Using Proxy IPs to Scrape Web Pages with Golang: Configuring Proxy IPs for Golang Web Crawlers

I. Why is your crawler always blocked? Try this trick

Crawler brothers understand that the biggest headache is the target site suddenly blocked IP. last month I helped a friend to catch a certain e-commerce data, just run for two days on the ban a dozen IP addresses. This time we have to use the proxy IP this magic weapon, especially like theipipgoThis dynamic IP pool provided by a professional service provider can make you as slippery as a loach.

Ordinary crawler direct connection is like holding up an ID card to break into the door, proxy IP is to give you a magic mask. ByipipgoThe proxy server relay, the target site to see is constantly changing IP address, simply can not feel your real identity.

Second, hands-on Golang agent configuration

Golang comes with http.Client actually hides a big baby, set the Transport can easily use the proxy. Look at this live code:

func createProxyClient(proxyURL string) http.Client {
    proxy, _ := url.Parse(proxyURL)
    transport := &http.Transport{
        Proxy: http.ProxyURL(proxy), // Remember to add this to prevent lagging.
        // Remember to add this to prevent snags
        TLSHandshakeTimeout: 10 time.
    Second, }
    return &http.Client{Transport: transport}
}

// Example of a proxy using ipipgo
client := createProxyClient("http://username:password@gateway.ipipgo.com:9021")
resp, err := client.Get("https://target-site.com/data")

Here's the point:ipipgoThe format of the proxy address to pay special attention to the username and password do not write directly in the code, it is recommended to use environment variables. Their API supports dynamic generation of authentication information, much safer than traditional static passwords.

III. Five guidelines for avoiding pitfalls (blood and tears experience)

1. IP switching frequencyDon't wave too much: some brothers change IP every request, the result is recognized as abnormal traffic. It is recommended to adjust the anti-climbing strategy according to the target site, generally 30 seconds to 5 minutes to change a suitable.

2. timeout settingIt's a life saver: I've seen people not setting a timeout, and the proxy server crashes and causes the program to freeze. It is recommended to configure it like this:

transport := &http.Transport{
    ResponseHeaderTimeout: 15 time.
    ExpectContinueTimeout: 2 time.
Second, ExpectContinueTimeout: 2 time.Second, }

3. error retryBe sure to have a brain: don't retry without thinking, and when you encounter 403/429 status codes, you should hibernate before changing IPs.ipipgo's API return header will indicate the recommended wait time, this should be utilized.

IV. Practical skills to give away

Engage in crawler can not only basic operation, these a few tart operation allows you to double the efficiency:

Share another cold knowledge: assign the proxy IP to use by geographic location. For example, when grabbing regional data, the success rate of accessing with local IP is higher.ipipgoSupport for filtering IPs by province and city, this feature is measured to improve 20% collection efficiency.

V. Demining of Common Problems

Q: What should I do if the proxy suddenly fails?
A: Immediately switch the backup proxy pool, it is recommended to prepare 2-3 at the same timeipipgoof different access points, their console can view the node health status in real time.

Q: What should I do if I encounter human verification?
A: This is a time when higher quality agents are needed thatipipgoThe enterprise package supports high stash mode, which in conjunction with request header randomization can effectively bypass basic authentication.

Q: Does agent speed affect acquisition efficiency?
A: It is important to choose the right protocol, HTTP proxy is suitable for common scenarios, HTTPS proxy is a bit slower but more secure.ipipgoThe SOCKS5 agent balances speed and security, with measured latency 40% lower than conventional solutions.

Finally, a true story: a customer couldn't get the proxy to work, but later found out that the code had put thehttp.TransportThe configuration is written outside the loop. So remember, it's best to use a newly created instance of Transport for each request, or do a good job of connection pooling management.