maeva-sockets

Client/server web sockets API to connect any database via maeva

Why

Even when you have a database server set up, you need a relay server (HTTP or Web Sockets) so that your client can connect to the database server. maeva-sockets gives a framework so you can easily create a server your client can talk to to transport database queries.

Server

It is easy to set up a server. Let's say you want to set up a server that can transport queries to a MongoDB server:

import sockets from 'maeva-sockets/server';
import mongodb from 'maeva-mongodb';

const WS_URL = 'ws://localhost:9999'; // Web sockets server URL
const DB_URL = 'mongodb://localhost:7777'; // Database URL

sockets
  .start(WS_URL, {connector: () => mongodb(DB_URL, {keepAlive: 5000})})
  .on('error', error => console.log(error));

Client

import * as data from 'maeva';
import sockets from 'maeva-sockets/client';

// Define your data model
const userModel = data.model('users', {name: String});

// Connect to sockets server
data.connect(sockets('ws://localhost:9999', {keepAlive: 3000}));

// Now you can call any queries
const users = await data.findMany(userModel);

Server methods

sockets.start(url: string, options: ServerOptions) => EventEmitter
sockets.start(options: ServerOptions) => EventEmitter

// Close server
const server = sockets.start('ws://localhost:9999');
server.emit('close');

// Off helper
server.off('event', fn) === server.removeListener('event', fn);

Server options

• port: number
• host: string
• path: string

Server events

• closed Web sockets server down
• connected Web sockets server successfully connected to database
• disconnected Web sockets server lost connection to database
• error Web sockets server had an error
• incoming New web socket client
• listening Web sockets server started
• outcoming Web socket sent a message to client
• response Web socket server got response from DB

Client

sockets(url: string, options: ClientOptions);

Client options

• debug: boolean
• keepAlive: number

When the sockets server is up, but the connection to database is down, client will receive an error that has code DISCONNECTED_FROM_DB.

const client = data.connect(sockets('ws://localhost:8080'));
client.emitter.on('error', (error) => {
  if (error.code === 'DISCONNECTED_FROM_DB') {
    console.log('server lost connection to db');
  }
})