Project Assignment: Credit Card Gateway Web Service

This project will give you experience working with web services. In this project,you will create a Web Service used by retailers to manage credit card accounts and transactions. You will create a Web Application(ASPX pages) that will be theWeb Service Client for the Web Service you will create. Important: only the Web Service can access and use the database.

Requirements:

You need to create a Web Application that utilizes a Web Service for a credit card processing gateway. The Web service will be responsible for working with the database, and it will be responsible for verifying, charging, and searching for credit card accounts. The ASPX page should allow the user to entercredit card information, verification information, and purchase information, and record the credit card transaction. The ASPX page (Web Service Consumer) should not contain any database connection code; it should rely on the Web Service to handle all database actions.

Database Requirements:

1. You need to design and implement a complete data model for the required functionality. You will be graded on your data model implementation.

Class Library Requirements:

1. You need to use component-based software design to create classes for this project that perform the necessary functionalities.

Web Application Requirements:

1. The Web Application needs to allow the user to enter credit card information, billing information, purchase information, and submit the transaction for approval.

a. You do not need to create a program where the user buys products. This can be implemented very simply by allowing the user to enter the payment information and a dollar amount to charge the credit card.

2. The Web Application needs to allow the user to add and update a credit card accounts. An employee of a company will need the ability to create credit cards for their customers, make changes to the data in the account, and apply payments to the account.

3. The Web Application should allow the user to retrieve all transactions for a specific credit card account.

4. Build a GUI that allows the user to perform these tasks, and use the Web Service Web Methods to perform the actual operations.

Web Service Requirements:

Your Web Service will contain at least the followingmethods:

1. The Web Service needs to contain a method that receives credit card account information including any verification information, billing information, and purchase information. This information must be passed to the Web Service using an array. This method will be responsible for processing the transaction and recording the transaction in the database. Processing the transaction will involve determining whether or not the transaction was accepted or declined, and the reason using some error code (integer value).

a. The Web Service will return an array containing information about the transaction.

i. It should return whether or not the transaction was accepted or decline, some error number indicating the issue, the date and time of the transaction.

b. The Web Service client will use thisinformation to display the outcome of the transaction.

2. The Web Service needs methods to add a credit card account and update an existing credit card account in the database.

a. These methods are needed for the company to deactivate a credit card that was stolen or cancelled/closed, create new credit card accounts, and apply payments to an account.

b. You must pass a user-defined class that represents this credit card account as input to the function.

c. You need to build in some security like a unique verification code or API key, so others cannot simply add credit card accounts fraudulently.

This code should not be a hard-coded value that gets used by everyone that adds a credit card.

3. The Web Service needs a method to retrieve all credit card transactions for a specific credit card account.

4. The Web Service may require other methods to complete other important operations. This is for you to determine.

a. For example, youshould not write all the logic in the first two methods. You should separate the functionality by creating a private method to verify the account, another private method to charge an account, etc... This can be also be done using component-based software design, so the logic can be reused in other applications.

Design principles:

a. Retailerslike Walmart and Targetwill use the Web Application to perform credit card transactions and manage credit card accounts for their store. A financial institute like Chase or Citibank would normally create the Web Service to allow their retail partners the ability to manage credit card accounts. This Web Service can used by applications written by the retailers to manage their credit cards. Think of this perspective when designing the application.

b. Provide a consistent and logical navigation system. The user should never have to use the browser's Back and Forward buttons to move between pages.

c. The user should be presented with an opening screen that presents the various transactions with links to respective pages to perform the selected transaction.

d. Make your presentation clear to the user, providing on-screen instructions wherever needed both for data entry and error correction. If required data is omitted or entries are incorrect, the user should not have to re-enter data that is already correct.

e. Create a good data model and implement the data model by creating the necessary tables in the database. The tables I listed above are just for explanation purposes. You are free to make a completely different set of tables since I expect you to implement your own data model. You will be graded on the implementation of your data model.

f. You need to use a proper naming convention for all controls and in your code. I expect you to properly name your classes, variables, functions, etc...

g. Your programs should not crash for any reason; it's poor design to have a program crash. Make sure to implement exception handling in appropriate places that can cause errors and handle them gracefully.

h. Perform server-side input validation where necessary.

i. You must use component-based software design. This means writing as much code in classes and functions of classes instead of in the GUI.

Approach to this Project

(1) Implement the Web Service (ASMX)

Create a Web Application Project for the Web Service. Reference your personal ClassLibrary that will contain the classes for this projectand the Utilities class library for the DBConnect class in the Web Service project. Make sure you have appropriate class definitions for all the classes needed by the Web Service.

(2) Create a separate Web Application Project for the Web Service Client and create a CreditCardSvcPxy Web Reference by performing the "Discovery" process on the Web Service Client (ASPX Web Form). The Web Reference should be to a Web Service in the localsolution until your program is ready to deploy. Otherwise, you will not be able to debug your Web Service Web Methods. When you are ready to deploy the project to the Web, right before project submission, you need publish the Web Service (ASMX) to the X:\Project4WS folder, and recreate the Web Reference to use the published Web service.

• After you create a Web Reference, you will be able to create a Web Service proxy object to use the Web Service.

(3) Implement your client Web Application (ASPX)

***If you try to import the Libraries or classes on the web service client (project where the ASPX pages exists) and use the classes to retrieve data from the Web Service, you will get an error message that says that the class definitions from the service side cannot be converted to the class definitions used on the web service clientside.This error is because you must use the web service's version of all user-defined types (complex types).