The SimpleDB web service API is made available through two interfaces: Query and SOAP. In this book we will use the Query interface.
The SimpleDB service implementation presented in this chapter
uses the Query API functionality implemented in the
AWS Ruby module (see Query API Implementation” in Chapter 2). The
AWS module includes methods that
perform authentication, transmission, and response checking of Query
Amazon uses version identifiers to label different versions of most of their service APIs. By assigning each API version its own identifier, Amazon can continue to develop and change the APIs without without breaking AWS client implementations that use the older versions. For this text, we used the most recent SimpleDB API version available at the time of writing: 2007-11-07.
In this chapter, we will gradually build up a complete
implementation class called
SimpleDB that you can use to interact with
the SimpleDB service. Example 13-1 defines a basic
code stub for the
to which we will add API implementation methods as we proceed through
the chapter. Save this code stub to a file named SimpleDB.rb in the
same directory as the
file AWS.rb defined in Chapter 2.
Example 13-1. SimpleDB class stub: SimpleDB.rb
require 'AWS' require 'bigdecimal' class SimpleDB include AWS # include the AWS module as a mixin ENDPOINT_URI = URI.parse("https://sdb.amazonaws.com/") API_VERSION = '2007-11-07' ...