2 # -*- coding: utf-8 -*-
4 # gPodder - A media aggregator and podcast client
5 # Copyright (c) 2005-2010 Thomas Perl and the gPodder Team
7 # gPodder is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation; either version 3 of the License, or
10 # (at your option) any later version.
12 # gPodder is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 # GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with this program. If not, see <http://www.gnu.org/licenses/>.
21 # gpodder.minidb - A simple SQLite store for Python objects
22 # Thomas Perl, 2010-01-28
24 # based on: "ORM wie eine Kirchenmaus - a very poor ORM implementation
25 # by thp, 2009-11-29 (thpinfo.com/about)"
28 # For Python 2.5, we need to request the "with" statement
29 from __future__
import with_statement
34 import sqlite3
.dbapi2
as sqlite
37 from pysqlite2
import dbapi2
as sqlite
39 raise Exception('Please install SQLite3 support.')
45 def __init__(self
, filename
=':memory:'):
46 self
.db
= sqlite
.connect(filename
, check_same_thread
=False)
47 self
.lock
= threading
.RLock()
49 def _schema(self
, class_
):
50 return class_
.__name
__, list(sorted(class_
.__slots
__))
52 def _set(self
, o
, slot
, value
):
53 # Set a slot on the given object to value, doing a cast if
54 # necessary. The value None is special-cased and never cast.
56 value
= o
.__class
__.__slots
__[slot
](value
)
57 setattr(o
, slot
, value
)
67 def _register(self
, class_
):
69 table
, slots
= self
._schema
(class_
)
70 cur
= self
.db
.execute('PRAGMA table_info(%s)' % table
)
71 available
= cur
.fetchall()
74 available
= [row
[1] for row
in available
]
75 missing_slots
= (s
for s
in slots
if s
not in available
)
76 for slot
in missing_slots
:
77 self
.db
.execute('ALTER TABLE %s ADD COLUMN %s TEXT' % (table
,
80 self
.db
.execute('CREATE TABLE %s (%s)' % (table
,
81 ', '.join('%s TEXT'%s for s
in slots
)))
83 def update(self
, o
, **kwargs
):
85 for k
, v
in kwargs
.items():
90 if hasattr(o
, '__iter__'):
96 self
._register
(o
.__class
__)
97 table
, slots
= self
._schema
(o
.__class
__)
99 # Only save values that have values set (non-None values)
100 slots
= [s
for s
in slots
if getattr(o
, s
, None) is not None]
102 values
= [str(getattr(o
, slot
)) for slot
in slots
]
103 self
.db
.execute('INSERT INTO %s (%s) VALUES (%s)' % (table
,
104 ', '.join(slots
), ', '.join('?'*len(slots
))), values
)
107 if hasattr(o
, '__iter__'):
113 self
._register
(o
.__class
__)
114 table
, slots
= self
._schema
(o
.__class
__)
116 # Use "None" as wildcard selector in remove actions
117 slots
= [s
for s
in slots
if getattr(o
, s
, None) is not None]
119 values
= [getattr(o
, slot
) for slot
in slots
]
120 self
.db
.execute('DELETE FROM %s WHERE %s' % (table
,
121 ' AND '.join('%s=?'%s for s
in slots
)), values
)
123 def load(self
, class_
, **kwargs
):
125 self
._register
(class_
)
126 table
, slots
= self
._schema
(class_
)
127 sql
= 'SELECT %s FROM %s' % (', '.join(slots
), table
)
129 sql
+= ' WHERE %s' % (' AND '.join('%s=?' % k
for k
in kwargs
))
131 cur
= self
.db
.execute(sql
, kwargs
.values())
136 o
= class_
.__new
__(class_
)
137 for attr
, value
in zip(slots
, row
):
138 self
._set
(o
, attr
, value
)
140 return [apply(row
) for row
in cur
]
142 def get(self
, class_
, **kwargs
):
143 result
= self
.load(class_
, **kwargs
)
149 if __name__
== '__main__':
150 class Person(object):
151 __slots__
= {'username': str, 'id': int}
153 def __init__(self
, username
, id):
154 self
.username
= username
158 return '<Person "%s" (%d)>' % (self
.username
, self
.id)
161 m
.save(Person('User %d' % x
, x
*20) for x
in range(50))
163 p
= m
.get(Person
, id=200)
166 p
= m
.get(Person
, id=200)
168 # Remove some persons again (deletion by value!)
169 m
.remove(Person('User %d' % x
, x
*20) for x
in range(40))
171 class Person(object):
172 __slots__
= {'username': str, 'id': int, 'mail': str}
174 def __init__(self
, username
, id, mail
):
175 self
.username
= username
180 return '<Person "%s" (%s)>' % (self
.username
, self
.mail
)
182 # A schema update takes place here
183 m
.save(Person('User %d' % x
, x
*20, 'user@home.com') for x
in range(50))