What is Web Crawler: Proxy IPs in Crawler Applications

What does a web crawler actually do?

Nowadays, you can often hear the word crawler when surfing the web, and to put it bluntly, it isAutomated program to capture web dataCrawler is a powerful tool to help you to find out the weather, compare prices and save news. For example, you want to batch check the weather, than the price, save the news, manual operation must be exhausted, with the crawler can automatically work 24 hours. But the problem is that many sites are installed "watchdog", found abnormal access directly blocked IP, this time it is the turn of the proxy IP show their hands.

Why does a proper crawler have to use a proxy?

To give a real example: an e-commerce platform price monitoring project, with a single IP request 30 times in a row, the 31st direct prompt "frequent operations". The more ruthless sites directly block IP segments, even the entire office disconnected. At this time, the proxy IP is likeTransformers (franchise)The website will be accessed by a different user, with a different "vest" for each request.

Proxy IP real-world three-piece suite

Choosing a proxy IP is not just a matter of grabbing one, you have to look at theThree hard indicators::

1. Survival time: short acting agents (1-30 minutes) suitable for high frequency switching
2. Connection method: recommended API dynamic extraction, more secure than static proxy
3. Geographic location: use the IP of the target web server wherever it is located

import requests
from ipipgo import get_proxy Here we use the ipipgo SDK.

def crawler(url): proxy = get_proxy(type='https', region='Shanghai')
    proxy = get_proxy(type='https', region='Shanghai')
    try.
        res = requests.get(url, proxies={'https': proxy}, timeout=10)
        return res.text
    except.
        print("This IP hangs, automatically switch to the next one.")
        return crawler(url)

Common Pitfalls and How to Crack Them

Question 1: Why was I blocked even though I used a proxy?
It could be that a blacklisted IP is being used, or that the switching is not frequent enough. This is the time to go with something like ipipgoReal-time update of IP poolsof service providers who add 200,000+ new pristine IPs every day.

Question 2: What should I do if the proxy affects the crawling speed?
It is recommended to use asynchronous request + proxy pool two-pronged. The actual test with ipipgo's exclusive bandwidth proxy, the speed can be more than 3 times faster than ordinary proxy, latency control in 200ms or less.

QA time

Q: Is there a big difference between free proxies and paid proxies?
A: Free agents are like public restrooms, anyone can use them and they are not hygienic. Professional services such as ipipgo not only provideEnterprise SLA AssuranceThere are also features such as automatic IP replacement and request failure retry.

Q: How many proxy IPs do I need to prepare to be enough?
A: There is a formula:Number of IPs = Requests per day ÷ (Average number of times a single IP is available per day x 0.8)For example, to send 100,000 requests per day, a single IP can be used 500 times. For example, if you want to send 100,000 requests per day, and a single IP can be used 500 times, you need at least 250 IPs. ipipgo's elastic scaling feature just matches this demand.

As a final word of caution, don't just look at price when choosing a proxy service. A service like ipipgo offers7×24 hours technical supportThe one that can also customize the agent's program on demand is the one that really saves money and effort. After all, the reptile program is not the most afraid of spending money, but the key moment to drop the chain.