OnlineShop Server/Client

Description:

A shopping solution that has both client side and server side using Sockets from .NET Framework, Multithreading, and Asynchronous programming concepts

Server Side:

• A console application, which it prints each response to the output window before sending back to the client side
• When it first runs, five per-defined products with random quantities (1-3) are initialized. Hence, products are the same every time the server starts, and the quantities for each product is randomized.
• Three accounts are created, each account has an account number and a user name.
• When the server is active, it stores ordering information to ConcurrentDictionary. And, the server does not store the ordering information to the local system, so once the server is shutdown, all information are disposed.
• Server sends back appropriate response depending on the client’s command. (The list of protocols is below)
• The handler code for the server is in separate class.
• The server is capable to establish communication with multiple clients at the same time.

Client Side:

• The client-side GUI is implemented using Windows Forms application, with an appropriate user interface. The user can select one product, then make the purchase. (quantity as one).
• When it first opens, a login form appears with two input fields: hostname/IP and the account number. (localhost as the default value for the hostname)
• If the server is not available, the application displays an error message; if the server is available/active but login failed, a different error message gets displayed.
• Once the user successfully connects to the server, the application gets all products information (names and quantities), then shows all information on the GUI.
• The user has the capability of disconnecting from the server gracefully. Upon disconnecting, the application closes. The application gracefully disconnect when the form is closed.
• When a product is not available during the process of user making a purchase, the application displays an appropriate message stating that the product is no longer available.
• The application also has the capability of showing the current purchase orders.
• The server handler code is in a separate class from the user interface.
• The application ensures that code that writes to or reads from the server does not block the GUI thread using Multithreading and Asynchronous programming.

Protocol Standards for this Project:

Client Commands	Server Response
DISCONNECT	No response. The server removes the client from the list of active clients. Both sides end the connection.
CONNECT:account_no	CONNECTED:user_name The client has successfully connected with the specified account number. The server returns the connected client's name. CONNECT_ERROR The client's connection attempt is unsuccessful. The account_no is not valid.
GET_PRODUCTS	PRODUCTS:product_name1,quantity1|product_name2,quantity2|… The server sends all product information (e.g. PRODUCTS:APPLE,2|ORANGE,1).
GET_ORDERS	ORDERS:product_name1,quantity1,user_name|product_name2,quantity2, user_name|… The server sends the purchase orders of all clients. (e.g. ORDERS:APPLE,1,John|ORANGE,1,Doe).
PURCHASE:product_name	DONE The order successfully placed NOT_AVAILABLE The product is not available (i.e., is already purchased by another client) and cannot be purchase. NOT_VALID The specified product is not valid.

Demo for the solution:

demo.mp4