爬虫技术：代理池的维护

一：代理池维护的模块

　　1. 抓取模块Crawl，负责从代理网站上抓取代理 ---------------抓取模块

　　2. 获取代理Getter，负责获取抓取模块返回的值，并判断是否超过存储模块的最大容量。---------------获取模块

　　3.存储模块Redis，负责将抓取的每一条代理存放至有序集合中。---------------存储模块

　　4.测试模块Tester，负责异步测试每个代理是否可用。---------------测试模块

　　5.调度模块Schedule，负责测试，获取，和对外api的接口运转。---------------调度模块

　　6.Flask对外接口，通过视图函数，获取jison值。---------------接口模块

　　7.utilis工具类，提供了每个网站的页面解析。---------------工具类模块

二：抓取模块

import re
from ulits import get_66ip_content,get_xc_content,get_89_content
from bs4 import BeautifulSoup

class Crawl(object):

    def get_proxy(self):
        proxies = list()
        for value in self.crawl_proxy_66(5):
            proxies.append(value)
        for value in self.crawl_get_89proxy(5):
            proxies.append(value)
        for value in self.crawl_xc_proxy(5):
            proxies.append(value)
        return proxies

    def crawl_proxy_66(self, total_page):
        """
        :return:代理
        """
        start_url = "http://www.66ip.cn/{}.html"
        url_list = [start_url.format(i) for i in range(1,total_page + 1)]
        for url in url_list:
            content = get_66ip_content(url)
            soup = BeautifulSoup(content,"lxml")
            div = soup.find("div", id="main")
            table = div.table
            tr_list = table.find_all("tr")
            for tr in tr_list[1:]:
                tr = str(tr) # 把soup.element强行变成str字符串
                pattern = re.compile(r"<td>(.*?)</td><td>(.*?)</td>",re.S)
                result = re.search(pattern,tr)
                ip = result.group(1)
                port = result.group(2)
                yield ":".join([ip,port])

    def crawl_xc_proxy(self,total_page):
        start_url = "https://www.xicidaili.com/wt/{}"
        url_list = [start_url.format(i) for i in range(1,total_page + 1)]
        for url in url_list:
            html = get_xc_content(url)
            soup = BeautifulSoup(html, "lxml")
            div = soup.find("div",id="body")
            table = div.table
            tr_list = table.find_all("tr")
            for tr in tr_list[1:]:
                tr = str(tr)
                pattern = re.compile("<td>(.*?)</td>", re.S)
                result = re.findall(pattern, tr)
                if len(result) > 2:
                    ip = result[0]
                    port = result[1]
                    yield ":".join([ip, port])

    def crawl_get_89proxy(self,total_page):
        start_url = "http://www.89ip.cn/index_{}.html"
        url_list = [start_url.format(i) for i in range(1,total_page+1)]
        for url in url_list:
            html = get_89_content(url)
            soup = BeautifulSoup(html, "lxml")
            # 获取class属性的标准写法
            div = soup.find(name="div", attrs={"class": "layui-form"})
            table = div.table
            tr_list = table.find_all("tr")
            for tr in tr_list[1:]:
                tr = str(tr)
                pattern = re.compile("<td>(.*?)</td>", re.S)
                result = re.findall(pattern, tr)
                if len(result) > 2:
                    ip = (result[0]).replace("\n", "")
                    ip = ip.replace("\t", "")
                    port = (result[1]).replace("\t", "")
                    port = port.replace("\n", "")
                    yield ":".join([ip, port])

三：获取模块

from Redis import ReidsClient
from Crawl import Crawl

POOL_MAX_COUNT = 10000
class Getter(object):

    def __init__(self):
       self.redis = ReidsClient()
       self.crwal = Crawl()

    def is_exceed_poolcount(self):
        """
        判读是否超过代理池的最大容量
        :return: True超过，False没有超过
        """
        ret = self.redis.get_count() > POOL_MAX_COUNT
        return ret

    def run(self):
        print("计数器开始计时")
        if not self.is_exceed_poolcount():
            proxies = self.crwal.get_proxy()
            for proxy in proxies:
                self.redis.add(proxy)


if __name__ == '__main__':
    g = Getter()
    g.run()

