extract（提取）

When to Use This Skill

Activate when the user wants to obtain data from a website:

• "Extract all product prices from this page"
• "Scrape the table of results from..."
• "Pull the list of authors and titles from arXiv search results"
• "Collect all job listings from this page"
• "Get the data from this dashboard table"
• "Harvest review scores from..."
• "Download all the links/images/cards from..."

The deliverable is always two artifacts:

1. Executable Playwright script — a standalone .cjs file that reproduces the extraction without Actionbook at runtime.
2. Extracted data — JSON (default), CSV, or user-specified format written to disk.

Decision Strategy

Use Actionbook as a conditional accelerator, not a mandatory step. The goal is reliable selectors in the shortest path.

User request
  │
  ├─► actionbook search "<site> <intent>"
  │     ├─ Results with Health Score ≥ 70%  ──► actionbook get "<ID>" ──► use selectors
  │     └─ No results / low score  ──► Fallback
  │
  └─► Fallback: actionbook browser open <url>
        ├─ actionbook browser snapshot   (accessibility tree → find selectors)
        ├─ actionbook browser screenshot (visual confirmation)
        └─ manual selector discovery via DOM inspection

Priority order for selector sources:

Non-negotiable rule: if search + get already provides usable selectors for required fields, start from get selectors and do not jump to full fallback (snapshot/screenshot) by default. Exception: lightweight mechanism probes (for hydration/virtualization/pagination) are allowed when runtime behavior may affect script correctness. Escalate to snapshot/screenshot only when probes/sample validation indicate selector gaps or instability.

Mechanism-Aware Script Strategy

Websites use patterns that break naive scraping. The generated Playwright script must account for these:

Streaming / SSR / RSC hydration

Pages may render a shell first, then stream or hydrate content.

// Wait for hydration to complete — not just DOMContentLoaded
await page.waitForSelector('[data-item]', { state: 'attached' });
await page.waitForFunction(() => {
  const items = document.querySelectorAll('[data-item]');
  return items.length > 0 && !document.querySelector('[data-pending]');
});

Detection cues: React root with data-reactroot, Next.js __NEXT_DATA__, empty containers that fill after JS runs. If actionbook browser text "<selector>" returns empty but the screenshot shows content, hydration hasn't completed.

Virtualized lists / virtual DOM

Only visible rows exist in the DOM. Scrolling renders new rows and destroys old ones.

// Scroll-and-collect loop for virtualized lists (scroll container aware)
const allItems = [];
const maxScrolls = 50;
let scrolls = 0;

const container = await page.$('<scroll-container-selector>');
if (!container) throw new Error('Scroll container not found');

let previousTop = await container.evaluate(el => el.scrollTop);
while (scrolls < maxScrolls) {
  const items = await page.$$eval('[data-row]', rows =>
    rows.map(r => ({ text: r.textContent.trim() }))
  );
  for (const item of items) {
    if (!allItems.find(i => i.text === item.text)) allItems.push(item);
  }

  await container.evaluate(el => el.scrollBy(0, 600));
  await page.waitForTimeout(300);

  const currentTop = await container.evaluate(el => el.scrollTop);
  if (currentTop === previousTop) break;

  previousTop = currentTop;
  scrolls += 1;
}

Detection cues: Container has fixed height with overflow: auto/scroll, row count in DOM is much smaller than stated total, rows have transform: translateY(...) or position: absolute; top:...px.

Infinite scroll / lazy loading

New content appends when the user scrolls near the bottom.

// Scroll to bottom until no new content loads (with no-growth tolerance)
let itemCount = 0;
let noGrowthStreak = 0;
const maxScrolls = 80;
let scrolls = 0;

while (scrolls < maxScrolls && noGrowthStreak < 3) {
  await page.evaluate(() => window.scrollTo(0, document.body.scrollHeight));
  await page.waitForTimeout(1200);

  const newCount = await page.$$eval('.item', els => els.length);
  if (newCount > itemCount) {
    itemCount = newCount;
    noGrowthStreak = 0;
  } else {
    noGrowthStreak += 1;
  }

  scrolls += 1;
}

Detection cues: Intersection Observer in page JS, "Load more" button, sentinel element at bottom, network requests firing on scroll.

Pagination

Multi-page results behind "Next" buttons or numbered pages.

// Click-through pagination (navigation-aware, SPA-safe)
const allData = [];
const maxPages = 50;
let pageIndex = 0;
while (pageIndex < maxPages) {
  const pageData = await page.$$eval('.result-item', items =>
    items.map(el => ({ title: el.querySelector('h3')?.textContent?.trim() }))
  );
  allData.push(...pageData);

  const nextBtn = await page.$('a.next-page:not([disabled])');
  if (!nextBtn) break;

  const previousUrl = page.url();
  const previousFirstItem = await page
    .$eval('.result-item', el => el.textContent?.trim() || '')
    .catch(() => '');

  await nextBtn.click();

