在進行網絡爬蟲時，會經常有封ip的現象。可以使用代理池來進行代理ip的處理。

代理池的要求：多站抓取，異步檢測。定時篩選，持續更新。提供接口，易於提取。

代理池架構：獲取器，過濾器，代理隊列，定時檢測。

使用https://github.com/Germey/ProxyPool/tree/master/proxypool代碼進行分析。

run.py裏面的代碼

from proxypool.api import app
from proxypool.schedule import Schedule

def main():

    s = Schedule()
    s.run()
    app.run()




 
if __name__ == ‘__main__‘:
    main()

首先運行了一個調度器，接著運行了一個接口。

調度器schedule.py代碼

import time
from multiprocessing import Process
import asyncio
import aiohttp
try:
    from aiohttp.errors import ProxyConnectionError,ServerDisconnectedError,ClientResponseError,ClientConnectorError
except:
    from aiohttp import
 
 ClientProxyConnectionError as ProxyConnectionError,ServerDisconnectedError,ClientResponseError,ClientConnectorError
from proxypool.db import RedisClient
from proxypool.error import ResourceDepletionError
from proxypool.getter import FreeProxyGetter
from proxypool.setting import *
from asyncio import
 
 TimeoutError


class ValidityTester(object):
    test_api = TEST_API

    def __init__(self):
        self._raw_proxies = None
        self._usable_proxies = []

    def set_raw_proxies(self, proxies):
        self._raw_proxies = proxies
        self._conn = RedisClient()

    async def test_single_proxy(self, proxy):
        """
        text one proxy, if valid, put them to usable_proxies.
        """
        try:
            async with aiohttp.ClientSession() as session:
                try:
                    if isinstance(proxy, bytes):
                        proxy = proxy.decode(‘utf-8‘)
                    real_proxy = ‘http://‘ + proxy
                    print(‘Testing‘, proxy)
                    async with session.get(self.test_api, proxy=real_proxy, timeout=get_proxy_timeout) as response:
                        if response.status == 200:
                            self._conn.put(proxy)
                            print(‘Valid proxy‘, proxy)
                except (ProxyConnectionError, TimeoutError, ValueError):
                    print(‘Invalid proxy‘, proxy)
        except (ServerDisconnectedError, ClientResponseError,ClientConnectorError) as s:
            print(s)
            pass

    def test(self):
        """
        aio test all proxies.
        """
        print(‘ValidityTester is working‘)
        try:
            loop = asyncio.get_event_loop()
            tasks = [self.test_single_proxy(proxy) for proxy in self._raw_proxies]
            loop.run_until_complete(asyncio.wait(tasks))
        except ValueError:
            print(‘Async Error‘)


class PoolAdder(object):
    """
    add proxy to pool
    """

    def __init__(self, threshold):
        self._threshold = threshold
        self._conn = RedisClient()
        self._tester = ValidityTester()
        self._crawler = FreeProxyGetter()

    def is_over_threshold(self):
        """
        judge if count is overflow.
        """
        if self._conn.queue_len >= self._threshold:
            return True
        else:
            return False

    def add_to_queue(self):
        print(‘PoolAdder is working‘)
        proxy_count = 0
        while not self.is_over_threshold():
            for callback_label in range(self._crawler.__CrawlFuncCount__):
                callback = self._crawler.__CrawlFunc__[callback_label]
                raw_proxies = self._crawler.get_raw_proxies(callback)
                # test crawled proxies
                self._tester.set_raw_proxies(raw_proxies)
                self._tester.test()
                proxy_count += len(raw_proxies)
                if self.is_over_threshold():
                    print(‘IP is enough, waiting to be used‘)
                    break
            if proxy_count == 0:
                raise ResourceDepletionError


class Schedule(object):
    @staticmethod
    def valid_proxy(cycle=VALID_CHECK_CYCLE):
        """
        Get half of proxies which in redis
        """
        conn = RedisClient()
        tester = ValidityTester()
        while True:
            print(‘Refreshing ip‘)
            count = int(0.5 * conn.queue_len)
            if count == 0:
                print(‘Waiting for adding‘)
                time.sleep(cycle)
                continue
            raw_proxies = conn.get(count)
            tester.set_raw_proxies(raw_proxies)
            tester.test()
            time.sleep(cycle)

