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index.js
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index.js
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"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.BlockingQueue = exports.sleep = exports.isNetworkError = exports.NetworkError = exports.newContract = void 0;
const uniqueNameSet = new Set();
function newContract(uniqueName) {
if (uniqueNameSet.has(uniqueName)) {
throw new Error(`A socket-generator Contract named ${uniqueName} already exists!`);
}
uniqueNameSet.add(uniqueName);
const responseTopic = `_res_${uniqueName}`;
const requestTopic = `_req_${uniqueName}`;
function newClient(socket, timeoutMs = Number.POSITIVE_INFINITY) {
let reqId = BigInt(1);
return async function* newClientRequest(...req) {
const curReqId = (reqId++).toString(36);
const queue = new BlockingQueue();
let timeoutRef = setTimeout(() => { }, 0);
const pendingTimeout = timeoutMs < Number.MAX_SAFE_INTEGER
? new Promise((res) => {
timeoutRef = setTimeout(() => {
res(new Error(`Request timed out for ${uniqueName}`));
}, timeoutMs);
})
: new Promise(() => { });
let rejectWithDisconnect = undefined;
const disconnect = new Promise((res) => {
rejectWithDisconnect = res;
});
const disconnectHandler = () => rejectWithDisconnect(new NetworkError('Network disconnected', 'network disconnect'));
socket.on('disconnect', disconnectHandler);
const responseHandler = (chunk) => {
const unwrapped = unwrap(chunk);
const reqId = Array.isArray(unwrapped) ? unwrapped[0] : unwrapped.i;
if (reqId === curReqId) {
queue.enqueue(unwrapped);
}
};
socket.on(responseTopic, responseHandler);
function cleanup() {
socket.off(responseTopic, responseHandler);
socket.off('disconnect', disconnectHandler);
clearTimeout(timeoutRef);
}
socket.emit(requestTopic, { id: curReqId, req });
while (true) {
const pendingChunk = queue.dequeue();
const winner = await Promise.race([pendingChunk, pendingTimeout, disconnect]);
if (isNetworkError(winner)) {
cleanup();
throw winner;
}
if (isError(winner)) {
cleanup();
throw winner;
}
if (isErrorWrapper(winner)) {
cleanup();
throw new Error(winner.err);
}
const unwrappedWinner = unwrap(winner);
if (isReturnWrapper(unwrappedWinner)) {
cleanup();
return unwrappedWinner.r;
}
else {
yield unwrappedWinner[1];
}
}
};
}
function newEndpoint(responseGenerator, logger) {
const log = logger || NOOP_LOGGER;
return {
bindClient: (socket) => {
log(`Opening endpoint ${uniqueName} for ${getSocketId(socket)}`);
const requestHandler = async (request) => {
const gen = responseGenerator(...request.req);
const isGenerator = isIterResult(gen);
while (true) {
try {
const next = isGenerator ?
await gen.next() :
{ done: true, value: (await gen) };
if (socket.disconnected) {
log(`Terminating in-flight response early, ${getSocketId(socket)} disconnected`);
return;
}
if (next.done) {
const returnWrapper = {
i: request.id,
r: next.value,
};
socket.emit(responseTopic, wrapUndefinedReturn(returnWrapper));
return;
}
const yieldWrapper = [request.id, next.value];
socket.emit(responseTopic, wrapUndefinedYield(yieldWrapper));
}
catch (e) {
const errorMsg = isError(e) ? e.message : e;
const msg = errorMsg || `Unknown Endpoint error for contract '${uniqueName}'`;
const errorWrapper = {
i: request.id,
err: msg,
};
socket.emit(responseTopic, errorWrapper);
const err = isError(e) ? e : new Error(JSON.stringify(e));
log(err.message);
return;
}
}
};
socket.on(requestTopic, requestHandler);
socket.once('disconnect', () => {
log(`${getSocketId(socket)} disconnected from ${uniqueName}`);
socket.off(requestTopic, requestHandler);
});
}
};
}
return {
newClient,
newEndpoint,
};
}
exports.newContract = newContract;
function getSocketId(socket) {
if (socket['handshake']) {
return socket.handshake.address;
}
return 'remote';
}
class NetworkError extends Error {
constructor(msg, cause) {
super(msg);
this.cause = cause;
}
}
exports.NetworkError = NetworkError;
function isNetworkError(e) {
return isError(e) && ['network disconnect'].includes(e['cause']);
}
exports.isNetworkError = isNetworkError;
const NOOP_LOGGER = () => { };
async function sleep(ms) {
return new Promise((res) => {
setTimeout(() => {
res();
}, ms);
});
}
exports.sleep = sleep;
function isIterResult(obj) {
return typeof (obj) === 'object' && obj['next'] !== undefined && typeof (obj['next']) === 'function';
}
function isError(e) {
return e && typeof (e) === 'object' && e['message'] !== undefined && e['name'] !== undefined;
}
function isReturnWrapper(r) {
return typeof r === 'object' && 'r' in r;
}
function isUndefinedWrapper(u) {
return typeof u === 'object' && 'u' in u;
}
function isErrorWrapper(r) {
return typeof r === 'object' && 'err' in r;
}
function wrapUndefinedYield(toWrap) {
if (toWrap[1] === undefined) {
return {
u: toWrap
};
}
return toWrap;
}
function wrapUndefinedReturn(toWrap) {
if (toWrap.r === undefined) {
return {
u: toWrap
};
}
return toWrap;
}
function unwrap(wrapped) {
if (isErrorWrapper(wrapped)) {
return wrapped;
}
if (isUndefinedWrapper(wrapped)) {
const inner = wrapped.u;
if (Array.isArray(inner)) {
return [inner[0], undefined];
}
else {
return {
i: inner.i,
r: undefined,
};
}
}
return wrapped;
}
class BlockingQueue {
constructor() {
this.resolvers = [];
this.promises = [];
}
_push() {
this.promises.push(new Promise((resolve) => {
this.resolvers.push(resolve);
}));
}
enqueue(t) {
if (!this.resolvers.length) {
this._push();
}
const shifted = this.resolvers.shift();
shifted(t);
}
dequeue() {
if (!this.promises.length) {
this._push();
}
return this.promises.shift();
}
}
exports.BlockingQueue = BlockingQueue;
//# sourceMappingURL=index.js.map