class Aws::SessionStore::DynamoDB::Locking::Base
This class provides a framework for implementing locking strategies.
Public Class Methods
Creates configuration object.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 7 def initialize(cfg) @config = cfg end
Public Instance Methods
Deletes session based on id
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 33 def delete_session(env, sid) handle_error(env) do @config.dynamo_db_client.delete_item(delete_opts(sid)) end end
Gets session data.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 28 def get_session_data(env, sid) raise NotImplementedError end
Each database operation is placed in this rescue wrapper. This wrapper will call the method, rescue any exceptions and then pass exceptions to the configured error handler.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 42 def handle_error(env = nil, &block) begin yield rescue Aws::DynamoDB::Errors::ServiceError => e @config.error_handler.handle_error(e, env) end end
Packs session data.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 23 def pack_data(data) [Marshal.dump(data)].pack("m*") end
Updates session in database
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 12 def set_session_data(env, sid, session, options = {}) return false if session.empty? packed_session = pack_data(session) handle_error(env) do save_opts = update_opts(env, sid, packed_session, options) @config.dynamo_db_client.update_item(save_opts) sid end end
Private Instance Methods
Attributes to be retrieved via client
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 147 def attr_opts {:attributes_to_get => ["data"], :consistent_read => @config.consistent_read} end
Attributes to update via client.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 95 def attr_updts(env, session, add_attrs = {}) data = data_unchanged?(env, session) ? {} : data_attr(session) { attribute_updates: merge_all(updated_attr, data, add_attrs, expire_attr), return_values: 'UPDATED_NEW' } end
Attribute for creation of session.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 109 def created_attr { "created_at" => updated_at } end
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 131 def data_attr(session) { "data" => {:value => session, :action => "PUT"} } end
Determine if data has been manipulated
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 136 def data_unchanged?(env, session) return false unless env['rack.initial_data'] env['rack.initial_data'] == session end
@return [Hash] Options for deleting session.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 53 def delete_opts(sid) table_opts(sid) end
Expected attributes
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 142 def expected_attributes(sid) { :expected => { @config.table_key => {:value => sid, :exists => true} } } end
Update client with current time + max_stale.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 114 def expire_at max_stale = @config.max_stale || 0 { value: (Time.now + max_stale).to_i, action: 'PUT' } end
Attribute for TTL expiration of session.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 120 def expire_attr { 'expire_at' => expire_at } end
@return [Hash] merged hash of all hashes passed in.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 153 def merge_all(*hashes) new_hash = {} hashes.each{|hash| new_hash.merge!(hash)} new_hash end
@return [Hash] Options for saving an existing sesison in the database.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 74 def save_exists_opts(env, sid, session, options = {}) add_attr = options[:add_attrs] || {} expected = options[:expect_attr] || {} attribute_opts = merge_all(attr_updts(env, session, add_attr), expected) merge_all(table_opts(sid), attribute_opts) end
@return [Hash] Options for saving a new session in database.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 68 def save_new_opts(env, sid, session) attribute_opts = attr_updts(env, session, created_attr) merge_all(table_opts(sid), attribute_opts) end
Table
options for client.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 87 def table_opts(sid) { :table_name => @config.table_name, :key => { @config.table_key => sid } } end
Unmarshal the data.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 82 def unpack_data(packed_data) Marshal.load(packed_data.unpack("m*").first) end
@return [Hash] Options for updating item in Session table.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 58 def update_opts(env, sid, session, options = {}) if env['dynamo_db.new_session'] updt_options = save_new_opts(env, sid, session) else updt_options = save_exists_opts(env, sid, session, options) end updt_options end
Update client with current time attribute.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 104 def updated_at { :value => "#{(Time.now).to_f}", :action => "PUT" } end
Attribute for updating session.
# File lib/aws/session_store/dynamo_db/locking/base.rb, line 125 def updated_attr { "updated_at" => updated_at } end