What is a web crawler | core technology analysis and data collection applications

First, what the hell is a web crawler?

To put it bluntly, the network crawler is like a diligent "data mover", automatically grabbing useful information on the Internet every day. For example, you want to compare the price of cell phones on ten e-commerce platforms, manually check the exhaustion, the crawler can help you in minutes to strip down the data. But there is a hurdle in this matter - many websites will beBlocking IP addresses with high frequency access, like a mall security guard keeping an eye on suspicious people who repeatedly come and go.

Second, engage in reptiles must know the three major propositions

1. Camouflage should be in place
Don't let the site realize you're a robot! By randomly switching User-Agents and setting reasonable delays, you can disguise the pace of visits as if they were being browsed by real people. Here's a hidden trick: visiting with an IP from a different region can make it harder for the anti-crawling system to recognize.

2. Breaking the frequency of visits
Many platforms have set the rule of "maximum 20 visits per minute from the same IP". Tests have shown that usingDynamic Residential Proxy IPRotation, the success rate is more than 3 times higher than the server room IP. Especially when collecting websites that require login, real residential IPs are less likely to trigger CAPTCHA.

3. Distributed deployment for crash prevention
Never put your eggs in one basket! Build a distributed crawler with multiple proxy IPs, so that even if one IP is blocked, the other nodes will continue to work. Here we recommend usingAPI interface for ipipgoThe IP resources of 240+ countries around the world are automatically scheduled, and the stability is directly pulled up to full capacity.

Third, the proxy IP of the actual combat wonderful use

Recently, I helped a friend to do a travel price comparison project, and I solved a big problem by proxy IP. They needed to monitor the prices of 50 booking sites around the world in real time, and used theDynamic residential IP for ipipgoIn conjunction with smart routing, it was successfully implemented:

Fourth, QA time: the most common pitfalls of crawler er

Q: Why does my crawler work at first and then go dead in a few days?
A: 80% of the IP is blacked out! Many websites will record the IP access characteristics, it is recommended to use theipipgo's pool of 90 million + residential IPs, switching to a different home broadband outlet for each visit, and personally running for half a month straight with no problems.

Q: How to choose between dynamic IP and static IP?
A: high-frequency collection with dynamic, long-term task with static. For example, if you need a lot of IP switching to grab a ticket, choose dynamic, and monitor a fixed page with static more stable. ipipgo supports both, and the background can also view the IP survival status in real time.

Q: How do I break the CAPTCHA when I encounter it?
A: Don't be rigid! Reasonable setup of collection speed + use of real life residential IP can reduce 90% CAPTCHA. ipipgo's IP comes with real life device fingerprints, together with automation tools to process the remaining CAPTCHA, the success rate directly soars.

Fifth, choose the right tool for twice the effort and half the effort

After doing a dozen crawler projects, I found that the proxy IP service providers are too deep! Some of them claim to have millions of IPs, but the actual availability rate is less than 30%.ipipgoAfter that, the most intuitive feelings are three:
1. Response rate increased by 2 seconds/request (don't underestimate this, saving 555 hours for millions of data)
2. support socks5/http(s) all protocols, docking code without major changes
3. Unique IP quality monitoring system, automatic filtering of failed nodes

Recently, they have a new IP customization function according to business scenarios, cross-border e-commerce friends used to collect multi-country commodity data, which is said to save 60% maintenance time than before. Engaged in technology understand, stable and reliable underlying support, is the hard truth of the success of the project.