Budowa warstwa Proxy Middleware do skracania

Dlaczego budować Proxy Middleware Warstwa

Kiedy projekt scrating rośnie poza jeden skrypt, potrzebujesz warstwy abstrakcyjnej pomiędzy kodem aplikacji i dostawcą proxy. Warstwa middleware obsługuje selekcję proxy, uwierzytelnianie, ponowną logikę, defeafover i logowanie - więc twoje scrappers martwić się tylko o pobieranie danych.

Bez middleware, każdy scraper w kodebase powiela konfigurację proxy, obsługę błędów i logikę rotacji. Ten przewodnik pokazuje, jak projektować i budować proxy proxy klasy produkcyjnej w Python i Node.js, za pomocą Rotacyjne proxy mieszkaniowe ProxyHat.

Proxy middleware znajduje się pomiędzy aplikacją a internetem. Przechwytuje wychodzące żądania, przekierowuje je przez proxy, obsługuje błędy i zwraca czyste odpowiedzi do kodu aplikacji.

Przegląd architektury

Dobrze zaprojektowany proxy middleware posiada cztery podstawowe elementy:

Wdrażanie programu Python Middleware

Główny menedżer proxy

import uuid
import time
import logging
from dataclasses import dataclass, field
from typing import Optional
logger = logging.getLogger(__name__)
@dataclass
class ProxyConfig:
    gateway: str = "gate.proxyhat.com"
    http_port: int = 8080
    socks5_port: int = 1080
    username: str = "USERNAME"
    password: str = "PASSWORD"
@dataclass
class RequestMetrics:
    total: int = 0
    success: int = 0
    failed: int = 0
    retries: int = 0
    total_latency: float = 0.0
    @property
    def success_rate(self) -> float:
        return (self.success / self.total * 100) if self.total > 0 else 0.0
    @property
    def avg_latency(self) -> float:
        return (self.total_latency / self.success) if self.success > 0 else 0.0
class ProxyManager:
    """Manages proxy sessions, geo-targeting, and protocol selection."""
    def __init__(self, config: Optional[ProxyConfig] = None):
        self.config = config or ProxyConfig()
        self.metrics = RequestMetrics()
    def get_proxy_url(
        self,
        protocol: str = "http",
        country: Optional[str] = None,
        session_id: Optional[str] = None,
        sticky: bool = False,
    ) -> str:
        username = self.config.username
        # Add session for sticky IPs
        if sticky and not session_id:
            session_id = uuid.uuid4().hex[:8]
        if session_id:
            username = f"{username}-session-{session_id}"
        # Add country targeting
        if country:
            username = f"{username}-country-{country}"
        if protocol == "socks5":
            port = self.config.socks5_port
            scheme = "socks5h"
        else:
            port = self.config.http_port
            scheme = "http"
        return f"{scheme}://{username}:{self.config.password}@{self.config.gateway}:{port}"
    def get_requests_proxies(self, **kwargs) -> dict:
        """Return a proxies dict compatible with the requests library."""
        url = self.get_proxy_url(**kwargs)
        return {"http": url, "https": url}

Silnik Retry z backoff

import requests
from requests.exceptions import RequestException
RETRYABLE_STATUS_CODES = {403, 429, 500, 502, 503, 504}
class RetryEngine:
    """Retries failed requests with exponential backoff and proxy rotation."""
    def __init__(
        self,
        proxy_manager: ProxyManager,
        max_retries: int = 3,
        base_delay: float = 1.0,
        max_delay: float = 30.0,
        rotate_on_failure: bool = True,
    ):
        self.proxy_manager = proxy_manager
        self.max_retries = max_retries
        self.base_delay = base_delay
        self.max_delay = max_delay
        self.rotate_on_failure = rotate_on_failure
    def _should_retry(self, response: Optional[requests.Response], error: Optional[Exception]) -> bool:
        if error:
            return True
        if response and response.status_code in RETRYABLE_STATUS_CODES:
            return True
        return False
    def _get_delay(self, attempt: int) -> float:
        delay = self.base_delay * (2 ** attempt)
        return min(delay, self.max_delay)
    def execute(
        self,
        method: str,
        url: str,
        country: Optional[str] = None,
        sticky: bool = False,
        **request_kwargs,
    ) -> requests.Response:
        session_id = uuid.uuid4().hex[:8] if sticky else None
        last_error = None
        for attempt in range(self.max_retries + 1):
            # Rotate proxy on retry if enabled
            if attempt > 0 and self.rotate_on_failure:
                session_id = uuid.uuid4().hex[:8]
                self.proxy_manager.metrics.retries += 1
            proxies = self.proxy_manager.get_requests_proxies(
                country=country, session_id=session_id
            )
            self.proxy_manager.metrics.total += 1
            start_time = time.time()
            try:
                response = requests.request(
                    method, url,
                    proxies=proxies,
                    timeout=request_kwargs.pop("timeout", 30),
                    **request_kwargs,
                )
                latency = time.time() - start_time
                self.proxy_manager.metrics.total_latency += latency
                if self._should_retry(response, None) and attempt < self.max_retries:
                    logger.warning(
                        f"Retryable status {response.status_code} for {url} "
                        f"(attempt {attempt + 1}/{self.max_retries + 1})"
                    )
                    time.sleep(self._get_delay(attempt))
                    continue
                self.proxy_manager.metrics.success += 1
                return response
            except RequestException as e:
                last_error = e
                latency = time.time() - start_time
                logger.error(f"Request failed for {url}: {e} (attempt {attempt + 1})")
                if attempt < self.max_retries:
                    time.sleep(self._get_delay(attempt))
                    continue
                self.proxy_manager.metrics.failed += 1
        raise last_error or Exception(f"All retries exhausted for {url}")