    @staticmethod
    def check_pool(lower_threshold=POOL_LOWER_THRESHOLD,
                   upper_threshold=POOL_UPPER_THRESHOLD,
                   cycle=POOL_LEN_CHECK_CYCLE):
        """
        If the number of proxies less than lower_threshold, add proxy
        """
        conn = RedisClient()
        adder = PoolAdder(upper_threshold)
        while True:
            if conn.queue_len < lower_threshold:
                adder.add_to_queue()
            time.sleep(cycle)

    def run(self):
        print(‘Ip processing running‘)
        valid_process = Process(target=Schedule.valid_proxy)
        check_process = Process(target=Schedule.check_pool)
        valid_process.start()
        check_process.start()

調度器裏面有個run方法，裏面運行了兩個進程。一個進程valid_process是從網上獲取代理放入數據庫；另外一個進程check_process是定時的從數據庫拿出代理進行檢測。

valid_proxy是定時檢測器，裏面傳入一個時間的參數cycle=VALID_CHECK_CYCLE，定義定時檢測的時間。方法裏首先定義一個RedisClient()進行數據庫的連接，該方法定義在db.py中

import redis
from proxypool.error import PoolEmptyError
from proxypool.setting import HOST, PORT, PASSWORD


class RedisClient(object):
    def __init__(self, host=HOST, port=PORT):
        if PASSWORD:
            self._db = redis.Redis(host=host, port=port, password=PASSWORD)
        else:
            self._db = redis.Redis(host=host, port=port)

    def get(self, count=1):
        """
        get proxies from redis
        """
        #從左側批量獲取的方法
        proxies = self._db.lrange("proxies", 0, count - 1)

        self._db.ltrim("proxies", count, -1)
        return proxies

    def put(self, proxy):
        """
        add proxy to right top
        """
        self._db.rpush("proxies", proxy)

    def pop(self):
        """
        get proxy from right.
        """
        try:
            return self._db.rpop("proxies").decode(‘utf-8‘)
        except:
            raise PoolEmptyError

    @property
    def queue_len(self):
        """
        get length from queue.
        """
        return self._db.llen("proxies")

    def flush(self):
        """
        flush db
        """
        self._db.flushall()


if __name__ == ‘__main__‘:
    conn = RedisClient()
    print(conn.pop())

接著還聲明了ValidityTester()，用來檢測代理是否可用，其中的test_single_proxy（）方法是實現異步檢測的關鍵。

check_pool（）方法裏面需要傳入三個參數：兩個代理池的上下界限，一個時間。裏面有個PoolAdder的add_to_queue()方法。

add_to_queue()方法中使用了一個從網站抓取ip的類FreeProxyGetter()，在getter.py裏面

from .utils import get_page
from pyquery import PyQuery as pq
import re


class ProxyMetaclass(type):
    """
        元類，在FreeProxyGetter類中加入
        __CrawlFunc__和__CrawlFuncCount__
        兩個參數，分別表示爬蟲函數，和爬蟲函數的數量。
    """

    def __new__(cls, name, bases, attrs):
        count = 0
        attrs[‘__CrawlFunc__‘] = []
        for k, v in attrs.items():
            if ‘crawl_‘ in k:
                attrs[‘__CrawlFunc__‘].append(k)
                count += 1
        attrs[‘__CrawlFuncCount__‘] = count
        return type.__new__(cls, name, bases, attrs)


class FreeProxyGetter(object, metaclass=ProxyMetaclass):
    def get_raw_proxies(self, callback):
        proxies = []
        print(‘Callback‘, callback)
        for proxy in eval("self.{}()".format(callback)):
            print(‘Getting‘, proxy, ‘from‘, callback)
            proxies.append(proxy)
        return proxies

    def crawl_ip181(self):
        start_url = ‘http://www.ip181.com/‘
        html = get_page(start_url)
        ip_adress = re.compile(‘<tr.*?>\s*<td>(.*?)</td>\s*<td>(.*?)</td>‘)
        # \s* 匹配空格，起到換行作用
        re_ip_adress = ip_adress.findall(html)
        for adress, port in re_ip_adress:
            result = adress + ‘:‘ + port
            yield result.replace(‘ ‘, ‘‘)

