module ActiveScaffold::AttributeParams

Provides support for param hashes assumed to be model attributes. Support is primarily needed for creating/editing associated records using a nested hash structure.

Paradigm Params Hash (should write unit tests on this):

params[:record] = {
  # a simple record attribute
  'name' => 'John',
  # a plural association hash
  'roles' => {
    # associate with an existing role
    '5' => {'id' => 5}
    # associate with an existing role and edit it
    '6' => {'id' => 6, 'name' => 'designer'}
    # create and associate a new role
    '124521' => {'name' => 'marketer'}
  }
  # a singular association hash
  'location' => {'id' => 12, 'city' => 'New York'}
}

Simpler association structures are also supported, like:

params[:record] = {
  # a simple record attribute
  'name' => 'John',
  # a plural association ... all ids refer to existing records
  'roles' => ['5', '6'],
  # a singular association ... all ids refer to existing records
  'location' => '12'

}

Protected Instance Methods

attributes_hash_is_empty?(hash, klass) click to toggle source

Determines whether the given attributes hash is “empty”. This isn’t a literal emptiness - it’s an attempt to discern whether the user intended it to be empty or not.

# File lib/active_scaffold/attribute_params.rb, line 173
def attributes_hash_is_empty?(hash, klass)
  ignore_column_types = [:boolean]
  hash.all? do |key,value|
    # convert any possible multi-parameter attributes like 'created_at(5i)' to simply 'created_at'
    parts = key.to_s.split('(')
    #old style date form management... ignore them too
    ignore_column_types = [:boolean, :datetime, :date, :time] if parts.length > 1
    column_name = parts.first
    column = klass.columns_hash[column_name]

    # booleans and datetimes will always have a value. so we ignore them when checking whether the hash is empty.
    # this could be a bad idea. but the current situation (excess record entry) seems worse.
    next true if column and ignore_column_types.include?(column.type)

    # defaults are pre-filled on the form. we can't use them to determine if the user intends a new row.
    next true if column and value == column.default.to_s

    if value.is_a?(Hash)
      attributes_hash_is_empty?(value, klass)
    elsif value.is_a?(Array)
      value.any? {|id| id.respond_to?(:empty?) ? !id.empty? : true}
    else
      value.respond_to?(:empty?) ? value.empty? : false
    end
  end
end
column_plural_assocation_value_from_value(column, value) click to toggle source
# File lib/active_scaffold/attribute_params.rb, line 118
def column_plural_assocation_value_from_value(column, value)
  # it's an array of ids
  if value and not value.empty?
    ids = value.select {|id| id.respond_to?(:empty?) ? !id.empty? : true}
    ids.empty? ? [] : column.association.klass.find(ids)
  end
end
column_value_from_param_hash_value(parent_record, column, value) click to toggle source
# File lib/active_scaffold/attribute_params.rb, line 126
def column_value_from_param_hash_value(parent_record, column, value)
  # this is just for backwards compatibility. we should clean this up in 2.0.
  if column.form_ui == :select
    ids = if column.singular_association?
      value[:id]
    else
      value.values.collect {|hash| hash[:id]}
    end
    (ids and not ids.empty?) ? column.association.klass.find(ids) : nil

  elsif column.singular_association?
    manage_nested_record_from_params(parent_record, column, value)
  elsif column.plural_association?
    # HACK to be able to delete all associated records, hash will include "0" => ""
    value.collect {|key, value| manage_nested_record_from_params(parent_record, column, value) unless value == ""}.compact
  else
    value
  end
end
column_value_from_param_simple_value(parent_record, column, value) click to toggle source
# File lib/active_scaffold/attribute_params.rb, line 101
def column_value_from_param_simple_value(parent_record, column, value)
  if column.singular_association?
    # it's a single id
    column.association.klass.find(value) if value and not value.empty?
  elsif column.plural_association?
    column_plural_assocation_value_from_value(column, Array(value))
  elsif column.number? && [:i18n_number, :currency].include?(column.options[:format])
    self.class.i18n_number_to_native_format(value)
  else
    # convert empty strings into nil. this works better with 'null => true' columns (and validations),
    # and 'null => false' columns should just convert back to an empty string.
    # ... but we can at least check the ConnectionAdapter::Column object to see if nulls are allowed
    value = nil if value.is_a? String and value.empty? and !column.column.nil? and column.column.null
    value
  end
end
column_value_from_param_value(parent_record, column, value) click to toggle source
# File lib/active_scaffold/attribute_params.rb, line 92
def column_value_from_param_value(parent_record, column, value)
  # convert the value, possibly by instantiating associated objects
  if value.is_a?(Hash)
    column_value_from_param_hash_value(parent_record, column, value)
  else
    column_value_from_param_simple_value(parent_record, column, value)
  end
end
find_or_create_for_params(params, parent_column, parent_record) click to toggle source

Attempts to create or find an instance of klass (which must be an ActiveRecord object) from the request parameters given. If params exists it will attempt to find an existing object otherwise it will build a new one.

