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

Constant Summary collapse

UNIX_EPOCH_DATE = 
Date.new(1970, 1, 1).freeze

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 14

def new_record
  @new_record
end

Instance Method Details

#decrement(attribute, by = 1) ⇒ Object

Initializes attribute to zero if nil and subtracts the value passed as by (default is 1). Only makes sense for number-based attributes. Returns self.



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# File 'lib/dynamoid/persistence.rb', line 236

def decrement(attribute, by = 1)
  self[attribute] ||= 0
  self[attribute] -= by
  self
end

#decrement!(attribute, by = 1) ⇒ Object

Wrapper around decrement that saves the record. Returns true if the record could be saved.



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# File 'lib/dynamoid/persistence.rb', line 244

def decrement!(attribute, by = 1)
  decrement(attribute, by)
  save
end

#delete ⇒ Object

Delete this object from the datastore.

Since:

  • 0.2.0



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# File 'lib/dynamoid/persistence.rb', line 266

def delete
  options = range_key ? { range_key: Dumping.dump_field(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?
        lock_version
      else
        changes[:lock_version][0]
      end
    options[:conditions] = conditions
  end
  Dynamoid.adapter.delete(self.class.table_name, 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 252

def destroy
  ret = run_callbacks(:destroy) do
    delete
  end
  ret == false ? false : self
end

#destroy! ⇒ Object 



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# File 'lib/dynamoid/persistence.rb', line 259

def destroy!
  destroy || (raise Dynamoid::Errors::RecordNotDestroyed, self)
end

#increment(attribute, by = 1) ⇒ Object

Initializes attribute to zero if nil and adds the value passed as by (default is 1). Only makes sense for number-based attributes. Returns self.



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# File 'lib/dynamoid/persistence.rb', line 221

def increment(attribute, by = 1)
  self[attribute] ||= 0
  self[attribute] += by
  self
end

#increment!(attribute, by = 1) ⇒ Object

Wrapper around increment that saves the record. Returns true if the record could be saved.



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# File 'lib/dynamoid/persistence.rb', line 229

def increment!(attribute, by = 1)
  increment(attribute, by)
  save
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 134

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 141

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
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 124

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 212

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

#update!(conditions = {}) ⇒ 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 189

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

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

        if Dynamoid::Config.timestamps
          time_now = DateTime.now.in_time_zone(Time.zone)
          time_now_dumped = Dumping.dump_field(time_now, self.class.attributes[:updated_at])
          t.set(updated_at: time_now_dumped)
        end

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

#update_attribute(attribute, value) ⇒ Object

Update a single attribute, saving the object afterwards.

Parameters:

  • attribute (Symbol) —

    the attribute to update

  • value (Object) —

    the value to assign it

Since:

  • 0.2.0



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# File 'lib/dynamoid/persistence.rb', line 179

def update_attribute(attribute, value)
  write_attribute(attribute, value)
  save
end

#update_attributes(attributes) ⇒ Object

Updates multiple attibutes at once, saving the object once the updates are complete.

Parameters:

  • attributes (Hash) —

    a hash of attributes to update

Since:

  • 0.2.0



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# File 'lib/dynamoid/persistence.rb', line 159

def update_attributes(attributes)
  attributes.each { |attribute, value| write_attribute(attribute, value) } unless attributes.nil? || attributes.empty?
  save
end

#update_attributes!(attributes) ⇒ Object

Updates multiple attibutes at once, saving the object once the updates are complete. Raises a Dynamoid::Errors::DocumentNotValid exception if there is vaidation and it fails.

Parameters:

  • attributes (Hash) —

    a hash of attributes to update



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# File 'lib/dynamoid/persistence.rb', line 168

def update_attributes!(attributes)
  attributes.each { |attribute, value| write_attribute(attribute, value) } unless attributes.nil? || attributes.empty?
  save!
end