To enhance the
PayPal Shopping Cart so that it can be used with dynamic server-side
technologies such as, ASP, JSP, PHP, CGI, or others, and to give their
cart a database back end such as MS Access, MS SQL, MySQL, Oracle, or
others. For our example, we will be using Active Server Pages (ASP), MS
Access database, and VBScript for our language. For more scripting
language and database versions, please visit our site.
OVERVIEW
The PayPal Shopping Cart technology
allows developers to easily create E-Commerce for their clients without
many of the hassles associated with traditional shopping carts, such as,
Credit Card Merchant Accounts, costly setup fees, design inflexibility,
and many other headaches a developer can run into when developing a simple
web store system for a client. The PayPal system is based on a form driven
questionnaire that asks the merchant specific information about a product
they would like to sell such as, the product name, the price, product ID
and more. After completing the form and submitting it, the PayPal system
generates a simple piece of code for developers to insert into their pages
and the product is then available to purchase without any further
modification.
The existing
system is fantastic in its simplicity, but can be somewhat tedious when a
store has many pages and product contained within. Basically, you would
have to fill out this form and paste the generated code into every page
for every product you wanted to display.
A better
solution for those developers who have access to a server side scripting
technology (i.e.- ASP, JSP, PHP, CF, etc.) would be to create a single
page to display a product and have the PayPal code dynamically generated
from a database. It may sound difficult, but in reality, it is one of the
easiest, timesaving development efforts a person can make when
implementing a PayPal Shopping Cart.
This system
will allow the creation of an robust, scalable, and highly reliable
solution that can be used for almost any size E-Commerce application that
a developer would encounter.
REQUIREMENTS
A Server Side Scripting Technology- Most of the current server side scripting languages will
work great, here are a few: ASP (Active Server Pages), JSP(Java Server
Pages), CF(Cold Fusion), and more. Many Internet Service and Hosting
Providers employ one of these technologies in their services.
A Database to Interface with the Dynamic Pages- Any common database can be easily
used in this application, a few examples are: MS Access, MS SQL, MySQL,
Oracle, Sybase, and many others. Just be sure to ask your Internet Hosting
provider which database technologies they support.
THE PAYPAL CART
As noted above, the PayPal shopping cart system is based on form driven data input about specific
products that generate a piece of code that can be inserted into HTML
pages. For each product you would like to sell, you have to log into your
PayPal account and fill out the form on their web site and insert the
generated code into your HTML pages.
Below is an example of the code generated by the PayPal Shopping Cart:
The first tag, is simply an 'href' which is used to create a hyperlink. In this case
it uses the 'Add to Cart' image. The <img> tag specifies the
location of the 'Add to Cart' button that is displayed in the page. This
can actually be changed to anything you like. This is useful if you do not
like the look of the default PayPal buttons and would like to use your
own. This can also be a relative link to the location of the product page
on your server is the files is located in the server as well.
The
"#" value is a placeholder for a text-based link. This can actually be
replaced with text, if you prefer to add your item with a text Link,
rather than the 'Add to Cart' image. It would simply be <a href= "Add
to Cart Text"... However, you would need to remove the <img> tag
that references the 'Add to Cart' image.
This tag tells
the browser to open a new window and defines that window's properties. The
window.open on click works with browsers 3.0 and above for images.
However, if you are using the text link modification noted above instead
of the 'Add to Cart' image, then it will only work for 5.0 browsers and
some IE 4.0 browsers.
'cartwin' is
the new window's name. If you use any other type of javascript in your
pages to control the new window (such as positioning), then define the
command to interact with the name 'cartwin' or modify this value to
anything else you like. Width/height define the window's size. Should be
kept as is in order to see all of the cart. 'scrollbars' are needed in
case your customer's shopping becomes so long that it does not fit into
the 400 pixel height.
'Location' is a variable that displays the
URL of your cart in the new window by giving the window an address bar. I
personally prefer to remove this, as customers can change string values
and product unwanted effects. I have not ran into a situation where the
address or location value is needed. I suggest removing it.
'
Resizeable' is not needed, but many site visitors like to have that
flexibility. Leave 'status' in tact as well, as it has no effect on
display or functionality.
This section of code actually calls the location of the PayPal Shopping cart on their
servers. This is where you must enter your PayPal username, directly after
the 'business=' section.. It is simply your E-Mail address that you use to
log into your account. Note: the 'add=1' snippet of code can be change to
another value to add more items at once, or to have it populated from a
form element, but that is a little tricky and goes beyond the scope of
this article.
