URL query parameters are lowercased in result.links, breaking case-sensitive URLs

[nanwio]

Description

When crawl4ai extracts links from a page, the query parameters in URLs are lowercased in result.links. This breaks websites where query parameters are case-sensitive.

Steps to Reproduce

import asyncio
from crawl4ai import AsyncWebCrawler, BrowserConfig, CrawlerRunConfig
from crawl4ai.deep_crawling import BFSDeepCrawlStrategy

async def test():
    browser_config = BrowserConfig(headless=True, java_script_enabled=True)
    crawler_config = CrawlerRunConfig(
        deep_crawl_strategy=BFSDeepCrawlStrategy(max_depth=0),
        delay_before_return_html=5.0,
    )

    async with AsyncWebCrawler(config=browser_config) as crawler:
        result = await crawler.arun('https://www.example.com/index', config=crawler_config)

        if isinstance(result, list):
            result = result[0]

        for link in result.links.get('internal', []):
            print(link.get('href', ''))

asyncio.run(test())

Expected Behavior

The original HTML contains: <a href="/page?documentId=123&viewMode=Full">Link</a>

result.links should preserve the original case: https://www.example.com/page?documentId=123&viewMode=Full

Actual Behavior

result.links returns lowercased query parameters: https://www.example.com/page?documentid=123&viewmode=full

Impact

Many websites have case-sensitive query parameters. When crawling child URLs with lowercased parameters, the server may return different content or empty pages.

Environment

• crawl4ai version: 0.7.8
• Python: 3.13

Suggested Fix

Preserve the original case of query parameters when extracting links, or add a configuration option to disable URL normalization.