Files
hpcore/examples/js_client/hp-client-lib.js
2020-12-21 11:56:04 +05:30

737 lines
27 KiB
JavaScript

(() => {
// Whether we are in Browser or NodeJs.
const isBrowser = !(typeof window === 'undefined');
// In browser, avoid duplicate initializations.
if (isBrowser && window.HotPocket)
return;
const supportedHpVersion = "0.0";
const serverChallengeSize = 16;
const connectionCheckIntervalMs = 1000;
const recentActivityThresholdMs = 3000;
// External dependency references.
let WebSocket = null;
let sodium = null;
let bson = null;
/*--- Included in public interface. ---*/
const protocols = {
json: "json",
bson: "bson" // (Requires nodejs or browserified hp client library on Browser)
}
Object.freeze(protocols);
/*--- Included in public interface. ---*/
const events = {
disconnect: "disconnect",
contractOutput: "contractOutput",
contractReadResponse: "contractReadResponse",
connectionChange: "connectionChange"
}
Object.freeze(events);
/*--- Included in public interface. ---*/
const generateKeys = async (privateKeyHex = null) => {
await initSodium();
if (!privateKeyHex) {
const keys = sodium.crypto_sign_keypair();
return {
privateKey: keys.privateKey,
publicKey: keys.publicKey
}
}
else {
const binPrivateKey = hexToUint8Array(privateKeyHex);
return {
privateKey: Uint8Array.from(binPrivateKey),
publicKey: Uint8Array.from(binPrivateKey.slice(32))
}
}
}
/*--- Included in public interface. ---*/
const createClient = async (servers, clientKeys, options) => {
const defaultOptions = {
contractId: null,
contractVersion: null,
validServerKeys: null,
protocol: protocols.json,
requiredConnectionCount: 1,
connectionTimeoutMs: 5000
};
const opt = options ? { ...defaultOptions, ...options } : defaultOptions;
if (!clientKeys)
throw "clientKeys not specified.";
if (opt.contractId == "")
throw "contractId not specified. Specify null to bypass contract id validation.";
if (opt.contractVersion == "")
throw "contractVersion not specified. Specify null to bypass contract version validation.";
if (!opt.protocol || (opt.protocol != protocols.json && opt.protocol != protocols.bson))
throw "Valid protocol not specified.";
if (!opt.requiredConnectionCount || opt.requiredConnectionCount == 0)
throw "requiredConnectionCount must be greater than 0.";
if (!opt.connectionTimeoutMs || opt.connectionTimeoutMs == 0)
throw "Connection timeout must be greater than 0.";
await initSodium();
initWebSocket();
if (opt.protocol == protocols.bson)
initBson();
// Load servers and serverKeys to object keys to avoid duplicates.
const serversLookup = {};
servers && servers.forEach(s => {
const url = s.trim();
if (url.length > 0)
serversLookup[url] = true
});
if (Object.keys(serversLookup).length == 0)
throw "servers not specified.";
if (opt.requiredConnectionCount > Object.keys(serversLookup).length)
throw "requiredConnectionCount is higher than no. of servers.";
let serverKeysLookup = null;
if (opt.validServerKeys) {
serverKeysLookup = {};
opt.validServerKeys.forEach(k => {
const key = k.trim();
if (key.length > 0)
serverKeysLookup[key] = true
});
}
if (serverKeysLookup && Object.keys(serverKeysLookup).length == 0)
throw "serverKeys must contain at least one key. Specify null to bypass key validation.";
return new HotPocketClient(opt.contractId, opt.contractVersion, clientKeys, serversLookup, serverKeysLookup, opt.protocol, opt.requiredConnectionCount, opt.connectionTimeoutMs);
}
function HotPocketClient(contractId, contractVersion, clientKeys, serversLookup, serverKeysLookup, protocol, requiredConnectionCount, connectionTimeoutMs) {
let emitter = new EventEmitter();
const nodes = Object.keys(serversLookup).map(s => {
return {
server: s, // Server address.
connection: null, // Hot Pocket connection (if any).
lastActivity: 0 // Last connection activity timestamp.
}
});
let status = 0; //0:none, 1:connected, 2:closed
// This will get fired whenever the required connection count gets fullfilled.
let initialConnectSuccess = null;
// Tracks when was the earliest time that we were missing some required connections.
