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This article mainly explains "what are the ways in which web crawlers use proxy IP". The explanation in the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what are the ways in which web crawlers use proxy IP"?

1. Each process randomly takes the IP list from the interface and reuses it. If it fails, call API to get it.

The general logic is as follows:

1. In each process, randomly retrieve part of the ip from the interface and try the ip directory repeatedly to get the data.

2. If the visit is successful, continue to catch the next one.

3. If it fails, take a batch of IP from the interface and continue to try.

The disadvantage of the solution: every IP has a deadline. If you extract 100 and use the 20th, most of the rest may not be available. If the connection time is more than 3 seconds and the read time is more than 5 seconds when setting the HTTP request, it may take 3-8 seconds, and hundreds of fetches may be made within 3-8 seconds.

Second, each process randomly takes an IP from the interface to use. If it fails, call API to get the IP.

The general logic is as follows:

1. For each process, randomly retrieve an ip from the interface and use it to browse resources

2. If the visit is successful, continue to catch the next one.

3. If it fails, randomly take an IP from the interface and continue to try.

Disadvantages of the solution: calling API to obtain IP is very frequent, which will put a lot of pressure on the proxy server, affect the stability of the API interface, and may limit extraction. This scheme is not suitable for long-term stable operation.

Third, first of all, extract a large number of IP into the local database, and extract IP from the database.

The general logic is as follows:

1. Create a table in the database, write an import script, how many API are needed per minute (consult the IP service provider for advice), and import the IP list into the database.

2. Record import time, IP, Port, expiration time, IP availability status and other fields

3. Write a crawl script to read the available IP from the database, and each process gets an IP from the database for use.

Perform fetching, judging results, processing cookie, etc. Whenever there is a CAPTCHA or fails, abandon the ip and replace the ip

Thank you for your reading, the above is the content of "what are the ways in which web crawlers use proxy IP". After the study of this article, I believe you have a deeper understanding of the way web crawlers use proxy IP, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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