOutstandingPings',
+	'maxReservedRemoteStreams',
+	'maxSendHeaderBlockLength',
+	'paddingStrategy',
+
+	// `tls.connect()` options
+	'localAddress',
+	'path',
+	'rejectUnauthorized',
+	'minDHSize',
+
+	// `tls.createSecureContext()` options
+	'ca',
+	'cert',
+	'clientCertEngine',
+	'ciphers',
+	'key',
+	'pfx',
+	'servername',
+	'minVersion',
+	'maxVersion',
+	'secureProtocol',
+	'crl',
+	'honorCipherOrder',
+	'ecdhCurve',
+	'dhparam',
+	'secureOptions',
+	'sessionIdContext'
+];
+
+const getSortedIndex = (array, value, compare) => {
+	let low = 0;
+	let high = array.length;
+
+	while (low < high) {
+		const mid = (low + high) >>> 1;
+
+		/* istanbul ignore next */
+		if (compare(array[mid], value)) {
+			// This never gets called because we use descending sort. Better to have this anyway.
+			low = mid + 1;
+		} else {
+			high = mid;
+		}
+	}
+
+	return low;
+};
+
+const compareSessions = (a, b) => {
+	return a.remoteSettings.maxConcurrentStreams > b.remoteSettings.maxConcurrentStreams;
+};
+
+// See https://tools.ietf.org/html/rfc8336
+const closeCoveredSessions = (where, session) => {
+	// Clients SHOULD NOT emit new requests on any connection whose Origin
+	// Set is a proper subset of another connection's Origin Set, and they
+	// SHOULD close it once all outstanding requests are satisfied.
+	for (const coveredSession of where) {
+		if (
+			// The set is a proper subset when its length is less than the other set.
+			coveredSession[kOriginSet].length < session[kOriginSet].length &&
+
+			// And the other set includes all elements of the subset.
+			coveredSession[kOriginSet].every(origin => session[kOriginSet].includes(origin)) &&
+
+			// Makes sure that the session can handle all requests from the covered session.
+			coveredSession[kCurrentStreamsCount] + session[kCurrentStreamsCount] <= session.remoteSettings.maxConcurrentStreams
+		) {
+			// This allows pending requests to finish and prevents making new requests.
+			gracefullyClose(coveredSession);
+		}
+	}
+};
+
+// This is basically inverted `closeCoveredSessions(...)`.
+const closeSessionIfCovered = (where, coveredSession) => {
+	for (const session of where) {
+		if (
+			coveredSession[kOriginSet].length < session[kOriginSet].length &&
+			coveredSession[kOriginSet].every(origin => session[kOriginSet].includes(origin)) &&
+			coveredSession[kCurrentStreamsCount] + session[kCurrentStreamsCount] <= session.remoteSettings.maxConcurrentStreams
+		) {
+			gracefullyClose(coveredSession);
+		}
+	}
+};
+
+const getSessions = ({agent, isFree}) => {
+	const result = {};
+
+	// eslint-disable-next-line guard-for-in
+	for (const normalizedOptions in agent.sessions) {
+		const sessions = agent.sessions[normalizedOptions];
+
+		const filtered = sessions.filter(session => {
+			const result = session[Agent.kCurrentStreamsCount] < session.remoteSettings.maxConcurrentStreams;
+
+			return isFree ? result : !result;
+		});
+
+		if (filtered.length !== 0) {
+			result[normalizedOptions] = filtered;
+		}
+	}
+
+	return result;
+};
+
+const gracefullyClose = session => {
+	session[kGracefullyClosing] = true;
+
+	if (session[kCurrentStreamsCount] === 0) {
+		session.close();
+	}
+};
+
+class Agent extends EventEmitter {
+	constructor({timeout = 60000, maxSessions = Infinity, maxFreeSessions = 10, maxCachedTlsSessions = 100} = {}) {
+		super();
+
+		// A session is considered busy when its current streams count
+		// is equal to or greater than the `maxConcurrentStreams` value.
