C# crawler development in practice: from the beginning to efficient collection

Hands-on with C crawlers to avoid anti-crawl traps

Recently, a lot of brothers asked me to write a crawler with C always be blocked IP how to do? Today, I'm going to tell you the truth. Let's take the capture of e-commerce price data, for example, without the use of proxy IP, will not last more than half an hour quasi-blocked. Here to teach you a masterpiece - useDynamic IP PoolPlay Guerrilla Warfare, see below for details on how to play.

Development environment preparation (don't rush to write code)

After installing Visual Studio first do not rush to jack code, we have to gear up neatly. HttpClient object to set the timeout, this many newbies will forget:

var handler = new HttpClientHandler { AutomaticDecompression = DecompressionMethods.All }; var client = new HttpClient(handler) { Timeout = TimeSpan.FromSeconds(30) };
var client = new HttpClient(handler) { Timeout = TimeSpan.FromSeconds(30) }; var client = new HttpClient(handler) { Timeout = TimeSpan.

Here's the kicker! Remember to keep ipipgo's API documentation open for backup, they providevolumetric billingpackages, newbies get the best value with the $5 experience package.

Basic Acquisition Process Treadmill Fact Sheet

First write the simplest collection demo, here is a blood lesson:Never use a fixed User-Agent.! Let me show you a counterexample:

// Wrong way to write it (immediately blocked)
client.DefaultRequestHeaders.UserAgent.ParseAdd("Mozilla/5.0");

The correct posture is to randomly change UA every 20 requests, with ipipgo's dynamic IP, the survival rate is directly doubled. Here we recommend theirIntelligent switching of nodesThe function of automatic IP change saves a lot of heart.

Proxy IP Integration Tips

Focus on how to access ipipgo's services in C. Their API return format is extra simple and understandable to a novice:

// Example of getting a proxy IP
var proxy = await GetIpipgoProxy(); handler.
handler.Proxy = new WebProxy($"{proxy.ip}:{proxy.port}");

Be careful to configureFailure Retry MechanismIt is recommended to set up 3 retries + auto reject failed IPs. remember to turn them on when using ipipgo.IP Survival DetectionThis feature saves a lot of work.

Efficient Acquisition Optimization Solution

Advanced players can try these tawdry maneuvers:
1. Multi-threading with different proxy IPs (ipipgo's concurrent package supports 50 threads)
2. Randomization of request header fingerprints (including but not limited to Accept-Language/Cookies)
3. Intelligent speed reduction strategy (automatically extends waiting time when encountering CAPTCHA)
The actual test with this program, the average daily collection can skyrocket from 10,000 to 200,000 +, the key is to choose the right proxy service provider. Here must boast ipipgoexclusive IP pool, use it and you'll know the world of difference from a free agent.

Frequently Asked Questions First Aid Kit

Q: What should I do if my proxy IP is not working after I use it?
A: Check the IP survival status, it is recommended to use ipipgo's API to get the latest IP in real time, their IP validity period is 3 times longer than others.

Q: What if the collection speed is slow as a snail?
A: 80% of the time, you don't have multithreading on! In conjunction with ipipgo'sMulti-geographic nodesThe IPs of the different threads are assigned to different regions.

Q: How do I break the CAPTCHA that keeps triggering?
A: Three steps: 1) Reduce the frequency of requests 2) Change the UA template 3) Switch ipipgo'sHigh Stash IPIt works.

Lastly, I would like to say a few words from the bottom of my heart, don't be greedy for cheap proxy services. I've used a few cheap ones before, and 8 out of 10 IPs didn't work. Then change ipipgoEnterprise PackageThe efficiency of the acquisition took off directly. Especially their technical support response is fast, the middle of the night out of the problem can find people, this point is truly praise.