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- import psycopg2
-
- from django.db.models import (
- CharField,
- Expression,
- Field,
- FloatField,
- Func,
- Lookup,
- TextField,
- Value,
- )
- from django.db.models.expressions import CombinedExpression, register_combinable_fields
- 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
-
-
- 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)
-
-
- register_combinable_fields(
- SearchVectorField, SearchVectorCombinable.ADD, SearchVectorField, SearchVectorField
- )
-
-
- 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)
-
-
- 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__()
-
-
- 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)
-
-
- 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)
-
-
- class TrigramWordBase(Func):
- output_field = FloatField()
-
- def __init__(self, string, expression, **extra):
- if not hasattr(string, "resolve_expression"):
- string = Value(string)
- super().__init__(string, expression, **extra)
-
-
- class TrigramSimilarity(TrigramBase):
- function = "SIMILARITY"
-
-
- class TrigramDistance(TrigramBase):
- function = ""
- arg_joiner = " <-> "
-
-
- class TrigramWordDistance(TrigramWordBase):
- function = ""
- arg_joiner = " <<-> "
-
-
- class TrigramWordSimilarity(TrigramWordBase):
- function = "WORD_SIMILARITY"
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