// 0 indicates we are no missing any connections.
let connectionsMissingFrom = new Date().getTime();
// Checks for missing connections and attempts to establish them.
const reviewConnections = () => {
if (status == 2)
return;
// Check for connection changes periodically.
setTimeout(() => {
reviewConnections();
}, connectionCheckIntervalMs);
// Check whether we have fullfilled all required connections.
if (nodes.filter(n => n.connection && n.connection.isConnected()).length == requiredConnectionCount) {
connectionsMissingFrom = 0;
initialConnectSuccess && initialConnectSuccess(true);
initialConnectSuccess = null;
status = 1;
return;
}
if (connectionsMissingFrom == 0) {
// Reaching here means we moved from connections-fullfilled state to missing-connections state.
connectionsMissingFrom = new Date().getTime();
}
else if ((new Date().getTime() - connectionsMissingFrom) > connectionTimeoutMs) {
// This means we were not able to maintain required connection count for the entire timeout period.
console.log("Missing-connections timeout reached.");
// Close and cleanup all connections if we hit the timeout.
this.close().then(() => {
if (initialConnectSuccess) {
initialConnectSuccess(false);
initialConnectSuccess = null;
}
else {
emitter && emitter.emit(events.disconnect);
}
});
return;
}
// Reaching here means we should attempt to establish more connections if we have available slots.
let currentConnectionCount = nodes.filter(n => n.connection).length;
if (currentConnectionCount == requiredConnectionCount)
return;
// Find out available slots.
// Skip nodes that are already connected or is currently establishing connection.
// Skip nodes that have recently shown some connection activity.
// Give priority to nodes that have not shown any activity recently.
const freeNodes = nodes.filter(n => !n.connection && (new Date().getTime() - n.lastActivity) > recentActivityThresholdMs);
freeNodes.sort((a, b) => a.lastActivity - b.lastActivity); // Oldest activity comes first.
while (currentConnectionCount < requiredConnectionCount && freeNodes.length > 0) {
// Get the next available node.
const n = freeNodes.shift();
n.connection = new HotPocketConnection(contractId, contractVersion, clientKeys, n.server, serverKeysLookup, protocol, connectionTimeoutMs, emitter);
n.lastActivity = new Date().getTime();
n.connection.connect().then(success => {
if (!success)
n.connection = null;
else
emitter && emitter.emit(events.connectionChange, n.server, "add");
});
n.connection.onClose = () => {
n.connection = null;
emitter && emitter.emit(events.connectionChange, n.server, "remove");
};
currentConnectionCount++;
}
}
this.connect = () => {
if (status > 0)
return;
reviewConnections();
return new Promise(resolve => {
initialConnectSuccess = resolve;
})
}
this.close = async () => {
if (status == 2)
return;
status = 2;
emitter.clear(events.connectionChange);
emitter.clear(events.contractOutput);
emitter.clear(events.contractReadResponse);
// Close all nodes connections.
await Promise.all(nodes.filter(n => n.connection).map(n => n.connection.close()));
nodes.forEach(n => n.connection = null);
}
this.on = (event, listener) => {
emitter.on(event, listener);
}
this.sendContractInput = async (input, nonce = null, maxLclOffset = null) => {
if (status == 2)
return;
await Promise.all(
nodes.filter(n => n.connection && n.connection.isConnected())
.map(n => n.connection.sendContractInput(input, nonce, maxLclOffset)));
}
this.sendContractReadRequest = (request) => {
if (status == 2)
return;
nodes.filter(n => n.connection && n.connection.isConnected()).forEach(n => {
n.connection.sendContractReadRequest(request);
});
}
}
function HotPocketConnection(contractId, contractVersion, clientKeys, server, serverKeysLookup, protocol, connectionTimeoutMs, emitter) {
// Create message helper with JSON protocol initially.
