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# frozen-string-literal: true
module Sequel
module Plugins
# The primary_key_lookup_check_values plugin typecasts given primary key
# values before performing a lookup by primary key. If the given primary
# key value cannot be typecasted correctly, the lookup returns nil
# without issuing a query. If the schema for the primary key column
# includes minimum and maximum values, this also checks the given value
# is not outside the range. If the given value is outside the allowed
# range, the lookup returns nil without issuing a query.
#
# This affects the following Model methods:
#
# * Model.[] (when called with non-Hash)
# * Model.with_pk
# * Model.with_pk!
#
# It also affects the following Model dataset methods:
#
# * Dataset#[] (when called with Integer)
# * Dataset#with_pk
# * dataset#with_pk!
#
# Note that this can break working code. The above methods accept
# any filter condition by default, not just primary key values. The
# plugin will handle Symbol, Sequel::SQL::Expression, and
# Sequel::LiteralString objects, but code such as the following will break:
#
# # Return first Album where primary key is one of the given values
# Album.dataset.with_pk([1, 2, 3])
#
# Usage:
#
# # Make all model subclasses support checking primary key values before
# # lookup # (called before loading subclasses)
# Sequel::Model.plugin :primary_key_lookup_check_values
#
# # Make the Album class support checking primary key values before lookup
# Album.plugin :primary_key_lookup_check_values
module PrimaryKeyLookupCheckValues
def self.configure(model)
model.instance_exec do
setup_primary_key_lookup_check_values if @dataset
end
end
module ClassMethods
Plugins.after_set_dataset(self, :setup_primary_key_lookup_check_values)
Plugins.inherited_instance_variables(self,
:@primary_key_type=>nil,
:@primary_key_value_range=>nil)
private
# Check the given primary key value. Typecast it to the appropriate
# database type if the database type is known. If it cannot be
# typecasted, or the typecasted value is outside the range of column
# values, return nil.
def _check_pk_lookup_value(pk)
return if nil == pk
case pk
when SQL::Expression, LiteralString, Symbol
return pk
end
return pk unless pk_type = @primary_key_type
if pk_type.is_a?(Array)
return unless pk.is_a?(Array)
return unless pk.size == pk_type.size
return if pk.any?(&:nil?)
pk_value_range = @primary_key_value_range
i = 0
pk.map do |v|
if type = pk_type[i]
v = _typecast_pk_lookup_value(v, type)
return if nil == v
if pk_value_range
min, max = pk_value_range[i]
return if min && v < min
return if max && v > max
end
end
i += 1
v
end
elsif pk.is_a?(Array)
return
elsif nil != (pk = _typecast_pk_lookup_value(pk, pk_type))
min, max = @primary_key_value_range
return if min && pk < min
return if max && pk > max
pk
end
end
# Typecast the value to the appropriate type,
# returning nil if it cannot be typecasted.
def _typecast_pk_lookup_value(value, type)
db.typecast_value(type, value)
rescue InvalidValue
nil
end
# Skip the primary key lookup if the typecasted and checked
# primary key value is nil.
def primary_key_lookup(pk)
unless nil == (pk = _check_pk_lookup_value(pk))
super
end
end
# Setup the primary key type and value range used for checking
# primary key values during lookup.
def setup_primary_key_lookup_check_values
if primary_key.is_a?(Array)
types = []
value_ranges = []
primary_key.each do |pk|
type, min, max = _type_min_max_values_for_column(pk)
types << type
value_ranges << ([min, max].freeze if min || max)
end
@primary_key_type = (types.freeze if types.any?)
@primary_key_value_range = (value_ranges.freeze if @primary_key_type && value_ranges.any?)
else
@primary_key_type, min, max = _type_min_max_values_for_column(primary_key)
@primary_key_value_range = ([min, max].freeze if @primary_key_type && (min || max))
end
end
# Return the type, min_value, and max_value schema entries
# for the column, if they exist.
def _type_min_max_values_for_column(column)
if schema = db_schema[column]
schema.values_at(:type, :min_value, :max_value)
end
end
end
module DatasetMethods
# Skip the primary key lookup if the typecasted and checked
# primary key value is nil.
def with_pk(pk)
unless nil == (pk = model.send(:_check_pk_lookup_value, pk))
super
end
end
end
end
end
end
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