How to Make a Web Crawler: A Guide to Building from Scratch

Teach you to build a crawler with proxy IPs!

Just started the white want to play crawler, the biggest headache is to be blocked IP. do not panic, today teach you to use theipipgoThe first thing you need to do is to use a proxy IP service to bypass the site's protection. Let's start with a basic Python crawler and then put a cloak on it.

import requests
from bs4 import BeautifulSoup

 Here's a sample proxy from ipipgo (you'll actually have to buy your own)
proxies = {
    'http': 'http://username:password@gateway.ipipgo.com:9020',
    'https': 'https://username:password@gateway.ipipgo.com:9020'
}

response = requests.get('https://目标网站.com', proxies=proxies)
soup = BeautifulSoup(response.text, 'html.parser')
 Followed by your data processing code...

Why are proxy IPs the lifeblood of crawlers?

Webmasters are not vegetarians, they catch frequently visited IPs and block them. UseipipgoThe pool of proxies is equivalent to preparing countless stand-ins for the crawler. Here's a comparison table for you guys:

The Three Doors to Choosing an Agent

There is a mixed bag of agency services on the market, and I've helped you through it. RecommendedipipgoThe main points to look for are these:

1. The IP pool is deep enough: Their family has more than 8 million dynamic IPs globally, two to three times more than their counterparts

2. Long survival time: A single IP can be used for an average of 12 hours, unlike some that expire in half an hour.

3. Complete agreement: HTTP/HTTPS/SOC5 are supported, adapted to a variety of crawler frameworks

Real-world anti-blocking tawdry operation

It's not enough to have an agent, you have to be able to play combos. I'll give you a few tips:

① random hibernation: Add 0.5-3 seconds of random delay between requests to mimic a real person's operation

② Replacement of UA: Prepare 20 browser logos to rotate

(iii) fail and try again: Auto-switching IP in case of 403 error, don't be so hard-headed!

import random
import time

headers_list = [
    {'User-Agent': 'Mozilla/5.0 (Windows NT 10.0)...'} ,
    {'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)...'}
]

def safe_request(url): {'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7...'} ]
    try: time.sleep(time.uniform(time.sleep(time.sleep(time.uniform))
        time.sleep(random.uniform(0.5, 3))
        headers = random.choice(headers_list)
        response = requests.get(url, headers=headers, proxies=proxies)
        return response
    except Exception as e.
        print(f "Request failed, automatically change IP and retry")
         Here we call the ipipgo API to change the IP address.
        return safe_request(url)

Common pitfalls for newbies QA

Q: What should I do if my proxy IP is slow?

A: SelectipipgoThe exclusive high-speed channel, their home has BGP intelligent routing, faster than ordinary lines 40%

Q: What should I do if I always encounter CAPTCHA?

A: It is recommended to buy their high stash of residential IPs for a higher degree of camouflage. At the same time control the speed of collection, don't push the website to the edge

Q: Do I need to build my own agent pool?

A: Personally, it's more cost-effective to buy ready-made directly. LikeipipgoWith this kind of professional service provider, the maintenance cost is much lower than building it yourself

Why the death of ipipgo?

After using the agency's services for more than two years and comparing a dozen of them: theyIP Survival 92%highest in the industry.Average daily update of 300,000 IPI've had a lot of problems with the product, and the customer service is very responsive. The last time I encountered technical problems, there are actually engineers online support at 2:00 in the morning.

Lastly, a word of advice: don't buy a junk proxy on the cheap, the data lost from being blocked can be much more expensive than the proxy fee. Use a goodipipgoThis type of reliable service is what allows the crawlers to work consistently over time.