calibre-web/lib/sqlalchemy_fulltext/__init__.py

89 lines
2.7 KiB
Python

# -*- coding: utf-8 -*-s
import re
from sqlalchemy import event
from sqlalchemy.schema import DDL
from sqlalchemy.orm.mapper import Mapper
from sqlalchemy.ext.compiler import compiles
from sqlalchemy.sql.expression import ClauseElement
import modes as FullTextMode
MYSQL = "mysql"
MYSQL_BUILD_INDEX_QUERY = u"""ALTER TABLE {0.__tablename__} ADD FULLTEXT ({1})"""
MYSQL_MATCH_AGAINST = u"""
MATCH ({0})
AGAINST ("{1}" {2})
"""
def escape_quote(string):
return re.sub(r"[\"\']+", "", string)
class FullTextSearch(ClauseElement):
"""
Search FullText
:param against: the search query
:param table: the table needs to be query
FullText support with in query, i.e.
>>> from sqlalchemy_fulltext import FullTextSearch
>>> session.query(Foo).filter(FullTextSearch('Spam', Foo))
"""
def __init__(self, against, model, mode=FullTextMode.DEFAULT):
self.model = model
self.against = escape_quote(against)
self.mode = mode
@compiles(FullTextSearch, MYSQL)
def __mysql_fulltext_search(element, compiler, **kw):
assert issubclass(element.model, FullText), "{0} not FullTextable".format(element.model)
return MYSQL_MATCH_AGAINST.format(",".join(
element.model.__fulltext_columns__),
element.against,
element.mode)
class FullText(object):
"""
FullText Minxin object for SQLAlchemy
>>> from sqlalchemy_fulltext import FullText
>>> class Foo(FullText, Base):
>>> __fulltext_columns__ = ('spam', 'ham')
>>> ...
fulltext search spam and ham now
"""
__fulltext_columns__ = tuple()
@classmethod
def build_fulltext(cls):
"""
build up fulltext index after table is created
"""
if FullText not in cls.__bases__:
return
assert cls.__fulltext_columns__, "Model:{0.__name__} No FullText columns defined".format(cls)
event.listen(cls.__table__,
'after_create',
DDL(MYSQL_BUILD_INDEX_QUERY.format(cls,
", ".join((escape_quote(c)
for c in cls.__fulltext_columns__)))
)
)
"""
TODO: black magic in the future
@classmethod
@declared_attr
def __contains__(*arg):
return True
"""
def __build_fulltext_index(mapper, class_):
if issubclass(class_, FullText):
class_.build_fulltext()
event.listen(Mapper, 'instrument_class', __build_fulltext_index)