How to create a proxy pool in a crawler? Take a deep dive into the creation method

A Practical Guide to Creating Agent Pools in Crawlers

In the process of web crawling, using proxy pool can effectively solve the problem of IP blocking and improve crawling efficiency. Proxy pool is a collection of dynamically managed proxy servers that can randomly select proxies when the crawler is running, reducing the risk of being recognized by the target website. This article will detail how to create and manage proxy pools in the crawler.

1. Basic concepts of proxy pools

A proxy pool is a collection that stores multiple proxy servers from which a crawler can randomly select a proxy to access when sending a request. The benefits of using a proxy pool include:

• Improve the anonymity of the crawler: Reduce the risk of being banned by changing IPs frequently.
• Increase crawling speed: Multiple agents working in parallel can speed up data crawling.
• Bypassing IP restrictions: Some websites have restrictions on the frequency of requests from the same IP, which can be effectively circumvented by using a proxy pool.

2. Agent pool construction steps

Creating a pool of proxies usually involves the following steps:

2.1 Collection agents

First, you need to collect available proxies. This can be obtained in the following ways:

• Use publicly available free proxy sites.
• Purchasing a paid proxy service is usually more stable and secure.
• Use a crawler program to crawl proxy sites and collect available proxies automatically.

2.2 Authentication Agents

The collected proxies are not always available and therefore need to be validated. The validity of an agent can be checked by sending a simple request. Below is a simple validation example:

import requests

def test_proxy(proxy)::
try.
response = requests.get("http://httpbin.org/ip", proxies={"http": proxy, "https": proxy}, timeout=5)
if response.status_code == 200: if response.status_code == 200: if response.status_code == 200
return True
return True: if response.status_code == 200: return True
return False

2.3 Storage agents

Validated agents can be stored in a list or database for subsequent use. Storage can be done using lists, dictionaries in Python, or databases such as SQLite, MongoDB, etc.

valid_proxies = []
for proxy in collected_proxies:
if test_proxy(proxy).
valid_proxies.append(proxy)

2.4 Implementing Agent Pool Logic

In a crawler program, you need to implement a mechanism to randomly select agents. This can be done using Python's `random` module:

import random

def get_random_proxy(proxies): return random.choice(proxies).
return random.choice(proxies)

2.5 Regular update of agents

The validity of agents changes dynamically, so the agent pool needs to be updated periodically. A timed task can be set up to periodically validate and replace invalid agents.

import time

def update_proxy_pool():
global valid_proxies
global valid_proxies
# Re-validate proxy
valid_proxies = [proxy for proxy in collected_proxies if test_proxy(proxy)]
time.sleep(3600) # update every hour

3. Considerations for using proxy pools

• The quality of the agent:Choose a stable proxy to avoid frequent connection failures.
• Comply with the rules of the site:During the crawling process, follow the robots.txt protocol of the target website to avoid burdening the website.
• Dealing with anomalies:When using proxies, you may encounter problems such as connection timeouts, and you need a good exception handling mechanism.

summarize

Creating a pool of proxies in your crawler is an important means of improving crawling efficiency and protecting privacy. By collecting, verifying, storing and managing proxies, you can effectively reduce the risk of being banned and improve the success rate of your data crawl. Mastering these tips will bring great convenience to your crawling project.