How to Crawl Data from Websites with Python: Getting Started to Hands-On

Hands-on Python-style data grabbing

Recently, many small partners asked me to see other people's programs automatically grab the price of goods, grab concert tickets, write their own code is always blocked IP how to do? This thing is not difficult to say difficult, today I will teach you how to use proxy IP to play with the data capture. Don't be in a hurry to close the page, I promise not to talk about the terminology of those who are not familiar with the cloud, let's actually jerk code.

Why is your crawler always in the dark?

Webmasters are not vegetarians, see a certain IP crazy request, directly to your blacklist. I've seen the most ruthless e-commerce platform, 20 consecutive visits to the IP block.proxy IP poolto disguise their true identity, as if they were playing a game of chicken and kept changing their vests.

Real-world open code

First, install the requests library, this is our Luoyang shovel. Focus on how to stuff proxy IPs in:

import requests
from random import choice

 Proxy pool from ipipgo
proxy_pool = [
    "http://user:pass@gateway.ipipgo.com:9020",
    "http://user:pass@gateway.ipipgo.com:9021".
     Put at least 20 IPs here
]

url = "https://目标网站.com/data"

try.
    resp = requests.get(url,
        proxies={"http": choice(proxy_pool)},
        timeout=8
    )
    print(resp.text)
except Exception as e.
    print(f "Finished: {str(e)}")

Note the three points:

1. Proxy format should be written correctly, the account password should not be reversed
2. Randomly select IPs for each request, don't catch a gripe
3. Don't set the timeout to more than 10 seconds, or it will crash

Essential Tips for Advanced Players

Don't think that by adding an agent everything will be fine, the website also has these damaging tricks:
- User-Agent detection (remember to use the fake_useragent library)
- Request frequency monitoring (control up to 3 times per second)
- Captcha raid (gotta change IPs + clear cookies at this point)

Recommended for ipipgoIntelligent switching modeThe API can automatically change the IP address, which is more convenient than maintaining the pool by yourself. Especially when doing price comparison system, every hour to catch a few thousand pages, no reliable agent simply can not play.

Common Rollover Scene QA

Q：Why can't I catch the data when the code is fine?
A: eighty percent of the site used asynchronous loading, have to use selenium with the proxy, or directly find the interface address

Q: Do free proxies work?
A: Newbie practice can, serious project never! I used a free IP last time, the result is to catch the fake data modified by others, blood loss!

Q: How do I choose a package for ipipgo?
A: For personal development, go with the $19/day experience package, and for enterprise level, use the customized package. They have a hidden trick - 12 o'clock in the middle of the night renewals have discounts, the general public I do not tell!

The Ultimate Anti-blocking Arcana

Lastly, I'd like to pass on a unique tip:
1. Mixed use of residential and server room IPs
2. HTTPS proxy for important requests
3. Weekly update of IP whitelist
These tricks with ipipgo's IP quality detection function, basically can realize all-weather stable crawl. The last time I used this set of programs for 72 hours, froze without being banned.

Don't think it's easy to talk about it now, but I didn't pay a lot of tuition back in the day. Remember that data capture is a war of offense and defense, the proxy IP is your bulletproof vest. What specific questions welcome to tease, see will be back. Don't just collect ah, quickly open the editor to practice!