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Python 兴趣小组第十周作业

学习目标

第十周的部分目标在第九周提前完成了,第十周实战章节的教程与我目前的能力不太符合。索性调整了计划,自己设计实现了一个简单地新闻爬取程序。

利用了第三方现有的接口,综合使用了之前学到的许多知识,勉强能让自己满意吧。

学习代码

学习代码

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# -*- coding: utf-8 -*-
import json

import requests
import logging
import mysql.connector
from datetime import datetime
from apscheduler.schedulers.blocking import BlockingScheduler

# 配置 log 等级
logging.basicConfig(level='INFO')

# 新闻 api 地址
REQUEST_URL = 'https://news.topurl.cn/api'
# api 抓取间隔,单位为秒
REQUEST_INTERVAL = 60
# 单个分类新闻最大数量
CATEGORY_ITEM_MAX_SIZE = 10
# 新闻抓取最大数量
NEWS_MAX_SIZE = 10
# 新闻时效,只查询过去 n 小时的新闻
PAST_HOURS_OF_NEWS = 23


class New(object):
def __init__(self, title, url, category):
self.title = title
self.url = url
self.id = int(url[-12:-5])
self.category = category

# @staticmethod
# def hash_str(string):
# """
# 计算字符串的 hash 值
# :param string: 待计算 hash 值的字符串
# :return: 整型 hash 值
# """
# if not isinstance(string, str):
# string = str(string)
#
# sha = sha1()
# sha.update(string.encode('utf-8'))
# return int(sha.hexdigest(), 16) % (10 ** 8)


def to_markdown_string(news_category):
"""
把抓取到的新闻组织成 markdown 文本
:param news_category: 新闻分类字典
:return: markdown 文本
"""
if not isinstance(news_category, dict):
return
keys = news_category.keys()
markdown = ''
for key in keys:
h1 = '# ' + key + ' \n\n'
markdown = markdown + h1
news = news_category.get(key)
for new in news:
list_item = '- [%s](%s) \n\n' % (new.title, new.url)
markdown = markdown + list_item

return markdown


def get_news_from_api():
"""
从 api 抓取新闻列表
:return: 新闻列表
"""
api = requests.get(REQUEST_URL)
logging.info('抓取内容为:' + api.text)
# 判断接口是否异常
if not api.ok:
logging.warning("访问频率过高被限制")
return []
# 判断是否被限制调用频率
response = json.loads(api.text)
if 403 == response.get('code'):
logging.warning("访问频率过高被限制")
return []

# 返回新闻列表
news_list = response['data']['newsList']
return [New(i['title'], i['url'], i['category']) for i in news_list]


def init_database():
"""
初始化数据库,建表等
:return: None
"""
conn = mysql.connector.connect(user='root', password='123456', host='127.0.0.1', port=3306)
cursor = conn.cursor()

# cursor.execute('DROP DATABASE IF EXISTS `morning_new`')
cursor.execute('CREATE DATABASE if not exists `morning_new`')
cursor.execute('USE `morning_new`')

# cursor.execute('DROP TABLE IF EXISTS `news`')
news_table_sql = r"""
create table if not exists `news` (
`id` bigint(0) not null auto_increment comment 'id',
`category` varchar(20) not null comment 'category',
`title` varchar(500) not null default '' comment 'title of the new',
`url` varchar(1500) not null default '' comment 'url of the new',
`create_time` timestamp not null default CURRENT_TIMESTAMP comment 'create_time',
primary key (`id`)
) charset=utf8mb4 comment 'news item';
"""
cursor.execute(news_table_sql)
cursor.close()
conn.close()


def get_mysql_connection():
"""
获取 mysql 连接
:return: mysql 连接
"""
return mysql.connector.connect(user='root', password='123456', host='127.0.0.1', port=3306, database='morning_new')


def remove_duplicates(news):
"""
去除重复新闻
:param news: 待去重新闻列表
:return: 去重后的新闻列表
"""
if not isinstance(news, list) or len(news) == 0:
return []
id_list = [i.id for i in news if isinstance(i, New)]
sql = r"select id from news where id in (%s)" % ','.join(['%s'] * len(id_list))
conn = get_mysql_connection()
cursor = conn.cursor()
cursor.execute(sql, id_list)
duplicates_new_id_list = [i[0] for i in cursor.fetchall()]
cursor.close()
conn.close()
non_duplicates_new_list = [i for i in news if not duplicates_new_id_list.__contains__(i.id)]

return non_duplicates_new_list


def save_news(news):
"""
把新闻写入数据库
:param news: 新闻列表
:return: None
"""
if not isinstance(news, list):
return None
# 新闻去重
news = remove_duplicates(news)
if len(news) <= 0:
return None

sql = r'insert into news (id, category, title, url) values '
param_list = []
for new in news:
if not isinstance(new, New):
continue
sql = sql + ' (%s, %s, %s, %s), '
param_list.append(new.id)
param_list.append(new.category)
param_list.append(new.title)
param_list.append(new.url)

sql = sql[0:-2]
conn = get_mysql_connection()
cursor = conn.cursor()
cursor.execute(sql, param_list)
conn.commit()
cursor.close()
conn.close()
logging.info('存入 %s 条新闻' % len(news))


def query_categories():
"""
获取当日新闻分类列表
:return: 当日新闻分类列表
"""
sql = r'select distinct category from news where create_time > (current_timestamp - interval %s hour)'
conn = get_mysql_connection()
cursor = conn.cursor()
cursor.execute(sql, (PAST_HOURS_OF_NEWS, ))
category_list = [i[0] for i in cursor.fetchall()]
cursor.close()
conn.close()

return category_list


def query_news():
"""
查询过去 23 小时内的最新几条新闻并分类返回
:return: 分类完成的过去 23 个小时内的最新几条新闻
"""
category_list = query_categories()
paper = {}
sql = r"""
select title, url
from news
where category = %s
and create_time > (current_timestamp - interval %s hour)
order by create_time desc
limit %s
"""
conn = get_mysql_connection()
cursor = conn.cursor()
for category in category_list:
cursor.execute(sql, (category, PAST_HOURS_OF_NEWS, CATEGORY_ITEM_MAX_SIZE))
fetch = cursor.fetchall()
news = [New(i[0], i[1], category) for i in fetch]
paper[category] = news
cursor.close()
conn.close()

return paper


def get_and_save_news():
"""
从 api 获取新闻并存储到数据库
:return: None
"""
news = get_news_from_api()
save_news(news)


def query_and_publish_news():
"""
查询并发布新闻
:return: None
"""
paper = query_news()
dt = datetime.now()
with open(dt.strftime('%Y%m%d%H%M%S') + '.md', 'w') as f:
f.write(to_markdown_string(paper))


def main():
init_database()
scheduler = BlockingScheduler()
# 新闻抓取
scheduler.add_job(get_and_save_news, 'interval', seconds=REQUEST_INTERVAL)
# 新闻读取
scheduler.add_job(query_and_publish_news, 'cron', minute="0")
try:
scheduler.start()
except (KeyboardInterrupt, SystemExit):
print('Exit')
pass


if __name__ == '__main__':
# todo 提取 SQL 执行部分代码为方法
main()
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