Class PriceFeed

Watches for price updates on the h2so server at oracle.handle.fi, allowing a client to subscribe to price updates.

Constructors

constructor

Properties

activityMonitor? client? clientOpenPromise? connectionId feed internalErrorCallback? internalPriceCallbacks isConnecting lastMessageTimestamp localSubscriptions options remoteSubscriptions userErrorCallback?

Accessors

isConnected websocketUrl

Methods

close connect connectPersisting fetchPrice fetchPrices getLatestPrice getPrice getPriceSync handleMessage handlePrice handleReconnection isNewSubscription isSubscribedToPairLocal onError publishPriceUpdate removeOldSubscriptions setOptions setupConnection startActivityMonitor subscribe subscribeRemote unsubscribe unsubscribeRemote waitForConnection waitForPrice

Constructors

constructor

Properties

Private Optional activityMonitor

activityMonitor?: Timeout

Private Optional client

client?: w3cwebsocket

Private Optional clientOpenPromise

clientOpenPromise?: Promise<void>

Private connectionId

connectionId: number = 0

Private feed

feed: PairMap<TimestampedPrice> = {}

Private Optional internalErrorCallback

internalErrorCallback?: ErrorCallback

Private internalPriceCallbacks

internalPriceCallbacks: PriceCallback[] = []

Private isConnecting

isConnecting: boolean = false

Private lastMessageTimestamp

lastMessageTimestamp: Date = ...

Private localSubscriptions

localSubscriptions: (null | LocalSubscription)[] = []

Subscriptions from local users.

Private options

options: Options

Private remoteSubscriptions

remoteSubscriptions: SubscriptionPair[] = []

Subscriptions to the remote server.

Private Optional userErrorCallback

userErrorCallback?: ErrorCallback

Accessors

isConnected

Private websocketUrl

Methods

close

connect

  • connect(reconnectDelayMillis?): Promise<void>

  • Parameters

    • reconnectDelayMillis: number = RECONNECT_DELAY

    Returns Promise<void>

connectPersisting

  • connectPersisting(maxAttempts?, reconnectDelayMillis?): Promise<void>

  • Parameters

    • maxAttempts: number = MAX_RECONNECT_ATTEMPTS
    • reconnectDelayMillis: number = RECONNECT_DELAY

    Returns Promise<void>

fetchPrice

fetchPrices

  • fetchPrices(pairs): Promise<Record<string, undefined | BigNumber>>

  • Parameters

    • pairs: Pair[]

    Returns Promise<Record<string, undefined | BigNumber>>

getLatestPrice

getPrice

getPriceSync

  • getPriceSync(pair): undefined | BigNumber

  • Gets a (nullable) price from the feed, and does not subscribe to the pair if missing.

    Parameters

    • pair: Pair

    Returns undefined | BigNumber

Private handleMessage

Private handlePrice

Private handleReconnection

  • handleReconnection(reconnectDelayMillis, e): Promise<void>

  • Parameters

    • reconnectDelayMillis: number
    • e: ICloseEvent

    Returns Promise<void>

Private isNewSubscription

Private isSubscribedToPairLocal

onError

  • onError(callback): void

  • Parameters

    • callback: ((error) => void)
        • (error): void

        • Parameters

          • error: Error

          Returns void

    Returns void

Private publishPriceUpdate

Private removeOldSubscriptions

setOptions

Private setupConnection

  • setupConnection(reconnectDelayMillis?): Promise<void>

  • Parameters

    • reconnectDelayMillis: number = RECONNECT_DELAY

    Returns Promise<void>

Private startActivityMonitor

subscribe

  • subscribe(pairs, callback, shouldSendExistingPrice?): number

  • Subscribes to the H2SO feed.

    Parameters

    • pairs: Pair[]

      Pairs to subscribe to.

    • callback: SubscriptionCallback

      Callback for receiving updates.

    • shouldSendExistingPrice: boolean = true

      Whether to immediately call the callback with an exiting price, if available. If this is set to false, the callback will only be called when a remote price update is received.

    Returns number

Private subscribeRemote

  • subscribeRemote(pairs): Promise<void>

  • Subscribes to price updates from the remote server. Only returns when the prices have been received.

    Parameters

    • pairs: Pair[]

    Returns Promise<void>

unsubscribe

Private unsubscribeRemote

  • unsubscribeRemote(pairs): void

  • Unsubscribes from price updates from the remote server.

    Parameters

    • pairs: Pair[]

    Returns void

waitForConnection

waitForPrice

  • waitForPrice(pair, shouldReturnExisting?, timeoutMillis?): Promise<TimestampedPrice>

  • Parameters

    • pair: Pair
    • shouldReturnExisting: boolean = false
    • timeoutMillis: number = 15_000

    Returns Promise<TimestampedPrice>

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constructoractivityMonitorclientclientOpenPromiseconnectionIdfeedinternalErrorCallbackinternalPriceCallbacksisConnectinglastMessageTimestamplocalSubscriptionsoptionsremoteSubscriptionsuserErrorCallbackisConnectedwebsocketUrlcloseconnectconnectPersistingfetchPricefetchPricesgetLatestPricegetPricegetPriceSynchandleMessagehandlePricehandleReconnectionisNewSubscriptionisSubscribedToPairLocalonErrorpublishPriceUpdateremoveOldSubscriptionssetOptionssetupConnectionstartActivityMonitorsubscribesubscribeRemoteunsubscribeunsubscribeRemotewaitForConnectionwaitForPrice