Python crawler proxy pool building | Scrapy automatically switch IP anti-blocking

How can Python crawlers avoid being blocked? Proxy pool building core ideas

When your crawler visits the target website continuously, the server will recognize abnormal traffic by request frequency, IP address and other characteristics. Many newbies will be puzzled:Why is it still blocked even though the random request header is clearly set?In fact, the core problem is thatOver-concentration of access trajectories from a single IPThe

By building a pool of proxy IPs, it is possible to use a different exit IP for each request. here's the key trick:Dynamic Residential Proxy IPHarder to identify than data center IP. For example, using the residential IP resources provided by ipipgo, the IP segments come from real home broadband and are naturally more anonymous.

Build a basic proxy pool in three minutes (with Python code)

The essence of proxy pooling is to maintain a list of available IPs and verify validity in real time. The leanest implementation is demonstrated here:

"`python
import requests
from concurrent.futures import ThreadPoolExecutor

class ProxyPool.
def __init__(self).
self.api_url = "https://api.ipipgo.com/getip" ip ipgo gets the API address of the IP
self.valid_ips = []

def fetch_ips(self).
resp = requests.get(self.api_url, params={'type': 'http'})
new_ips = [f"{ip}:{port}" for ip,port in resp.json()['data']]
with ThreadPoolExecutor(10) as ex.
ex.map(self.validate_ip, new_ips)

def validate_ip(self, ip).
try.
resp = requests.get('http://httpbin.org/ip',
proxies={'http': f'http://{ip}'},
timeout=5)
if resp.json()['origin'] in ip.
self.valid_ips.append(ip)
except.
pass
“`

Batch verify IP availability through thread pool, it is recommended to set up a timed task to update the IP pool every hour. Note that selecting support forHigh Concurrency APIservice provider, ipipgo's API response speed is measured within 200ms, which is suitable for high-frequency acquisition.

Scrapy automatically switch IP anti-blocking configuration details

In the Scrapy framework, intelligent switching agents are implemented through middleware:

"`python
class CustomProxyMiddleware.
def __init__(self, proxy_pool).
self.proxy_pool = proxy_pool

@classmethod
def from_crawler(cls, crawler).
return cls(crawler.settings.get('PROXY_POOL'))

def process_request(self, request, spider).
if 'proxy' is not in request.meta:
proxy = self.proxy_pool.get_random_ip()
request.meta['proxy'] = f'http://{proxy}'

def process_response(self, request, response, spider).
if response.status in [403, 429]:
self.proxy_pool.mark_bad(request.meta['proxy'])
return request
return response
“`

There are two key points here:

1. Automatic injection of valid proxies before requests
2. Automatically eliminates invalid IPs when encountering blocking status codes

Suggested to go with ipipgo'ssession hold functionWhen it is necessary to keep the same IP (e.g. login status), their long-lasting proxy service can be used.

Proxy IP Usage Frequently Asked Questions QA

Q: What should I do if the proxy IP connection times out?
A: Check whether the proxy protocol matches (HTTP/HTTPS/SOCKS5), ipipgo supports full protocol auto adaption, no need to configure separately.

Q: How can I avoid reusing IPs in the proxy pool?
A: Recommendedweight polling algorithmIf you want to set a limit on the number of times each IP can be used, ipipgo's API supports the return of unused new IPs.

Q: Why do you recommend using ipipgo's proxy service?
A: Their residential IP covers 240+ countries and regions around the world, 90 million+ real home IP resources, supports dynamic/static multiple modes, and is especially suitable for crawler scenarios that require high anonymity.

Five guidelines for avoiding pitfalls in the real world

Lastly, it is recommended to set up reasonable request intervals, rotate the use of User-Agent, and comply with the website robots protocol. Through the above methods, the actual test can be crawler survival cycle from a few hours to weeks level.