Glücklicherweise gibt es in PHP noch mindestens 3 “Herausfinde-Möglichkeiten”:

1. Möglichkeit:

echo PHP_OS;
Ergibt bei einem Windows Server üblicherweise den Wert  “WINNT”.

echo php_uname(’s’);
Liefert bei einem Windows-Server einen Wert wie “Windows NT” zurück. In einer strpos()-Abfrage könnte man das dann so nutzen:

if (strpos($os_info,’Windows’) !== FALSE){
    echo “JA, das ist ein Windows-Teil…”;
 }

if (strpos(DIRECTORY_SEPARATOR != ‘/’){
    echo “Schon wieder eine Windows-Kiste”;
 }

A while ago we tried to find out, which online payment gateways are around. There are more than one may expect.  
We have listed our ‘findings’ aphabetically for you – additional information will follow.
There are actually more; in case your favorite Payment Gateway is not listed here – let us know. Let us also why you think its a good online payment gateway.

2CheckOut

AlertPay

Amazon FPS

Authorize.net

Barclays EPDQ

BBS

Beanstream

ChronoPay

ClickandBuy

DIBS Payment

DeltaPay

eWay

ExperCash

FastCharge

FAST TRANSACT

Flo2Cash

GoogleCheckout

HeidelPay

iDeal

iPay88

iPayment

IPPAY

MoneyBookers

mPAY24

myGate

NETBilling

NetCash

NOCHEX

NOVALNET

ogone

paybox

paycenter

PayEase

PAYER

Payment Express

PAYONE

PayPal

PayPoint

PaySimple

protx

Qenta

QUANTUM

sofortüberweisung.de

twyp

UOS

WorldPay

Starting digit:
Every credit card type has it’s fixed starting digit – good to know:

Amex/Diners Club: 3
VisaCard: 4
Mastercard: 5
Discover: 6

Length of number:
Also the length of the number is fixed according to card type:

DinersClub: 13
Amex: 15
All others: 16

So, customer wants to pay via American Express with a 16 digit CC number?
We don’t think so.

Luhn or Mod10 algorithm – the CC checksum has to be right
This checksum algorithm was invented by Hans Luhn. If the generated checksum can be divided by 10 without rest – then the number is valid – so the basic idea.
Here a practical PHP function to validate a credit card numer with it:

—
Comments, improvments are welcome!

USA:

JOE DOE
1500 E MAIN AVE STE 201
SPRINGFIELD VA 22162–1010
UNITED STATES OF AMERICA

Germany:

Joe Doe
Teststr.  1a
11111 TESTSTADT
GERMANY

If I typed the data of the second Joe Doe into the address form of my E-Commerce application fitting for US-addresses, then I would get an address like this:

JOE DOE
1A TESTSTRASSE
TESTSTADT BAYERN 11111
GERMANY

I can assure you that this will confuse German shop owners + the German national postal delivery services (Deutsche Bundespost).

Ok – so where can I get the information from?
Happily, there exists an international organization which takes care of these issues – the UPU, Universal Postal Union.
Actuall to find address formats on UPU’s own website is not so easy. I finally found a nice&complete list on ZenCarts wiki pages: http://www.zen-cart.com/wiki/index.php/International_Address_Formats
This list contains all the postal address format data for any country of this world.

The pie chart above can be created on the fly with this simple piece of html code:

<img src=”http://chart.apis.google.com/chart?
chs=250×100
&amp;chd=t:10,90
&amp;cht=p3
&amp;chl=Smart|Silly”
alt=”Sample chart” />

Interesting here:

1. With http://chart.apis.google.com/chart you call the Google Chart Api

2. This alone gives us of course not yet a nice pie chart – we have to add some parameters

For example with &amp;chd=t:10,90 we get a 10% | 90% ratio of the pie chart.
Means you could manipulate this ratio with some php values. The number of smart people might increase…

<?php
$silly = 5;
$smart = 95;
?>

<img src=”http://chart.apis.google.com/chart?
chs=250×100
&amp;chd=t:<?= $silly ?>,<?= $smart ?>
&amp;cht=p3
&amp;chl=Smart|Silly”
alt=”Sample chart” />

Ideal for web statistics…

3. More information about cool charts with the Google Chart Api you can find here: http://code.google.com/intl/en/apis/chart/types.html#pie_charts

4. And, its also possible to highlight countries on a map

According to statistics form 2008 Germans prefer to pay in webshops this way:
- 31% Banktransfer in advance + on account
- 18% Direct debit
- 16% Collect on delivery
- 15% Credit Card
- 11% Internet Payment Systems like PayPal,T-Pay,Click and Buy..