    def crawl_kuaidaili(self):
        for page in range(1, 4):
            # 國內高匿代理
            start_url = ‘https://www.kuaidaili.com/free/inha/{}/‘.format(page)
            html = get_page(start_url)
            ip_adress = re.compile(
                ‘<td data-title="IP">(.*)</td>\s*<td data-title="PORT">(\w+)</td>‘
            )
            re_ip_adress = ip_adress.findall(html)
            for adress, port in re_ip_adress:
                result = adress + ‘:‘ + port
                yield result.replace(‘ ‘, ‘‘)

    def crawl_xicidaili(self):
        for page in range(1, 4):
            start_url = ‘http://www.xicidaili.com/wt/{}‘.format(page)
            html = get_page(start_url)
            ip_adress = re.compile(
                ‘<td class="country"><img src="http://fs.xicidaili.com/images/flag/cn.png" alt="Cn" /></td>\s*<td>(.*?)</td>\s*<td>(.*?)</td>‘
            )
            # \s* 匹配空格，起到換行作用
            re_ip_adress = ip_adress.findall(html)
            for adress, port in re_ip_adress:
                result = adress + ‘:‘ + port
                yield result.replace(‘ ‘, ‘‘)

    def crawl_daili66(self, page_count=4):
        start_url = ‘http://www.66ip.cn/{}.html‘
        urls = [start_url.format(page) for page in range(1, page_count + 1)]
        for url in urls:
            print(‘Crawling‘, url)
            html = get_page(url)
            if html:
                doc = pq(html)
                trs = doc(‘.containerbox table tr:gt(0)‘).items()
                for tr in trs:
                    ip = tr.find(‘td:nth-child(1)‘).text()
                    port = tr.find(‘td:nth-child(2)‘).text()
                    yield ‘:‘.join([ip, port])

    def crawl_data5u(self):
        for i in [‘gngn‘, ‘gnpt‘]:
            start_url = ‘http://www.data5u.com/free/{}/index.shtml‘.format(i)
            html = get_page(start_url)
            ip_adress = re.compile(
                ‘ <ul class="l2">\s*<span><li>(.*?)</li></span>\s*<span style="width: 100px;"><li class=".*">(.*?)</li></span>‘
            )
            # \s * 匹配空格，起到換行作用
            re_ip_adress = ip_adress.findall(html)
            for adress, port in re_ip_adress:
                result = adress + ‘:‘ + port
                yield result.replace(‘ ‘, ‘‘)

    def crawl_kxdaili(self):
        for i in range(1, 4):
            start_url = ‘http://www.kxdaili.com/ipList/{}.html#ip‘.format(i)
            html = get_page(start_url)
            ip_adress = re.compile(‘<tr.*?>\s*<td>(.*?)</td>\s*<td>(.*?)</td>‘)
            # \s* 匹配空格，起到換行作用
            re_ip_adress = ip_adress.findall(html)
            for adress, port in re_ip_adress:
                result = adress + ‘:‘ + port
                yield result.replace(‘ ‘, ‘‘)

    def crawl_premproxy(self):
        for i in [‘China-01‘, ‘China-02‘, ‘China-03‘, ‘China-04‘, ‘Taiwan-01‘]:
            start_url = ‘https://premproxy.com/proxy-by-country/{}.htm‘.format(
                i)
            html = get_page(start_url)
            if html:
                ip_adress = re.compile(‘<td data-label="IP:port ">(.*?)</td>‘)
                re_ip_adress = ip_adress.findall(html)
                for adress_port in re_ip_adress:
                    yield adress_port.replace(‘ ‘, ‘‘)

    def crawl_xroxy(self):
        for i in [‘CN‘, ‘TW‘]:
            start_url = ‘http://www.xroxy.com/proxylist.php?country={}‘.format(
                i)
            html = get_page(start_url)
            if html:
                ip_adress1 = re.compile(
                    "title=‘View this Proxy details‘>\s*(.*).*")
                re_ip_adress1 = ip_adress1.findall(html)
                ip_adress2 = re.compile(
                    "title=‘Select proxies with port number .*‘>(.*)</a>")
                re_ip_adress2 = ip_adress2.findall(html)
                for adress, port in zip(re_ip_adress1, re_ip_adress2):
                    adress_port = adress + ‘:‘ + port
                    yield adress_port.replace(‘ ‘, ‘‘)

具體使用方法可以看GitHub。。。。。。

使用redis+flask維護動態代理池