+
+		// A session is considered free when its current streams count
+		// is less than the `maxConcurrentStreams` value.
+
+		// SESSIONS[NORMALIZED_OPTIONS] = [];
+		this.sessions = {};
+
+		// The queue for creating new sessions. It looks like this:
+		// QUEUE[NORMALIZED_OPTIONS][NORMALIZED_ORIGIN] = ENTRY_FUNCTION
+		//
+		// The entry function has `listeners`, `completed` and `destroyed` properties.
+		// `listeners` is an array of objects containing `resolve` and `reject` functions.
+		// `completed` is a boolean. It's set to true after ENTRY_FUNCTION is executed.
+		// `destroyed` is a boolean. If it's set to true, the session will be destroyed if hasn't connected yet.
+		this.queue = {};
+
+		// Each session will use this timeout value.
+		this.timeout = timeout;
+
+		// Max sessions in total
+		this.maxSessions = maxSessions;
+
+		// Max free sessions in total
+		// TODO: decreasing `maxFreeSessions` should close some sessions
+		this.maxFreeSessions = maxFreeSessions;
+
+		this._freeSessionsCount = 0;
+		this._sessionsCount = 0;
+
+		// We don't support push streams by default.
+		this.settings = {
+			enablePush: false
+		};
+
+		// Reusing TLS sessions increases performance.
+		this.tlsSessionCache = new QuickLRU({maxSize: maxCachedTlsSessions});
+	}
+
+	static normalizeOrigin(url, servername) {
+		if (typeof url === 'string') {
+			url = new URL(url);
+		}
+
+		if (servername && url.hostname !== servername) {
+			url.hostname = servername;
+		}
+
+		return url.origin;
+	}
+
+	normalizeOptions(options) {
+		let normalized = '';
+
+		if (options) {
+			for (const key of nameKeys) {
+				if (options[key]) {
+					normalized += `:${options[key]}`;
+				}
+			}
+		}
+
+		return normalized;
+	}
+
+	_tryToCreateNewSession(normalizedOptions, normalizedOrigin) {
+		if (!(normalizedOptions in this.queue) || !(normalizedOrigin in this.queue[normalizedOptions])) {
+			return;
+		}
+
+		const item = this.queue[normalizedOptions][normalizedOrigin];
+
+		// The entry function can be run only once.
+		// BUG: The session may be never created when:
+		// - the first condition is false AND
+		// - this function is never called with the same arguments in the future.
+		if (this._sessionsCount < this.maxSessions && !item.completed) {
+			item.completed = true;
+
+			item();
+		}
+	}
+
+	getSession(origin, options, listeners) {
+		return new Promise((resolve, reject) => {
+			if (Array.isArray(listeners)) {
+				listeners = [...listeners];
+
+				// Resolve the current promise ASAP, we're just moving the listeners.
+				// They will be executed at a different time.
+				resolve();
+			} else {
+				listeners = [{resolve, reject}];
+			}
+
+			const normalizedOptions = this.normalizeOptions(options);
+			const normalizedOrigin = Agent.normalizeOrigin(origin, options && options.servername);
+
+			if (normalizedOrigin === undefined) {
+				for (const {reject} of listeners) {
+					reject(new TypeError('The `origin` argument needs to be a string or an URL object'));
+				}
+
+				return;
+			}
+
+			if (normalizedOptions in this.sessions) {
+				const sessions = this.sessions[normalizedOptions];
+
+				let maxConcurrentStreams = -1;
+				let currentStreamsCount = -1;
+				let optimalSession;
+
+				// We could just do this.sessions[normalizedOptions].find(...) but that isn't optimal.
+				// Additionally, we are looking for session which has biggest current pending streams count.
