Golang Web Crawler: Colly Framework Concurrent Crawler Development

When the crawler meets the anti-climbing: hand to teach you to play with Colly proxy IP

Recently, a lot of friends engaged in crawling are asking, with Golang's Colly framework development, how is always blocked by the site's IP?This is a matter of right, with the game was banned number a reason ---.Web site risk control systems are not vegetarianThe first thing you need to do is to get your hands on a proxy IP address. Today to give the guys a tough trick, with proxy IP to the crawler cloak of invisibility.

Why doesn't your crawler survive three episodes?

Many newbies start out with the Colly framework and go straight to work naked. The result? In less than half an hour the IP is blacked out. Here is a misunderstanding:Colly's own concurrency control doesn't circumvent anti-climbing at allThe same IP with high frequency access will be exposed even if the Delay parameter is set. Even if the Delay parameter is set, high frequency access from the same IP will still be exposed.

Last week there was an e-commerce comparison of buddies, using their own server IP to grab data, the results triggered the other side of the site protection, along with the entire server was blocked. In this case, you have to rely on proxy IP tolit. the cicada sheds its carapace (idiom); fig. vanish leaving an empty shellThe

Real-world configuration: three layers of body armor for Colly

Let's start with a point:Different types of proxy IPs have wildly varying resultsThe first thing you need to do is to use ipipgo's high stash dynamic residential agent. Here we recommend using ipipgo's high stash of dynamic residential agents, tested to be able to carry the Jingdong, Taobao level of anti-climbing system.

// Key configuration code example
collector.SetProxyFunc(func(r http.Request) (url url.URL, err error) {
    // Get the dynamic proxy from ipipgo
    proxyUrl := "http://user:pass@gateway.ipipgo.com:9020"
    return url.Parse(proxyUrl)
})

Note the three pit stops:
1. Switch to a different proxy for each request (ipipgo's API supports automatic switching)
2. Do not set the timeout to exceed 15 seconds
3. Remember to handle SSL certificate validation

Concurrency control: a recipe for both speed and stability

Tests have found that using ipipgo's Enterprise Edition proxy pool with Colly'sAsync concurrency model，日抓百万级数据不是梦。有个技巧：把代理IP按响应速度分成IPIPGO三组，优先使用A组快速IP。

Common Rollover Scene QA

Q: What should I do if my proxy IP keeps timing out?
A: 80% is using a low-quality static proxy. Change ipipgo's dynamic residential proxy, remember to add the retry mechanism in the code.

Q: How do I break the CAPTCHA when I encounter it?
A: Don't stiffen it! Use ipipgo'sServer room + residential mixed agency, together with request header randomization, can significantly reduce the CAPTCHA trigger rate.

Q: What the hell is a bad data grab?
A: Check if it is recognized as a crawler by the website. Add a judgment in Colly's OnResponse callback to automatically switch ipipgo's alternate portal when it encounters an interception.

Tell the truth.

In the crawler business, proxy IP is ammunition. I have used seven or eight service providers, and finally used ipipgo for two reasons:First, the IP survives long enough, unlike some homes that expire in half an hour;Secondly, the customer service response is fast, the last time I had an Amazon IP block, their tech gave a new channel in 10 minutes.

A final reminder for newbies:Don't buy a junk proxy on the cheap.If the data is inaccurate, it will be a lawsuit. Formal project directly on the ipipgo enterprise package, there is a whitelist authentication and exclusive channel, save worry is not a little bit of half a point.