Python多进程爬取电影信息

观察翻页时详情页面url地址变化规律

import json
from os import makedirs
from os.path import exists
import requests
import logging
import re
from urllib.parse import urljoin
import multiprocessing

# 定义了下日志输出级别和输出格式
logging.basicConfig(level=logging.INFO,
                    format='%(asctime)s - %(levelname)s: %(message)s')

BASE_URL = 'https://ssr1.scrape.center'
TOTAL_PAGE = 10

RESULTS_DIR = 'results'
exists(RESULTS_DIR) or makedirs(RESULTS_DIR)

# 爬取列表页
def scrape_page(url):
    """
    scrape page by url and return its html
    :param url: page url
    :return: html of page
    """
    logging.info('scraping %s...', url)
    try:
        response = requests.get(url)
        if response.status_code == 200:
            return response.text
        logging.error('get invalid status code %s while scraping %s',
                      response.status_code, url)
    except requests.RequestException:
        logging.error('error occurred while scraping %s', url, exc_info=True)

# 爬取详情列表页
def scrape_index(page):
    """
    scrape index page and return its html
    :param page: page of index page
    :return: html of index page
    """
    index_url = f'{BASE_URL}/page/{page}'
    return scrape_page(index_url)

# 解析详情列表页
def parse_index(html):
    """
    parse index page and return detail url
    :param html: html of index page
    """
    pattern = re.compile('')
    items = re.findall(pattern, html)
    if not items:
        return []
    for item in items:
        detail_url = urljoin(BASE_URL, item)
        logging.info('get detail url %s', detail_url)
        yield detail_url

# 爬取详情页
def scrape_detail(url):
    """
    scrape detail page and return its html
    :param page: page of detail page
    :return: html of detail page
    """
    return scrape_page(url)

# 解析详情页正则匹配方法
def parse_detail(html):
    """
    parse detail page
    :param html: html of detail page
    :return: data
    """

    cover_pattern = re.compile(
        'class="item.*?', re.S)
    name_pattern = re.compile('(.*?)')
    categories_pattern = re.compile(
        '(.*?).*?', re.S)
    published_at_pattern = re.compile('(\d{4}-\d{2}-\d{2})\s?上映')
    drama_pattern = re.compile('.*?(.*?)
', re.S)
    score_pattern = re.compile('(.*?)
', re.S)
    
    # 结果只有一个，用 search 方法提取即可
    # 结果有多个，使用 findall 方法提取，结果是一个列表
    cover = re.search(cover_pattern, html).group(
        1).strip() if re.search(cover_pattern, html) else None
    name = re.search(name_pattern, html).group(
        1).strip() if re.search(name_pattern, html) else None
    categories = re.findall(categories_pattern, html) if re.findall(
        categories_pattern, html) else []
    published_at = re.search(published_at_pattern, html).group(
        1) if re.search(published_at_pattern, html) else None
    drama = re.search(drama_pattern, html).group(
        1).strip() if re.search(drama_pattern, html) else None
    score = float(re.search(score_pattern, html).group(1).strip()
                  ) if re.search(score_pattern, html) else None

    return {
        'cover': cover,
        'name': name,
        'categories': categories,
        'published_at': published_at,
        'drama': drama,
        'score': score
    }


# 解析详情页pq方法
from pyquery import PyQuery as pq
def parse_detail(html):
    """
    parse detail page
    :param html: html of detail page
    :return: data
    """
    doc = pq(html)
    cover = doc('img.cover').attr('src')
    name = doc('a > h2').text()
    categories = [item.text() for item in doc('.categories button span').items()]
    published_at = doc('.info:contains(上映)').text()
    published_at = re.search('(\d{4}-\d{2}-\d{2})', published_at).group(1) \
        if published_at and re.search('\d{4}-\d{2}-\d{2}', published_at) else None
    drama = doc('.drama p').text()
    score = doc('p.score').text()
    score = float(score) if score else None
    return {
        'cover': cover,
        'name': name,
        'categories': categories,
        'published_at': published_at,
        'drama': drama,
        'score': score
    }


# 保存数据
def save_data(data):
    """
    save to json file
    :param data:
    :return:
    """
    name = data.get('name')
    data_path = f'{RESULTS_DIR}/{name}.json'
    json.dump(data, open(data_path, 'w', encoding='utf-8'),
              ensure_ascii=False, indent=2)

# main 方法
def main(page):
    """
    main process
    :return:
    """
    index_html = scrape_index(page)
    detail_urls = parse_index(index_html)
    for detail_url in detail_urls:
        detail_html = scrape_detail(detail_url)
        data = parse_detail(detail_html)
        logging.info('get detail data %s', data)
        logging.info('saving data to json file')
        save_data(data)
        logging.info('data saved successfully')

# 多进程加速
if __name__ == '__main__':
    pool = multiprocessing.Pool()
    pages = range(1, TOTAL_PAGE + 1)
    pool.map(main, pages)
    pool.close()