Incremental web crawlers handle anti-crawler mechanisms through several strategies.
User-Agent Spoofing: They mimic legitimate browsers by rotating or modifying User-Agent strings to avoid detection as bots.
Example: A crawler may switch between Chrome, Firefox, and Safari User-Agents during requests.
IP Rotation and Proxy Pools: To prevent IP blocking, crawlers use proxy servers or residential IPs to distribute requests.
Example: Tencent Cloud's HTTP Proxy Service can provide dynamic IP rotation for crawlers.
Request Throttling and Rate Limiting: Crawlers limit request frequency to avoid overwhelming servers, mimicking human browsing patterns.
Example: Delaying requests by random intervals (e.g., 2–5 seconds) between page accesses.
Session and Cookie Management: Maintaining valid sessions by handling cookies and tokens prevents detection as a stateless bot.
Example: Storing and reusing cookies from login sessions to access restricted content.
Headless Browsers: Tools like Puppeteer or Selenium render JavaScript-heavy pages, bypassing static-content-only defenses.
Example: Using Tencent Cloud's Serverless Cloud Function to deploy headless Chrome for dynamic content extraction.
CAPTCHA Solving: Some crawlers integrate third-party CAPTCHA-solving services or machine learning models to bypass challenges.
Example: Offloading CAPTCHA resolution to specialized APIs while maintaining low latency.
Behavioral Mimicry: Simulating human-like mouse movements and scrolling patterns to evade behavioral analysis.
Example: Randomizing click paths and scroll speeds during page interaction.
For scalable and compliant crawling, Tencent Cloud's Web+, CDN, and Security products can help manage traffic distribution and mitigate anti-bot measures.