// After challenge handshake, we will change this to use the protocol specified by user.
const msgHelper = new MessageHelper(clientKeys, protocols.json);
let connectionStatus = 0; // 0:none, 1:server challenge sent, 2:handshake complete.
let serverChallenge = null; // The hex challenge we have issued to the server.
let reportedContractId = null;
let reportedContractVersion = null;
let ws = null;
let handshakeTimer = null; // Timer to track connection handshake timeout.
let handshakeResolver = null;
let closeResolver = null;
let statResponseResolvers = [];
let contractInputResolvers = {};
const handshakeMessageHandler = (m) => {
if (connectionStatus == 0 && m.type == "user_challenge" && m.hp_version && m.contract_id) {
if (m.hp_version != supportedHpVersion) {
console.log(`Incompatible Hot Pocket server version. Expected:${supportedHpVersion} Got:${m.hp_version}`);
return false;
}
else if (!m.contract_id) {
console.log("Server did not specify contract id.");
return false;
}
else if (contractId && m.contract_id != contractId) {
console.log(`Contract id mismatch. Expected:${contractId} Got:${m.contract_id}`);
return false;
}
else if (!m.contract_version) {
console.log("Server did not specify contract version.");
return false;
}
else if (contractVersion && m.contract_version != contractVersion) {
console.log(`Contract version mismatch. Expected:${contractVersion} Got:${m.contract_version}`);
return false;
}
reportedContractId = m.contract_id;
reportedContractVersion = m.contract_version;
// Generate the challenge we are sending to server.
serverChallenge = uint8ArrayToHex(sodium.randombytes_buf(serverChallengeSize));
// Sign the challenge and send back the response
const response = msgHelper.createUserChallengeResponse(m.challenge, serverChallenge, protocol);
ws.send(msgHelper.serializeObject(response));
connectionStatus = 1;
return true;
}
else if (connectionStatus == 1 && serverChallenge && m.type == "server_challenge_response" && m.sig && m.pubkey) {
// If server keys has been specified, validate whether this server's pubkey is among the valid list.
if (serverKeysLookup && !serverKeysLookup[m.pubkey]) {
console.log(`${server} key '${m.pubkey}' not among the valid keys.`);
return false;
}
// Verify server challenge response.
const stringToVerify = serverChallenge + reportedContractId + reportedContractVersion;
const serverPubkeyHex = m.pubkey.substring(2); // Skip 'ed' prefix;
if (!sodium.crypto_sign_verify_detached(hexToUint8Array(m.sig), stringToVerify, hexToUint8Array(serverPubkeyHex))) {
console.log(`${server} challenge response verification failed.`);
return false;
}
clearTimeout(handshakeTimer); // Cancel the handshake timeout monitor.
handshakeTimer = null;
serverChallenge = null; // Clear the sent challenge as we no longer need it.
msgHelper.useProtocol(protocol); // Here onwards, use the message protocol specified by user.
connectionStatus = 2; // Handshake complete.
// If we are still connected, report handshaking as successful.
// (If websocket disconnects, handshakeResolver will be already null)
handshakeResolver && handshakeResolver(true);
console.log(`Connected to ${server}`);
return true;
}
console.log(`${server} invalid message during handshake. Connection status:${connectionStatus}`);
console.log(m);
return false;
}
const contractMessageHandler = (m) => {
if (m.type == "contract_read_response") {
emitter && emitter.emit(events.contractReadResponse, msgHelper.deserializeOutput(m.content));
}
else if (m.type == "contract_input_status") {
const sigKey = msgHelper.stringifySignature(m.input_sig);
const resolver = contractInputResolvers[sigKey];
if (resolver) {
if (m.status == "accepted")
resolver("ok");
else
resolver(m.reason);
delete contractInputResolvers[sigKey];
}
}
else if (m.type == "contract_output") {
emitter && emitter.emit(events.contractOutput, msgHelper.deserializeOutput(m.content));
}
else if (m.type == "stat_response") {
statResponseResolvers.forEach(resolver => {
resolver({
lcl: m.lcl,
lclSeqNo: m.lcl_seqno
});
})
statResponseResolvers = [];
}
else {
console.log("Received unrecognized contract message: type:" + m.type);
return false;
}
return true;
}
const messageHandler = async (rcvd) => {
const data = (connectionStatus < 2 || protocol == protocols.json) ?