  // Post-click detection only: advance must be caused by this click
  const advanced = await Promise.any([
    page
      .waitForURL(url => url.toString() !== previousUrl, { timeout: 5000 })
      .then(() => true),
    page
      .waitForFunction(
        prev => {
          const first = document.querySelector('.result-item');
          return !!first && (first.textContent || '').trim() !== prev;
        },
        previousFirstItem,
        { timeout: 5000 }
      )
      .then(() => true),
  ]).catch(() => false);

  if (!advanced) break;

  await page.waitForLoadState('networkidle').catch(() => {});
  pageIndex += 1;
}

Execution Chain

Step 1: Understand the target

Identify from the user request:

• URL — the page to extract from
• Data shape — what fields / columns are needed
• Scope — single page, paginated, infinite scroll, or multi-page crawl
• Output format — JSON (default), CSV, or other

Step 2: Obtain selectors and choose execution path

# Try Actionbook index first
actionbook search "<site> <data-description>" --domain <domain>

# If good results (health ≥ 70%), get full selectors
actionbook get "<ID>"

Use this routing strictly:

• Path A (default when get is good): requested fields are covered by get selectors and quality is acceptable.

- Start from get selectors and move to script draft quickly. - You may run lightweight mechanism probes (browser text, quick scroll checks) before finalizing script strategy. - Do not run full fallback (snapshot / screenshot) before first draft unless probe/sample validation shows mismatch. - Field mapping must default to get selectors and mark source as actionbook_get.

• Path B (partial / unstable): get exists but required fields are missing, selector resolves 0 elements, or validation fails.

- Run targeted fallback only for failed fields/steps.

• Path C (no usable coverage): search/get has no usable result.

- Run full fallback discovery.

Step 3: Probe page mechanisms and fallback only when needed

Path A mechanism detection timing:

• Run minimal probes either before final script draft or during sample validation.
• Before any probe command, ensure the correct page context is open:

- actionbook browser open "<url>" (if current tab context is unknown/stale)

• If probes/sample run indicate mismatch (missing rows, unstable selectors, wrong pagination behavior), escalate to Path B targeted fallback.

Fallback discovery by path:

Path B targeted fallback (only failed fields/steps):

actionbook browser open "<url>"     # if not already open
actionbook browser snapshot          # focus on failed field/container mapping
# actionbook browser screenshot      # optional visual confirmation for failed area

Path C full fallback (no usable coverage):

actionbook browser open "<url>"
actionbook browser snapshot
actionbook browser screenshot

Mechanism probes (run when script strategy needs confirmation):

# Hydration / streaming check
actionbook browser text "<container-selector>"

# Infinite scroll quick signal (explicit before/after decision)
actionbook browser eval "document.querySelectorAll('<item-selector>').length"   # before
actionbook browser click "<scroll-container-selector-or-body>"                    # focus scroll context
actionbook browser eval "const c=document.querySelector('<scroll-container-selector>') || document.scrollingElement; c.scrollBy(0, c.clientHeight || window.innerHeight);"
actionbook browser eval "document.querySelectorAll('<item-selector>').length"   # after
# If count increases, treat page as lazy-load/infinite-scroll.

Fallback trigger conditions:

• actionbook get cannot map all required fields.
• actionbook get selectors return empty/unstable values in sample run.
• Runtime behavior conflicts with expected mechanism (e.g., virtualized container, delayed hydration).

Step 4: Generate Playwright script

Write a standalone Playwright script (extract_<domain>_<slug>.cjs) that:

1. Navigates to the target URL.
2. Waits for the correct readiness signal (not just load — see mechanisms above).
3. Handles the detected mechanism (virtual scroll, pagination, etc.).
4. Extracts data into structured objects.
5. Writes output to disk (JSON.stringify / CSV).
6. Closes the browser.
7. Enforces guardrails (maxPages, maxScrolls, timeout budget) to avoid infinite loops.

Script template:

// extract_<domain>_<slug>.cjs
// Generated by Actionbook extract skill
// Usage: node extract_<domain>_<slug>.cjs

const { chromium } = require('playwright');

(async () => {
  const browser = await chromium.launch();
  const page = await browser.newPage();

  await page.goto('<URL>', { waitUntil: 'domcontentloaded' });

  // -- wait for readiness --
  await page.waitForSelector('<container>', { state: 'visible' });

  // -- extract --
  const data = await page.$$eval('<item-selector>', items =>
    items.map(el => ({
      // fields mapped from user request
    }))
  );

  // -- output --
  const fs = require('fs');
  fs.writeFileSync('output.json', JSON.stringify(data, null, 2));
  console.log(`Extracted ${data.length} items → output.json`);

  await browser.close();
})();

Step 5: Execute and validate

Run the script to confirm it works:

node extract_<domain>_<slug>.cjs

Validation rules:

If validation fails, inspect the output, adjust selectors or wait strategy, and re-run.

Step 6: Deliver

Present to the user:

1. Script path — the .cjs file they can re-run anytime.
2. Data path — the output JSON/CSV file.
3. Record count — how many items were extracted.
4. Notes — any mechanism-specific caveats (e.g., "this site uses infinite scroll; the script scrolls up to 50 pages by default").

Output Contract

Every extract invocation produces:

The script must be re-runnable — a user should be able to execute it later without Actionbook installed, as long as Node.js + Playwright are available in the runtime environment.

Selector Priority

When multiple selector types are available from actionbook get:

Error Handling