+				for (const session of sessions) {
+					const sessionMaxConcurrentStreams = session.remoteSettings.maxConcurrentStreams;
+
+					if (sessionMaxConcurrentStreams < maxConcurrentStreams) {
+						break;
+					}
+
+					if (session[kOriginSet].includes(normalizedOrigin)) {
+						const sessionCurrentStreamsCount = session[kCurrentStreamsCount];
+
+						if (
+							sessionCurrentStreamsCount >= sessionMaxConcurrentStreams ||
+							session[kGracefullyClosing] ||
+							// Unfortunately the `close` event isn't called immediately,
+							// so `session.destroyed` is `true`, but `session.closed` is `false`.
+							session.destroyed
+						) {
+							continue;
+						}
+
+						// We only need set this once.
+						if (!optimalSession) {
+							maxConcurrentStreams = sessionMaxConcurrentStreams;
+						}
+
+						// We're looking for the session which has biggest current pending stream count,
+						// in order to minimalize the amount of active sessions.
+						if (sessionCurrentStreamsCount > currentStreamsCount) {
+							optimalSession = session;
+							currentStreamsCount = sessionCurrentStreamsCount;
+						}
+					}
+				}
+
+				if (optimalSession) {
+					/* istanbul ignore next: safety check */
+					if (listeners.length !== 1) {
+						for (const {reject} of listeners) {
+							const error = new Error(
+								`Expected the length of listeners to be 1, got ${listeners.length}.\n` +
+								'Please report this to https://github.com/szmarczak/http2-wrapper/'
+							);
+
+							reject(error);
+						}
+
+						return;
+					}
+
+					listeners[0].resolve(optimalSession);
+					return;
+				}
+			}
+
+			if (normalizedOptions in this.queue) {
+				if (normalizedOrigin in this.queue[normalizedOptions]) {
+					// There's already an item in the queue, just attach ourselves to it.
+					this.queue[normalizedOptions][normalizedOrigin].listeners.push(...listeners);
+
+					// This shouldn't be executed here.
+					// See the comment inside _tryToCreateNewSession.
+					this._tryToCreateNewSession(normalizedOptions, normalizedOrigin);
+					return;
+				}
+			} else {
+				this.queue[normalizedOptions] = {};
+			}
+
+			// The entry must be removed from the queue IMMEDIATELY when:
+			// 1. the session connects successfully,
+			// 2. an error occurs.
+			const removeFromQueue = () => {
+				// Our entry can be replaced. We cannot remove the new one.
+				if (normalizedOptions in this.queue && this.queue[normalizedOptions][normalizedOrigin] === entry) {
+					delete this.queue[normalizedOptions][normalizedOrigin];
+
+					if (Object.keys(this.queue[normalizedOptions]).length === 0) {
+						delete this.queue[normalizedOptions];
+					}
+				}
+			};
+
+			// The main logic is here
+			const entry = () => {
+				const name = `${normalizedOrigin}:${normalizedOptions}`;
+				let receivedSettings = false;
+
+				try {
+					const session = http2.connect(origin, {
+						createConnection: this.createConnection,
+						settings: this.settings,
+						session: this.tlsSessionCache.get(name),
+						...options
+					});
+					session[kCurrentStreamsCount] = 0;
+					session[kGracefullyClosing] = false;
+
+					const isFree = () => session[kCurrentStreamsCount] < session.remoteSettings.maxConcurrentStreams;
+					let wasFree = true;
+
+					session.socket.once('session', tlsSession => {
+						this.tlsSessionCache.set(name, tlsSession);
+					});
+
+					session.once('error', error => {
+						// Listeners are empty when the session successfully connected.
+						for (const {reject} of listeners) {
+							reject(error);
+						}
+
+						// The connection got broken, purge the cache.
+						this.tlsSessionCache.delete(name);
+					});
+
+					session.setTimeout(this.timeout, () => {
+						// Terminates all streams owned by this session.
+						// TODO: Maybe the streams should have a "Session timed out" error?
+						session.destroy();
+					});
+
+					session.once('close', () => {
+						if (receivedSettings) {
+							// 1. If it wasn't free then no need to decrease because
+							//    it has been decreased already in session.request().
