Class: Datasource::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/datasource/base.rb,
lib/datasource/attributes/loader.rb,
lib/datasource/attributes/query_attribute.rb,
lib/datasource/attributes/computed_attribute.rb

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(scope, adapter = nil) ⇒ Base

Returns a new instance of Base.



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# File 'lib/datasource/base.rb', line 76

def initialize(scope, adapter = nil)
  @adapter = adapter || self.class.default_adapter
  @scope =
    if self.class._update_scope
      self.class._update_scope.call(scope)
    else
      scope
    end
  @expose_attributes = []
  @expose_associations = {}
end

Class Attribute Details

._associations ⇒ Object

Returns the value of attribute _associations.



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# File 'lib/datasource/base.rb', line 4

def _associations
  @_associations
end

._attributes ⇒ Object

Returns the value of attribute _attributes.



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# File 'lib/datasource/base.rb', line 4

def _attributes
  @_attributes
end

._loaders ⇒ Object

Returns the value of attribute _loaders.



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# File 'lib/datasource/base.rb', line 4

def _loaders
  @_loaders
end

._update_scope ⇒ Object

Returns the value of attribute _update_scope.



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# File 'lib/datasource/base.rb', line 4

def _update_scope
  @_update_scope
end

.orm_klass ⇒ Object 



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# File 'lib/datasource/base.rb', line 23

def orm_klass
  fail Datasource::Error, "Model class not set for #{name}. You should define it:\nclass YourDatasource\n  @orm_klass = MyModelClass\nend"
end

Instance Attribute Details

#adapter ⇒ Object (readonly)

Returns the value of attribute adapter.



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# File 'lib/datasource/base.rb', line 74

def adapter
  @adapter
end

#expose_associations ⇒ Object (readonly)

Returns the value of attribute expose_associations.



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# File 'lib/datasource/base.rb', line 74

def expose_associations
  @expose_associations
end

#expose_attributes ⇒ Object (readonly)

Returns the value of attribute expose_attributes.



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# File 'lib/datasource/base.rb', line 74

def expose_attributes
  @expose_attributes
end

#scope ⇒ Object (readonly)

Returns the value of attribute scope.



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# File 'lib/datasource/base.rb', line 74

def scope
  @scope
end

Class Method Details

.computed(name, *_deps) ⇒ Object 



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# File 'lib/datasource/attributes/computed_attribute.rb', line 29

def self.computed(name, *_deps)
  deps = _deps.select { |dep| dep.kind_of?(Hash) }
  _deps.reject! { |dep| dep.kind_of?(Hash) }
  unless _deps.empty?
    self_key = default_adapter.get_table_name(orm_klass)
    deps.push(self_key => _deps)
  end

  klass = Class.new(Attributes::ComputedAttribute) do
    depends *deps
  end

  attribute name, klass
end

.consumer_adapter ⇒ Object 



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# File 'lib/datasource/base.rb', line 19

def consumer_adapter
  @consumer_adapter = Datasource::ConsumerAdapters::ActiveModelSerializers
end

.default_adapter ⇒ Object 



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# File 'lib/datasource/base.rb', line 13

def default_adapter
  @adapter ||= begin
    Datasource::Adapters.const_get(Datasource::Adapters.constants.first)
  end
end

.inherited(base) ⇒ Object 



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# File 'lib/datasource/base.rb', line 7

def inherited(base)
  base._attributes = (_attributes || {}).dup
  base._associations = (_associations || {}).dup
  base._loaders = (_loaders || {}).dup
end

.loaded(name, _options = {}, &block) ⇒ Object 



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# File 'lib/datasource/attributes/loader.rb', line 69

def self.loaded(name, _options = {}, &block)
  loader(name, _options, &block)
  renamed_existing_method = :"#{name}_without_datasource"
  orm_klass.class_eval do
    alias_method renamed_existing_method, name if method_defined?(name)
    fail "#{name} already defined on #{to_s}, would be overridden by datasource loaded method" if method_defined?(name)
    define_method name do |*args, &block|
      if loaded_values || !method_defined?(renamed_existing_method)
        loaded_values[name.to_sym]
      else
        send(renamed_existing_method, *args, &block)
      end
    end
  end
  computed name, loader: name
end

.loader(name, _options = {}, &block) ⇒ Object 



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# File 'lib/datasource/attributes/loader.rb', line 60

def self.loader(name, _options = {}, &block)
  klass = Class.new(Attributes::Loader) do
    # depends deps
    options(_options)
    self._load_proc = block
  end
  @_loaders[name.to_sym] = klass
end

.primary_key ⇒ Object 



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# File 'lib/datasource/base.rb', line 27

def primary_key
  :id
end

.query(name, deps = nil, value = nil, &block) ⇒ Object 



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# File 'lib/datasource/attributes/query_attribute.rb', line 20

def self.query(name, deps = nil, value = nil, &block)
  klass = Class.new(Attributes::QueryAttribute) do
    depends deps if deps

    if block
      define_singleton_method(:select_value, &block)
    else
      define_singleton_method(:select_value) { value }
    end
  end
  attribute name, klass
end

.reflection_select(reflection, parent_select, assoc_select) ⇒ Object 



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# File 'lib/datasource/base.rb', line 31

def reflection_select(reflection, parent_select, assoc_select)
  # append foreign key depending on assoication
  if reflection[:macro] == :belongs_to
    parent_select.push(reflection[:foreign_key])
  elsif [:has_many, :has_one].include?(reflection[:macro])
    assoc_select.push(reflection[:foreign_key])
  else
    fail Datasource::Error, "unsupported association type #{reflection[:macro]} - TODO"
  end
end

