13e9a19e63a0960d751421f287823da91a233eff
[zzz-pokedex.git] / pokedex / db / __init__.py
1 from sqlalchemy import MetaData, Table, engine_from_config, orm
2
3 from ..defaults import get_default_db_uri
4 from .tables import metadata
5
6
7 def connect(uri=None, session_args={}, engine_args={}, engine_prefix=''):
8 """Connects to the requested URI. Returns a session object.
9
10 With the URI omitted, attempts to connect to a default SQLite database
11 contained within the package directory.
12
13 Calling this function also binds the metadata object to the created engine.
14 """
15
16 # If we didn't get a uri, fall back to the default
17 if uri is None:
18 uri = engine_args.get(engine_prefix + 'url', None)
19 if uri is None:
20 uri = get_default_db_uri()
21
22 ### Do some fixery for MySQL
23 if uri[0:5] == 'mysql':
24 # MySQL uses latin1 for connections by default even if the server is
25 # otherwise oozing with utf8; charset fixes this
26 if 'charset' not in uri:
27 uri += '?charset=utf8'
28
29 # Tables should be InnoDB, in the event that we're creating them, and
30 # use UTF-8 goddammit!
31 for table in metadata.tables.values():
32 table.kwargs['mysql_engine'] = 'InnoDB'
33 table.kwargs['mysql_charset'] = 'utf8'
34
35 ### Connect
36 engine_args[engine_prefix + 'url'] = uri
37 engine = engine_from_config(engine_args, prefix=engine_prefix)
38 conn = engine.connect()
39 metadata.bind = engine
40
41 all_session_args = dict(autoflush=True, autocommit=False, bind=engine)
42 all_session_args.update(session_args)
43 sm = orm.sessionmaker(**all_session_args)
44 session = orm.scoped_session(sm)
45
46 return session