The client requires Node.js v16 or newer version.
npm i -s @questdb/nodejs-clientDetailed description of the client's configuration options can be found in the SenderOptions documentation.
The examples below demonstrate how to use the client.
For more details, please, check the Sender's documentation.
const { Sender } = require('@questdb/nodejs-client');
async function run() {
// create a sender using HTTP protocol
const sender = Sender.fromConfig('http::addr=localhost:9000');
// add rows to the buffer of the sender
await sender.table('prices').symbol('instrument', 'EURUSD')
.floatColumn('bid', 1.0195).floatColumn('ask', 1.0221)
.at(Date.now(), 'ms');
await sender.table('prices').symbol('instrument', 'GBPUSD')
.floatColumn('bid', 1.2076).floatColumn('ask', 1.2082)
.at(Date.now(), 'ms');
// flush the buffer of the sender, sending the data to QuestDB
// the buffer is cleared after the data is sent, and the sender is ready to accept new data
await sender.flush();
// add rows to the buffer again, and send it to the server
await sender.table('prices').symbol('instrument', 'EURUSD')
.floatColumn('bid', 1.0197).floatColumn('ask', 1.0224)
.at(Date.now(), 'ms');
await sender.flush();
// close the connection after all rows ingested
await sender.close();
}
run()
.then(console.log)
.catch(console.error);const { Sender } = require('@questdb/nodejs-client');
async function run() {
// create a sender using HTTPS protocol with username and password authentication
const sender = Sender.fromConfig('https::addr=localhost:9000;username=user1;password=pwd');
// send the data over the authenticated and secure connection
await sender.table('prices').symbol('instrument', 'EURUSD')
.floatColumn('bid', 1.0197).floatColumn('ask', 1.0224)
.at(Date.now(), 'ms');
await sender.flush();
// close the connection after all rows ingested
await sender.close();
}
run().catch(console.error);import { Sender } from '@questdb/nodejs-client';
async function run(): Promise<number> {
// create a sender using HTTPS protocol with bearer token authentication
const sender: Sender = Sender.fromConfig('https::addr=localhost:9000;token=Xyvd3er6GF87ysaHk');
// send the data over the authenticated and secure connection
sender.table('prices').symbol('instrument', 'EURUSD')
.floatColumn('bid', 1.0197).floatColumn('ask', 1.0224).at(Date.now(), 'ms');
await sender.flush();
// close the connection after all rows ingested
await sender.close();
}
run().catch(console.error);const { Sender } = require('@questdb/nodejs-client');
const { Worker, isMainThread, parentPort, workerData } = require('worker_threads');
// fake venue
// generates random prices for a ticker for max 5 seconds, then the feed closes
function* venue(ticker) {
let end = false;
setTimeout(() => { end = true; }, rndInt(5000));
while (!end) {
yield {'ticker': ticker, 'price': Math.random()};
}
}
// market data feed simulator
// uses the fake venue to deliver price updates to the feed handler (onTick() callback)
async function subscribe(ticker, onTick) {
const feed = venue(workerData.ticker);
let tick;
while (tick = feed.next().value) {
await onTick(tick);
await sleep(rndInt(30));
}
}
async function run() {
if (isMainThread) {
const tickers = ['t1', 't2', 't3', 't4'];
// main thread to start a worker thread for each ticker
for (let ticker in tickers) {
const worker = new Worker(__filename, { workerData: { ticker: ticker } })
.on('error', (err) => { throw err; })
.on('exit', () => { console.log(`${ticker} thread exiting...`); })
.on('message', (msg) => {
console.log(`Ingested ${msg.count} prices for ticker ${msg.ticker}`);
});
}
} else {
// it is important that each worker has a dedicated sender object
// threads cannot share the sender because they would write into the same buffer
const sender = Sender.fromConfig('http::addr=localhost:9000');
// subscribe for the market data of the ticker assigned to the worker
// ingest each price update into the database using the sender
let count = 0;
await subscribe(workerData.ticker, async (tick) => {
await sender
.table('prices')
.symbol('ticker', tick.ticker)
.floatColumn('price', tick.price)
.at(Date.now(), 'ms');
await sender.flush();
count++;
});
// let the main thread know how many prices were ingested
parentPort.postMessage({'ticker': workerData.ticker, 'count': count});
// close the connection to the database
await sender.close();
}
}
function sleep(ms) {
return new Promise(resolve => setTimeout(resolve, ms));
}
function rndInt(limit) {
return Math.floor((Math.random() * limit) + 1);
}
run()
.then(console.log)
.catch(console.error);
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