# Sd Download

> Download PDF from ScienceDirect articles. Requires institutional or subscriber access.

- Skill: `cookjohn/sd-download` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cookjohn/sd-download`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cookjohn/sd-download/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Docs & Writing
- Author: cookjohn (https://skillmd.com/u/cookjohn)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cookjohn/sd-download

---


# ScienceDirect PDF Download

Download PDF files from ScienceDirect articles to the user's local disk.

## Prerequisites

- The user must have access to the article (institutional subscription, open access, or personal subscription).
- If the article is behind a paywall and the user has no access, the download will fail.

## Single Article Download

### Step 1: Navigate to article page and extract PDF link

If already on the article page, skip navigation. Otherwise use `navigate_page` with `initScript`:

```
navigate_page({
  url: "{BASE_URL}/science/article/pii/{PII}",
  initScript: "Object.defineProperty(navigator, 'webdriver', {get: () => undefined})"
})
```

Then extract the PDF URL with `evaluate_script`:

```javascript
async () => {
  // Wait for page to load
  for (let i = 0; i < 20; i++) {
    if (document.querySelector('a[href*="pdfft"]') || document.querySelector('.access-options')) break;
    await new Promise(r => setTimeout(r, 500));
  }

  const pdfLink = document.querySelector('a[href*="pdfft"][class*="accessbar"]')
               || document.querySelector('a[href*="pdfft"]');
  if (pdfLink) {
    return { pdfUrl: pdfLink.href };
  }

  const noAccess = document.querySelector('.access-options, .get-access, [class*="GetAccess"]');
  if (noAccess) {
    return { error: 'No access. User needs institutional or subscriber access.' };
  }
  return { error: 'PDF link not found on this page.' };
}
```

### Step 2: Navigate to PDF URL

Open the PDF URL with `initScript`:

```
navigate_page({
  url: "{pdfUrl}",
  initScript: "Object.defineProperty(navigator, 'webdriver', {get: () => undefined})"
})
```

### Step 3: Handle Cloudflare verification

After navigation, wait 5s then check the page state with `evaluate_script`:

```javascript
async () => {
  await new Promise(r => setTimeout(r, 5000));
  return {
    contentType: document.contentType,
    title: document.title,
    url: window.location.href.substring(0, 80)
  };
}
```

Three possible outcomes:

**A) `contentType === 'application/pdf'`** → PDF loaded directly. Skip to Step 4.

**B) Title is "Security verification" or body contains "Are you a robot"** → Turnstile checkbox appeared. Auto-click:

1. Use `take_snapshot` to get the a11y tree. Find the checkbox inside the Cloudflare iframe:
   ```
   Iframe "包含 Cloudflare 安全质询的小组件"
     checkbox "确认您是真人"   ← target uid
   ```
2. Use `click(uid)` on the checkbox element. (Chrome DevTools MCP works at CDP protocol level and can interact with cross-origin iframes.)
3. Wait 5s, then re-check `document.contentType`:
   - If `application/pdf` → success, proceed to Step 4.
   - If still on verification → retry click once. After 2 failed attempts, tell user: "请在浏览器中完成验证后告知我。"

**C) Title is "请稍候…"** → JS challenge still running. Wait another 5s and re-check. Usually resolves to A or B.

### Step 4: Trigger download to local disk

Once `contentType === 'application/pdf'`, the PDF is displayed in browser but NOT saved to disk yet. Trigger the actual download with `evaluate_script`:

```javascript
(pii) => {
  const a = document.createElement('a');
  a.href = window.location.href;
  a.download = pii + '-main.pdf';
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  return { downloaded: true, filename: pii + '-main.pdf' };
}
```

Pass the PII as an argument so the filename is meaningful (e.g. `S0022169426003136-main.pdf`).

Tell the user the PDF has been downloaded and the filename.

## Batch Download from Search Results

**Note**: Batch download requires authentication. Checkboxes and download buttons are only visible to logged-in users.

### Step 1: Select articles

On the search results page, select articles using checkboxes. Each checkbox `id` is the PII.

### Step 2: Submit download form

Use `evaluate_script`:

```javascript
(piis) => {
  piis.forEach(pii => {
    const cb = document.getElementById(pii);
    if (cb && !cb.checked) cb.click();
  });

  const downloadBtn = document.querySelector('.download-all-link-button');
  if (downloadBtn) {
    downloadBtn.click();
    return { success: true, message: 'Download initiated for selected articles.' };
  }

  const form = document.querySelector('form[action*="pdf/download"]');
  if (!form) return { error: 'Download form not found. User may need to log in.' };
  return { error: 'Download button not found.' };
}
```

## PDF URL Pattern

```
{BASE_URL}/science/article/pii/{PII}/pdfft?md5={HASH}&pid=1-s2.0-{PII}-main.pdf
```

The `md5` hash is unique per article and session. It **cannot** be constructed — it must be extracted from the page.

## Notes

- This skill is set to `disable-model-invocation: true` — it must be explicitly invoked with `/sd-download`.
- Open access articles can be downloaded without authentication.
- For subscription articles, the user must be authenticated (institutional access, VPN, or personal subscription).
- After solving Cloudflare once, subsequent PDF downloads in the same session work without interruption.
- If download fails, suggest the user check their access status or try logging in.