+							// 2. `stream.once('close')` won't increment the count
+							//    because the session is already closed.
+							if (wasFree) {
+								this._freeSessionsCount--;
+							}
+
+							this._sessionsCount--;
+
+							// This cannot be moved to the stream logic,
+							// because there may be a session that hadn't made a single request.
+							const where = this.sessions[normalizedOptions];
+							where.splice(where.indexOf(session), 1);
+
+							if (where.length === 0) {
+								delete this.sessions[normalizedOptions];
+							}
+						} else {
+							// Broken connection
+							const error = new Error('Session closed without receiving a SETTINGS frame');
+							error.code = 'HTTP2WRAPPER_NOSETTINGS';
+
+							for (const {reject} of listeners) {
+								reject(error);
+							}
+
+							removeFromQueue();
+						}
+
+						// There may be another session awaiting.
+						this._tryToCreateNewSession(normalizedOptions, normalizedOrigin);
+					});
+
+					// Iterates over the queue and processes listeners.
+					const processListeners = () => {
+						if (!(normalizedOptions in this.queue) || !isFree()) {
+							return;
+						}
+
+						for (const origin of session[kOriginSet]) {
+							if (origin in this.queue[normalizedOptions]) {
+								const {listeners} = this.queue[normalizedOptions][origin];
+
+								// Prevents session overloading.
+								while (listeners.length !== 0 && isFree()) {
+									// We assume `resolve(...)` calls `request(...)` *directly*,
+									// otherwise the session will get overloaded.
+									listeners.shift().resolve(session);
+								}
+
+								const where = this.queue[normalizedOptions];
+								if (where[origin].listeners.length === 0) {
+									delete where[origin];
+
+									if (Object.keys(where).length === 0) {
+										delete this.queue[normalizedOptions];
+										break;
+									}
+								}
+
+								// We're no longer free, no point in continuing.
+								if (!isFree()) {
+									break;
+								}
+							}
+						}
+					};
+
+					// The Origin Set cannot shrink. No need to check if it suddenly became covered by another one.
+					session.on('origin', () => {
+						session[kOriginSet] = session.originSet;
+
+						if (!isFree()) {
+							// The session is full.
+							return;
+						}
+
+						processListeners();
+
+						// Close covered sessions (if possible).
+						closeCoveredSessions(this.sessions[normalizedOptions], session);
+					});
+
+					session.once('remoteSettings', () => {
+						// Fix Node.js bug preventing the process from exiting
+						session.ref();
+						session.unref();
+
+						this._sessionsCount++;
+
+						// The Agent could have been destroyed already.
+						if (entry.destroyed) {
+							const error = new Error('Agent has been destroyed');
+
+							for (const listener of listeners) {
+								listener.reject(error);
+							}
+
+							session.destroy();
+							return;
+						}
+
+						session[kOriginSet] = session.originSet;
+
+						{
+							const where = this.sessions;
+
+							if (normalizedOptions in where) {
+								const sessions = where[normalizedOptions];
+								sessions.splice(getSortedIndex(sessions, session, compareSessions), 0, session);
+							} else {
+								where[normalizedOptions] = [session];
+							}
+						}
+
+						this._freeSessionsCount += 1;
+						receivedSettings = true;
+
+						this.emit('session', session);
+
+						processListeners();
+						removeFromQueue();
+
+						// TODO: Close last recently used (or least used?) session
+						if (session[kCurrentStreamsCount] === 0 && this._freeSessionsCount > this.maxFreeSessions) {
+							session.close();
+						}
+
+						// Check if we haven't managed to execute all listeners.
+						if (listeners.length !== 0) {
+							// Request for a new session with predefined listeners.
