How does a web crawler use proxy ip

This article introduces the relevant knowledge of "how to use proxy ip for web crawler". In the operation process of actual cases, many people will encounter such difficulties. Next, let Xiaobian lead you to learn how to deal with these situations! I hope you can read carefully and learn something!

1. Each process interface randomly obtains the IP list and uses it repeatedly. After it is invalid, call API to obtain it.

The general logic is as follows:

1. Each process randomly recovers a part of ip from the interface and repeatedly tries the ip directory to capture data.

If the visit is successful, move on to the next one.

3. After failure, take IP from the interface and continue to try.

Disadvantages: All IPs have a deadline, extract 100, use the 20th, the rest may not be used. Set HTTP request connection time to more than 3 seconds, read time to more than 5 seconds, may take 3 to 8 seconds, in these 3 to 8 seconds may catch hundreds of times.

First extract a large number of IPs, import them into the local database, and then extract IPs from the database.

The general logic is as follows:

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

2. Record the fields such as import time, IP, port, expiration time, IP availability status, etc. into the database;

Write a grab script that reads available IPs from the database, and each process gets an IP usage from the database.

4. Capture, judge results, process cookies, etc. As long as Captcha or error appears, abandon IP and replace IP again.

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