Query API and authentication

There are two interfaces to SimpleDB. The SOAP interface uses the SOAP protocol for the messages, while the ReST Requests uses HTTP requests with request parameters to describe the various SimpleDB methods and operations. In this book, we will be focusing on using the ReST Requests for talking to SimpleDB, as it is a much simpler protocol and utilizes straightforward HTTP-based requests and responses for communication, and the requests are sent to SimpleDB using either a HTTP GET or POST method.

The ReST Requests need to be authenticated in order to establish that they are originating from a valid SimpleDB user, and also for accounting and billing purposes. This authentication is performed using your access key identifiers. Every request to SimpleDB must contain a request signature calculated by constructing a string based on the Query API and then calculating an RFC 2104-compliant HMAC-SHA1 hash, using the Secret Access Key.

The basic steps in the authentication...