api/docs/api-provider/classes/_ws_index_.wsprovider.md

name: WsProvider

summary: The WebSocket Provider allows sending requests using WebSocket to a WebSocket RPC server TCP port.

description: Unlike the HttpProvider, it does support subscriptions and allows listening to events such as new blocks or balance changes.

example:

import Api from '@polkadot/api';
import WsProvider from '@polkadot/api-provider/ws';

const provider = new WsProvider('ws://127.0.0.1:9944');
const api = new Api(provider);

see: HttpProvider

Type parameters

EventTypes : string | symbol

Hierarchy

EventEmitter

↳ WsProvider

Implements

• WSProviderInterface

Constructors

constructor

⊕ new WsProvider(endpoint: string, autoConnect?: boolean): WsProvider

Defined in ws/index.ts:73

Parameters:

Param	Type	Default value	Description
endpoint	string	-	The endpoint url. Usually `ws://ip:9944` or `wss://ip:9944`
Default value autoConnect	boolean	true	Whether to connect automatically or not.

Returns: WsProvider

---

Properties

<Static> prefixed

● prefixed: * string | boolean *

Inherited from EventEmitter.prefixed

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:6

---

Methods

addListener

▸ addListener(event: EventTypes, fn: ListenerFn, context?: any): this

Inherited from EventEmitter.addListener

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:33

Parameters:

Param	Type
event	EventTypes
fn	ListenerFn
Optional context	any

Returns: this

---

connect

▸ connect(): void

Defined in ws/index.ts:104

summary: Manually connect

description: The WsProvider connects automatically by default, however if you decided otherwise, you may connect manually using this method.

Returns: void

---

emit

▸ emit(event: EventTypes, ...args: Array<any>): boolean

Inherited from EventEmitter.emit

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:27

Calls each of the listeners registered for a given event.

Parameters:

Param	Type
event	EventTypes
Rest args	Array<any>

Returns: boolean

---

eventNames

▸ eventNames(): Array<EventTypes>

Inherited from EventEmitter.eventNames

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:12

Return an array listing the events for which the emitter has registered listeners.

Returns: Array<EventTypes>

---

isConnected

▸ isConnected(): boolean

Defined in ws/index.ts:121

summary: Whether the node is connected or not.

Returns: boolean true if connected

---

listenerCount

▸ listenerCount(event: EventTypes): number

Inherited from EventEmitter.listenerCount

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:22

Return the number of listeners listening to a given event.

Parameters:

Param	Type
event	EventTypes

Returns: number

---

listeners

▸ listeners(event: EventTypes): Array<ListenerFn>

Inherited from EventEmitter.listeners

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:17

Return the listeners registered for a given event.

Parameters:

Param	Type
event	EventTypes

Returns: Array<ListenerFn>

---

off

▸ off(event: EventTypes, fn?: ListenerFn, context?: any, once?: * undefined | false | true*): this

Inherited from EventEmitter.off

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:44

Parameters:

Param	Type
event	EventTypes
Optional fn	ListenerFn
Optional context	any
Optional once	undefined | false | true

Returns: this

---

on

▸ on(type: ProviderInterface$Emitted, sub: ProviderInterface$EmitCb): this

Overrides EventEmitter.on

Defined in ws/index.ts:131

summary: Listens on events after having subscribed using the subscribe function.

Parameters:

Param	Type	Description
type	ProviderInterface$Emitted	Event
sub	ProviderInterface$EmitCb	Callback

Returns: this [description]

---

once

▸ once(event: EventTypes, fn: ListenerFn, context?: any): this

Inherited from EventEmitter.once

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:38

Add a one-time listener for a given event.

Parameters:

Param	Type
event	EventTypes
fn	ListenerFn
Optional context	any

Returns: this

---

removeAllListeners

▸ removeAllListeners(event?: EventTypes): this

Inherited from EventEmitter.removeAllListeners

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:49

Remove all listeners, or those of the specified event.

Parameters:

Param	Type
Optional event	EventTypes

Returns: this

---

removeListener

▸ removeListener(event: EventTypes, fn?: ListenerFn, context?: any, once?: * undefined | false | true*): this

Inherited from EventEmitter.removeListener

Defined in /home/travis/build/polkadot-js/api/node_modules/eventemitter3/index.d.ts:43

Remove the listeners of a given event.

Parameters:

Param	Type
event	EventTypes
Optional fn	ListenerFn
Optional context	any
Optional once	undefined | false | true

Returns: this

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send

▸ send(method: string, params: Array<any>, subscription?: SubscriptionHandler): Promise<any>

Defined in ws/index.ts:138

summary: Send JSON data using WebSockets to configured HTTP Endpoint or queue.

Parameters:

Param	Type
method	string
params	Array<any>
Optional subscription	SubscriptionHandler

Returns: Promise<any>

---

subscribe

▸ subscribe(type: string, method: string, params: Array<any>, callback: ProviderInterface$Callback): Promise<number>

Defined in ws/index.ts:194

name: subscribe

summary: Allows subscribing to a specific event.

example:

const provider = new WsProvider('ws://127.0.0.1:9944');
const api = new Api(provider);

api.state.storage([[storage.balances.freeBalance, <Address>]], (_, values) => {
  console.log(values)
}).then((subscriptionId) => {
  console.log('balance changes subscription id: ', subscriptionId)
})

Parameters:

Param	Type	Description
type	string	Subscription type
method	string	Subscription method
params	Array<any>	Parameters
callback	ProviderInterface$Callback	Callback

Returns: Promise<number> Promise resolving to the dd of the subscription you can use with unsubscribe.

---

unsubscribe

▸ unsubscribe(type: string, method: string, id: number): Promise<boolean>

Defined in ws/index.ts:203

summary: Allows unsubscribing to subscriptions made with subscribe.

Parameters:

Param	Type
type	string
method	string
id	number

Returns: Promise<boolean>

---