Is there a feature for rate limiting requests in WebMagic?

WebMagic is an open-source web crawling framework for Java. Out of the box, WebMagic provides some level of control over the frequency of your requests to avoid overloading the server you're scraping from, which can be seen as a form of rate limiting.

When you're configuring a Spider in WebMagic, you can set both the "sleep time" between each request and the number of threads to use. Adjusting these parameters enables you to effectively rate limit your requests.

Here's an example of how to configure a Spider to control request frequency:

import us.codecraft.webmagic.Spider;
import us.codecraft.webmagic.Site;

public class MyCrawler {
    public static void main(String[] args) {
        Spider.create(new MyPageProcessor())
            // Set the domain name
            .addUrl("http://mywebsite.com")
            // Set the number of threads
            .thread(5)
            // Set the delay between requests for each thread
            .setDownloader(new HttpClientDownloader() {
                @Override
                protected void onSuccess(Request request) {
                    try {
                        // Sleep time in milliseconds
                        Thread.sleep(1000); 
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            })
            .run();
    }
}

In this example, Thread.sleep(1000); causes each thread to wait for 1000 milliseconds (1 second) after each successful request. You can adjust this number to increase or decrease the delay, effectively rate-limiting your crawler.

However, WebMagic does not provide a built-in feature specifically named "rate limiting" that dynamically adjusts request rates based on server responses (like HTTP 429 Too Many Requests). For more sophisticated rate-limiting features, you might need to implement custom logic or use middleware that can handle such scenarios.

If you find that WebMagic's built-in functionality is not sufficient for your needs, you might consider integrating it with a more advanced HTTP client or using a different toolkit altogether that provides built-in rate-limiting features, such as Scrapy with its AUTOTHROTTLE extension for Python.

Remember to always respect the robots.txt file of any website and the website's terms of service when scraping to avoid legal issues and potential blocking of your IP address. Consider contacting the website owner for permission or using their official API if available.