happner-client

happner-client

The client for happner-2 and happner cluster services.

npm install happner-client

Usage

Create client instance.

var HappnerClient = require('happner-client');
var client = new HappnerClient({
  requestTimeout: 10 * 1000, // (default) milliseconds timeout on api request (set ack)
  responseTimeout: 20 * 1000, // (default) timeout awaiting response
  logger: null // (defualt) optional happner-logger
});

Connect

var optionalInfo = {
  // meta data for login
  ///////////////////// in $origin
}
client.connect(
  { // connection
    host: 'localhost',
    port: 55000
  },
  { // options
    protocol: 'https',
  	username: '_ADMIN',
    password: 'happn',
    allowSelfSignedCerts: true,
    info: {}
  }
).then(...).catch(...); // also supports callback


// connection can be defaulted (eg. in browser)
client.connect(null, {username: '_ADMIN', password: 'happn'}, function (e) {
})

Create and connect

the simpler way: (v12.6 onwards)

const client = await HappnerClient.create({
  host: 'localhost',
  port: 55000,
  username: '_ADMIN',
  password: 'xxx'
});

Login with token and logout

it is possible to connect with another clients token, the call to .logout() will invalidate your connection token, and disconnect all clients that have used it to login with:

const connectionOptions = {
  host: 'localhost',
  port: 55000,
  username: '_ADMIN',
};
const client = await HappnerClient.create({ ...connectionOptions, password: 'xxx' });
let token = client.dataClient().session.token;
let otherClient = await HappnerClient.create({ ...connectionOptions, token });
test.expect(otherClient.dataClient().status).to.be(1); // status 1 is connected
await client.logout();
await test.delay(2e3); // wait a second
test.expect(otherClient.dataClient().status).to.be(2); // status 2 is disconnected

Events

client.on('connected', function () {
  // event fired on successful connection to server
});

client.on('reconnected', function () {
  // event fired on successful reconnection to server
});

client.on('disconnected', function () {
  // event fired when disconnected from server
});

client.on('reconnecting', function () {
  // event fired when attempting to reconnect
});

client.on('error', function (e) {
  // includes model verification mismatches
});

Construct your API

var kitchenModel = {
  fridge: {
    version: '^1.0.0', // requires that server has matching version of fridge component
    methods: {
      getTemperature: {
        // optional parameters for clientside validation
        params: [
          {name: 'shelves', type: 'array'}
        ]
      }
    }
  }
};

var kitchen = client.construct(kitchenModel);

Use API functions

// with callback
kitchen.exchange.fridge.getTemperature(['top', 'middle'], function (e, temps) {});

// with promise
kitchen.exchange.fridge.getTemperature(['top', 'middle'])
	.then(function (temps) {})
	.catch(function (e) {})

Listen to API events

kitchen.event.fridge.on('/eventName', function (data) {});

Discover component methods

NB: this will only work if you connect before you construct

//initialize the client with discover Methods true
const client = new HappnerClient({ discoverMethods: true });

//set up your model, declaring which components you wish to discover
var model = {
  component1: {
    version: '^1.0.0'
    //no need for method declarations
  },
  component2: {
    version: '^1.0.0'
    //no need for method declarations
  }
};
//on connection the remote mesh schema will be pulled
await client.connect(null, {
  username: '_ADMIN',
  password: 'xxx'
});
//on construct the components in the model will be updated with the available methods
const createdApi = createdClient.construct(model);
await createdApi.component1.discoveredMethod();

Access happn data points directly, via the dataClient

//assuming we have connected
//var client = new HappnerClient(...
//client.connect(...
var dataClient = client.dataClient();

//dataClient is the underlying happn-3 client for the happner-client connection, so you have all the happn-3 goodness:
dataClient.on('/test/point', function(data){

}).then(...);

dataClient.set('/test/point', {my: 'data'}).then(...)

dataClient.get('/test/point').then(...)

dataClient.remove('/test/point').then(...)

