src/backend/nopaste.py

   1 #!/usr/bin/python
   2
   3 import magic
   4
   5 from misc import Object
   6
   7 class Nopaste(Object):
   8         def create(self, subject, content, type="text", expires=None, account=None, address=None):
   9                 self._cleanup_database()
  10
  11                 uid = None
  12                 if account:
  13                         uid = account.uid
  14
  15                 # Escape any backslashes. PostgreSQL tends to think that they lead octal
  16                 # values or something that confuses the convertion from text to bytea.
  17                 if type == "text":
  18                         content = content.replace("\\", "\\\\")
  19                         mimetype = "text/plain"
  20
  21                 elif type == "file":
  22                         content = buffer(content)
  23                         mimetype = self._guess_mimetype(content)
  24
  25                 # http://blog.00null.net/easily-generating-random-strings-in-postgresql/
  26                 res = self.db.get("INSERT INTO nopaste(uuid, subject, content, time_expires, address, \
  27                         uid, mimetype, size) VALUES(random_slug(), %s, %s, \
  28                                 (CASE WHEN %s = 0 THEN NULL ELSE NOW() + INTERVAL '%s seconds' END), \
  29                         %s, %s, %s, %s) RETURNING uuid",
  30                         subject, content, expires, expires, address, uid, mimetype, len(content))
  31
  32                 if res:
  33                         return res.uuid
  34
  35         def _guess_mimetype(self, buf):
  36                 ms = magic.open(magic.NONE)
  37                 ms.load()
  38
  39                 # Return the mime type
  40                 ms.setflags(magic.MAGIC_MIME_TYPE)
  41
  42                 buf = "%s" % buf
  43
  44                 try:
  45                         return ms.buffer(buf)
  46                 finally:
  47                         ms.close()
  48
  49         def get(self, uuid):
  50                 res = self.db.get("SELECT uuid, subject, time_created, time_expires, address, uid, \
  51                         mimetype, views, size FROM nopaste WHERE uuid = %s AND (CASE WHEN time_expires \
  52                         IS NULL THEN TRUE ELSE NOW() < time_expires END)", uuid)
  53
  54                 if res:
  55                         # Get the account that uploaded this if available
  56                         res.account = None
  57                         if res.uid:
  58                                 res.account = self.backend.accounts.get_by_uid(res.uid)
  59
  60                         # Touch the entry so it won't be deleted when it is still used
  61                         self._update_lastseen(uuid)
  62
  63                 return res
  64
  65         def get_content(self, uuid):
  66                 # Try fetching the object from memcache. If found, we return it right away.
  67                 content = self.memcache.get("nopaste-%s" % uuid)
  68
  69                 # If the object was not in the cache, we need to fetch it from the database.
  70                 if not content:
  71                         res = self.db.get("SELECT content, views FROM nopaste WHERE uuid = %s", uuid)
  72
  73                         # Convert the content to a byte string
  74                         content = "%s" % res.content
  75
  76                         # Save it in the cache for later when it has been requested a couple
  77                         # of times
  78                         if res.views >= 5:
  79                                 self.memcache.set("nopaste-%s" % uuid, content, 6 * 3600)
  80
  81                 return content
  82
  83         def _update_lastseen(self, uuid):
  84                 self.db.execute("UPDATE nopaste SET time_lastseen = NOW(), views = views + 1 \
  85                         WHERE uuid = %s", uuid)
  86
  87         def _cleanup_database(self):
  88                 # Delete old pastes when they are expired or when they have not been
  89                 # accessed in a long time.
  90                 self.db.execute("DELETE FROM nopaste WHERE (CASE \
  91                         WHEN time_expires IS NULL \
  92                                 THEN time_lastseen + INTERVAL '6 months' <= NOW() \
  93                         ELSE NOW() >= time_expires END)")