This section defines the details about the product that you are adding to the shopping
cart. 'Item_name' is simply the product's name. 'Item_number' is the
unique number the vendor uses to track its specific item, can be anything.
'Amount' is how much you want your customers to pay for an
item.
'Image_url' this optional section of code is used to display
a company's logo within the PayPal Shopping Cart window. You can use this
to point to a location of a logo on a remote server, but it must have the
full URL included. Note: the 'https' at the beginning of this section
indicates that the image must be on a secure server, or it will not show
up. If you specify a location with a regular 'http' then, the customer
will be prompted by the browser to display secure and non-secure items and
ask if they want to continue. A work around would be to embed the cart
page in a frameset, but that again is tricky and goes beyond the scope of
this article.
'Return_url' is where the visitor will be brought
after they have successfully completed the payment process. It must use
the full URL even if it resides on your server. 'Cancel_url' serves the
same purpose, but is used when a customer cancels their purchase during
the payment process.
THE DATABASE
The database is the back-end
engine for our simple E-Commerce system. Any web capable database will
work and its configuration can be as simple or as complex as you like. In
this case we will keep it simple:
Table Name: tblProducts
Field Name
Definition
Description
ID
Autonumber
A key column for the database used as a placeholder.
Item_Name
Text
Used for the name of the products.
Item_Description
Memo, Long Text
Used to display detailed information for a product. Can be used as a keyword search feature.
Item_ID
Number
This is the item number used for the vendor to track a specific item.
Item_Price
Decimal
The cost field of the item.
Page_Success
Text
Holds the URL of the page customers are taken to after a successful payment.
Page_Cancel
Text
Holds the URL of the page a customer is taken to after a customer cancels a payment.
Logo_Location
Text
A field for the URL of the location of the logo. Not required.
Item_Image
Text
Used as a location to specify where an item's image is located. Optional.
THE PRODUCT PAGE
Now we will construct a page that will display our image. This is a detail page which can be
linked from a search page that can be created to search an item's
description. In our case, we will use the Product's ID field value that is
automatically created in our database to ensure we get a unique record.
In our page, our recordset, called 'rsProduct', will be created
with a simple select statement: SELECT * FROM tblProduct WHERE ID = vID
vID is defined as Request("ID") or
Request.Querystring("ID")
Now, create a page to display to the product and insert any dynamic field elements onto
the page like the product image, the price, and any other information to
be displayed about an item.
After the page is designed and
created, we simply add our original PayPal link into the HTML, replacing
the previously static variable with dynamic ones:
- You should keep an eye on how PayPal formats their string that calls the shopping cart. It
has already changed since I began using it. Previously, it generated a
'shipping' section that allowed you to tag specific shipping costs to
items. Now it is done in the customer preferences section of their site.
Do not worry about the changes in the string, as they will need to
continue supporting any older methods as there are thousands of pages that
use it.
- Adding a
logo to your cart is a very nice touch. If you do not have one, the cart
displays a large 'PayPal' logo. If you use your own, then it simply says
'Powered by PayPal' to the right of your logo in small text. You really
should have the logo on a secure server calling it with 'https' or your
customers will get a security prompt that they must click. There is a
workaround though. Create a frameset for your cart. Define the frames as
0,* in size and populate the * frame with the url string as the source.
May need some tweaking though.
- Having a
'keywords' field in the database is a good idea. On your main store page
you can use a text search box to select products with specific keywords
and on their descriptions. This is ideal for larger sites, where the item
description does not cover all of the relative terms.
- Building an
online administrative section is also a good idea to handle all of the
product additions, edits, and deletes. While doing it in the database is
all right for most cases, there are some where people would rather use a
web form driven input method.
CONCLUSION
The sky is really the limit with
the PayPal cart. All of the energies that were previously wasted on
securing CCMA's or coordinating setup costs with clients are now gone with
this system. Using the methods above, a developer can modify the PayPal
cart to work with almost any dynamic server technology, including CGI. It
can even be fitted to work with many of the existing carts that are out
there, some even free.
If you have any questions or comments about
this article, feel free to contact us at, paypal@superfreaker.com.
You can also visit the PayPal section of our site which has pre-made
storefronts using the techniques above in a variety of server languages
and databases at www.superfreaker.com/paypal.
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