see this test for a full demonstration

Browser usage

Assuming served from happner-2 packaged /api/client script

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>

  <!-- includes Happner.HappnerClient -->
  <script src="/api/client"></script>

  </head>
<body>

  <script>

    var client = new Happner.HappnerClient({
      requestTimeout: 10 * 1000,
      responseTimeout: 20 * 1000
    });

    var model = {
      'component': {
        version: '^2.0.0',
        methods: {
          method1: {}
        }
      }
    };

    var api = client.construct(model);

    client.connect()

      .then(function () {
        // subscribe to events (requires connected)
        api.event.component.on('test/event', function (data, meta) {
          console.log('EVENT', meta.path);
        });
      })

      .catch(function (error) {
        console.error('connection error', error);
      });

    // repeat call on exchange
    setInterval(function () {

      api.exchange.component.method1()
        .then(function (reply) {
          console.log('REPLY', reply);
        })
        .catch(function (error) {
          console.error('ERROR', error);
        });

    }, 1000);

  </script>

</body>
</html>

happn-client lite

this version of the client does not require the construction of the expected API, the calls are transactional with a the same payload structure

connect, login with a token, call a method, listen to an event and finally logout

const LightClient = require('happner-client').Light;
const Happner = require('happner-2');
const DOMAIN = 'DOMAIN_NAME';

const serverInstance = await Happner.create({
  domain: DOMAIN,
  happn: {
    secure: true,
    adminPassword: 'xxx',
  },
  modules: {
    remoteComponent: {
      instance: {
        remoteMethod: async (arg1, arg2, $happn) => {
          $happn.emit(`remoteEvents/1`, { arg1, arg2 });
          return `${arg1}/${arg2}`;
        },
      },
    },
  },
  components: {
    remoteComponent: {},
  },
});

const connectionOptions = {
  host: 'localhost',
  port: 55000,
  username: '_ADMIN',
  domain: DOMAIN, // the domain of the cluster or the name of the happner mesh you are connecting to
};

const myClient = await LightClient.create({ ...connectionOptions, password: 'xxx' });

// call a remote method like so, will throw a not implemented error if the remote component or method does not exist:
const result = await myClient.exchange.$call({
  component: 'remoteComponent',
  method: 'remoteMethod',
  arguments: ['arg1', 'arg2'],
});

// eslint-disable-next-line no-console
console.log(result);

// listen for an event every time it happens
const onEventId = await myClient.event.$on(
  { component: 'remoteComponent', path: 'remoteEvents/*' },
  function (eventData) {
    // our handler does something with the event data
    // eslint-disable-next-line no-console
    console.log('$on:' + JSON.stringify(eventData));
  }
);

// unlisten by event handle
await myClient.event.$off(onEventId);

// or unlisten by component and path
await myClient.event.$offPath({ component: 'remoteComponent', path: 'remoteEvents/*' });

// listen for an event once only, does equivalent of $off after the event is handled
await myClient.event.$once(
  { component: 'remoteComponent', path: 'remoteEvents/*' },
  function (eventData) {
    // our handler does something with the event data
    // eslint-disable-next-line no-console
    console.log('$once:' + JSON.stringify(eventData));
  }
);

// call again for our once to kick in
await myClient.exchange.$call({
  component: 'remoteComponent',
  method: 'remoteMethod',
  arguments: ['arg1', 'arg2'],
});

// call yet again - ensure once only fired once
await myClient.exchange.$call({
  component: 'remoteComponent',
  method: 'remoteMethod',
  arguments: ['arg1', 'arg2'],
});

// grab our session token
let token = myClient.dataClient().session.token;
// create a new session off the token
let myOtherClient = await LightClient.create({ ...connectionOptions, token });
// eslint-disable-next-line no-console
console.log(`status === 1: ${myOtherClient.dataClient().status === 1}`);

// parent client logout
await myClient.logout();
// possible need for delay...then:
// eslint-disable-next-line no-console
console.log(`status === 2: ${myOtherClient.dataClient().status === 2}`); // child myOtherClient disconnected, as it was authenticated via parent myClient's token
serverInstance.stop();