Instance Method Details

#attribute_exposed?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/datasource/base.rb', line 182

def attribute_exposed?(name)
  @expose_attributes.include?(name.to_s)
end

#can_upgrade?(records) ⇒ Boolean

assume records have all attributes selected (default ORM record)

Returns:

  • (Boolean) 


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# File 'lib/datasource/base.rb', line 187

def can_upgrade?(records)
  query_attributes = @expose_attributes.select do |name|
    klass = self.class._attributes[name][:klass]
    if klass
      klass.ancestors.include?(Attributes::QueryAttribute)
    end
  end

  return true if query_attributes.empty?
  Array(records).all? do |record|
    query_attributes.all? do |name|
      adapter.has_attribute?(record, name)
    end
  end
end

#fail_missing_attributes(names) ⇒ Object 



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# File 'lib/datasource/base.rb', line 127

def fail_missing_attributes(names)
  message = if names.size > 1
    "attributes or associations #{names.join(', ')} don't exist "
  else
    "attribute or association #{names.first} doesn't exist "
  end
  message += "for #{self.class.orm_klass.name}, "
  message += "did you forget to call \"computed :#{name}, <dependencies>\" in your datasource_module?"
  fail Datasource::Error, message
end

#get_select_values ⇒ Object 



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# File 'lib/datasource/base.rb', line 162

def get_select_values
  scope_table = adapter.primary_scope_table(self)

  # SQL select values
  select_values = Set.new
  select_values.add("#{scope_table}.#{self.class.primary_key}")

  self.class._attributes.values.each do |att|
    if attribute_exposed?(att[:name])
      if att[:klass] == nil
        select_values.add("#{scope_table}.#{att[:name]}")
      elsif att[:klass].ancestors.include?(Attributes::QueryAttribute)
        select_values.add("(#{att[:klass].select_value}) as #{att[:name]}")
      end
    end
  end

  select_values.to_a
end

#results(rows = nil) ⇒ Object 



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# File 'lib/datasource/base.rb', line 207

def results(rows = nil)
  rows ||= adapter.get_rows(self)

  @expose_attributes.each do |name|
    att = self.class._attributes[name]
    fail Datasource::Error, "attribute #{name} doesn't exist for #{self.class.orm_klass.name}, did you forget to call \"computed :#{name}, :db_column_dependency\" in your datasource_module? See https://github.com/mrbrdo/datasource#model-methods--virtual-attributes" unless att
    klass = att[:klass]
    next unless klass

    next if rows.empty?

    if att[:klass].ancestors.include?(Attributes::ComputedAttribute)
      att[:klass]._loader_depends.each do |name|
        if loader = self.class._loaders[name]
          if loaded_values = loader.load(rows.map(&self.class.primary_key), rows, @scope)
            unless rows.first.loaded_values
              rows.each do |row|
                row.loaded_values = {}
              end
            end
            rows.each do |row|
              row.loaded_values[name] = loaded_values[row.send(self.class.primary_key)] || loader.default_value
            end
          end
        else
          raise Datasource::Error, "loader with name :#{name} could not be found"
        end
      end
    end
  end

  rows
end

#select(*names) ⇒ Object 



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# File 'lib/datasource/base.rb', line 92

def select(*names)
  failure = ->(name) { fail Datasource::Error, "attribute or association #{name} doesn't exist for #{self.class.orm_klass.name}, did you forget to call \"computed :#{name}, <dependencies>\" in your datasource_module?" }
  newly_exposed_attributes = []
  missing_attributes = []
  names.each do |name|
    if name.kind_of?(Hash)
      name.each_pair do |assoc_name, assoc_select|
        assoc_name = assoc_name.to_s
        if self.class._associations.key?(assoc_name)
          @expose_associations[assoc_name] ||= []
          @expose_associations[assoc_name] += Array(assoc_select)
          @expose_associations[assoc_name].uniq!
        else
          missing_attributes << assoc_name
          failure.call(assoc_name)
        end
      end
    else
      name = name.to_s
      if self.class._attributes.key?(name)
        unless @expose_attributes.include?(name)
          @expose_attributes.push(name)
          newly_exposed_attributes.push(name)
        end
      else
        missing_attributes << name
        failure.call(name)
      end
    end
  end
  update_dependencies(newly_exposed_attributes) unless newly_exposed_attributes.empty?
  fail_missing_attributes(missing_attributes) unless missing_attributes.blank?
  self
end

#select_all ⇒ Object 



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# File 'lib/datasource/base.rb', line 88

def select_all
  @expose_attributes = self.class._attributes.keys.dup
end

#update_dependencies(names) ⇒ Object 



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# File 'lib/datasource/base.rb', line 138

def update_dependencies(names)
  scope_table = adapter.primary_scope_table(self)

  self.class._attributes.values.each do |att|
    next unless names.include?(att[:name])
    next unless att[:klass]

    if att[:klass].ancestors.include?(Attributes::ComputedAttribute)
      att[:klass]._depends.each_pair do |key, value|
        if key.to_s == scope_table
          select(*value)
        else
          select(key => value)
        end
      end
    elsif att[:klass].ancestors.include?(Attributes::QueryAttribute)
      att[:klass]._depends.each do |name|
        next if name == scope_table
        adapter.ensure_table_join!(self, name, att)
      end
    end
  end
end

#upgrade_records(records) ⇒ Object 



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# File 'lib/datasource/base.rb', line 203

def upgrade_records(records)
  adapter.upgrade_records(self, Array(records))
end