画像ダウンローダーを作ろう

import requests, os, time, json
import urllib.parse
from bs4 import BeautifulSoup

# 初期設定
shodou_url = 'http://uta.pw/shodou/index.php?master'
save_dir = os.path.join(os.path.dirname(__file__), 'images')
logfile = 'image.json'

# 画像をダウンロード

def download_shodou(target_url):
    if not os.path.exists(save_dir):
        os.mkdir(save_dir)
    html = requests.get(target_url).text
    time.sleep(1)
    soup = BeautifulSoup(html, 'html.parser')
    a_div = soup.select('#contents_body > div')
    if len(a_div) == 0:
        print('[エラー] 要素の取得に失敗')
        return
    images = []
    for img in a_div[0].find_all('img'):
        src = img.attrs['src']
        alt = img.attrs['alt']
        a_url = urllib.parse.urljoin(target_url, src)
        fname = os.path.join(save_dir, src.replace('/', '_'))
        download_to_file(a_url, fname)
        images.append({'title': alt, 'url': a_url, 'file': fname})
　　# images(JSON形式）をログとして出力（indent、ensure_~ないと見にくい）
    with open(logfile, 'w', encoding='utf-8') as fp:
        json.dump(images, fp, indent=4, ensure_ascii=False)

#　画像のDLも With Open でバイナリモードで1回ずつ保存すればよい
def download_to_file(url, file):
    print('download:', url)
    bin = requests.get(url).content
    time.sleep(1)
    with open(file, 'wb') as fp:
        fp.write(bin)

if __name__ == '__main__':
    download_shodou(shodou_url)