Oracle APEX Architecture and Listener Options - Session 2 of 7 - Tutorial Agenda

This free tutorial explains APEX architecture, i.e. how the HTTP request/response cycle works, how an APEX application works (prerequesite knowledge), then introduces the options for an HTTP listening service: the embedded PL/SQL gateway, the Apache mod_plsql module, and the APEX listener deployed to either a Glassfish or a WebLogic container.

We summarize with benefits and recommendations for the various listener options.

John: Thank you very much for the introduction, Dave. Now what we want to talk about today in this short lecture is options for Listener architectures for APEX applications.

I'm going to run through some basics here in this as well and just to set the background to make sure we're all on the same page that the manual as it were. Because I found over the years that web listening architecture tends to be something that slips between domains at many IT shops.

Setting up listeners should not be done by a database administrator team nor should it be part of the development domain. No one really seems to know and in some environment, it's the head lead developers who manage the web listeners in other environments as the DBA who manages all system administration even manage the web listeners.

It's always split. There's a role split between the two domains of development and administration in most circumstances. Some of what I'm going to go through may seem a bit trivial to developers, some of it may seem a bit trivial to administrators, but please bear with me on that. That's just the way it is because the product does set between those two domains.

I'll begin by looking at what is the HTTP request-response cycle? We have to have a basic understanding and make sure we're all on the same level with that so we can then see how HTTP is used to get to APEX applications.

I'll run through what an APEX application is. It's nothing magical. It's just PL/SQL, the setup wizard for developing PL/SQL applications and I'll run through how to design the PL/SQL web application from basics and then we'll move on to APEX itself.

Having understood how the APEX application works, we can then look at the options for the listening architecture, the way users actually connect to your APEX applications, the way developers connect to APEX applications. The three significant options for that, the embedded gateway using a module and Oracle supplied module for an Apache Web Listener or the APEX Listener which is a custom written servlet or in effect to servlet written specifically to handle APEX listening requests.