Class: Activr::Activity

Inherits:
Object
  • Object
show all
Extended by:
ActiveModel::Callbacks
Defined in:
lib/activr/activity.rb

Overview

An activity is an event that is (most of the time) performed by a user in your application.

When defining an activity you specify allowed entities and a humanization template.

When instanciated, an activity contains:

- Concrete `entities` instances
- A timestamp (the `at` field)
- User-defined `meta` data

By default, entities are mandatory and the exception MissingEntityError is raised when trying to store an activity with a missing entity.

When an activity is stored in database, its ‘_id` field is filled.

Model callbacks:

- `before_store`, `around_store` and `after_store` are called when activity is stored in database
- `before_route`, `around_route` and `after_route` are called when activity is routed by the dispatcher

Examples:

class AddPictureActivity < Activr::Activity

  entity :actor, :class => User, :humanize => :fullname
  entity :picture, :humanize => :title
  entity :album, :humanize => :name

  humanize "{{{actor}}} added picture {{{picture}}} to the album {{{album}}}"

  before_store :set_bar_meta

  def set_bar_meta
    self[:bar] = 'baz'
    true
  end

end

activity = AddPictureActivity.new(:actor => user, :picture => picture, :album => album, :foo => 'bar')

activity.humanize
# => John WILLIAMS added picture My Face to the album My Selfies

activity[:foo]
=> 'bar'

activity.store!

activity._id
=> BSON::ObjectId('529cca3d61796d296e020000')

activity[:bar]
=> 'baz'

Defined Under Namespace

Classes: MissingEntityError

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data_hash = { }) ⇒ Activity 



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# File 'lib/activr/activity.rb', line 251

def initialize(data_hash = { })
  @_id = nil
  @at  = nil

  @entities = { }
  @meta     = { }

  data_hash.each do |data_name, data_value|
    data_name = data_name.to_sym

    if (self.allowed_entities[data_name] != nil)
      # entity
      @entities[data_name] = Activr::Entity.new(data_name, data_value, self.allowed_entities[data_name].merge(:activity => self))
    elsif (data_name == :_id)
      # activity id
      @_id = data_value
    elsif (data_name == :at)
      # timestamp
      raise "Wrong :at class: #{data_value.inspect}" unless data_value.is_a?(Time)
      @at = data_value
    elsif self.respond_to?("#{data_name}=")
      # ivar
      self.send("#{data_name}=", data_value)
    elsif (data_name == :kind)
      # ignore it
    elsif (data_name == :meta)
      # meta
      @meta.merge!(data_value.symbolize_keys)
    else
      # sugar for meta data
      self[data_name] = data_value
    end
  end

  # default timestamp
  @at ||= Time.now.utc
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(sym, *args, &blk) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Sugar so that we can try to fetch an entity defined for another activity (yes, I hate myself for that…)



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# File 'lib/activr/activity.rb', line 423

def method_missing(sym, *args, &blk)
  # match: actor_entity | actor_id | actor
  match_data = sym.to_s.match(/(.+)_(entity|id)$/)
  entity_name = match_data ? match_data[1].to_sym : sym

  if Activr.registry.entities_names.include?(entity_name)
    # ok, don't worry...
    # define an instance method so that future calls on that method do not rely on method_missing
    self.instance_eval "      def \#{sym}(*args, &blk)\n        nil\n      end\n    RUBY\n\n    self.__send__(sym, *args, &blk)\n  else\n    # super Michel !\n    super\n  end\nend\n"

Instance Attribute Details

#_id ⇒ Object 



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# File 'lib/activr/activity.rb', line 239

def _id
  @_id
end

#at ⇒ Time 



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# File 'lib/activr/activity.rb', line 242

def at
  @at
end

#entities ⇒ Hash{Symbol=>Entity} (readonly) 



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# File 'lib/activr/activity.rb', line 245

def entities
  @entities
end

#meta ⇒ Hash{Symbol=>Object} (readonly) 