Pełna klasa Middleware

class ProxyMiddleware:
    """High-level middleware that wraps all proxy logic."""
    def __init__(
        self,
        config: Optional[ProxyConfig] = None,
        max_retries: int = 3,
        default_country: Optional[str] = None,
    ):
        self.proxy_manager = ProxyManager(config)
        self.retry_engine = RetryEngine(
            proxy_manager=self.proxy_manager,
            max_retries=max_retries,
        )
        self.default_country = default_country
        self.default_headers = {
            "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
            "Accept-Language": "en-US,en;q=0.9",
            "Accept-Encoding": "gzip, deflate, br",
        }
    def get(self, url: str, **kwargs) -> requests.Response:
        kwargs.setdefault("headers", self.default_headers)
        kwargs.setdefault("country", self.default_country)
        return self.retry_engine.execute("GET", url, **kwargs)
    def post(self, url: str, **kwargs) -> requests.Response:
        kwargs.setdefault("headers", self.default_headers)
        kwargs.setdefault("country", self.default_country)
        return self.retry_engine.execute("POST", url, **kwargs)
    @property
    def stats(self) -> dict:
        m = self.proxy_manager.metrics
        return {
            "total_requests": m.total,
            "successful": m.success,
            "failed": m.failed,
            "retries": m.retries,
            "success_rate": f"{m.success_rate:.1f}%",
            "avg_latency": f"{m.avg_latency:.3f}s",
        }
# Usage
middleware = ProxyMiddleware(max_retries=3, default_country="us")
# Simple GET — all proxy logic is hidden
response = middleware.get("https://httpbin.org/ip")
print(response.json())
# Geo-targeted request
response = middleware.get("https://example.com/pricing", country="de")
print(response.text[:200])
# Check performance
print(middleware.stats)

Node.js Wdrażanie Middleware

Główny menedżer proxy

const crypto = require('crypto');
const { HttpsProxyAgent } = require('https-proxy-agent');
const { SocksProxyAgent } = require('socks-proxy-agent');
class ProxyManager {
  constructor(config = {}) {
    this.gateway = config.gateway || 'gate.proxyhat.com';
    this.httpPort = config.httpPort || 8080;
    this.socks5Port = config.socks5Port || 1080;
    this.username = config.username || 'USERNAME';
    this.password = config.password || 'PASSWORD';
    this.metrics = {
      total: 0,
      success: 0,
      failed: 0,
      retries: 0,
      totalLatency: 0,
    };
  }
  getProxyUrl({ protocol = 'http', country, sessionId, sticky = false } = {}) {
    let username = this.username;
    if (sticky && !sessionId) {
      sessionId = crypto.randomBytes(4).toString('hex');
    }
    if (sessionId) username += `-session-${sessionId}`;
    if (country) username += `-country-${country}`;
    const port = protocol === 'socks5' ? this.socks5Port : this.httpPort;
    const scheme = protocol === 'socks5' ? 'socks5h' : 'http';
    return `${scheme}://${username}:${this.password}@${this.gateway}:${port}`;
  }
  createAgent(options = {}) {
    const url = this.getProxyUrl(options);
    if (options.protocol === 'socks5') {
      return new SocksProxyAgent(url);
    }
    return new HttpsProxyAgent(url);
  }
  get stats() {
    const m = this.metrics;
    return {
      total: m.total,
      success: m.success,
      failed: m.failed,
      retries: m.retries,
      successRate: m.total > 0 ? ((m.success / m.total) * 100).toFixed(1) + '%' : '0%',
      avgLatency: m.success > 0 ? (m.totalLatency / m.success).toFixed(3) + 's' : '0s',
    };
  }
}

