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         if not os.path.exists(self.db_file):
  31             return
  32
  33         # collect modification times of numbered .bak files
  34         print('DEBUG BACKUP')
  35         bak_prefix = f'{self.db_file}.bak.'
  36         # backup_dates = []
  37         mtimes_to_paths = {}
  38         for path in [path for path in os.listdir(os.path.dirname(bak_prefix))
  39                      if path.startswith(os.path.basename(bak_prefix))]:
  40             mod_time = os.path.getmtime(path)
  41             print(f'DEBUG pre-exists: {path} {mod_time}')
  42             mtimes_to_paths[str(datetime.fromtimestamp(mod_time))] = path
  43             # backup_dates += [str(datetime.fromtimestamp(mod_time))]
  44
  45         for mtime in sorted(mtimes_to_paths.keys()):
  46             print(f'DEBUG mtimes_to_paths: {mtime}:{mtimes_to_paths[mtime]}')
  47
  48         # collect what numbered .bak files to save: the older, the fewer; for each
  49         # timedelta, keep the newest file that's older
  50         ages_to_keep = [timedelta(minutes=4**i) for i in range(0, 8)]
  51         print(f'DEBUG ages_to_keep: {ages_to_keep}')
  52         now = datetime.now()
  53         to_save = {}
  54         for age in ages_to_keep:
  55             limit = now - age
  56             for mtime in reversed(sorted(mtimes_to_paths.keys())):
  57                 print(f'DEBUG checking if {mtime} < {limit} ({now} - {age})')
  58                 if datetime.strptime(mtime, '%Y-%m-%d %H:%M:%S.%f') < limit:
  59                     print('DEBUG it is, adding!')
  60                     to_save[mtime] = mtimes_to_paths[mtime]
  61                     break
  62
  63         for path in [path for path in mtimes_to_paths.values()
  64                      if path not in to_save.values()]:
  65             print(f'DEBUG removing {path} cause not in to_save')
  66             os.remove(path)
  67
  68         i = 0
  69         for mtime in sorted(to_save.keys()):
  70             source = to_save[mtime]
  71             target = f'{bak_prefix}{i}'
  72             print(f'DEBUG to_save {source} -> {target}')
  73             if source != target:
  74                 shutil.move(source, target)
  75             i += 1
  76
  77         # put copy of current state at end of bak list
  78         print(f'DEBUG saving current state to {bak_prefix}{i}')
  79         shutil.copy(self.db_file, f'{bak_prefix}{i}')
  80
  81     def write_text_to_db(self, text, mode='w'):
  82         self.lock()
  83         self.backup()
  84         with open(self.db_file, mode) as f:
  85             f.write(text);
  86         self.unlock()
  87
  88
  89 class PlomHandler(BaseHTTPRequestHandler):
  90     homepage = '/'
  91     html_head = '<!DOCTYPE html>\n<html>\n<meta charset="UTF-8">'
  92     html_foot = '</body>\n</html>'
  93
  94     def fail_400(self, e):
  95         self.send_HTML(f'ERROR: {e}', 400)
  96
  97     def send_HTML(self, html, code=200):
  98         self.send_code_and_headers(code, [('Content-type', 'text/html')])
  99         self.wfile.write(bytes(f'{self.html_head}\n{html}\n{self.html_foot}', 'utf-8'))
 100
 101     def send_code_and_headers(self, code, headers=[]):
 102         self.send_response(code)
 103         for fieldname, content in headers:
 104             self.send_header(fieldname, content)
 105         self.end_headers()
 106
 107     def redirect(self, url='/'):
 108         self.send_code_and_headers(302, [('Location', url)])
 109
 110     def try_do(self, do_method):
 111         try:
 112             do_method()
 113         except PlomException as e:
 114             self.fail_400(e)
 115
 116
 117
 118 def run_server(port, handler_class):
 119     from http.server import HTTPServer
 120     webServer = HTTPServer(('localhost', port), handler_class)
 121     print(f"Server started http://localhost:{port}")
 122     try:
 123         webServer.serve_forever()
 124     except KeyboardInterrupt:
 125         pass
 126     webServer.server_close()
 127     print("Server stopped.")