diff options
Diffstat (limited to 'packages/0x.js/src/order_watcher/event_watcher.ts')
| -rw-r--r-- | packages/0x.js/src/order_watcher/event_watcher.ts | 148 |
1 files changed, 74 insertions, 74 deletions
diff --git a/packages/0x.js/src/order_watcher/event_watcher.ts b/packages/0x.js/src/order_watcher/event_watcher.ts index 3e3cd978d..5d05bfb60 100644 --- a/packages/0x.js/src/order_watcher/event_watcher.ts +++ b/packages/0x.js/src/order_watcher/event_watcher.ts @@ -9,8 +9,8 @@ import { assert } from '../utils/assert'; const DEFAULT_EVENT_POLLING_INTERVAL_MS = 200; enum LogEventState { - Removed, - Added, + Removed, + Added, } /* @@ -18,76 +18,76 @@ enum LogEventState { * depth. */ export class EventWatcher { - private _web3Wrapper: Web3Wrapper; - private _pollingIntervalMs: number; - private _intervalIdIfExists?: NodeJS.Timer; - private _lastEvents: Web3.LogEntry[] = []; - constructor(web3Wrapper: Web3Wrapper, pollingIntervalIfExistsMs: undefined | number) { - this._web3Wrapper = web3Wrapper; - this._pollingIntervalMs = _.isUndefined(pollingIntervalIfExistsMs) - ? DEFAULT_EVENT_POLLING_INTERVAL_MS - : pollingIntervalIfExistsMs; - } - public subscribe(callback: EventWatcherCallback): void { - assert.isFunction('callback', callback); - if (!_.isUndefined(this._intervalIdIfExists)) { - throw new Error(ZeroExError.SubscriptionAlreadyPresent); - } - this._intervalIdIfExists = intervalUtils.setAsyncExcludingInterval( - this._pollForBlockchainEventsAsync.bind(this, callback), - this._pollingIntervalMs, - (err: Error) => { - this.unsubscribe(); - callback(err); - }, - ); - } - public unsubscribe(): void { - this._lastEvents = []; - if (!_.isUndefined(this._intervalIdIfExists)) { - intervalUtils.clearAsyncExcludingInterval(this._intervalIdIfExists); - delete this._intervalIdIfExists; - } - } - private async _pollForBlockchainEventsAsync(callback: EventWatcherCallback): Promise<void> { - const pendingEvents = await this._getEventsAsync(); - if (_.isUndefined(pendingEvents)) { - // HACK: This should never happen, but happens frequently on CI due to a ganache bug - return; - } - if (pendingEvents.length === 0) { - // HACK: Sometimes when node rebuilds the pending block we get back the empty result. - // We don't want to emit a lot of removal events and bring them back after a couple of miliseconds, - // that's why we just ignore those cases. - return; - } - const removedEvents = _.differenceBy(this._lastEvents, pendingEvents, JSON.stringify); - const newEvents = _.differenceBy(pendingEvents, this._lastEvents, JSON.stringify); - await this._emitDifferencesAsync(removedEvents, LogEventState.Removed, callback); - await this._emitDifferencesAsync(newEvents, LogEventState.Added, callback); - this._lastEvents = pendingEvents; - } - private async _getEventsAsync(): Promise<Web3.LogEntry[]> { - const eventFilter = { - fromBlock: BlockParamLiteral.Pending, - toBlock: BlockParamLiteral.Pending, - }; - const events = await this._web3Wrapper.getLogsAsync(eventFilter); - return events; - } - private async _emitDifferencesAsync( - logs: Web3.LogEntry[], - logEventState: LogEventState, - callback: EventWatcherCallback, - ): Promise<void> { - for (const log of logs) { - const logEvent = { - removed: logEventState === LogEventState.Removed, - ...log, - }; - if (!_.isUndefined(this._intervalIdIfExists)) { - callback(null, logEvent); - } - } - } + private _web3Wrapper: Web3Wrapper; + private _pollingIntervalMs: number; + private _intervalIdIfExists?: NodeJS.Timer; + private _lastEvents: Web3.LogEntry[] = []; + constructor(web3Wrapper: Web3Wrapper, pollingIntervalIfExistsMs: undefined | number) { + this._web3Wrapper = web3Wrapper; + this._pollingIntervalMs = _.isUndefined(pollingIntervalIfExistsMs) + ? DEFAULT_EVENT_POLLING_INTERVAL_MS + : pollingIntervalIfExistsMs; + } + public subscribe(callback: EventWatcherCallback): void { + assert.isFunction('callback', callback); + if (!_.isUndefined(this._intervalIdIfExists)) { + throw new Error(ZeroExError.SubscriptionAlreadyPresent); + } + this._intervalIdIfExists = intervalUtils.setAsyncExcludingInterval( + this._pollForBlockchainEventsAsync.bind(this, callback), + this._pollingIntervalMs, + (err: Error) => { + this.unsubscribe(); + callback(err); + }, + ); + } + public unsubscribe(): void { + this._lastEvents = []; + if (!_.isUndefined(this._intervalIdIfExists)) { + intervalUtils.clearAsyncExcludingInterval(this._intervalIdIfExists); + delete this._intervalIdIfExists; + } + } + private async _pollForBlockchainEventsAsync(callback: EventWatcherCallback): Promise<void> { + const pendingEvents = await this._getEventsAsync(); + if (_.isUndefined(pendingEvents)) { + // HACK: This should never happen, but happens frequently on CI due to a ganache bug + return; + } + if (pendingEvents.length === 0) { + // HACK: Sometimes when node rebuilds the pending block we get back the empty result. + // We don't want to emit a lot of removal events and bring them back after a couple of miliseconds, + // that's why we just ignore those cases. + return; + } + const removedEvents = _.differenceBy(this._lastEvents, pendingEvents, JSON.stringify); + const newEvents = _.differenceBy(pendingEvents, this._lastEvents, JSON.stringify); + await this._emitDifferencesAsync(removedEvents, LogEventState.Removed, callback); + await this._emitDifferencesAsync(newEvents, LogEventState.Added, callback); + this._lastEvents = pendingEvents; + } + private async _getEventsAsync(): Promise<Web3.LogEntry[]> { + const eventFilter = { + fromBlock: BlockParamLiteral.Pending, + toBlock: BlockParamLiteral.Pending, + }; + const events = await this._web3Wrapper.getLogsAsync(eventFilter); + return events; + } + private async _emitDifferencesAsync( + logs: Web3.LogEntry[], + logEventState: LogEventState, + callback: EventWatcherCallback, + ): Promise<void> { + for (const log of logs) { + const logEvent = { + removed: logEventState === LogEventState.Removed, + ...log, + }; + if (!_.isUndefined(this._intervalIdIfExists)) { + callback(null, logEvent); + } + } + } } |