plomlompom.com Git - url-catcher/blob - url_catcher.py

   1 #!/usr/bin/python3
   2
   3 import bottle
   4 import validators
   5 import html
   6 import os
   7 import os.path
   8 import time
   9 import json
  10 import smtplib
  11 import email.mime.text
  12 import tempfile
  13 import shutil
  14
  15 slowdown_reset = 60 * 60 * 24
  16 ips_dir = 'ips'
  17 lists_dir = 'lists'
  18 captchas_dir = 'captchas'
  19 customizations_path = 'customizations.json'
  20 messages = {
  21     'internalServerError': 'Internal server error.',
  22     'badPageName': 'Bad page name.',
  23     'wrongCaptcha': 'Wrong captcha.',
  24     'invalidURL': 'Invalid URL.',
  25     'recordedURL': 'Recorded URL: ',
  26     'pleaseWait': 'Too many attempts from your IP. Wait this many seconds: ',
  27     'mailSubject': '[url_catcher.py] New URL submitted',
  28     'mailBodyPage': 'New URL submitted for page: ',
  29     'mailBodyURL': 'URL is: ',
  30 }
  31 mail_config = {
  32     'from': 'foo@example.org',
  33     'to': 'bar@example.org',
  34 }
  35 if os.path.isfile(customizations_path):
  36     customizations_file = open(customizations_path)
  37     customizations = json.load(customizations_file)
  38     customizations_file.close()
  39     for key in customizations['translations']:
  40         messages[key] = customizations['translations'][key]
  41     for key in customizations['mailConfig']:
  42         mail_config[key] = customizations['mailConfig'][key]
  43     if 'slowdownReset' in customizations:
  44         slowdown_reset = customizations['slowdownReset']
  45 os.makedirs(ips_dir, exist_ok=True)
  46 os.makedirs(lists_dir, exist_ok=True)
  47
  48
  49 def atomic_write(path, content, mode):
  50     """Atomic write/append to file."""
  51     _, tmpPath = tempfile.mkstemp()
  52     if 'a' == mode:
  53         shutil.copy2(path, tmpPath)
  54     f = open(tmpPath, mode)
  55     f.write(content)
  56     f.flush()
  57     os.fsync(f.fileno())
  58     f.close()
  59     os.rename(tmpPath, path)
  60
  61
  62 def send_mail(page, url):
  63     """Send mail telling about page URL list update."""
  64     body = messages['mailBodyPage'] + page + '\n' + messages['mailBodyURL'] + \
  65         url
  66     msg = email.mime.text.MIMEText(body)
  67     msg['Subject'] = messages['mailSubject']
  68     msg['From'] = mail_config['from']
  69     msg['To'] = mail_config['to']
  70     s = smtplib.SMTP('localhost')
  71     s.send_message(msg)
  72     s.quit()
  73
  74
  75 @bottle.error(500)
  76 def internal_error(error):
  77     """If trouble, don't leak bottle.py's detailed error description."""
  78     return messages['internalServerError']
  79
  80
  81 @bottle.post('/uwsgi/post_link')
  82 def post_link():
  83     """Record URL if all sane, send mail to curator."""
  84
  85     # Slow down repeat requests.
  86     now = int(time.time())
  87     start_date = now
  88     attempts = 0
  89     rewrite = True
  90     ip = bottle.request.environ.get('REMOTE_ADDR')
  91     ip_file_path = ips_dir + '/' + ip
  92     try:
  93         if os.path.isfile(ip_file_path):
  94             ip_file = open(ip_file_path, 'r')
  95             ip_data = ip_file.readlines()
  96             ip_file.close()
  97             old_start_date = int(ip_data[0])
  98             if old_start_date + slowdown_reset > now:
  99                 attempts = int(ip_data[1])
 100                 start_date = old_start_date
 101                 wait_period = 2**attempts
 102                 if start_date + wait_period > now:
 103                     limit = min(start_date + wait_period,
 104                         start_date + slowdown_reset)
 105                     rewrite = False
 106                     remaining_wait = limit - now
 107                     msg = messages['pleaseWait'] + str(remaining_wait)
 108                     return bottle.HTTPResponse(msg, 429,
 109                         {'Retry-After': str(remaining_wait)})
 110                 attempts += 1
 111     except:
 112         raise
 113     finally:
 114         if rewrite:
 115             atomic_write(ip_file_path,
 116                 str(start_date) + '\n' + str(attempts), 'w')
 117
 118     # Derive page / page file name.
 119     page = bottle.request.forms.get('page')
 120     if '\0' in page or '/' in page or '.' in page or len(page.encode()) > 255:
 121         return bottle.HTTPResponse(messages['badPageName'], 400)
 122
 123     # Test captcha.
 124     captcha_file = open(captchas_dir + '/' + page, 'r')
 125     captcha_correct = captcha_file.readline().rstrip()
 126     captcha_file.close()
 127     captcha_input = bottle.request.forms.get('captcha')
 128     if captcha_correct != captcha_input:
 129         return bottle.HTTPResponse(messages['wrongCaptcha'], 400)
 130
 131     # Record URL.
 132     url = bottle.request.forms.get('url')
 133     if not validators.url(url):
 134         return bottle.HTTPResponse(messages['invalidURL'], 400)
 135     send_mail(page, url)
 136     atomic_write(lists_dir + '/' + page, url + '\n', 'a')
 137     url_html = html.escape(url)
 138
 139     # Response body.
 140     return messages['recordedURL'] + url_html
 141
 142
 143 bottle.debug(True)
 144 # Non-uWSGI mode.
 145 if __name__ == '__main__':
 146     bottle.run(host='localhost', port=8080)
 147 # uWSGI mode.
 148 else:
 149     app = application = bottle.default_app()