四：存储模块

MAX_SOCRE = 100
MIN_SCORE = 0
INITIAL_SCORE = 10
REDIS_HOST = "127.0.0.1"
REDIS_PORT = 6379
REDIS_PASSWORD = None
REDIS_KEY = "proxies"
import redis
from random import choice

class ReidsClient(object):

    def __init__(self,host=REDIS_HOST,port=REDIS_PORT, password=REDIS_PASSWORD):
        self.db = redis.StrictRedis(host=host,port=port,password=password,decode_responses=True) # 这样写存的数据是字符串格式

    def add(self, proxy, score=INITIAL_SCORE):
        """
        添加代理，设置分数最高
        :param proxy:代理
        :param score:分数
        :return:添加结果
        """
        # 从有序集合REDIS_KEY中获取proxy的权重分，没有添加
        if not self.db.zscore(REDIS_KEY,proxy):
            # 将新的proxy放入redis的REDIS_KEY集合中，
            return self.db.zadd(REDIS_KEY,score,proxy)   # 这里容易报一个错是：AttributionErro：int object have no arrtibution items,原因是redis这个包的版本问题
　　　　　　　# 解决包的版本问题：pip install redis==2.10.6
    def get_random(self):
        """
        随机获取代理，获取顺序是最高分的代理
        :return:随机代理
        """
        # 获取分数最高分数
        result = self.db.zrangebyscore(REDIS_KEY,MAX_SOCRE,MAX_SOCRE)
        if len(result):
            return choice(result) # 随机抽取，保证每个代理都可能被获取到。
        else:
            result = self.db.zrevrange(REDIS_KEY,MIN_SCORE,MAX_SOCRE) # 拿不到最高分的代理，那么就拿次高分的代理
            if len(result) > 1:
                return result[0]
            else:
                return "代理池为空"

    def decrease(self,proxy):
        """
        代理不能用的话，分数就减1，分数为0，从代理池中删除
        :param proxy:代理
        :return:修改后的分数
        """
        score = self.db.zscore(REDIS_KEY,proxy)
        if score and score > MIN_SCORE:
            print("代理",proxy,"当前的分数",score,"减1")
            return self.db.zincrby(REDIS_KEY,proxy,-1)

        else:
            print("代理", proxy, "当前的分数", score, "移除")
            return self.db.zrem(REDIS_KEY,proxy)  # 删除无效代理


    def exist(self,proxy):
        """
        判断代理是否存在
        :param proxy:代理
        :return:True or False
        """
        result = self.db.zscore(REDIS_KEY,proxy)
        if result != None:
            return True
        else:
            return False

    def set_max_value(self,proxy):
        """
         将代理设置为MAX_SCORE值
        :param proxy: 代理
        :return:设置结束
        """
        print("代理",proxy,"可用","设置值为",MAX_SOCRE)
        return self.db.zadd(REDIS_KEY,MAX_SOCRE,proxy)

    def get_count(self):
        """
        :return: 返回有序集合中的数量
        """
        return self.db.zcard(REDIS_KEY)

    def get_all(self):
        """
        :return: 获取所有元素,返回列表
        """
        return self.db.zrangebyscore(REDIS_KEY,MIN_SCORE,MAX_SOCRE)

五：测试模块

import time

VALID_STATUSC_CODES = [200]
TEST_URL = "http://www.baidu.com"
BATCH_TEST_SIZE = 100
from Redis import ReidsClient
import aiohttp
import asyncio

class Test(object):
    def __init__(self):
        self.redis = ReidsClient()

    async def test_single_proxy(self,proxy):
        """
        测试单个代理
        :param proxy: 代理
        :return: None
        """
        coon = aiohttp.TCPConnector(verify_ssl=False)  # 区别于requests库;是一个异步非阻塞的库
        async with aiohttp.ClientSession(connector=coon) as session:
            try:
                if isinstance(proxy,bytes):
                    proxy = proxy.decode("utf-8")
                real_proxy = "http://" + proxy
                print("正在测试",proxy)
                async with session.get(TEST_URL,proxy=real_proxy,timeout=15) as response:
                    if response.status in VALID_STATUSC_CODES:
                        self.redis.set_max_value(proxy) # 能用，给代理设置最高的权重分，存入数据库
                        print("代理可以用",proxy)
                    else:
                        self.redis.decrease(proxy) # 超时未请求到，给此代理减分
                        print("响应码不合格",proxy)