Silnik bieżnikowy

const RETRYABLE_STATUS_CODES = new Set([403, 429, 500, 502, 503, 504]);
class RetryEngine {
  constructor(proxyManager, options = {}) {
    this.proxyManager = proxyManager;
    this.maxRetries = options.maxRetries || 3;
    this.baseDelay = options.baseDelay || 1000;
    this.maxDelay = options.maxDelay || 30000;
    this.rotateOnFailure = options.rotateOnFailure !== false;
  }
  _getDelay(attempt) {
    return Math.min(this.baseDelay * Math.pow(2, attempt), this.maxDelay);
  }
  _sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
  }
  async execute(url, options = {}) {
    const { country, sticky, ...fetchOptions } = options;
    let sessionId = sticky ? crypto.randomBytes(4).toString('hex') : undefined;
    let lastError;
    for (let attempt = 0; attempt <= this.maxRetries; attempt++) {
      if (attempt > 0 && this.rotateOnFailure) {
        sessionId = crypto.randomBytes(4).toString('hex');
        this.proxyManager.metrics.retries++;
      }
      const agent = this.proxyManager.createAgent({ country, sessionId });
      this.proxyManager.metrics.total++;
      const startTime = Date.now();
      try {
        const response = await fetch(url, {
          ...fetchOptions,
          agent,
          signal: AbortSignal.timeout(fetchOptions.timeout || 30000),
        });
        const latency = (Date.now() - startTime) / 1000;
        this.proxyManager.metrics.totalLatency += latency;
        if (RETRYABLE_STATUS_CODES.has(response.status) && attempt < this.maxRetries) {
          console.warn(
            `Retryable status ${response.status} for ${url} ` +
            `(attempt ${attempt + 1}/${this.maxRetries + 1})`
          );
          await this._sleep(this._getDelay(attempt));
          continue;
        }
        this.proxyManager.metrics.success++;
        return response;
      } catch (err) {
        lastError = err;
        console.error(`Request failed for ${url}: ${err.message} (attempt ${attempt + 1})`);
        if (attempt < this.maxRetries) {
          await this._sleep(this._getDelay(attempt));
          continue;
        }
        this.proxyManager.metrics.failed++;
      }
    }
    throw lastError || new Error(`All retries exhausted for ${url}`);
  }
}

Pełna klasa Middleware

class ProxyMiddleware {
  constructor(options = {}) {
    this.proxyManager = new ProxyManager(options.proxy);
    this.retryEngine = new RetryEngine(this.proxyManager, {
      maxRetries: options.maxRetries || 3,
    });
    this.defaultCountry = options.defaultCountry || null;
    this.defaultHeaders = {
      'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
      'Accept-Language': 'en-US,en;q=0.9',
      'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36',
    };
  }
  async get(url, options = {}) {
    return this.retryEngine.execute(url, {
      method: 'GET',
      headers: { ...this.defaultHeaders, ...options.headers },
      country: options.country || this.defaultCountry,
      ...options,
    });
  }
  async post(url, body, options = {}) {
    return this.retryEngine.execute(url, {
      method: 'POST',
      headers: { ...this.defaultHeaders, ...options.headers },
      body: typeof body === 'string' ? body : JSON.stringify(body),
      country: options.country || this.defaultCountry,
      ...options,
    });
  }
  get stats() {
    return this.proxyManager.stats;
  }
}
// Usage
const middleware = new ProxyMiddleware({
  maxRetries: 3,
  defaultCountry: 'us',
});
// Simple GET
const response = await middleware.get('https://httpbin.org/ip');
const data = await response.json();
console.log(data);
// Check stats
console.log(middleware.stats);

Dodawanie dostawcy

Do celów misyjno-krytycznego skrobania, można rozszerzyć oprogramowanie middleware, aby wspierać wielu dostawców proxy z automatycznym przełączeniem.

