Class: Ransack::Adapters::ActiveRecord::Context

Inherits:
Context
  • Object
show all
Defined in:
lib/ransack/adapters/active_record/context.rb

Instance Attribute Summary

Attributes inherited from Context

#arel_visitor, #auth_object, #base, #engine, #klass, #object, #search, #search_key

Instance Method Summary collapse

Methods inherited from Context

#association_path, #bind, #bind_pair_for, #chain_scope, #contextualize, for, for_class, for_object, #initialize, #ransackable_alias, #ransackable_association?, #ransackable_attribute?, #ransackable_scope?, #ransackable_scope_skip_sanitize_args?, #scope_arity, #searchable_associations, #searchable_attributes, #sortable_attributes, #traverse, #unpolymorphize_association

Constructor Details

This class inherits a constructor from Ransack::Context

Instance Method Details

#alias_trackerObject


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# File 'lib/ransack/adapters/active_record/context.rb', line 126

def alias_tracker
  @join_dependency.send(:alias_tracker)
end

#attribute_method?(str, klass = @klass) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/ransack/adapters/active_record/context.rb', line 64

def attribute_method?(str, klass = @klass)
  exists = false
  if ransackable_attribute?(str, klass)
    exists = true
  elsif (segments = str.split(Constants::UNDERSCORE)).size > 1
    remainder = []
    found_assoc = nil
    while !found_assoc && remainder.unshift(segments.pop) &&
    segments.size > 0 do
      assoc, poly_class = unpolymorphize_association(
        segments.join(Constants::UNDERSCORE)
        )
      if found_assoc = get_association(assoc, klass)
        exists = attribute_method?(
          remainder.join(Constants::UNDERSCORE),
          poly_class || found_assoc.klass
          )
      end
    end
  end
  exists
end

#build_correlated_subquery(association) ⇒ Object

Build an Arel subquery that selects keys for the top query, drawn from the first join association's foreign_key.

Example: for an Article that has_and_belongs_to_many Tags

context = Article.search.context
attribute = Attribute.new(context, "tags_name").tap do |a|
  context.bind(a, a.name)
end
context.build_correlated_subquery(attribute.parent).to_sql

# SELECT "articles_tags"."article_id" FROM "articles_tags"
# INNER JOIN "tags" ON "tags"."id" = "articles_tags"."tag_id"
# WHERE "articles_tags"."article_id" = "articles"."id"

The WHERE condition on this query makes it invalid by itself, because it is correlated to the primary key on the outer query.


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# File 'lib/ransack/adapters/active_record/context.rb', line 163

def build_correlated_subquery(association)
  join_constraints = extract_joins(association)
  join_root = join_constraints.shift
  correlated_key = extract_correlated_key(join_root)
  subquery = Arel::SelectManager.new(association.base_klass)
  subquery.from(join_root.left)
  subquery.project(correlated_key)
  join_constraints.each do |j|
    subquery.join_sources << Arel::Nodes::InnerJoin.new(j.left, j.right)
  end
  subquery.where(correlated_key.eq(primary_key))
end

#evaluate(search, opts = {}) ⇒ Object


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# File 'lib/ransack/adapters/active_record/context.rb', line 24

def evaluate(search, opts = {})
  viz = Visitor.new
  relation = @object.where(viz.accept(search.base))