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# File 'lib/activr/activity.rb', line 248

def meta
  @meta
end

Class Method Details

.entity(name, options = { }) ⇒ Object

Note:

By convention the entity that correspond to a user performing an action should be named ‘:actor`

Define an allowed entity for that activity class

Examples:

That method creates several instance methods, for example with ‘entity :album`:


# Get the entity model instance
def album
  # ...
end

# Set the entity model instance
def album=(value)
  # ...
end

# Get the entity id
def album_id
  # ...
end

# Get the Activr::Entity instance
def album_entity
  # ...
end

Options Hash (options):

  • :class (Class) —

    Entity model class

  • :humanize (Symbol) —

    A method name to call on entity model instance to humanize it

  • :default (String) —

    Default humanization value

  • :optional (true, false) —

    Is it an optional entity ?



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# File 'lib/activr/activity.rb', line 168

def entity(name, options = { })
  name = name.to_sym
  raise "Entity already defined: #{name}" unless self.allowed_entities[name].nil?

  if options[:class].nil?
    options = options.dup
    options[:class] = name.to_s.camelize.constantize
  end

  # NOTE: always use a setter on a class_attribute (cf. http://apidock.com/rails/Class/class_attribute)
  self.allowed_entities = self.allowed_entities.merge(name => options)

  # create entity methods
  class_eval "    # eg: actor\n    def \#{name}\n      @entities[:\#{name}] && @entities[:\#{name}].model\n    end\n\n    # eg: actor = ...\n    def \#{name}=(value)\n      @entities.delete(:\#{name})\n\n      if (value != nil)\n        @entities[:\#{name}] = Activr::Entity.new(:\#{name}, value, self.allowed_entities[:\#{name}])\n      end\n    end\n\n    # eg: actor_id\n    def \#{name}_id\n      @entities[:\#{name}] && @entities[:\#{name}].model_id\n    end\n\n    # eg: actor_entity\n    def \#{name}_entity\n      @entities[:\#{name}]\n    end\n  EOS\n\n  if (name == :actor) && options[:class] &&\n     (options[:class] < Activr::Entity::ModelMixin) &&\n     options[:class].activr_entity_settings[:name].nil?\n    # sugar so that we don't have to explicitly call `activr_entity` on model class\n    options[:class].activr_entity_settings = options[:class].activr_entity_settings.merge(:name => :actor)\n  end\n\n  # register used entity\n  Activr.registry.add_entity(name, options, self)\nend\n", __FILE__, __LINE__

.from_hash(data_hash) ⇒ Activity

Note:

Correct activity subclass is resolved thanks to ‘kind` field

Instanciate an activity from a hash



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# File 'lib/activr/activity.rb', line 98

def from_hash(data_hash)
  activity_kind = data_hash['kind'] || data_hash[:kind]
  raise "No kind found in activity hash: #{data_hash.inspect}" unless activity_kind

  klass = Activr.registry.class_for_activity(activity_kind)
  klass.new(data_hash)
end

.humanize(tpl) ⇒ Object

Define a humanization template for that activity class



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# File 'lib/activr/activity.rb', line 221

def humanize(tpl)
  raise "Humanize already defined: #{self.humanize_tpl}" unless self.humanize_tpl.blank?

  self.humanize_tpl = tpl
end

.kind ⇒ String

Note:

Kind is inferred from class name, unless ‘#set_kind` method is used to force a custom value

Get activity class kind

Examples:

AddPictureActivity.kind
=> 'add_picture'



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# File 'lib/activr/activity.rb', line 88

def kind
  @kind ||= @forced_kind || Activr::Utils.kind_for_class(self, 'activity')
end

.set_kind(forced_kind) ⇒ Object

Note:

Default kind is inferred from class name

Set activity kind



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# File 'lib/activr/activity.rb', line 232

def set_kind(forced_kind)
  @forced_kind = forced_kind.to_s
end

.unserialize_hash(data_hash) ⇒ Hash

Unserialize an activity hash

That method fixes issues remaining after an activity hash has been unserialized partially:

- the `at` field is converted from String to Time
- the `_id` field is converted from `{ '$oid' => [String] }` format to correct `ObjectId` class (`BSON::ObjectId` or `Moped::BSON::ObjectId`)



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# File 'lib/activr/activity.rb', line 115

def unserialize_hash(data_hash)
  result = { }

  data_hash.each do |key, val|
    result[key] = if Activr.storage.serialized_id?(val)
      Activr.storage.unserialize_id(val)
    elsif (key == 'at') && val.is_a?(String)
      Time.parse(val)
    else
      val
    end
  end

  result
end

Instance Method Details

#[](key) ⇒ Object

Get a meta

Examples:

activity[:foo]
# => 'bar'



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# File 'lib/activr/activity.rb', line 297

def [](key)
  @meta[key.to_sym]
end

#[]=(key, value) ⇒ Object

Set a meta

Examples:

activity[:foo] = 'bar'



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# File 'lib/activr/activity.rb', line 308

def []=(key, value)
  @meta[key.to_sym] = value
end

#check! ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Check if activity is valid

Raises:



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# File 'lib/activr/activity.rb', line 389

def check!
  # check mandatory entities
  self.allowed_entities.each do |entity_name, entity_options|
    if !entity_options[:optional] && @entities[entity_name].blank?
      raise Activr::Activity::MissingEntityError, "Missing '#{entity_name}' entity in this '#{self.kind}' activity: #{self.inspect}"
    end
  end
end

#humanization_bindings(options = { }) ⇒ Hash

Bindings for humanization sentence

For each entity, returned hash contains:

:<entity_name>       => <entity humanization>
:<entity_name>_model => <entity model instance>

All ‘meta` are merged in returned hash too.



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# File 'lib/activr/activity.rb', line 363

def humanization_bindings(options = { })
  result = { }

  @entities.each do |entity_name, entity|
    result[entity_name] = entity.humanize(options.merge(:activity => self))
    result["#{entity_name}_model".to_sym] = entity.model
  end

  result.merge(@meta)
end

#humanize(options = { }) ⇒ String

Humanize that activity

Options Hash (options):

  • :html (true, false) —

    Output HTML (default: ‘false`)



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# File 'lib/activr/activity.rb', line 379

def humanize(options = { })
  raise "No humanize_tpl defined" if self.humanize_tpl.blank?

  Activr.sentence(self.humanize_tpl, self.humanization_bindings(options))
end

#kind ⇒ String

Note:

Kind is inferred from Class name

Activity kind

Examples:

AddPictureActivity.new(...).kind
=> 'add_picture'



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# File 'lib/activr/activity.rb', line 349

def kind
  self.class.kind
end

#store! ⇒ Object

Note:

SIDE EFFECT: The ‘_id` field is set

Store activity in database

Raises:



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# File 'lib/activr/activity.rb', line 410

def store!
  run_callbacks(:store) do
    # check validity
    self.check!

    # store
    @_id = Activr.storage.insert_activity(self)
  end
end

#stored? ⇒ true, false

Check if activity is stored in database



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# File 'lib/activr/activity.rb', line 401

def stored?
  !@_id.nil?
end

#to_hash ⇒ Hash

Note:

All keys are stringified (ie. there is no Symbol)

Serialize activity to a hash



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# File 'lib/activr/activity.rb', line 317

def to_hash
  result = { }

  # id
  result['_id'] = @_id if @_id

  # timestamp
  result['at'] = @at

  # kind
  result['kind'] = kind.to_s

  # entities
  @entities.each do |entity_name, entity|
    result[entity_name.to_s] = entity.model_id
  end

  # meta
  result['meta'] = @meta.stringify_keys unless @meta.blank?

  result
end