3-tier in PHP

Anon

Dear all,

Is any bodi experienced with 3-tier architecture in PHP?
I have developed a 3-tier application in ASP. SO, all the business rules are in the middle tier (in DLLs), in the ASP COde, i only create an object, (using CreateObject), and i call the methods of those objects, that do all the routines.

Now i wanna convert this application in PHP, is there any possibility to use the same architecture? If you know any web site where i can read about this, please tell me.

Thank you
Ardian

van__

With PHP, you don't need a 3-tier setup.

Now...I know...
You are probably thinking
it's so not right to do anything less than 3-tier, but the fact is with just PHP acting as a 2-tier interface, your application will be much faster and ultimately, more scalable.

PHP unlike ASP is Object Oriented.
Sure, ASP can use objects, but ASP cannot be an object. There's the difference.

Your DLLs could be written as Objects in PHP and executed within your scripts, simple as that. No funky crap, no performance hit. Just speed and power.

What more could you ask for?

Anon

Thank you for the answer. I know that PHP is more object oriented that ASP is, and that's why i decided to move to PHP, but in ASP you put the DBConnection routines in DLL, even the ASP developer does not need to know th DB user and the DB pass, every thing is iside the DLL. Is there any equivalence in PHP?

Ardian

figment

Yes. In fact a lot of people have written their own database connection classes and functions.

I have not personaly used any yet, as Ive not had a need to, but I see them all over the place on freshmeat.net, and sourceforge.net

:Figment

Anon

So you think I can create classes in PHP, and I can ecapsulate all the Information needed for DB operation inside classes, and the classess and PHP scripts+templates in the same server???

Thank you

Anon

Yes, thats the way I do it in my PHP apps, but consider the following:

Biggy! PHP objects have no private or friend properties or methods. Everything is public. Everything. I hope this is to change, but the only way to make it so would be to provide a mechanism to compile the code after you write it. As is right now, the objects are nothing more than pages of uncompiled code that anyone with access to your directory and the actual PHP files can see. There are programs out that that will compile your scripts, I've seen reference to them here, but still, no private properties and methods.
3-tier is based on your requirements, not on the language you opt to use to implement those requirements. The fact that you move from ASP to PHP does not necessarily change the structure. Even when you have all the templates and classes on the same server (which you will), if you are using the same business logic, rules, and requirements as the original application, you are still implementing a 3-tier application. In development I do the client, business, and data services tiers on the same machine, but this is still a 3-tier app. I am probably preaching to the choir here, but I saw the message earlier about using the PHP objects and going to 2-tier and just wanted to say this in reply.
There are pluses and minuses in moving from ASP/COM to PHP, make sure you weigh them all.

I use both PHP and VB/COM/ASP in web high end application development, and use both extensively. Like using Corel PhotoPaint and Adobe PhotoShop, I like them both because each can do things the other can't, and use them as the situation deems necessary. If I had my druthers I would use PHP to develop COMs, but that will never happen...lol.

HTH, Jim

Anon

Thank you Jim.
One more question:

What do you mean with Client tier, business tier and data tier in PHP?

Anon

The situation I described are the logical tiers, not the physical.

Client tier (user services) - the client, the browser. This one is a bit muddled at time in the web world, because the browser can actually house part of the business tier if you are using client-side scripting like Javascript, Java, VBScript or the like to manipulate data prior to sending it back to the server.

Business tier (business services) - contains business logic, rules, and the like. The pages that are served from the web server that make the rules and provide the HTML to the client (alot more to it, but thats it in a nutshell).

Data tier (data services) - database, datastore, what the business tier access based on the rules set and client requests.

I know

Jim

(Thank god we aren't talking n-tier apps here..lol)