  if search.sorts.any?
    relation = relation.except(:order)
    # Rather than applying all of the search's sorts in one fell swoop,
    # as the original implementation does, we apply one at a time.
    #
    # If the sort (returned by the Visitor above) is a symbol, we know
    # that it represents a scope on the model and we can apply that
    # scope.
    #
    # Otherwise, we fall back to the applying the sort with the "order"
    # method as the original implementation did. Actually the original
    # implementation used "reorder," which was overkill since we already
    # have a clean slate after "relation.except(:order)" above.
    viz.accept(search.sorts).each do |scope_or_sort|
      if scope_or_sort.is_a?(Symbol)
        relation = relation.send(scope_or_sort)
      else
        case Ransack.options[:postgres_fields_sort_option]
        when :nulls_first
          scope_or_sort = scope_or_sort.direction == :asc ? Arel.sql("#{scope_or_sort.to_sql} NULLS FIRST") : Arel.sql("#{scope_or_sort.to_sql} NULLS LAST")
        when :nulls_last
          scope_or_sort = scope_or_sort.direction == :asc ? Arel.sql("#{scope_or_sort.to_sql} NULLS LAST") : Arel.sql("#{scope_or_sort.to_sql} NULLS FIRST")
        when :nulls_always_first
          scope_or_sort = Arel.sql("#{scope_or_sort.to_sql} NULLS FIRST")
        when :nulls_always_last
          scope_or_sort = Arel.sql("#{scope_or_sort.to_sql} NULLS LAST")
        end

        relation = relation.order(scope_or_sort)
      end
    end
  end

  opts[:distinct] ? relation.distinct : relation
end

#join_sourcesObject

All dependent Arel::Join nodes used in the search query.

This could otherwise be done as `@object.arel.join_sources`, except that ActiveRecord's build_joins sets up its own JoinDependency. This extracts what we need to access the joins using our existing JoinDependency to track table aliases.


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# File 'lib/ransack/adapters/active_record/context.rb', line 110

def join_sources
  base, joins = begin
    alias_tracker = ::ActiveRecord::Associations::AliasTracker.create(self.klass.connection, @object.table.name, [])
    constraints   = @join_dependency.join_constraints(@object.joins_values, alias_tracker, @object.references_values)

    [
      Arel::SelectManager.new(@object.table),
      constraints
    ]
  end
  joins.each do |aliased_join|
    base.from(aliased_join)
  end
  base.join_sources
end

#klassify(obj) ⇒ Object


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# File 'lib/ransack/adapters/active_record/context.rb', line 91

def klassify(obj)
  if Class === obj && ::ActiveRecord::Base > obj
    obj
  elsif obj.respond_to? :klass
    obj.klass
  elsif obj.respond_to? :base_klass
    obj.base_klass
  else
    raise ArgumentError, "Don't know how to klassify #{obj}"
  end
end

#lock_association(association) ⇒ Object


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# File 'lib/ransack/adapters/active_record/context.rb', line 130

def lock_association(association)
  @lock_associations << association
end

#primary_keyObject


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# File 'lib/ransack/adapters/active_record/context.rb', line 176

def primary_key
  @object.table[@object.primary_key]
end

#relation_for(object) ⇒ Object


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# File 'lib/ransack/adapters/active_record/context.rb', line 9

def relation_for(object)
  object.all
end

#remove_association(association) ⇒ Object


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# File 'lib/ransack/adapters/active_record/context.rb', line 134

def remove_association(association)
  return if @lock_associations.include?(association)
  @join_dependency.instance_variable_get(:@join_root).children.delete_if { |stashed|
    stashed.eql?(association)
  }
  @object.joins_values.delete_if { |jd|
    jd.instance_variables.include?(:@join_root) &&
    jd.instance_variable_get(:@join_root).children.map(&:object_id) == [association.object_id]
  }
end

#table_for(parent) ⇒ Object


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# File 'lib/ransack/adapters/active_record/context.rb', line 87

def table_for(parent)
  parent.table
end

#type_for(attr) ⇒ Object


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# File 'lib/ransack/adapters/active_record/context.rb', line 13

def type_for(attr)
  return nil unless attr && attr.valid?
  name         = attr.arel_attribute.name.to_s
  table        = attr.arel_attribute.relation.table_name
  schema_cache = self.klass.connection.schema_cache
  unless schema_cache.send(:data_source_exists?, table)
    raise "No table named #{table} exists."
  end
  attr.klass.columns.find { |column| column.name == name }.type
end