/usr/share/doc/python-werkzeug-doc/examples/simplewiki/database.py is in python-werkzeug-doc 0.9.4+dfsg-1.1ubuntu2.1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 | # -*- coding: utf-8 -*-
"""
simplewiki.database
~~~~~~~~~~~~~~~~~~~
The database.
:copyright: (c) 2009 by the Werkzeug Team, see AUTHORS for more details.
:license: BSD.
"""
from datetime import datetime
from sqlalchemy import Table, Column, Integer, String, DateTime, \
ForeignKey, MetaData, join
from sqlalchemy.orm import relation, create_session, scoped_session, \
mapper
from simplewiki.utils import application, local_manager, parse_creole
# create a global metadata
metadata = MetaData()
def new_db_session():
"""
This function creates a new session if there is no session yet for
the current context. It looks up the application and if it finds
one it creates a session bound to the active database engine in that
application. If there is no application bound to the context it
raises an exception.
"""
return create_session(application.database_engine, autoflush=True,
autocommit=False)
# and create a new global session factory. Calling this object gives
# you the current active session
session = scoped_session(new_db_session, local_manager.get_ident)
# our database tables.
page_table = Table('pages', metadata,
Column('page_id', Integer, primary_key=True),
Column('name', String(60), unique=True)
)
revision_table = Table('revisions', metadata,
Column('revision_id', Integer, primary_key=True),
Column('page_id', Integer, ForeignKey('pages.page_id')),
Column('timestamp', DateTime),
Column('text', String),
Column('change_note', String(200))
)
class Revision(object):
"""
Represents one revision of a page.
This is useful for editing particular revision of pages or creating
new revisions. It's also used for the diff system and the revision
log.
"""
query = session.query_property()
def __init__(self, page, text, change_note='', timestamp=None):
if isinstance(page, (int, long)):
self.page_id = page
else:
self.page = page
self.text = text
self.change_note = change_note
self.timestamp = timestamp or datetime.utcnow()
def render(self):
"""Render the page text into a genshi stream."""
return parse_creole(self.text)
def __repr__(self):
return '<%s %r:%r>' % (
self.__class__.__name__,
self.page_id,
self.revision_id
)
class Page(object):
"""
Represents a simple page without any revisions. This is for example
used in the page index where the page contents are not relevant.
"""
query = session.query_property()
def __init__(self, name):
self.name = name
@property
def title(self):
return self.name.replace('_', ' ')
def __repr__(self):
return '<%s %r>' % (self.__class__.__name__, self.name)
class RevisionedPage(Page, Revision):
"""
Represents a wiki page with a revision. Thanks to multiple inhertiance
and the ability of SQLAlchemy to map to joins we can combine `Page` and
`Revision` into one class here.
"""
query = session.query_property()
def __init__(self):
raise TypeError('cannot create WikiPage instances, use the Page and '
'Revision classes for data manipulation.')
def __repr__(self):
return '<%s %r:%r>' % (
self.__class__.__name__,
self.name,
self.revision_id
)
# setup mappers
mapper(Revision, revision_table)
mapper(Page, page_table, properties=dict(
revisions=relation(Revision, backref='page',
order_by=Revision.revision_id.desc())
))
mapper(RevisionedPage, join(page_table, revision_table), properties=dict(
page_id=[page_table.c.page_id, revision_table.c.page_id],
))
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