Исходный код django.contrib.postgres.search

import psycopg2

from django.db.models import (
    CharField, Expression, Field, FloatField, Func, Lookup, TextField, Value,
)
from django.db.models.expressions import CombinedExpression
from django.db.models.functions import Cast, Coalesce


class SearchVectorExact(Lookup):
    lookup_name = 'exact'

    def process_rhs(self, qn, connection):
        if not isinstance(self.rhs, (SearchQuery, CombinedSearchQuery)):
            config = getattr(self.lhs, 'config', None)
            self.rhs = SearchQuery(self.rhs, config=config)
        rhs, rhs_params = super().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' % (lhs, rhs), params


[документация]class SearchVectorField(Field): def db_type(self, connection): return 'tsvector'
class SearchQueryField(Field): def db_type(self, connection): return 'tsquery' class SearchConfig(Expression): def __init__(self, config): super().__init__() if not hasattr(config, 'resolve_expression'): config = Value(config) self.config = config @classmethod def from_parameter(cls, config): if config is None or isinstance(config, cls): return config return cls(config) def get_source_expressions(self): return [self.config] def set_source_expressions(self, exprs): self.config, = exprs def as_sql(self, compiler, connection): sql, params = compiler.compile(self.config) return '%s::regconfig' % sql, params class SearchVectorCombinable: ADD = '||' def _combine(self, other, connector, reversed): if not isinstance(other, SearchVectorCombinable): raise TypeError( 'SearchVector can only be combined with other SearchVector ' 'instances, got %s.' % type(other).__name__ ) if reversed: return CombinedSearchVector(other, connector, self, self.config) return CombinedSearchVector(self, connector, other, self.config)
[документация]class SearchVector(SearchVectorCombinable, Func): function = 'to_tsvector' arg_joiner = " || ' ' || " output_field = SearchVectorField() def __init__(self, *expressions, config=None, weight=None): super().__init__(*expressions) self.config = SearchConfig.from_parameter(config) 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().resolve_expression(query, allow_joins, reuse, summarize, for_save) if self.config: 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): clone = self.copy() clone.set_source_expressions([ Coalesce( expression if isinstance(expression.output_field, (CharField, TextField)) else Cast(expression, TextField()), Value('') ) for expression in clone.get_source_expressions() ]) config_sql = None config_params = [] if template is None: if clone.config: config_sql, config_params = compiler.compile(clone.config) template = '%(function)s(%(config)s, %(expressions)s)' else: template = clone.template sql, params = super(SearchVector, clone).as_sql( compiler, connection, function=function, template=template, config=config_sql, ) extra_params = [] if clone.weight: weight_sql, extra_params = compiler.compile(clone.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().__init__(lhs, connector, rhs, output_field) class SearchQueryCombinable: BITAND = '&&' BITOR = '||' def _combine(self, other, connector, reversed): if not isinstance(other, SearchQueryCombinable): raise TypeError( 'SearchQuery can only be combined with other SearchQuery ' 'instances, got %s.' % type(other).__name__ ) if reversed: return CombinedSearchQuery(other, connector, self, self.config) return CombinedSearchQuery(self, connector, other, self.config) # 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)
[документация]class SearchQuery(SearchQueryCombinable, Func): output_field = SearchQueryField() SEARCH_TYPES = { 'plain': 'plainto_tsquery', 'phrase': 'phraseto_tsquery', 'raw': 'to_tsquery', 'websearch': 'websearch_to_tsquery', } def __init__(self, value, output_field=None, *, config=None, invert=False, search_type='plain'): self.function = self.SEARCH_TYPES.get(search_type) if self.function is None: raise ValueError("Unknown search_type argument '%s'." % search_type) if not hasattr(value, 'resolve_expression'): value = Value(value) expressions = (value,) self.config = SearchConfig.from_parameter(config) if self.config is not None: expressions = (self.config,) + expressions self.invert = invert super().__init__(*expressions, output_field=output_field) def as_sql(self, compiler, connection, function=None, template=None): sql, params = super().as_sql(compiler, connection, function, template) if self.invert: sql = '!!(%s)' % sql return sql, params def __invert__(self): clone = self.copy() clone.invert = not self.invert return clone def __str__(self): result = super().__str__() return ('~%s' % result) if self.invert else result
class CombinedSearchQuery(SearchQueryCombinable, CombinedExpression): def __init__(self, lhs, connector, rhs, config, output_field=None): self.config = config super().__init__(lhs, connector, rhs, output_field) def __str__(self): return '(%s)' % super().__str__()
[документация]class SearchRank(Func): function = 'ts_rank' output_field = FloatField() def __init__( self, vector, query, weights=None, normalization=None, cover_density=False, ): if not hasattr(vector, 'resolve_expression'): vector = SearchVector(vector) if not hasattr(query, 'resolve_expression'): query = SearchQuery(query) expressions = (vector, query) if weights is not None: if not hasattr(weights, 'resolve_expression'): weights = Value(weights) expressions = (weights,) + expressions if normalization is not None: if not hasattr(normalization, 'resolve_expression'): normalization = Value(normalization) expressions += (normalization,) if cover_density: self.function = 'ts_rank_cd' super().__init__(*expressions)
[документация]class SearchHeadline(Func): function = 'ts_headline' template = '%(function)s(%(expressions)s%(options)s)' output_field = TextField() def __init__( self, expression, query, *, config=None, start_sel=None, stop_sel=None, max_words=None, min_words=None, short_word=None, highlight_all=None, max_fragments=None, fragment_delimiter=None, ): if not hasattr(query, 'resolve_expression'): query = SearchQuery(query) options = { 'StartSel': start_sel, 'StopSel': stop_sel, 'MaxWords': max_words, 'MinWords': min_words, 'ShortWord': short_word, 'HighlightAll': highlight_all, 'MaxFragments': max_fragments, 'FragmentDelimiter': fragment_delimiter, } self.options = { option: value for option, value in options.items() if value is not None } expressions = (expression, query) if config is not None: config = SearchConfig.from_parameter(config) expressions = (config,) + expressions super().__init__(*expressions) def as_sql(self, compiler, connection, function=None, template=None): options_sql = '' options_params = [] if self.options: # getquoted() returns a quoted bytestring of the adapted value. options_params.append(', '.join( '%s=%s' % ( option, psycopg2.extensions.adapt(value).getquoted().decode(), ) for option, value in self.options.items() )) options_sql = ', %s' sql, params = super().as_sql( compiler, connection, function=function, template=template, options=options_sql, ) return sql, params + options_params
SearchVectorField.register_lookup(SearchVectorExact) class TrigramBase(Func): output_field = FloatField() def __init__(self, expression, string, **extra): if not hasattr(string, 'resolve_expression'): string = Value(string) super().__init__(expression, string, **extra)
[документация]class TrigramSimilarity(TrigramBase): function = 'SIMILARITY'
[документация]class TrigramDistance(TrigramBase): function = '' arg_joiner = ' <-> '
Вернуться на верх