plomlompom.com Git - misc/blob - plomlib.py

   1 import os
   2 from http.server import BaseHTTPRequestHandler
   3
   4
   5 class PlomException(Exception):
   6     pass
   7
   8
   9 class PlomDB:
  10
  11     def __init__(self, db_name):
  12         self.db_file = db_name
  13         self.lock_file = db_name+ '.lock'
  14         if os.path.exists(self.db_file):
  15             with open(self.db_file, 'r') as f:
  16                 self.read_db_file(f)
  17
  18     def lock(self):
  19         if os.path.exists(self.lock_file):
  20             raise PlomException('Sorry, lock file!')
  21         f = open(self.lock_file, 'w+')
  22         f.close()
  23
  24     def unlock(self):
  25         os.remove(self.lock_file)
  26
  27     def backup(self):
  28         import shutil
  29         from datetime import datetime, timedelta
  30         # collect modification times of numbered .bak files
  31         bak_prefix = f'{self.db_file}.bak.'
  32         backup_dates = []
  33         i = 0
  34         bak_as = f'{bak_prefix}{i}'
  35         while os.path.exists(bak_as):
  36             mod_time = os.path.getmtime(bak_as)
  37             backup_dates += [str(datetime.fromtimestamp(mod_time))]
  38             i += 1
  39             bak_as = f'{bak_prefix}{i}'
  40
  41         # collect what numbered .bak files to save: the older, the fewer; for each
  42         # timedelta, keep the newest file that's older
  43         ages_to_keep = [timedelta(minutes=4**i) for i in range(0, 8)]
  44         now = datetime.now()
  45         to_save = []
  46         for age in ages_to_keep:
  47             limit = now - age
  48             for i, date in enumerate(reversed(backup_dates)):
  49                 if datetime.strptime(date, '%Y-%m-%d %H:%M:%S.%f') < limit:
  50                     unreversed_i = len(backup_dates) - i - 1
  51                     if unreversed_i not in to_save:
  52                         to_save += [unreversed_i]
  53                     break
  54
  55         # remove redundant backup files
  56         j = 0
  57         for i in to_save:
  58             if i != j:
  59                 source = f'{bak_prefix}{i}'
  60                 target = f'{bak_prefix}{j}'
  61                 shutil.move(source, target)
  62             j += 1
  63         for i in range(j, len(backup_dates)):
  64             try:
  65                 os.remove(f'{bak_prefix}{i}')
  66             except FileNotFoundError:
  67                 pass
  68
  69         # put copy of current state at end of bak list
  70         shutil.copy(self.db_file, f'{bak_prefix}{j}')
  71
  72     def write_text_to_db(self, text, mode='w'):
  73         self.lock()
  74         self.backup()
  75         with open(self.db_file, mode) as f:
  76             f.write(text);
  77         self.unlock()
  78
  79
  80 class PlomHandler(BaseHTTPRequestHandler):
  81     homepage = '/'
  82     html_head = '<!DOCTYPE html>\n<html>\n<meta charset="UTF-8">'
  83     html_foot = '</body>\n</html>'
  84
  85     def fail_400(self, e):
  86         self.send_HTML(f'ERROR: {e}', 400)
  87
  88     def send_HTML(self, html, code=200):
  89         self.send_code_and_headers(code, [('Content-type', 'text/html')])
  90         self.wfile.write(bytes(f'{self.html_head}\n{html}\n{self.html_foot}', 'utf-8'))
  91
  92     def send_code_and_headers(self, code, headers=[]):
  93         self.send_response(code)
  94         for fieldname, content in headers:
  95             self.send_header(fieldname, content)
  96         self.end_headers()
  97
  98     def redirect(self, url='/'):
  99         self.send_code_and_headers(302, [('Location', url)])
 100
 101
 102
 103 def run_server(port, handler_class):
 104     from http.server import HTTPServer
 105     webServer = HTTPServer(('localhost', port), handler_class)
 106     print(f"Server started http://localhost:{port}")
 107     try:
 108         webServer.serve_forever()
 109     except KeyboardInterrupt:
 110         pass
 111     webServer.server_close()
 112     print("Server stopped.")