class MultiProviderMiddleware:
    """Falls back to secondary proxy providers on failure."""
    def __init__(self, providers: list[ProxyConfig], max_retries: int = 3):
        self.providers = [
            ProxyMiddleware(config=cfg, max_retries=max_retries)
            for cfg in providers
        ]
    def get(self, url: str, **kwargs) -> requests.Response:
        last_error = None
        for i, provider in enumerate(self.providers):
            try:
                response = provider.get(url, **kwargs)
                if response.status_code < 400:
                    return response
            except Exception as e:
                last_error = e
                logger.warning(f"Provider {i} failed for {url}: {e}")
                continue
        raise last_error or Exception(f"All providers failed for {url}")
# Primary: ProxyHat | Fallback: backup provider
providers = [
    ProxyConfig(
        gateway="gate.proxyhat.com",
        username="USERNAME",
        password="PASSWORD",
    ),
    ProxyConfig(
        gateway="backup-proxy.example.com",
        username="BACKUP_USER",
        password="BACKUP_PASS",
    ),
]
middleware = MultiProviderMiddleware(providers)
response = middleware.get("https://example.com/data")

Async Middleware (Python)

Dla wysokiej przepustowości scrating, używać wersji async z aiohttpWięcej wzorów współrzędnych, zobacz nasz przewodnik na skalowanie wniosków o pełnomocnictwo za pomocą kontroli konkursowej.

import aiohttp
import asyncio
class AsyncProxyMiddleware:
    def __init__(self, config: Optional[ProxyConfig] = None, max_retries: int = 3):
        self.proxy_manager = ProxyManager(config)
        self.max_retries = max_retries
    async def get(self, url: str, country: Optional[str] = None) -> str:
        for attempt in range(self.max_retries + 1):
            session_id = uuid.uuid4().hex[:8]
            proxy_url = self.proxy_manager.get_proxy_url(
                country=country, session_id=session_id
            )
            try:
                async with aiohttp.ClientSession() as session:
                    async with session.get(
                        url, proxy=proxy_url, timeout=aiohttp.ClientTimeout(total=30)
                    ) as response:
                        if response.status in RETRYABLE_STATUS_CODES and attempt < self.max_retries:
                            await asyncio.sleep(2 ** attempt)
                            continue
                        self.proxy_manager.metrics.success += 1
                        return await response.text()
            except Exception as e:
                if attempt == self.max_retries:
                    self.proxy_manager.metrics.failed += 1
                    raise
                await asyncio.sleep(2 ** attempt)
# Usage
async def main():
    middleware = AsyncProxyMiddleware(max_retries=3)
    urls = [f"https://example.com/page/{i}" for i in range(100)]
    tasks = [middleware.get(url) for url in urls]
    results = await asyncio.gather(*tasks, return_exceptions=True)
    success = sum(1 for r in results if not isinstance(r, Exception))
    print(f"Success: {success}/{len(results)}")
    print(middleware.proxy_manager.metrics)
asyncio.run(main())

Integracja z ramkami scraping

Middleware integruje się czysto ze wspólnymi wzorami skrobania. Oto jak używać go z Playwright i ze standardem Żądania Pythona.

# With Playwright (Node.js)
const { chromium } = require('playwright');
class PlaywrightProxyMiddleware {
  constructor(proxyManager) {
    this.proxyManager = proxyManager;
    this.browser = null;
  }
  async init() {
    this.browser = await chromium.launch();
  }
  async scrape(url, options = {}) {
    const proxyUrl = this.proxyManager.getProxyUrl({
      sessionId: crypto.randomBytes(4).toString('hex'),
      country: options.country,
    });
    const parsed = new URL(proxyUrl);
    const context = await this.browser.newContext({
      proxy: {
        server: `${parsed.protocol}//${parsed.hostname}:${parsed.port}`,
        username: decodeURIComponent(parsed.username),
        password: decodeURIComponent(parsed.password),
      },
    });
    const page = await context.newPage();
    try {
      await page.goto(url, { timeout: 30000 });
      return await page.content();
    } finally {
      await context.close();
    }
  }
  async close() {
    if (this.browser) await this.browser.close();
  }
}

W celu zapoznania się z wzorcami proxy, patrz nasz Przewodnik rotacji proxy Playwright. Aby monitorować mierniki Twoje middleware zbiera, zobacz Monitorowanie wydajności proxy.

Zbadaj Python SDK, Węzeł SDKlub Go SDK dla built- in middleware funkcji, i sprawdzić Ceny proksyHat Na początek. Aby uzyskać pełną dokumentację integracji, odwiedź docs.proxyhat.com.

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