How should novice crawlers use http agents to avoid website detection of crawlers

This article is about how novice crawlers should use http agents to avoid site detection of crawlers. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

1. Block IP detection, that is, detect the speed of users'IP access.

If the access speed reaches the set threshold, the restriction blocking IP is turned on, so that the crawler can no longer obtain data. For blocking IP detection, Sun HTTP can be used to proxy IP, and a large number of IP addresses can be switched, thus breaking the IP limit.

2. Request header detection.

The crawler is not a user and has no other features when accessing it. The website can detect whether the crawler is a user or a crawler by detecting the crawler's request header.

3. CAPTCHA detection is the setting of login CAPTCHA limit.

Login CAPTCHA limit setting. If you do not enter the correct CAPTCHA, you will not be able to check. Because crawlers can use other tools to identify CAPTCHA, the website continues to deepen the difficulty of verification, from ordinary pure data source CAPTCHA to mixed CAPTCHA, sliding CAPTCHA, image CAPTCHA and so on.

4. Cookie detection.

The browser will save the cookie, so the site will check the cookie to determine if you are a real user, and if the crawler is not camouflaged, it will trigger access restrictions.

Reptiles can be monitored through the website of the above methods, and reptiles practitioners can also break them one by one according to these methods. Reptiles and anti-reptiles are a lasting battle.

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