Posted by Brent Baisley on 09/30/81 11:11

You may want to look into design patterns. This will help you create
applications that adapt to change well. When designing your
application, figure out what changes when a module is present and
separate it out. Find out what every module will use and group that
together. You're going to want different actions to be taken depending
on which modules are present without needing to change a function call.
Object oriented programming and design patterns will allow you to do
this well. Implementing certain design patterns can be a bit difficult
in PHP4, but design patterns in general is an area that will make you a
better programmer.

Your concept is almost the same as a complete system with restrictions
to certain modules. In your case, you are just saying the modules
aren't there rather than being restricted. Your idea for having a
script that would build the menu is good for a system with user level
restrictions because things change depending on who is logged in. But I
wouldn't build the menu from scratch every time if you are just
checking for modules. The menu should be built when a module is
installed or removed. That's the only time it will change anyway.
If you are looking for dynamic discovery of the modules that are
present, then you are doing something similar to WDS and UDDI.


On Mar 21, 2005, at 6:56 PM, Chris W. Parker wrote:

> Hello,
>
> So I was thinking about building some modularity into future projects
> and wanted to bounce some ideas off my fellow list members.
>
> My definition of "modular application" is: A modular application is one
> that can have it's major functions added/removed with the click of a
> button, or the creating/deleting of a file without breaking the
> application on any level. The user should be able to add/remove a
> module* from the filesystem and have the application update itself
> automatically without any (or very little) interaction with the user of
> the application.
>
> For example, here is what I've come up with at this point for how a
> modular application could be built.
>
> First of all there would need to be some kind of script that
> controls/integrats/manages the individual modules. I imagine this task
> to be performed within an include file that is included at the top of
> every file in the application (let's call it adjuster.php). This
> include
> file would determine how to build the main menu based on certain
> factors
> within the applications directory tree. Said another way, this file
> would take an inventory of the available modules and build a menu based
> on what it found. In this way a module could be added/removed without
> any interaction** from the user and the menu would update
> automatically.
>
> This in and of itself is not difficult. What I think the difficult part
> of it will be is finding the appropriate way to construct modules. At
> this point I'm imaging a directory called modules/ where each directory
> within the modules/ directory is a module itself. It would contain all
> the classes and functions associated with that module as well as a
> definition file for that module (could be a simple .txt file).
> Adjuster.php would read the modules/ directory and recursively discover
> each module and then build the main menu accordingly.
>
>
> Having said all that I think what I'm looking for is some feedback from
> experienced person(s) on the list with building modular applications. I
> can see this being really helpful for something like a shopping cart,
> CRM, or CMS app.
>
>
> Thanks,
> Chris.
>
> * In the short time I've been thinking about what a "module" is I've
> determined it to be one of a few things (or a combination thereof). A
> module could be (a) a single file, (b) a set of files, or (c) a
> directory containing one or more files and/or directories.
>
> ** Not having any interaction with the user does not have to be a
> requirement, but it would sure be helpful when upgrading the
> application. For example: Customer comes to your website, buys a new
> module (or downloads for free, however you choose to license the
> software), and simply adds it to the module repository. Yadda yadda
> yadda, a new, full functional menu option is available.
>
> p.s. Are there any lists out there that deal with programming in
> general?
>
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>
>
>
--
Brent Baisley
Systems Architect
Landover Associates, Inc.
Search & Advisory Services for Advanced Technology Environments
p: 212.759.6400/800.759.0577

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