database.py

"""Convenience methods for interacting with the database.

Calling get_db_connection() will return the open database handle.
"""
import psycopg2
from psycopg2.extras import DictConnection

from contextlib import closing

import configure

_conn = None
"""The database connection."""


def get_db_connection():
    """Get a reference to the open database connection, or create a new
    connection if one does not already exist.

    Returns an instance of psycopg2's connection object.
    """
    global _conn
    if conn is None or conn.closed:
        # Create a new connection object and store it on g.
        _conn = DictConnection(configure.PG_CONNECT_INFO)
    return _conn


def disconnect_db():
    """Disconnect from PostgreSQL.

    This method should be called on request shutdown.
    """
    global _conn
    if _conn is not None and not _conn.closed:
        _conn.close()