This means in practical terms: If you offer a German customer PayPal as the only payment option, there is a risk to loose him as visitor of your ecommerce website. That would hold true also with credit card payments only. Despite high fees Germans might still pay via bank transfer.

—
Source: BITKOM-12/2008

So what about PrestaShop?
The PrestaShop team uses at least two ways:
- customization for people who ask for it
- the newly opened “PrestaStore” marketplace for addons – http://www.prestastore.com/

The opening of the PrestaStore marketplace (this week) was, in our opinion, a smart move.
Several websites started to offer “PrestaShop” templates & modules. With the marketplace PrestaShop will manage (very likely) to keep the users where every opensource developer wants his users to be – at the original project website. Since the developement team also sells his own modules there (at the moment over 25), a steady flow of funds is assured.

People who place templates & modules there have two advantages:
- good exposure
- you receive a 100% of the sales price, no commisions charged

So opensource developers continue to watch them because…
… who doesn’t need some funding?

WordPress mu is the multi-user version of WordPress. We consider as a genius invention.
It’s possible to run a single webshop with Wordpress, therefore WordPress mu allows for multiple stores in one installation.

Why would you be interested in this?

• 1. This is esp. interesting for you if you run several webshops, but you dont want to install WordPress several times.
• 2. Instead of running webshops yourself, you rent out webshops to others and earn your money like this.
  This could be a flat rate or a percentage of the turnover of your client stores.

In other words: multiple stores can easily multiply your internet income.

Why would you like to do this?
The main reason are Smarty’s caching capabilities. It caches complete pages but it is also possible to define area’s which should not be cached – with the {insert} tag. This ability is missing in many WP caching plugins.  And of course, maybe a developer is used to Smarty already.

What we tried – the steps
The following steps take place within the wp-content/your-theme/ folder. 

1. Create these new directories in your theme folder

- cache/
- template
- template_c/
- lib/smarty/

Give
cache/
template_c/
a 777 chmod

2. Download the Smarty package and put into the lib/smarty/directory

3. Create an extra file smarty.php and put it into the lib/ directory

var $tp;

function initTemplates(){

#$root = ((substr($_SERVER['DOCUMENT_ROOT'],-1)) == ‘/’ ? substr($_SERVER['DOCUMENT_ROOT'], 0, -1) : $_SERVER['DOCUMENT_ROOT']);
define(DOCROOT,((substr($_SERVER['DOCUMENT_ROOT'],-1)) == ‘/’ ? substr($_SERVER['DOCUMENT_ROOT'], 0, -1) : $_SERVER['DOCUMENT_ROOT']));

define(’SMARTY_DIR’, DOCROOT . ‘/wp-content/themes/’ . ‘default’ . ‘/lib/smarty/’);
require(SMARTY_DIR . ‘Smarty.class.php’);
$this->tp = new Smarty;

define(FE_TEMPLATE_PATH, DOCROOT . ‘/wp-content/themes/’ . ‘default’ . ‘/templates/’.'blue/’);
$this->tp->template_dir = FE_TEMPLATE_PATH;
$this->tp->compile_dir = DOCROOT.’/wp-content/themes/’.'/default/templates_c/’;
$this->tp->cache_dir = DOCROOT .’/wp-content/themes/’ .’default/cache/’;
#$this->tp->caching = false;
$this->tp->caching = true;
}

function showPage($data,$filename=’index’){
$this->initTemplates();

foreach($data as $k => $v){
$this->tp->assign($k,$v);
}

$page = $filename.’.tpl’;
$this->tp->display($page);
}
}

$mySmarty = new wpSmarty();

4. Link to this file and call the smarty template file

Lets say, you like to use this in your theme’s header.php:  

$mySmarty->showPage($data,’header’);

5. Create an header.tpl

Thats it.
Advantage: Caching without caching plugins.
Disadvantage: WordPress has nice template functions which echo things, with Smarty we need functions with return values. 
Here some sample code fitting for the ‘default’ theme: smarty.zip – Improvements welcome!