Book Image

PostgreSQL Server Programming

Book Image

PostgreSQL Server Programming

Overview of this book

Learn how to work with PostgreSQL as if you spent the last decade working on it. PostgreSQL is capable of providing you with all of the options that you have in your favourite development language and then extending that right on to the database server. With this knowledge in hand, you will be able to respond to the current demand for advanced PostgreSQL skills in a lucrative and booming market."PostgreSQL Server Programming" will show you that PostgreSQL is so much more than a database server. In fact, it could even be seen as an application development framework, with the added bonuses of transaction support, massive data storage, journaling, recovery and a host of other features that the PostgreSQL engine provides. This book will take you from learning the basic parts of a PostgreSQL function, then writing them in languages other than the built-in PL/PgSQL. You will see how to create libraries of useful code, group them into even more useful components, and distribute them to the community. You will see how to extract data from a multitude of foreign data sources, and then extend PostgreSQL to do it natively. And you can do all of this in a nifty debugging interface that will allow you to do it efficiently and with reliability.
Table of Contents (17 chapters)
PostgreSQL Server Programming
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Simple single-server chat


Perhaps, the simplest application needing this kind of scalability is a messaging (or chat) application; so let's write one.

The initial single-server implementation has the following specifications:

  • There should be users and messages.

  • Each user has a username, password, e-mail, list of friends, and a flag to indicate if the user wants to get messages from only their friends, or from everybody.

  • For users, there are methods for:

    • Registering new users

    • Updating the list of friends

    • Logging in

  • Each message has a sender, receiver, message body, and timestamps for sending and reading the message.

  • For messages, there are methods for:

    • Sending a message

    • Retrieving new messages

A minimalistic system implementing this could look like the following:

Here, a web page opens a WebSocket (ws://) to a HUB (a message concentrator) which in turn talks to a database. On each new connection, the HUB logs in and on successful login opens a WebSocket connection to the web page. It then sends all new...