DiscoveryService

Kind: Service

Source: atloria-monorepo/apps/screenshot-worker/src/app/discovery/discovery.service.ts

DiscoveryService is a NestJS service in the screenshot worker responsible for discovering a site's structure and returning it as a SiteMap. It provides a standard scan() operation and a scanWithPage() variant for workflows that require page-aware discovery before downstream processing such as screenshot capture.

Methods

Dependencies

• PlaywrightService
• PageProfilerService

Where it refuses work

• DiscoveryService stops the work with Error when !userSelector || !passSelector — “Could not find login form fields”.
• DiscoveryService stops the work with Error when await this.isOn2FAPage(page) — “Login requires 2FA/verification code — automated login cannot proceed. Please use an acco…”.
• DiscoveryService stops the work with Error when await this.isOn2FAPage(page) — “Login triggered 2FA/verification — automated discovery cannot proceed. The account may ne…”.
• DiscoveryService stops the work with an early return when document.querySelector(sel), in 2 places.
• DiscoveryService stops the work with an early return when url.includes('/login') || url.includes('/signin') || url.includes('/auth').
• DiscoveryService stops the work with an early return when lower.match(/dashboard|home|main|my-desk/).

When something fails

• DiscoveryService handles failure in 5 places: it logs it and continues in 4, and turns it into a return value in 1.

Diagram

mermaid
sequenceDiagram
    participant Worker as Screenshot Worker
    participant Discovery as DiscoveryService
    participant SiteMap as SiteMap

    Worker->>Discovery: scan() or scanWithPage()
    Discovery->>Discovery: Discover site URLs/pages
    Discovery-->>SiteMap: Build SiteMap
    SiteMap-->>Worker: Return discovered structure
    Worker->>Worker: Process pages for screenshots

Usage

ts
import { Injectable } from '@nestjs/common';
import { DiscoveryService } from './discovery/discovery.service';

@Injectable()
export class ScreenshotJobService {
  constructor(private readonly discoveryService: DiscoveryService) {}

  async runDiscovery() {
    // Use the standard discovery flow.
    const siteMap = await this.discoveryService.scan();

    // Use this variant when the job requires page-aware discovery.
    const pageSiteMap = await this.discoveryService.scanWithPage();

    return {
      siteMap,
      pageSiteMap,
    };
  }
}

AI Coding Instructions

• Use DiscoveryService through NestJS dependency injection; do not manually construct it outside the Nest container.
• Await both scan() and scanWithPage(), since each returns a Promise<SiteMap>.
• Use scan() for the default discovery workflow and scanWithPage() only when the calling pipeline needs its page-inclusive behavior.
• Treat the returned SiteMap as the handoff contract for downstream screenshot, crawling, or page-processing jobs.
• Keep discovery orchestration in worker/job services; avoid duplicating URL or site-map discovery logic in screenshot handlers.

Relationships

• DEPENDS_ON → PlaywrightService
• DEPENDS_ON → PageProfilerService

Referenced By

• DiscoveryController (DEPENDS_ON)
• DiscoveryModule (MODULE_PROVIDES)
• DiscoveryModule (MODULE_EXPORTS)
• BatchScreenshotService (DEPENDS_ON)