# File lib/active_scaffold/attribute_params.rb, line 149
def find_or_create_for_params(params, parent_column, parent_record)
  current = parent_record.send(parent_column.name)
  klass = parent_column.association.klass
  pk = klass.primary_key.to_sym
  return nil if parent_column.show_blank_record?(current) and attributes_hash_is_empty?(params, klass)

  if params.has_key? pk
    # modifying the current object of a singular association
    pk_val = params[pk] 
    if current and current.is_a? ActiveRecord::Base and current.id.to_s == pk_val
      current
    # modifying one of the current objects in a plural association
    elsif current and current.respond_to?(:any?) and current.any? {|o| o.id.to_s == pk_val}
      current.detect {|o| o.id.to_s == pk_val}
    # attaching an existing but not-current object
    else
      klass.find(pk_val)
    end
  else
    build_associated(parent_column, parent_record) if klass.authorized_for?(:crud_type => :create)
  end
end
manage_nested_record_from_params(parent_record, column, attributes) click to toggle source
# File lib/active_scaffold/attribute_params.rb, line 81
def manage_nested_record_from_params(parent_record, column, attributes)
  record = find_or_create_for_params(attributes, column, parent_record)
  if record
    record_columns = active_scaffold_config_for(column.association.klass).subform.columns
    record_columns.constraint_columns = [column.association.reverse]
    update_record_from_params(record, record_columns, attributes)
    record.unsaved = true
  end
  record
end
update_record_from_params(parent_record, columns, attributes) click to toggle source

Takes attributes (as from params) and applies them to the parent_record. Also looks for association attributes and attempts to instantiate them as associated objects.

This is a secure way to apply params to a record, because it’s based on a loop over the columns set. The columns set will not yield unauthorized columns, and it will not yield unregistered columns.

# File lib/active_scaffold/attribute_params.rb, line 38
def update_record_from_params(parent_record, columns, attributes)
  crud_type = parent_record.new_record? ? :create : :update
  return parent_record unless parent_record.authorized_for?(:crud_type => crud_type)

  multi_parameter_attributes = {}
  attributes.each do |k, v|
    next unless k.include? '('
    column_name = k.split('(').first.to_sym
    multi_parameter_attributes[column_name] ||= []
    multi_parameter_attributes[column_name] << [k, v]
  end

  columns.each :for => parent_record, :crud_type => crud_type, :flatten => true do |column|
    # Set any passthrough parameters that may be associated with this column (ie, file column "keep" and "temp" attributes)
    unless column.params.empty?
      column.params.each{|p| parent_record.send("#{p}=", attributes[p]) if attributes.has_key? p}
    end

    if multi_parameter_attributes.has_key? column.name
      parent_record.send(:assign_multiparameter_attributes, multi_parameter_attributes[column.name])
    elsif attributes.has_key? column.name
      value = column_value_from_param_value(parent_record, column, attributes[column.name]) 

      # we avoid assigning a value that already exists because otherwise has_one associations will break (AR bug in has_one_association.rb#replace)
      parent_record.send("#{column.name}=", value) unless parent_record.send(column.name) == value
    end
  end

  if parent_record.new_record?
    parent_record.class.reflect_on_all_associations.each do |a|
      next unless [:has_one, :has_many].include?(a.macro) and not (a.options[:through] || a.options[:finder_sql])
      next unless association_proxy = parent_record.send(a.name)

      raise ActiveScaffold::ReverseAssociationRequired, "Association #{a.name} in class #{parent_record.class.name}: In order to support :has_one and :has_many where the parent record is new and the child record(s) validate the presence of the parent, ActiveScaffold requires the reverse association (the belongs_to)." unless a.reverse

      association_proxy = [association_proxy] if a.macro == :has_one
      association_proxy.each { |record| record.send("#{a.reverse}=", parent_record) }
    end
  end

  parent_record
end