(isBrowser ? await rcvd.data.text() : rcvd.data) :
(isBrowser ? await rcvd.data.arrayBuffer() : rcvd.data);
try {
m = msgHelper.deserializeMessage(data);
}
catch (e) {
console.log(e);
console.log("Exception deserializing: ");
console.log(data || rcvd);
// If we get invalid message during handshake, close the socket.
if (connectionStatus < 2)
this.close();
return;
}
let isValid = false;
if (connectionStatus < 2)
isValid = handshakeMessageHandler(m);
else if (connectionStatus == 2)
isValid = contractMessageHandler(m);
if (!isValid) {
// If we get invalid message during handshake, close the socket.
if (connectionStatus < 2)
this.close();
}
}
const openHandler = () => {
ws.addEventListener("message", messageHandler);
ws.addEventListener("close", closeHandler);
handshakeTimer = setTimeout(() => {
// If handshake does not complete within timeout, close the connection.
this.close();
handshakeTimer = null;
}, connectionTimeoutMs);
}
const closeHandler = () => {
if (closeResolver)
console.log("Closing connection to " + server);
else
console.log("Disconnected from " + server);
emitter = null;
if (handshakeTimer)
clearTimeout(handshakeTimer);
// If there are any ongoing resolvers resolve them with error output.
handshakeResolver && handshakeResolver(false);
handshakeResolver = null;
statResponseResolvers.forEach(resolver => resolver(null));
statResponseResolvers = [];
Object.values(contractInputResolvers).forEach(resolver => resolver(null));
contractInputResolvers = {};
this.onClose && this.onClose();
closeResolver && closeResolver();
}
const errorHandler = (e) => {
handshakeResolver && handshakeResolver(false);
}
this.isConnected = () => {
return connectionStatus == 2;
};
this.connect = () => {
console.log("Connecting to " + server);
return new Promise(resolve => {
ws = isBrowser ? new WebSocket(server) : new WebSocket(server, { rejectUnauthorized: false });
handshakeResolver = resolve;
ws.addEventListener("error", errorHandler);
ws.addEventListener("open", openHandler);
});
}
this.close = () => {
if (ws.readyState == WebSocket.OPEN) {
return new Promise(resolve => {
closeResolver = resolve;
ws.close();
});
}
else {
return Promise.resolve();
}
}
this.getStatus = () => {
if (connectionStatus != 2)
return Promise.resolve(null);
const p = new Promise(resolve => {
statResponseResolvers.push(resolve);
});
// If this is the only awaiting stat request, then send an actual stat request.
// Otherwise simply wait for the previously sent request.
if (statResponseResolvers.length == 1) {
const msg = msgHelper.createStatusRequest();
ws.send(msgHelper.serializeObject(msg));
}
return p;
}
this.sendContractInput = async (input, nonce = null, maxLclOffset = null) => {
if (connectionStatus != 2)
return null;
if (!maxLclOffset)
maxLclOffset = 10;
if (!nonce)
nonce = (new Date()).getTime().toString();
else
nonce = nonce.toString();
// Acquire the current lcl and add the specified offset.
const stat = await this.getStatus();
if (!stat)
return new Promise(resolve => resolve("ledger_status_error"));
const maxLclSeqNo = stat.lclSeqNo + maxLclOffset;
const msg = msgHelper.createContractInput(input, nonce, maxLclSeqNo);
const sigKey = msgHelper.stringifySignature(msg.sig);
const p = new Promise(resolve => {
contractInputResolvers[sigKey] = resolve;
});
ws.send(msgHelper.serializeObject(msg));
return p;
}
this.sendContractReadRequest = (request) => {
if (connectionStatus != 2)
return;
const msg = msgHelper.createReadRequest(request);
ws.send(msgHelper.serializeObject(msg));
}
}
function MessageHelper(keys, protocol) {
this.useProtocol = (p) => {
protocol = p;
}
this.binaryEncode = (data) => {
return protocol == protocols.json ?
uint8ArrayToHex(data) :
(Buffer.isBuffer(data) ? data : Buffer.from(data));
}
this.serializeObject = (obj) => {
return protocol == protocols.json ? JSON.stringify(obj) : bson.serialize(obj);
}
this.deserializeMessage = (m) => {
return protocol == protocols.json ? JSON.parse(m) : bson.deserialize(m);
}
this.serializeInput = (input) => {
return protocol == protocols.json ?
