#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Author: Nick
# @Date:  2019-10-24 15:40:58
# @Last Modified by:  Nick
# @Last Modified time: 2019-10-24 16:54:31
import random
import re
import time
import urllib
import requests

from bs4 import BeautifulSoup
from fake_useragent import UserAgent

try:
  from lxml import etree
except Exception as e:
  import lxml.html
  # 實例化一個etree對象（解決通過from lxml import etree導包失敗）
  etree = lxml.html.etree

# 實例化UserAgent對象，用于產生隨機UserAgent
ua = UserAgent()


class BlogSpider(object):
  """
  Increase the number of CSDN blog visits.
  """

  def __init__(self):
    self.url = "https://blog.csdn.net/PY0312/article/list/{}"
    self.headers = {
      "Referer": "https://blog.csdn.net/PY0312/",
      "User-Agent": ua.random
    }
    self.firefoxHead = {
      "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0"}
    self.IPRegular = r"(([1-9]?\d|1\d{2}|2[0-4]\d|25[0-5]).){3}([1-9]?\d|1\d{2}|2[0-4]\d|25[0-5])"

  def send_request(self, num):
    """
    模擬瀏覽器發起請求
    :param num: num
    :return: html_str
    """
    html_str = requests.get(self.url.format(
      num), headers=self.headers).content.decode()
    # print(html_str)

    return html_str

  def parse_data(self, html_str):
    """
    用于解析發起請求返回的數據
    :param html_str:
    :return: each_page_urls
    """
    # 將返回的 html字符串 轉換為 element對象，用于xpath操作
    element_obj = etree.HTML(html_str)
    # print(element_obj)

    # 獲取每一頁所有blog的url
    each_page_urls = element_obj.xpath(
      '//*[@id="mainBox"]/main/div[2]/div/h5/a/@href')
    # print(each_page_urls)

    return each_page_urls

  def parseIPList(self, url="http://www.xicidaili.com/"):
    """
    爬取最新代理ip，來源：西刺代理
    注意：西刺代理容易被封，如遇到IP被封情況，采用以下兩種方法即可解決：
    方法一：請參考我上一篇博客《Python 實現快代理IP爬蟲》 ===> 喜歡研究的同學，可參考對接此接口
    方法二：直接屏蔽掉此接口，不使用代理也能正常使用
    :param url: "http://www.xicidaili.com/"
    :return: 代理IP列表ips
    """
    ips = []
    request = urllib.request.Request(url, headers=self.firefoxHead)
    response = urllib.request.urlopen(request)
    soup = BeautifulSoup(response, "lxml")
    tds = soup.find_all("td")
    for td in tds:
      string = str(td.string)
      if re.search(self.IPRegular, string):
        ips.append(string)
    # print(ips)
    return ips

  def main(self, total_page, loop_times, each_num):
    """
    調度方法
    :param total_page: 設置博客總頁數
    :param loop_times: 設置循環次數
    :param each_num: 設置每一頁要隨機挑選文章數
    :return:
    """
    i = 0
    # 根據設置次數，打開循環
    while i < loop_times:
      # 遍歷，得到每一頁的頁碼
      for j in range(total_page):
        # 拼接每一頁的url，并模擬發送請求, 返回響應數據
        html_str = self.send_request(j + 1)

        # 解析響應數據，得到每一頁所有博文的url
        each_page_urls = self.parse_data(html_str)

        # 調用parseIPList隨機產生代理IP，防反爬
        # ips = self.parseIPList()
        # proxies = {"http": "{}:8080".format(
        #   ips[random.randint(0, 40)])}

        # 遍歷，每一頁隨機挑選each_num篇文章
        for x in range(each_num):
          # 隨機抽取每一頁的一篇博文進行訪問，防反爬
          current_url = random.choice(each_page_urls)
          status = True if requests.get(
            current_url, headers=self.headers).content.decode() else False
          print("當前正在訪問的文章是：{}，訪問狀態：{}".format(current_url, status))
          time.sleep(1)  # 延時1秒，防反爬
        time.sleep(1)  # 延時1秒，防反爬
      i += 1


if __name__ == '__main__':
  bs = BlogSpider()
  bs.main(7, 200, 3) # 參數參照main方法說明，酌情設置