What is a web crawler: principles of work and data crawling technology to begin to analyze

What's a web crawler? Put a vacuum cleaner on your data and find out.

Imagine you have a smart vacuum cleaner in your house that goes around every room at regular intervals every day collecting dust. A web crawler is like this vacuum cleaner, except that it sucks up data from web pages. This program will follow a set route (professionally called aCrawl Strategy) Wander around the various pages of the site and save the text, images, and links you see into a database.

But the reality of the crawler can be more troublesome than a vacuum cleaner - many sites are standing at the door of the "security", found abnormal access to the direct blocking of IP. this time you need to give the crawler set a "cloak", that is, proxy IP. In this case, it is necessary to put a "cloak" on the crawler, that is, a proxy IP, such as using ipipgo's residential IP pool, so that the website will think that you are a real user surfing the Internet at home, rather than a robot in the server room furiously scrubbing data.

Crawler stuck in three pits Proxy IP to fill the gap

Newbies playing with crawlers often run into these hurdles:

To give a chestnut, there is a do price comparison website friends, with their own office IP to catch e-commerce data, the results of the next day the entire company network are blocked. Later, he switched to ipipgoLong-lasting static residential IPNot only is the success rate mentioned in 98%, but you don't have to worry about implicating the company network.

Choose proxy IP to see the doorway Do not be fooled by parameters

There are three types of proxy IPs on the market:

• Server Room IP: Cheap but easy to recognize, suitable for short-term testing
• Residential IP: from a real home network, which is only available from specialized service providers like ipipgo.
• Mobile IP: Dynamic allocation of base stations with the highest level of covertness

Focusing on residential IPs, ipipgo has a resource pool covering 240+ countries and regions, which is equivalent to having "data relay stations" in every city in the world. For example, if you want to capture regionally restricted content, it is much more reliable to access it with a local home IP than with a server room IP.

Here's one.cold knowledge: Many websites will detect IP affiliation. If different accounts always log in with the same IP, it is easy to be judged as a related account. With ipipgo's dynamic IP pool, you can effectively avoid this risk by changing residential IPs in different regions for each request.

Practical Configuration Guide Hands-On Mine Avoidance

Take the Python crawler as an example of the correct posture for setting up a proxy with the requests library:

import requests

proxies = {
    "http": "http://用户名:密码@gateway.ipipgo.com:端口",
    "https": "http://用户名:密码@gateway.ipipgo.com:端口"
}

response = requests.get("destination URL", proxies=proxies, timeout=10)

Be careful to turn onFailure Retry MechanismAfter all, the network environment is complicated. It is recommended to set up 3 retries, switching different country nodes each time. ipipgo's API supports accurate IP location by country, city, and carrier, which is especially useful for projects that require localized data.

Frequently Asked Questions First Aid Kit

Q: What should I do if I always encounter 403 bans?
A: three-pronged solution: 1. check whether the request header simulates the browser 2. reduce the frequency of requests 3. replace ipipgo's high stash proxy type

Q: How to choose between dynamic IP and static IP?
A: Static IPs are needed to keep the session continuous (e.g., login state), and dynamic IPs are used for large-scale data collection. ipipgo supports both types, and you can mix and match as needed.

Q: High proxy IP latency affects efficiency?
A: Enable smart routing in the ipipgo console to automatically select the node with the lowest latency. Also adjust the number of concurrency of the crawler to find a balance between bandwidth and stability.

Lastly, I would like to remind you that using a proxy IP is not a get-out-of-jail-free card, and you have to work with a reasonable crawling strategy. Just like driving a car can not just rely on seat belts, but also to comply with traffic rules. Consider ipipgo's proxy service as infrastructure, and combine it with business needs to formulate a capture program in order to obtain a long-term stable data gold mine.