Structured Data Extraction: XPath and CSS Selectors Advanced

I. When data localization meets dynamic IP pooling

The old iron engaged in data capture know that the structure of the web page changes every day just like the temper of the girlfriend. This time XPath and CSS selectors are your lynch pin, but there is a dodgy problem - theThe anti-crawl mechanism of the target website will remember your IPIt's time for ipipgo's Dynamic Residential Proxy to take over. At this time it is time for ipipgo's dynamic residential proxy to take the field, it has 20 million+ real residential IPs in its IP pool, which is automatically switched for each request, and with accurate selector positioning, it is like putting a cloak of invisibility on the crawler.

Second, the selector practical guide to avoid pitfalls

A common misconception among newbies is to stick to absolute paths, such as having to use the/html/body/div[3]/div[2]/spanThis way of writing. In fact, it is more stable to use relative path + attribute positioning, such as//div[@class='price']/span[contains(text(),'¥')]The proxy service of ipipgo has a good use: when accessing from different IPs, you can find that the class names of certain elements will be localized.css selector div[class^='price_']This fuzzy match is particularly fragrant.

III. The three axes of the anti-anti-crawl

Don't panic when you encounter a CAPTCHA pop-up, try these three tricks: 1) Use ipipgo'sLong-lasting static residential IPEstablishing Trusted Sessions 2) Combining//meta[@name='robots']Detecting Crawler Rules 3) CSS Selectorsdiv:not([data-anti])Excluding trap elements. It is measured that with this method, the success rate of merchandise data collection of an e-commerce platform is directly dried from 47% to 89%.

IV. Cold techniques for doubling efficiency

Don't underestimate the browser developer tools, look for them in the Network panel.XHR RequestTaking the data interface directly is more than 10 times faster than parsing the DOM. This is where using ipipgo'sAPI proxy modelIf you want to use the proxy address directly in the proxies parameter of the requests, remember to set 5 seconds to switch the IP automatically, and test that you can bypass the interface frequency limit of 99%.

V. Practical QA First Aid Kit

Q: What should I do if I always get redirected to the verification page?
A: 80% of the IP is tagged, change to ipipgo's mobile cellular proxy, remember to add in the XPath//noscriptContent parsing, many sites will hide the real data in noscript.

Q: Do selectors work in the browser but not in the code?
A: Check if it's a dynamically rendered page with ipipgo'sSelenium Specialized AgentsIn conjunction with explicit waiting, waiting for an element to finish loading before grabbing it is much more reliable than implicit waiting.

Q: How do you handle infinite scrolling waterfalls?
A: Use the CSS selector firstwindow.scrollTo(0,document.body.scrollHeight)Trigger the loading, then use ipipgo'sMulti-threaded asynchronous proxy, different threads are collected in chunks with different regional IPs.

Lastly, I'd like to apologize for using ipipgo.Intelligent Routing AgentThere is a hidden trick: the domestic target station to go static business IP, overseas resources to go dynamic residential IP, so that the success rate of selector positioning directly pull full. Their proxy manager can also automatically detect IP availability, than manually change the IP to save not half a star.