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

@polkadot/rpc-provider/ws

name: WsProvider

description: The WebSocket Provider allows sending requests using WebSocket to a WebSocket RPC server TCP port. 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/promise';
import WsProvider from '@polkadot/rpc-provider/ws';

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

see: HttpProvider

Hierarchy

WsProvider

Implements

• WSProviderInterface

Constructors

constructor

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

Defined in ws/index.ts:75

Parameters:

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

Returns: WsProvider

---

Accessors

hasSubscriptions

gethasSubscriptions(): boolean

Defined in ws/index.ts:101

summary: true when this provider supports subscriptions

Returns: boolean

---

Methods

connect

▸ connect(): void

Defined in ws/index.ts:110

summary: Manually connect

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

Returns: void

---

isConnected

▸ isConnected(): boolean

Defined in ws/index.ts:127

summary: Whether the node is connected or not.

Returns: boolean true if connected

---

on

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

Defined in ws/index.ts:136

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

Parameters:

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

Returns: void

---

send

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

Defined in ws/index.ts:146

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

Parameters:

Name	Type	Description
method	string	The RPC methods to execute
params	Array<any>	Encoded paramaters as appliucable for the method
Optional subscription	SubscriptionHandler	Subscription details (internally used)

Returns: Promise<any>

---

subscribe

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

Defined in ws/index.ts:200

name: subscribe

summary: Allows subscribing to a specific event.

example:

const provider = new WsProvider('ws://127.0.0.1:9944');
const rpc = new Rpc(provider);

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

Parameters:

Name	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:209

summary: Allows unsubscribing to subscriptions made with subscribe.

Parameters:

Name	Type
type	string
method	string
id	number

Returns: Promise<boolean>

---