BlogA way to ensure that crawlers successfully access public data

A way to ensure that crawlers successfully access public data

2023-08-08 10:22:44

When performing crawling tasks, one common problem is often encountered: public data cannot be successfully accessed via IP. As the access measures of major websites continue to strengthen and upgrade, the crawler work becomes more challenging. However, there are some measures that can help us to minimize the problem of crawlers not being able to access public data and ensure that the task goes smoothly.

1. Use distributed crawlers

Distributed crawlers can not only improve the efficiency of crawling, but also effectively deal with the dilemma of IP blocking to ensure continuous barrier-free data access.

The operating principle of distributed crawler is to decompose a crawler task into multiple subtasks, and assign these subtasks to different crawler nodes to execute. Such division of labor cooperation not only shares the burden of a single node, but also makes the whole grasping process can be executed in parallel, which greatly improves the efficiency. At the same time, by allocating tasks properly, too frequent requests for a single IP address can be avoided, thus reducing the risk of being blocked by the website.

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Another advantage of distributed crawlers is the use of multiple ips. By distributing tasks to different IP addresses, you're actually spreading the stress of access across multiple sources. This helps to reduce the frequency of visits to each IP, making it difficult for websites to recognize abnormal access behavior from a single IP. Therefore, even if one IP address is blocked, other IP addresses can still continue to access, ensuring the continuity of data acquisition. To further increase the anti-blocking strategy, the distributed crawler can also take turns using different proxy IP between different nodes. In this way, even if the IP of one node is blocked, the IP used by the next node is still brand new, avoiding the chain effect of being blocked. By dynamically changing the IP address, the distributed crawler ensures the stability of data acquisition while maintaining efficient fetching.

2. Use multiple IP addresses

In the face of the access mechanism and frequency restrictions of websites, the adoption of multi-IP strategy has become a key measure to ensure that crawlers can successfully access public data. Many websites monitor the frequency of account visits, and when the frequency reaches a certain threshold, the access mechanism is triggered, resulting in the IP being blocked. To circumvent this problem, a multi-IP strategy can reduce the risk of being blocked to some extent.

When implementing a multi-IP strategy, it is first necessary to test the crawl threshold of a single account, that is, the maximum number of requests that can trigger the access mechanism of the website. Once this threshold is mastered, it is possible to switch to a different proxy IP before reaching it, thus spreading out the frequency of access. This method effectively reduces the number of requests for a single IP address and reduces the probability of being blocked.

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Using multiple different IP addresses also helps to simulate multi-user access behavior, closer to natural network access patterns. The multi-IP strategy makes the crawler appear to be coming from multiple users, reducing the risk of being identified as a crawler by the site. This strategy of simulating multiple users not only helps to circumvent the blocking problem, but also reduces the pressure on a single IP request, thus ensuring continuous data acquisition.

3. Solve the verification code problem

In the process of crawling for a long time, sometimes you will encounter a situation where you need to enter a verification code. This may be because the target site has already identified you as a crawler. One way to solve this problem is to manually enter the CAPTCHA. When the crawler encounters the need to input the verification code, it can download the verification code to the local, and then manually input it to simulate manual operation. This bypasses automated identification and improves access success.

4. Ways to bypass website restrictions

In addition to the above methods, there are some other tips that can help us bypass the access restrictions of the website and ensure that the crawler can successfully access the public data. For example, the visit frequency of the crawler can be adjusted to avoid too many requests in a short time; Random access intervals can be set to simulate the behavior of real users. Different user-agents can also be selected to make the crawler look more like a normal browser access.

It's common to encounter situations where you can't access public data when doing crawler tasks. By using distributed crawlers, multiple ips, solving captcha issues, and other ways around restrictions, we can minimize this problem and ensure that crawlers can successfully access the data they need. It can not only improve the grasping efficiency, but also ensure the smooth completion of the task.

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