link:http://www.piaproxy.com/?utm-source=crax&utm-keyword=?C01
1. Blocked IP detection: Some websites may detect the speed of user IP access. If the access speed reaches the set threshold, the IP will be restricted and blocked, making the crawler unable to continue to obtain data. In this case, a large number of HTTP proxy IPs can be used, and a large number of IP addresses can be switched to break through IP restrictions.
2. Request header detection: The website can detect whether it is a user or a crawler by detecting the request header of the crawler. Because the crawler has no other characteristics when visiting, the website can identify the crawler by detecting the crawler's request header.
3. Trap settings: Some websites will set traps, such as adding some hidden links. These links are invisible in normal browsing and can only be accessed through spiders or crawlers, so that the website can identify crawlers and block access.
4. Behavior analysis: The website can determine whether the request comes from a crawler by analyzing the IP address of the request source, request frequency, request content and other factors. For example, if an IP address visits a large number of links in a short period of time, or visits the same link repeatedly, this may be identified as crawler behavior.
5. Anti-crawling mechanism: In order to prevent data from being captured by crawlers, many websites will set up anti-crawling mechanisms. These mechanisms may determine whether it is a crawler behavior based on factors such as access frequency and access content, and take corresponding measures, such as blocking IP addresses, returning error pages, etc. When performing crawling operations, you need to understand the anti-crawling mechanism of the target site and take corresponding countermeasures to reduce the risk of being blocked.
1. Blocked IP detection: Some websites may detect the speed of user IP access. If the access speed reaches the set threshold, the IP will be restricted and blocked, making the crawler unable to continue to obtain data. In this case, a large number of HTTP proxy IPs can be used, and a large number of IP addresses can be switched to break through IP restrictions.
2. Request header detection: The website can detect whether it is a user or a crawler by detecting the request header of the crawler. Because the crawler has no other characteristics when visiting, the website can identify the crawler by detecting the crawler's request header.
3. Trap settings: Some websites will set traps, such as adding some hidden links. These links are invisible in normal browsing and can only be accessed through spiders or crawlers, so that the website can identify crawlers and block access.
4. Behavior analysis: The website can determine whether the request comes from a crawler by analyzing the IP address of the request source, request frequency, request content and other factors. For example, if an IP address visits a large number of links in a short period of time, or visits the same link repeatedly, this may be identified as crawler behavior.
5. Anti-crawling mechanism: In order to prevent data from being captured by crawlers, many websites will set up anti-crawling mechanisms. These mechanisms may determine whether it is a crawler behavior based on factors such as access frequency and access content, and take corresponding measures, such as blocking IP addresses, returning error pages, etc. When performing crawling operations, you need to understand the anti-crawling mechanism of the target site and take corresponding countermeasures to reduce the risk of being blocked.
