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try pattern for database connection with the close method

Skip Montanaro skip.montanaro at gmail.com
Sun Feb 22 14:15:09 EST 2015 
On Sun, Feb 22, 2015 at 12:41 PM, Mario Figueiredo <marfig at gmail.com> wrote:
> The sqlite context manager doesn't close a database connection on
> exit. It only ensures, commits and rollbacks are performed.

Sorry, I haven't paid careful attention to this thread, so perhaps
this has already been suggested, however... Can't you write your own
class which delegates to the necessary sqlite3 bits and has a context
manager with the desired behavior? Thinking out loud, you could define
a ConnectionMgr class which accepts a sqlite3 connection as a
parameter:

class ConnectionMgr(object):
  def __init__(self, conn):
    self.conn = conn

  def __enter__(self):
    ...

  def __exit__(self, type, value, exception):
    if self.conn is not None:
      ... close self.conn connection here ...
    self.conn = None

  def __getattr__(self, attr):
    return getattr(self.conn, attr)

then...

  try:
    with MyConnection(lite.connect('data.db')) as db:
      ...
  except lite.DatabaseError:
    ...

Might also have to __enter__ and __exit__ self.conn as appropriate.

Skip
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