Module: Dynamoid::Persistence

Extended by:
ActiveSupport::Concern
Included in:
Components
Defined in:
lib/dynamoid/persistence.rb

Overview

Persistence is responsible for dumping objects to and marshalling objects from the datastore. It tries to reserialize values to be of the same type as when they were passed in, based on the fields in the class.

Defined Under Namespace

Modules: ClassMethods

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#new_record ⇒ Object Also known as: new_record?

Returns the value of attribute new_record.



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# File 'lib/dynamoid/persistence.rb', line 13

def new_record
  @new_record
end

Instance Method Details

#delete ⇒ Object

Delete this object from the datastore.

Since:

  • 0.2.0



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# File 'lib/dynamoid/persistence.rb', line 253

def delete
  options = range_key ? {:range_key => dump_field(self.read_attribute(range_key), self.class.attributes[range_key])} : {}

  # Add an optimistic locking check if the lock_version column exists
  if(self.class.attributes[:lock_version])
    conditions = {:if => {}}
    conditions[:if][:lock_version] =
      if changes[:lock_version].nil?
        self.lock_version
      else
        changes[:lock_version][0]
      end
    options[:conditions] = conditions
  end
  Dynamoid.adapter.delete(self.class.table_name, self.hash_key, options)
rescue Dynamoid::Errors::ConditionalCheckFailedException
  raise Dynamoid::Errors::StaleObjectError.new(self, 'delete')
end

#destroy ⇒ Object

Delete this object, but only after running callbacks for it.

Since:

  • 0.2.0



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# File 'lib/dynamoid/persistence.rb', line 243

def destroy
  run_callbacks(:destroy) do
    self.delete
  end
  self
end

#dump ⇒ Object

Dump this object’s attributes into hash form, fit to be persisted into the datastore.

Since:

  • 0.2.0



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# File 'lib/dynamoid/persistence.rb', line 275

def dump
  Hash.new.tap do |hash|
    self.class.attributes.each do |attribute, options|
      hash[attribute] = dump_field(self.read_attribute(attribute), options)
    end
  end
end

#persisted? ⇒ Boolean

Is this object persisted in the datastore? Required for some ActiveModel integration stuff.

Returns:

  • (Boolean)

Since:

  • 0.2.0



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# File 'lib/dynamoid/persistence.rb', line 187

def persisted?
  !new_record?
end

#save(options = {}) ⇒ Object

Run the callbacks and then persist this object in the datastore.

Since:

  • 0.2.0



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# File 'lib/dynamoid/persistence.rb', line 194

def save(options = {})
  self.class.create_table

  if new_record?
    conditions = { :unless_exists => [self.class.hash_key]}
    conditions[:unless_exists] << range_key if(range_key)

    run_callbacks(:create) { persist(conditions) }
  else
    persist
  end

  self
end

#touch(name = nil) ⇒ Object

Set updated_at and any passed in field to current DateTime. Useful for things like last_login_at, etc.



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# File 'lib/dynamoid/persistence.rb', line 177

def touch(name = nil)
  now = DateTime.now
  self.updated_at = now
  attributes[name] = now if name
  save
end

#update(conditions = {}, &block) ⇒ Object 



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# File 'lib/dynamoid/persistence.rb', line 233

def update(conditions = {}, &block)
  update!(conditions, &block)
  true
rescue Dynamoid::Errors::StaleObjectError
  false
end

#update!(conditions = {}, &block) ⇒ Object

update!() will increment the lock_version if the table has the column, but will not check it. Thus, a concurrent save will never cause an update! to fail, but an update! may cause a concurrent save to fail.



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# File 'lib/dynamoid/persistence.rb', line 214

def update!(conditions = {}, &block)
  run_callbacks(:update) do
    options = range_key ? {:range_key => dump_field(self.read_attribute(range_key), self.class.attributes[range_key])} : {}

    begin
      new_attrs = Dynamoid.adapter.update_item(self.class.table_name, self.hash_key, options.merge(:conditions => conditions)) do |t|
        if(self.class.attributes[:lock_version])
          t.add(lock_version: 1)
        end

        yield t
      end
      load(new_attrs)
    rescue Dynamoid::Errors::ConditionalCheckFailedException
      raise Dynamoid::Errors::StaleObjectError.new(self, 'update')
    end
  end
end