Implementation:Webdriverio Webdriverio RequestQueueHandler Class

Knowledge Sources	Webdriverio_Webdriverio
Domains	BrowserStack, Request_Management
Last Updated	2026-02-12 00:00 GMT

Overview

The RequestQueueHandler class is a singleton batching queue that accumulates upload requests and dispatches them in configurable batches via interval-based polling.

Description

RequestQueueHandler implements a producer-consumer pattern for batching test observability events before sending them to BrowserStack's data collection API. Events are added to an internal queue via add(). A polling interval (configured by DATA_BATCH_INTERVAL, default 2000ms) periodically invokes sendBatch(), which splices up to DATA_BATCH_SIZE (default 1000) events from the queue and passes them to a callback function. The queue also triggers immediate batch dispatch when the queue reaches the batch size threshold, or when tearDownInvoked is set (force-flushing remaining events). The shutdown() method stops the polling interval and drains all remaining events. The class enforces singleton access via getInstance().

Usage

Use this handler as the transport layer for sending test, hook, log, and screenshot events to the BrowserStack observability API. It is initialized by the Listener class with a callback that calls batchAndPostEvents.

Code Reference

Source Location

Repository: Webdriverio_Webdriverio
File: packages/wdio-browserstack-service/src/request-handler.ts
Lines: 9-92

Signature

export default class RequestQueueHandler {
    private queue: UploadType[]
    private readonly callback: Function | undefined
    public static tearDownInvoked: boolean
    static instance: RequestQueueHandler

    private constructor(callback: Function)

    public static getInstance(callback?: Function): RequestQueueHandler

    add(event: UploadType): void
    async shutdown(): Promise<void>
    startEventBatchPolling(): void
    async sendBatch(): Promise<void>
    resetEventBatchPolling(): void
    removeEventBatchPolling(tag: string): void
    shouldProceed(): boolean
}

Import

import RequestQueueHandler from './request-handler.js'

I/O Contract

Inputs

Name	Type	Required	Description
callback	`Function`	Yes (on first getInstance)	Callback function invoked with batched data; receives `(data: UploadType[], kind: string)`
event	`UploadType`	Yes	Individual event to add to the queue (test run, hook run, log, or screenshot)

Outputs

Name	Type	Description
Batched callback invocation	`void`	The callback is invoked with arrays of up to `DATA_BATCH_SIZE` events
Queue draining on shutdown	`void`	All remaining events are flushed through the callback during shutdown

Usage Examples

Initializing the queue handler with a callback

import RequestQueueHandler from './request-handler.js'
import { batchAndPostEvents } from './util.js'
import { DATA_BATCH_ENDPOINT } from './constants.js'

const handler = RequestQueueHandler.getInstance(async (data: UploadType[]) => {
    await batchAndPostEvents(DATA_BATCH_ENDPOINT, 'BATCH', data)
})

Adding events to the queue

const handler = RequestQueueHandler.getInstance()
handler.add({
    event_type: 'TestRunFinished',
    test_run: testData
})
// Event is queued; will be sent in the next batch interval or
// immediately if queue size >= DATA_BATCH_SIZE

Graceful shutdown

const handler = RequestQueueHandler.getInstance()
await handler.shutdown()
// Stops polling, drains all remaining events through the callback

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