Javascript Client

The deepstream JavaScript client can be used by both browsers and Node.js. You can get it via NPM or Bower as @deepstream/client or browse the source on Github

deepstream(url, options)

Argument Type Optional Description
url String false The server URL
options Object true A map of options. Please find a list of available options here

Creates a client instance and initialises the connection to the deepstream server. The connection will be kept in a quarantine state and won’t be fully usable until login() is called.

const { DeepstreamClient } = require('@deepstream/client')
const client = new DeepstreamClient('localhost:6020')
client.login()

Constants

  • deepstream.CONSTANTS grants access to constants. See constants for a full list
  • deepstream.MERGE_STRATEGIES grants access to the default merge strategies used globally as mergeStrategy client option or per record with record.mergeStrategy()

Events

connectionStateChanged

Emitted every time the connectionstate changes. The connectionState is passed to the callback and can also be retrieved using getConnectionState(). A list of possible connection states is available here

error

Aggregates all errors that are encountered. Some errors like CONNECTION_ERROR or MESSAGE_PARSE_ERROR are exlusively emitted by the client. Others like ACK_TIMEOUT or VERSION_EXISTS that relate to a specific Record, Event or RPC are emitted first by the object they relate to and are then forwarded to the client. You can find a list of all errors here.

client.on('error', ( error, event, topic ) =>
  console.log(error, event, topic);
)

Methods

login(authParams, callback)

Argument Type Optional Description
authParams Object false An object with authentication parameters
callback Function true A function that will be called once the response to the authentication request is received.

Authenticates the client against the server. To learn more about how authentication works, please have a look at the Security Overview.

Callback will be called with: success (Boolean), data (Object).

const { DeepstreamClient } = require('@deepstream/client')
const client = new DeepstreamClient('localhost:6020')
// client.getConnectionState() will now return 'AWAITING_AUTHENTICATION'

client.login({username: 'peter', password: 'sesame'}, (success, data) => {
  if (success) {
    // start application
    // client.getConnectionState() will now return 'OPEN'
  } else {
    // extra data can be optionaly sent from deepstream for
    // both successful and unsuccesful logins
    alert(data)

    // client.getConnectionState() will now return
    // 'AWAITING_AUTHENTICATION' or 'CLOSED'
    // if the maximum number of authentication
    // attempts has been exceeded.
  }
})

// client.getConnectionState() will now return 'AUTHENTICATING'

close()

Closes the connection to the server.

client.on('connectionStateChanged', connectionState => {
  // will be called with 'CLOSED' once the connection is successfully closed.
})

client.close()

getConnectionState()

Returns the current connectionState. Please find a list of available connectionStates here.

getUid()

Returnes a unique id. The uid starts with a Base64 encoded timestamp to allow for semi-sequentual ordering and ends with a random string.

client.getUid() // 'i9i6db5q-1xak1s2sfzk'