((typeof input === "string" || input instanceof String) ? input : input.toString()) :
(Buffer.isBuffer(input) ? input : Buffer.from(input));
}
this.deserializeOutput = (content) => {
return protocol == protocols.json ? content : content.buffer;
}
// Used for generating strings to hold signature as js object keys.
this.stringifySignature = (sig) => {
if (typeof sig === 'string' || sig instanceof String)
return sig;
else if (sig instanceof Uint8Array)
return uint8ArrayToHex(sig);
else if (sig.buffer) // BSON binary.
return uint8ArrayToHex(new Uint8Array(sig.buffer));
else
throw "Cannot stringify signature.";
}
this.createUserChallengeResponse = (userChallenge, serverChallenge, msgProtocol) => {
// For challenge response encoding Hot Pocket always uses json.
// Challenge response will specify the protocol to use for contract messages.
const sigBytes = sodium.crypto_sign_detached(userChallenge, keys.privateKey);
return {
type: "user_challenge_response",
sig: this.binaryEncode(sigBytes),
pubkey: "ed" + this.binaryEncode(keys.publicKey),
server_challenge: serverChallenge,
protocol: msgProtocol
}
}
this.createContractInput = (input, nonce, maxLclSeqNo) => {
if (input.length == 0)
return null;
const inpContainer = {
input: this.serializeInput(input),
nonce: nonce,
max_lcl_seqno: maxLclSeqNo
}
const serlializedInpContainer = this.serializeObject(inpContainer);
const sigBytes = sodium.crypto_sign_detached(serlializedInpContainer, keys.privateKey);
const signedInpContainer = {
type: "contract_input",
input_container: serlializedInpContainer,
sig: this.binaryEncode(sigBytes)
}
return signedInpContainer;
}
this.createReadRequest = (request) => {
if (request.length == 0)
return null;
return {
type: "contract_read_request",
content: this.serializeInput(request)
}
}
this.createStatusRequest = () => {
return { type: "stat" };
}
}
function hexToUint8Array(hexString) {
return new Uint8Array(hexString.match(/.{1,2}/g).map(byte => parseInt(byte, 16)));
}
function uint8ArrayToHex(bytes) {
return bytes.reduce((str, byte) => str + byte.toString(16).padStart(2, "0"), "");
}
function EventEmitter() {
const registrations = {};
this.on = (eventName, listener) => {
if (!registrations[eventName])
registrations[eventName] = [];
registrations[eventName].push(listener);
}
this.emit = (eventName, ...value) => {
if (registrations[eventName])
registrations[eventName].forEach(listener => listener(...value));
}
this.clear = (eventName) => {
if (eventName)
delete registrations[eventName]
else
Object.keys(registrations).forEach(k => delete registrations[k]);
}
}
// Set sodium reference.
async function initSodium() {
if (sodium) { // If already set, do nothing.
return;
}
else if (isBrowser && window.sodium) { // browser (if sodium already loaded)
sodium = window.sodium;
}
else if (isBrowser && !window.sodium) { // If sodium not yet loaded in browser, wait for sodium ready.
await new Promise(resolve => {
window.sodium = {
onload: async function (sodiumRef) {
sodium = sodiumRef;
resolve();
}
}
})
}
else if (!isBrowser) { // nodejs
sodium = require('libsodium-wrappers');
await sodium.ready;
}
else {
throw "Sodium reference not found. Please include sodium js lib in browser scripts.";
}
}
// Set bson reference.
function initBson() {
if (bson) // If already set, do nothing.
return;
else if (isBrowser && window.BSON) // browser
bson = window.BSON;
else if (!isBrowser) // nodejs
bson = require('bson');
else
throw "BSON reference not found.";
}
// Set WebSocket reference.
function initWebSocket() {
if (WebSocket) // If already set, do nothing.
return;
else if (isBrowser && window.WebSocket) // browser
WebSocket = window.WebSocket;
else if (!isBrowser) // nodejs
WebSocket = require('ws');
else
throw "WebSocket reference not found.";
}
const hotPocketLib = {
generateKeys,
createClient,
events,
protocols
}
if (isBrowser)
window.HotPocket = hotPocketLib;
else
module.exports = hotPocketLib;
})();