+							this.getSession(normalizedOrigin, options, listeners);
+							listeners.length = 0;
+						}
+
+						// `session.remoteSettings.maxConcurrentStreams` might get increased
+						session.on('remoteSettings', () => {
+							processListeners();
+
+							// In case the Origin Set changes
+							closeCoveredSessions(this.sessions[normalizedOptions], session);
+						});
+					});
+
+					// Shim `session.request()` in order to catch all streams
+					session[kRequest] = session.request;
+					session.request = (headers, streamOptions) => {
+						if (session[kGracefullyClosing]) {
+							throw new Error('The session is gracefully closing. No new streams are allowed.');
+						}
+
+						const stream = session[kRequest](headers, streamOptions);
+
+						// The process won't exit until the session is closed or all requests are gone.
+						session.ref();
+
+						++session[kCurrentStreamsCount];
+
+						if (session[kCurrentStreamsCount] === session.remoteSettings.maxConcurrentStreams) {
+							this._freeSessionsCount--;
+						}
+
+						stream.once('close', () => {
+							wasFree = isFree();
+
+							--session[kCurrentStreamsCount];
+
+							if (!session.destroyed && !session.closed) {
+								closeSessionIfCovered(this.sessions[normalizedOptions], session);
+
+								if (isFree() && !session.closed) {
+									if (!wasFree) {
+										this._freeSessionsCount++;
+
+										wasFree = true;
+									}
+
+									const isEmpty = session[kCurrentStreamsCount] === 0;
+
+									if (isEmpty) {
+										session.unref();
+									}
+
+									if (
+										isEmpty &&
+										(
+											this._freeSessionsCount > this.maxFreeSessions ||
+											session[kGracefullyClosing]
+										)
+									) {
+										session.close();
+									} else {
+										closeCoveredSessions(this.sessions[normalizedOptions], session);
+										processListeners();
+									}
+								}
+							}
+						});
+
+						return stream;
+					};
+				} catch (error) {
+					for (const listener of listeners) {
+						listener.reject(error);
+					}
+
+					removeFromQueue();
+				}
+			};
+
+			entry.listeners = listeners;
+			entry.completed = false;
+			entry.destroyed = false;
+
+			this.queue[normalizedOptions][normalizedOrigin] = entry;
+			this._tryToCreateNewSession(normalizedOptions, normalizedOrigin);
+		});
+	}
+
+	request(origin, options, headers, streamOptions) {
+		return new Promise((resolve, reject) => {
+			this.getSession(origin, options, [{
+				reject,
+				resolve: session => {
+					try {
+						resolve(session.request(headers, streamOptions));
+					} catch (error) {
+						reject(error);
+					}
+				}
+			}]);
+		});
+	}
+
+	createConnection(origin, options) {
+		return Agent.connect(origin, options);
+	}
+
+	static connect(origin, options) {
+		options.ALPNProtocols = ['h2'];
+
+		const port = origin.port || 443;
+		const host = origin.hostname || origin.host;
+
+		if (typeof options.servername === 'undefined') {
+			options.servername = host;
+		}
+
+		return tls.connect(port, host, options);
+	}
+
+	closeFreeSessions() {
+		for (const sessions of Object.values(this.sessions)) {
+			for (const session of sessions) {
+				if (session[kCurrentStreamsCount] === 0) {
+					session.close();
+				}
+			}
+		}
+	}
+
+	destroy(reason) {
+		for (const sessions of Object.values(this.sessions)) {
+			for (const session of sessions) {
+				session.destroy(reason);
+			}
+		}
+
+		for (const entriesOfAuthority of Object.values(this.queue)) {
+			for (const entry of Object.values(entriesOfAuthority)) {
+				entry.destroyed = true;
+			}
+		}
+
+		// New requests should NOT attach to destroyed sessions
+		this.queue = {};
+	}
+
+	get freeSessions() {
+		return getSessions({agent: this, isFree: true});
+	}
+
+	get busySessions() {
+		return getSessions({agent: this, isFree: false});
+	}
+}
+
+Agent.kCurrentStreamsCount = kCurrentStreamsCount;
+Agent.kGracefullyClosing = kGracefullyClosing;
+
+module.exports = {
+	Agent,
+	globalAgent: new Agent()
+};