#!/usr/bin/python3
# coding: utf-8 
"""
__title__ = "my crawler"
__author__ = "Hans"
__mtime__ = "2017/3/30 0030"
# code is far away from bugs with the god animal protecting
I love animals. They taste delicious.
┏┓ ┏┓
┏┛┻━━━┛┻┓
┃ ☃ ┃
┃ ┳┛ ┗┳ ┃
┃ ┻ ┃
┗━┓ ┏━┛
┃ ┗━━━┓
┃ 神兽保佑 ┣┓
┃　永无BUG！ ┏┛
┗┓┓┏━┳┓┏┛
┃┫┫ ┃┫┫
┗┻┛ ┗┻┛
"""
from bs4 import BeautifulSoup
import socket
import urllib.parse
import time
from sqlalchemy import Column, String, create_engine, Integer
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from urllib import request
import asyncio

# 创建数据库对象基类
Base = declarative_base()

# 定义Pic 对象
class Pic(Base):
    __tablename__ = 'pic'
    id = Column(Integer(), primary_key=True)
    site = Column(String(100))
    pic = Column(String(1000))
# 初始化数据库连接
engine = create_engine('mysql+pymysql://root:root@localhost:3306/crawler')
# 创建DBsession类型
DBsession = sessionmaker(bind=engine)
session = DBsession()

url_seen = set(['/'])  # 已经扒过的页面
url_todo = set(['/'])  # 准备扒的页面
img_set = set([])   # 扒到的图片集合


site = 'www.yangqq.com'


async def get_response(query):
    return request.urlopen(query)



async def fetch(url, flag, site=site):
    print(url, flag)
    query = ('http', site, url, '', '', '')
    query = urllib.parse.urlunparse(query)   # 组合成一个可以访问的url

    try:
        response = await get_response(query)  # 和socket不一样的是这里得到的响应内容可以使用response 的方法单独读取
    except:
        url_seen.add(url)
        url_todo.remove(url)
        return

    body = response.read()
    # print('body:', body)

    # 根据 body 得到 一个 soup 对象
    soup = BeautifulSoup(body, 'html.parser')


    # 找到当前页面所有的本站的跳转链接
    links = soup.find_all('a')
    # print(len(links))
    for link in links:
        # print(link['href'])
        try:
            f_url = link['href']
        except:
            url_seen.add(url)
            url_todo.remove(url)
            return

        f_url = urllib.parse.urljoin(url, f_url)
        # 将url解析
        p_url = urllib.parse.urlparse(f_url)
        # 排除不是http的请求
        if p_url.scheme not in ('', 'http', 'https'):
            continue
        # 排除不是本站的请求
        if p_url.netloc not in ('', site):
            continue
        # 获取当前连接
        c_url = p_url.path
        # 判断这个url 是否已经扒过了
        if c_url not in url_seen:   # 如果不再扒过的集合中,就添加到url_todo
            url_todo.add(c_url)

    # 找到本页面所有的图片连接
    images = soup.find_all('img')
    for img in images:
        img_url = img['src']
        # print(img_url)
        # 直接将连接加入到 img_set
        img_set.add(img_url)
        # 将图片添加到数据库
        try:
            result = session.query(Pic).filter(Pic.pic==img_url).first()
            if not result:
                session.add(Pic(site=site, pic=img_url))
                session.commit()
        except:
            pass


    # 在最后将当前url, 添加到url_seen, 从url_todo中去掉
    url_seen.add(url)
    url_todo.remove(url)

if __name__ == '__main__':
    async def main(flag):
        while url_todo:
            await fetch(list(url_todo)[0], flag)

    start = time.time()
    # fetch('/', 'init')
    loop = asyncio.get_event_loop() #获取EventLoop
    loop.run_until_complete(fetch('/', 'init'))
    tasks = [main('one'), main('two'), main('three'), main('four')]
    loop.run_until_complete(asyncio.gather(*tasks))   #执行协程
    loop.close()
    session.close()

print('抓取了 {} 页面, 共耗时 {:.1f} s'.format(len(url_seen), time.time() - start))
print('-'*30)
print('抓取到的图片共 {} 张'.format(len(img_set)))