            except (ConnectionError,TimeoutError,AttributeError):
                self.redis.decrease(proxy)  # 发生故障给此代理减分
                print("代理请求失败",proxy)

    def run(self):
        """
        测试主函数
        :return:
        """
        print("测试函数开始运行")
        try:
            proxies = self.redis.get_all() # 从数据库中获取全部的代理
            loop = asyncio.get_event_loop()
            for i in range(0,len(proxies),BATCH_TEST_SIZE):
                test_proxies = proxies[i:i + BATCH_TEST_SIZE]
                tasks = [self.test_single_proxy(proxy) for proxy in test_proxies]
                loop.run_until_complete(asyncio.wait(tasks))
                time.sleep(5)
        except Exception as e:
            print("测试器发生错误",e.args)

六：调度模块

import time

TESTER_CYCLE = 20
GETTER_CYCLE = 20
TESTER_ENABLED = True
GETTER_ENABLED = True
API_ENABLED = True
API_HOST="localhost"
API_PORT="8888"

from multiprocessing import Process
from Flask import app
from Getter import Getter
from Tester import Test

class Scheduler(object):
    def schedule_tester(self,cycle=TESTER_CYCLE):
        """
        定时测试代理
        :param cycle:
        :return:
        """
        tester = Test()
        while True:
            print("测试器开始运行")
            tester.run()
            time.sleep(cycle)

    def scheduler_getter(self,cycle=GETTER_CYCLE):
        """
        定时获取代理
        :param cycle:
        :return:
        """
        getter = Getter()
        while True:
            print("开始抓取代理")
            getter.run()
            time.sleep(cycle)

    def scheduler_api(self):
        """
        开启api
        :return:
        """
        app.run(API_HOST,API_PORT)

    def run(self):
        print("代理池开始运行")
        if TESTER_ENABLED:
            tester_process = Process(target=self.schedule_tester)
            tester_process.start()
        if GETTER_ENABLED:
            getter_process = Process(target=self.scheduler_getter)
            getter_process.start()
        if TESTER_ENABLED:
            api_process = Process(target=self.scheduler_api)
            api_process.start()


if __name__ == '__main__':

    s = Scheduler()
    s.run()

七：接口

from flask import Flask,g
from Redis import ReidsClient

__all__ = ["app"]
app = Flask(__name__)

def get_coon():
    if not hasattr(g,"redis"):
        g.redis = ReidsClient()
    return g.redis

@app.route("/")
def index():
    return "<h2>Welcome to Proxy Pool System</h2>"

@app.route("/random")
def get_proxy():
    """
    获得随机代理
    :return: 随机代理
    """
    coon = get_coon()
    return coon.get_random()

@app.route("/count")
def get_count():
    """
    获取代理池的总量
    :return:
    """
    coon = get_coon()
    return str(coon.get_count())

if __name__ == '__main__':
    app.run()

八：运行结果截图

程序运行情况

数据库情况

接口访问情况

九：本地使用

import requests
PROXY_URL = "http://localhost:8888/random"

def get_proxy():
    try:
        response = requests.get(PROXY_URL)
        if response.status_code == 200:
            return response.content.decode("utf-8")

    except ConnectionError:
        return None


get_proxy()
print(get_proxy())

十：总结

为什么要使用Flask接口呢：

　　1.使用本地的redis链接，直接调取里面的random方法也可以拿到可用的代理，但是这样就暴露了reids的用户名和密码，对数据不安全。

　　2.代理池要部署到远端服务器，而远端的reids只允许本地连接，那么我们就不能获取代理。

　　3.爬虫主机，不是用python语言编写，就无法使用RedisClient这个类了，这样没有扩展性。

　　4.如果reids数据库有更新，那么我们就得修改爬虫端的程序，比较麻烦。

原文地址：https://www.cnblogs.com/meloncodezhang/p/11592325.html