In today's most mainstream data acquisition methods, using crawler to get data has become a common choice. However, in the actual crawling process, many users may experience crawler timeouts or error codes, which means that the crawler is limited. In order to ensure the normal operation of the crawler and avoid being restricted, we can take some effective protective measures. Here are some ways to prevent crawlers from being confined:
1. Use a proxy server
The proxy server can act as an intermediate site to forward and process the communication between the crawler and the target website. By using a proxy server, the crawler can hide the real IP address when crawling data, thus increasing the anonymity and security of the crawler.
When selecting a proxy service provider, the user needs to choose a reliable proxy service provider according to the needs of the crawler task. Different proxy service providers may offer different types of proxy IP, such as data center proxy and residential IP proxy. Data center agents usually come from data center or server providers and have high stability and speed. The residential IP agent uses the IP address of the common residential network, which is closer to the IP of the real user, and is suitable for the crawl task that simulates the behavior of the real user.
An important role of using a proxy server is to rotate IP addresses. Frequent requests sent from the same IP address may be detected and restricted by the target website. By using a proxy server, the IP address can be changed periodically to make the crawler's requests appear to be from different users, thus reducing the risk of being restricted. The proxy server provides an IP pool from which the crawler can obtain different IP addresses for requests, which increases the diversity and concealability of the crawling data.
In addition, the proxy server can also provide other auxiliary functions, such as providing high-speed channels and data compression, to help the crawler obtain data more efficiently. Some proxy service providers also support multiple protocols and user agent configurations that allow crawlers to emulate different types of devices and browsers, increasing the applicability and flexibility of crawlers.
2. Use alternate IP addresses
The target site often monitors for too many requests from the same IP address, perceives it as a threat and limits it, which is a common challenge for crawlers that do frequent data scraping. In order to bypass this limitation, the strategy of rotating IP has become one of the solutions.
The core idea of rotating IP is to periodically change the IP address used by the crawler, making each request appear to come from a different Internet user. In this way, even if the target website restricts crawlers, it will only affect the IP address currently in use, and will not affect other IP addresses. By constantly rotating IP, crawlers can maintain anonymity and diversity, reducing the risk of being restricted.
There are many ways to implement IP rotation, and one common way is to use a proxy server. The proxy server provides an IP pool that contains a large number of different IP addresses. The crawler can get an IP address from the proxy server and use it to send the request. After a period of time, the crawler can again get another IP address from the proxy server, and so on. In this way, the crawler uses a different IP address for each request, thus achieving the effect of rotating the IP.
Another way to implement IP rotation is to use IP proxy pools. An IP proxy pool is a regularly updated list of IP addresses from which a crawler can randomly select IP addresses to send requests. Similar to proxy servers, IP proxy pools are also able to provide different IP addresses, allowing crawlers to rotate these IP addresses, thus increasing anonymity and diversity.
3. Change the crawling mode
Frequent use of the same basic crawling pattern is easily detected by the target site and is considered a crawler. To prevent being restricted, the crawling mode can be changed to add behaviors such as random clicking, scrolling, and mouse movement, making the crawler look more like the actions of real users and less predictable. It is a best practice to consider how the average user navigates a website and apply these principles to the working mode of the crawler.
4. Crawling during off-peak hours
Crawlers typically navigate pages much faster than regular users because they don't actually read the content. Therefore, an unrestricted web crawler tool has a greater impact on server load than any average Internet user. In order to avoid being restricted, crawling can be carried out during off-peak hours, reducing the burden on the target website and improving the efficiency of crawling.
In summary, the use of proxy servers, IP rotation, changing the crawling mode, and crawling during off-peak hours are effective measures to prevent crawling from being restricted. Through rational use of these methods, the stability and security of the crawler can be improved to ensure the smooth progress of data acquisition.