url-fetcher（网址获取器）

URL Fetcher

Fetch web content without API keys or external dependencies. Uses Python standard library only.

Quick Start

url_fetcher.py fetch <url>
url_fetcher.py fetch --markdown <url> [output_file]

Examples:

# Fetch and preview
url_fetcher.py fetch https://example.com

# Fetch and save HTML
url_fetcher.py fetch https://example.com ~/workspace/page.html

# Fetch and convert to basic markdown
url_fetcher.py fetch --markdown https://example.com ~/workspace/page.md

Features

• No dependencies - Uses Python stdlib (urllib) only
• No API keys - Completely free to use
• URL validation - Blocks localhost/internal networks
• Basic markdown conversion - Extract content from HTML
• Path validation - Safe file writes only (workspace, home, /tmp)
• Error handling - Timeout and network error handling

When to Use

• Content aggregation - Collect pages for processing
• Research collection - Save articles/pages locally
• Simple scraping - Extract text from web pages
• Markdown conversion - Basic HTML to text/markdown
• No-API alternatives - When you can't use paid APIs

Limitations

• Basic markdown - Simple regex-based conversion (not a full parser)
• No JavaScript - Only fetches static HTML
• Rate limiting - No built-in rate limiting (add your own if needed)
• Bot detection - Some sites may block the default User-Agent

Security Features

URL Validation

• ✅ Allows: http/https URLs
• ❌ Blocks: file://, data://, javascript: URLs
• ❌ Blocks: localhost, 127.0.0.1, ::1 (internal networks)

File Path Validation

• ✅ Allows: workspace, home directory, /tmp
• ❌ Blocks: system paths (/etc, /usr, /var, etc.)
• ❌ Blocks: sensitive dotfiles (~/.ssh, ~/.bashrc, etc.)

Error Handling

• Timeout after 10 seconds
• HTTP error handling
• Network error handling
• Character encoding handling

Usage Patterns

Collecting Research

# Fetch multiple articles
url_fetcher.py fetch https://example.com/article1.md ~/workspace/research/article1.md
url_fetcher.py fetch https://example.com/article2.md ~/workspace/research/article2.md

# Convert to markdown for reading
url_fetcher.py fetch --markdown https://example.com/article.md ~/workspace/research/article.md

Content Aggregation

# Fetch pages for processing
url_fetcher.py fetch https://news.example.com ~/workspace/content/latest.html

# Extract text
url_fetcher.py fetch --markdown https://blog.example.com ~/workspace/content/post.md

Quick Preview

# Just preview content (no file save)
url_fetcher.py fetch https://example.com

Advanced Usage

Batch Fetching

#!/bin/bash
# batch_fetch.sh

URLS=(
    "https://example.com/page1"
    "https://example.com/page2"
    "https://example.com/page3"
)

OUTPUT_DIR="$HOME/workspace/fetched"
mkdir -p "$OUTPUT_DIR"

for url in "${URLS[@]}"; do
    filename=$(echo $url | sed 's|/||g')
    url_fetcher.py fetch --markdown "$url" "$OUTPUT_DIR/$filename.md"
    sleep 1  # Be nice to servers
done

Integration with Other Skills

Combine with research-assistant:

# Fetch article
url_fetcher.py fetch --markdown https://example.com/article.md ~/workspace/article.md

# Extract key points
# Then use research-assistant to organize findings

Combine with task-runner:

# Add task to fetch content
task_runner.py add "Fetch article on topic X" "research"

# Fetch when ready
url_fetcher.py fetch https://example.com/topic-x.md ~/workspace/research/topic-x.md

Troubleshooting

Connection Timeout

Error: Request timeout after 10s

Solution: The server is slow or unreachable. Try again later or check the URL.

HTTP 403/429 Errors

Error: HTTP 403: Forbidden

Solution: The site blocks automated requests. Try:

• Add delay between requests
• Use a different User-Agent (modify source)
• Respect robots.txt
• Consider using an API if available

Encoding Issues

Error with special characters

Solution: The tool uses UTF-8 with error-ignore. Some characters may be lost.

Markdown Quality

Note: Basic markdown extraction

Solution: This tool uses simple regex for HTML→MD conversion. For better results:

• Use dedicated markdown parsers
• Or post-process the output
• Or use a paid API with better parsing

Best Practices

1. Be respectful - Add delays between requests (don't hammer servers)
2. Check robots.txt - Respect site's crawling policies
3. Rate limit yourself - Don't fetch too fast
4. Validate URLs - Only fetch from trusted sources
5. Save safely - Always use path-validated outputs
6. Preview first - Use preview mode before saving

Integration Examples

Python Integration

from pathlib import Path
import subprocess

def fetch_and_process(url):
    """Fetch URL and process"""
    output = Path.home() / "workspace" / "fetched" / "page.md"
    output.parent.mkdir(parents=True, exist_ok=True)
    
    # Fetch
    subprocess.run([
        "python3",
        "/path/to/url_fetcher.py",
        "fetch",
        "--markdown",
        url,
        str(output)
    ])
    
    # Process content
    content = output.read_text()
    return content

Bash Integration

# Function for fetching
fetch_content() {
    local url="$1"
    local output="$2"
    python3 ~/workspace/skills/url-fetcher/scripts/url_fetcher.py \
        fetch --markdown "$url" "$output"
}

# Usage
fetch_content "https://example.com" ~/workspace/example.md

Alternatives

When You Need More Features

For full-featured scraping:

• Use requests + beautifulsoup4 (requires pip install)
• Or use scrapy framework (requires pip install)
• Or use paid APIs (Firecrawl, Apify)

For better markdown:

• markdownify library (requires pip install)
• Or use AI-based parsing (OpenAI, Anthropic APIs)

For complex workflows:

• Browser automation (OpenClaw browser tool)
• Headless Chrome (Puppeteer, Playwright)
• Or use scraping APIs (Zyte, ScraperAPI)

Zero-Cost Advantage

This skill requires:

• ✅ Python 3 (included with OpenClaw)
• ✅ No API keys
• ✅ No external packages
• ✅ No paid services
• ✅ No rate limiting (other than what you add)

Perfect for autonomous agents with budget constraints.

Contributing

If you improve this skill, please:

1. Test with security-checker
2. Document new features
3. Publish to ClawHub with credit

License

Use freely in your OpenClaw skills and workflows.