188 lines
7.2 KiB
Python
188 lines
7.2 KiB
Python
from django.db.models import Field, FloatField
|
|
from django.db.models.expressions import CombinedExpression, Func, Value
|
|
from django.db.models.functions import Coalesce
|
|
from django.db.models.lookups import Lookup
|
|
|
|
|
|
class SearchVectorExact(Lookup):
|
|
lookup_name = 'exact'
|
|
|
|
def process_rhs(self, qn, connection):
|
|
if not hasattr(self.rhs, 'resolve_expression'):
|
|
config = getattr(self.lhs, 'config', None)
|
|
self.rhs = SearchQuery(self.rhs, config=config)
|
|
rhs, rhs_params = super(SearchVectorExact, self).process_rhs(qn, connection)
|
|
return rhs, rhs_params
|
|
|
|
def as_sql(self, qn, connection):
|
|
lhs, lhs_params = self.process_lhs(qn, connection)
|
|
rhs, rhs_params = self.process_rhs(qn, connection)
|
|
params = lhs_params + rhs_params
|
|
return '%s @@ %s = true' % (lhs, rhs), params
|
|
|
|
|
|
class SearchVectorField(Field):
|
|
|
|
def db_type(self, connection):
|
|
return 'tsvector'
|
|
|
|
|
|
class SearchQueryField(Field):
|
|
|
|
def db_type(self, connection):
|
|
return 'tsquery'
|
|
|
|
|
|
class SearchVectorCombinable(object):
|
|
ADD = '||'
|
|
|
|
def _combine(self, other, connector, reversed, node=None):
|
|
if not isinstance(other, SearchVectorCombinable) or not self.config == other.config:
|
|
raise TypeError('SearchVector can only be combined with other SearchVectors')
|
|
if reversed:
|
|
return CombinedSearchVector(other, connector, self, self.config)
|
|
return CombinedSearchVector(self, connector, other, self.config)
|
|
|
|
|
|
class SearchVector(SearchVectorCombinable, Func):
|
|
function = 'to_tsvector'
|
|
arg_joiner = " || ' ' || "
|
|
_output_field = SearchVectorField()
|
|
config = None
|
|
|
|
def __init__(self, *expressions, **extra):
|
|
super(SearchVector, self).__init__(*expressions, **extra)
|
|
self.source_expressions = [
|
|
Coalesce(expression, Value('')) for expression in self.source_expressions
|
|
]
|
|
self.config = self.extra.get('config', self.config)
|
|
weight = self.extra.get('weight')
|
|
if weight is not None and not hasattr(weight, 'resolve_expression'):
|
|
weight = Value(weight)
|
|
self.weight = weight
|
|
|
|
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
|
|
resolved = super(SearchVector, self).resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
if self.config:
|
|
if not hasattr(self.config, 'resolve_expression'):
|
|
resolved.config = Value(self.config).resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
else:
|
|
resolved.config = self.config.resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
return resolved
|
|
|
|
def as_sql(self, compiler, connection, function=None, template=None):
|
|
config_params = []
|
|
if template is None:
|
|
if self.config:
|
|
config_sql, config_params = compiler.compile(self.config)
|
|
template = "%(function)s({}::regconfig, %(expressions)s)".format(config_sql.replace('%', '%%'))
|
|
else:
|
|
template = self.template
|
|
sql, params = super(SearchVector, self).as_sql(compiler, connection, function=function, template=template)
|
|
extra_params = []
|
|
if self.weight:
|
|
weight_sql, extra_params = compiler.compile(self.weight)
|
|
sql = 'setweight({}, {})'.format(sql, weight_sql)
|
|
return sql, config_params + params + extra_params
|
|
|
|
|
|
class CombinedSearchVector(SearchVectorCombinable, CombinedExpression):
|
|
def __init__(self, lhs, connector, rhs, config, output_field=None):
|
|
self.config = config
|
|
super(CombinedSearchVector, self).__init__(lhs, connector, rhs, output_field)
|
|
|
|
|
|
class SearchQuery(Value):
|
|
invert = False
|
|
_output_field = SearchQueryField()
|
|
config = None
|
|
|
|
BITAND = '&&'
|
|
BITOR = '||'
|
|
|
|
def __init__(self, value, output_field=None, **extra):
|
|
self.config = extra.pop('config', self.config)
|
|
self.invert = extra.pop('invert', self.invert)
|
|
super(SearchQuery, self).__init__(value, output_field=output_field)
|
|
|
|
def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
|
|
resolved = super(SearchQuery, self).resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
if self.config:
|
|
if not hasattr(self.config, 'resolve_expression'):
|
|
resolved.config = Value(self.config).resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
else:
|
|
resolved.config = self.config.resolve_expression(query, allow_joins, reuse, summarize, for_save)
|
|
return resolved
|
|
|
|
def as_sql(self, compiler, connection):
|
|
params = [self.value]
|
|
if self.config:
|
|
config_sql, config_params = compiler.compile(self.config)
|
|
template = 'plainto_tsquery({}::regconfig, %s)'.format(config_sql)
|
|
params = config_params + [self.value]
|
|
else:
|
|
template = 'plainto_tsquery(%s)'
|
|
if self.invert:
|
|
template = '!!({})'.format(template)
|
|
return template, params
|
|
|
|
def _combine(self, other, connector, reversed, node=None):
|
|
combined = super(SearchQuery, self)._combine(other, connector, reversed, node)
|
|
combined.output_field = SearchQueryField()
|
|
return combined
|
|
|
|
# On Combinable, these are not implemented to reduce confusion with Q. In
|
|
# this case we are actually (ab)using them to do logical combination so
|
|
# it's consistent with other usage in Django.
|
|
def __or__(self, other):
|
|
return self._combine(other, self.BITOR, False)
|
|
|
|
def __ror__(self, other):
|
|
return self._combine(other, self.BITOR, True)
|
|
|
|
def __and__(self, other):
|
|
return self._combine(other, self.BITAND, False)
|
|
|
|
def __rand__(self, other):
|
|
return self._combine(other, self.BITAND, True)
|
|
|
|
def __invert__(self):
|
|
extra = {
|
|
'invert': not self.invert,
|
|
'config': self.config,
|
|
}
|
|
return type(self)(self.value, **extra)
|
|
|
|
|
|
class SearchRank(Func):
|
|
function = 'ts_rank'
|
|
_output_field = FloatField()
|
|
|
|
def __init__(self, vector, query, **extra):
|
|
if not hasattr(vector, 'resolve_expression'):
|
|
vector = SearchVector(vector)
|
|
if not hasattr(query, 'resolve_expression'):
|
|
query = SearchQuery(query)
|
|
weights = extra.get('weights')
|
|
if weights is not None and not hasattr(weights, 'resolve_expression'):
|
|
weights = Value(weights)
|
|
self.weights = weights
|
|
super(SearchRank, self).__init__(vector, query, **extra)
|
|
|
|
def as_sql(self, compiler, connection, function=None, template=None):
|
|
extra_params = []
|
|
extra_context = {}
|
|
if template is None and self.extra.get('weights'):
|
|
if self.weights:
|
|
template = '%(function)s(%(weights)s, %(expressions)s)'
|
|
weight_sql, extra_params = compiler.compile(self.weights)
|
|
extra_context['weights'] = weight_sql
|
|
sql, params = super(SearchRank, self).as_sql(
|
|
compiler, connection,
|
|
function=function, template=template, **extra_context
|
|
)
|
|
return sql, extra_params + params
|
|
|
|
|
|
SearchVectorField.register_lookup(SearchVectorExact)
|