clickhouse-client for NodeJS

ClickHouse® is an open-source, high performance columnar OLAP database management system for real-time analytics using SQL. ClickHouse combined with TypeScript helps you develop better type safety with your ClickHouse queries, giving you end-to-end typing.

Installation

Install the following package:

$ npm i --save @depyronick/clickhouse-client

Quick Start

• Importing the module
• Methods
  • Query
    • ClickHouseClient.query<T>(query: string): Observable<string | T>
    • ClickHouseClient.queryPromise<T>(query: string): Promise<string | T[]>
  • Query with parameters
    • ClickHouseClient.query<T>(query: string, params: Record<string, string | number>): Observable<string | T>
    • ClickHouseClient.queryPromise<T>(query: string, params: Record<string, string | number>): Promise<string | T[]>
  • Insert
    • ClickHouseClient.insert<T>(table: string, data: T[]): Observable<void>
    • ClickHouseClient.insertPromise<T>(table: string, data: T[]): Promise<void>
  • Other
    • ClickHouseClient.ping(timeout: number = 3000): Promise<boolean>
• Notes

Importing the module

Once the installation process is complete, you can import the ClickHouseClient

const { ClickHouseClient } = require('@depyronick/clickhouse-client');

// or:
// import { ClickHouseClient } from '@depyronick/clickhouse-client';

const analyticsServer = new ClickHouseClient({
  host: '127.0.0.1',
  password: '7h3ul71m473p4555w0rd'
});

// you can create multiple clients
const chatServer = new ClickHouseClient({
  host: '127.0.0.2',
  password: '7h3ul71m473p4555w0rd'
});

new ClickHouseClient(options: ClickHouseOptions) will create a ClickHouse client with the specified connection options.

See ClickHouseOptions object for more information.

Methods

Query

ClickHouseClient.query<T>(query: string): Observable<string | T>

this.analyticsServer.query('SELECT * FROM visits LIMIT 10').subscribe({
  error: (err) => {
    // called when an error occurred during query
  },
  next: (row) => {
    // if specified format is any of JSON formats, `row` here is the json representation of the row
    // if format is not any of JSON, then `row` represents string chunk from http stream
  },
  complete: () => {
    // called when stream is completed
  }
});

ClickHouseClient.queryPromise<T>(query: string): Promise<string | T[]>

this.analyticsServer
  .queryPromise('SELECT * FROM visits LIMIT 10')
  .then((rows) => {
    // if specified format is any of JSON formats, rows is an array of all retrieved rows
    // if not, then rows is the raw string result from clickhouse-server
  })
  .catch((err) => {
    // called when an error occurred during query
  });

// or

const rows = await this.analyticsServer.queryPromise(
  'SELECT * FROM visits LIMIT 10'
);

Query with params

Clickhouse-server supports performing queries with paramaters. Both query and queryPromise accept a second argument which respresents the query paramaters value as a Record<string, string | number>.

The query can contain parameters placeholders that have the following syntax:

{<name>:<data type>}
-- a parameter called "limit" that will be interpreted as an 8-bit unsigned integer
{limit:UInt8}

So, you can pass parameters as the following:

SELECT * FROM visits LIMIT {limit:UInt8}

Official documentation (HTTP Interface - Query with paramters)

ClickHouseClient.query<T>(query: string, params: Record<string, string | number>): Observable<string | T>

const yersterday = new Date();
yesterday.setDate(yesterday.getDate() - 1);

const params = {
  yesterday: yesterday.getTime(),
  osName: 'OSX'
};

const query =
  'SELECT * FROM visits WHERE timestamp >= {yesterday:DateTime} AND os = {osName:String} LIMIT 10';

this.analyticsServer.query(query, params).subscribe({
  error: (err) => {
    // called when an error occurred during query
  },
  next: (row) => {
    // if specified format is any of JSON formats, `row` here is the json representation of the row
    // if format is not any of JSON, then `row` represents string chunk from http stream
  },
  complete: () => {
    // called when stream is completed
  }
});

ClickHouseClient.queryPromise<T>(query: string, params: Record<string, string | number>): Promise<string | T[]>

const yersterday = new Date();
yesterday.setDate(yesterday.getDate() - 1);

const params = {
  yesterday: yesterday.getTime(),
  osName: 'OSX'
};

const query =
  'SELECT * FROM visits WHERE timestamp >= {yesterday:DateTime} AND os = {osName:String} LIMIT 10';

this.analyticsServer
  .queryPromise(query, params)
  .then((rows) => {
    // if specified format is any of JSON formats, rows is an array of all retrieved rows
    // if not, then rows is the raw string result from clickhouse-server
  })
  .catch((err) => {
    // called when an error occurred during query
  });

// or

const rows = await this.analyticsServer.queryPromise(query, params);

Insert

ClickHouseClient.insert<T>(table: string, data: T[]): Observable<void>

The insert method accepts two inputs.

• table is the name of the table that you'll be inserting data to.
  • Table value could be prefixed with database like analytics_db.visits.
• data: T[] array of JSON objects to insert.

analyticsServer
  .insert('visits', [
    {
      timestamp: new Date().getTime(),
      ip: '127.0.0.1',
      os: 'OSX',
      userAgent:
        'Mozilla/5.0 (Windows NT 10.0; Win64; x64) Chrome/95.0.4638.69 Safari/537.36',
      version: '1.0.0'
    }
  ])
  .subscribe({
    error: (err) => {
      // called when an error occurred during insert
    },
    next: () => {
      // currently next does not emits anything for inserts
    },
    complete: () => {
      // called when insert is completed
    }
  });

ClickHouseClient.insertPromise<T>(table: string, data: T[]): Promise<void>

The insertPromise method accepts the same inputs as insert but returns a Promise, instead of Observable.

analyticsServer
  .insertPromise('visits', [
    {
      timestamp: new Date().getTime(),
      ip: '127.0.0.1',
      os: 'OSX',
      userAgent:
        'Mozilla/5.0 (Windows NT 10.0; Win64; x64) Chrome/95.0.4638.69 Safari/537.36',
      version: '1.0.0'
    }
  ])
  .then(() => {
    // insert was success
  })
  .catch((err) => {
    // called when an error occurred during insert
  });

Other

ClickHouseClient.ping(timeout: number = 3000): Promise<boolean>

The ping method accepts one input.

• timeout is the time in milliseconds to wait for the server to send ping response Ok.\n.

// if you're using async/await
const ping = await analyticsServer.ping();

// or

analyticsServer
  .then((pingResult) => {
    // ping result is a boolean
    // it will return `true` if we were able to receive `Ok.\n`
    // and `false` if anything but `Ok.\n`
  })
  .catch((reason) => {
    // reason is the full response of the error
    // see more details at https://axios-http.com/docs/handling_errors
  });

Notes

• This repository will be actively maintained and improved.
• Planning to implement TCP protocol, if ClickHouse decides to documentate it.
• Planning to implement inserts with streams.
• This library supports http response compressions such as brotli, gzip and deflate.

Stay in touch

• Author - Ali Demirci

License

MIT licensed.