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# Copyright 2011-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
module AWS
module Record
class HashModel
require 'aws/record/hash_model/attributes'
require 'aws/record/hash_model/finder_methods'
require 'aws/record/hash_model/scope'
extend AbstractBase
def self.inherited(sub_class)
sub_class.string_attr :id,
:hash_key => true,
:default_hash_key_attribute => true
end
# @return [String,nil]
def hash_key
self[self.class.hash_key]
end
class << self
# Creates the DynamoDB table that is configured for this class.
#
# class Product < AWS::Record::HashModel
# end
#
# # create the table 'Product' with 10 read/write capacity units
# Product.create_table 10, 10
#
# If you shard you data across multiple tables, you can specify the
# shard name:
#
# # create two tables, with the given names
# Product.create_table 500, 10, :shard_name => 'products-1'
# Product.create_table 500, 10, :shard_name => 'products-2'
#
# If you share a single AWS account with multiple applications, you
# can provide a table prefix to group tables and to avoid name
# collisions:
#
# AWS::Record.table_prefix = 'myapp-'
#
# # creates the table 'myapp-Product'
# Product.create_table 250, 50
#
# # creates the table 'myapp-products-1'
# Product.create_table 250, 50, :shard_name => 'products-1'
#
# @param [Integer] read_capacity_units
# See {DynamoDB::TableCollection#create} for more information.
#
# @param [Integer] write_capacity_units
# See {DynamoDB::TableCollection#create} for more information.
#
# @param [Hash] options
#
# @option options [String] :shard_name Defaults to the class name. The
# shard name will be prefixed with {AWS::Record.table_prefix},
# and that becomes the table name.
#
# @return [DynamoDB::Table]
#
def create_table read_capacity_units, write_capacity_units, options = {}
table_name = dynamo_db_table_name(options[:shard_name])
create_opts = {}
create_opts[:hash_key] = { hash_key => :string }
dynamo_db.tables.create(
table_name,
read_capacity_units,
write_capacity_units,
create_opts)
end
# @return [DynamoDB::Table]
# @api private
def dynamo_db_table shard_name = nil
table = dynamo_db.tables[dynamo_db_table_name(shard_name)]
table.hash_key = [hash_key, :string]
table
end
# @api private
def hash_key
hash_key_attribute.name
end
# @api private
def hash_key_attribute
@hash_key_attribute
end
private
def set_hash_key_attribute(attribute)
if
hash_key_attribute and
hash_key_attribute.options[:default_hash_key_attribute]
then
remove_attribute(hash_key_attribute)
end
@hash_key_attribute = attribute
end
def dynamo_db_table_name shard_name = nil
"#{Record.table_prefix}#{self.shard_name(shard_name)}"
end
def dynamo_db
AWS::DynamoDB.new
end
def add_attribute(attribute)
set_hash_key_attribute(attribute) if attribute.options[:hash_key]
super(attribute)
end
end
private
def populate_id
hash_key = self.class.hash_key_attribute
if hash_key.options[:default_hash_key_attribute]
self[hash_key.name] = SecureRandom.uuid
end
end
# @return [DynamoDB::Item] Returns a reference to the item as stored in
# simple db.
# @api private
private
def dynamo_db_item
dynamo_db_table.items[hash_key]
end
# @return [SimpleDB::Domain] Returns the domain this record is
# persisted to or will be persisted to.
private
def dynamo_db_table
self.class.dynamo_db_table(shard)
end
private
def create_storage
dynamo_db_table.items.create(serialize_attributes, opt_lock_conditions)
end
private
def update_storage
# Only enumerating dirty (i.e. changed) attributes. Empty
# (nil and empty set) values are deleted, the others are replaced.
dynamo_db_item.attributes.update(opt_lock_conditions) do |u|
changed.each do |attr_name|
attribute = self.class.attribute_for(attr_name)
value = serialize_attribute(attribute, @_data[attr_name])
if value.nil? or value == []
u.delete(attr_name)
else
u.set(attr_name => value)
end
end
end
end
private
def delete_storage
dynamo_db_item.delete(opt_lock_conditions)
end
private
def deserialize_item_data data
data.inject({}) do |hash,(attr_name,value)|
if attribute = self.class.attributes[attr_name]
hash[attr_name] = value.is_a?(Set) ?
value.map{|v| attribute.deserialize(v) } :
attribute.deserialize(value)
end
hash
end
end
end
end
end
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