Overview of State Management in ASP.Net

Laminations of cookies

• It is a small textual file so it can store a small amount of data.
• It is not secure since it is stored on the client side and can be tempered. For example, risk of username/password is being stored on the client machine.
• In some cases, the browser blocks the cookies.

Query string

• The query string is also a Client-Side State Management technique. It is the information that is appended to the URL.
• A Query string can be viewed in the address bar of the browser.
• The query string starts with a question mark (?) and an attribute/value pair, called “category”.
• A Query string provides a simple way to maintain state information. For example, they are an easy way to pass information from one page to another, such as passing a product number from one page to another page where it will be processed.
• The page is submitted using an HTTP GET command for query string values to be available during page processing.
• Information passed in a query string cannot be used to send sensitive data since a user can send a URL to other users and pass the information.

Laminations of the query string

• It is not a secure way since it can be read and modified in the address bar of the browser.
• Only a small amount of data can be transferred.
• Some browsers also limit the length of a URL.

Server-side state management

In the Server-Side State Management, the state of the page is maintained at the server side. The following are the various techniques for Server-Side State Management.

• Application State (Variable)
• Session State (Variable)
• SQL Server database

Server-side state Management provides better security. The state is saved on the server and isn't delivered to the client. The server side reduces the traffic to and from the client because the data is not sent to the browser.

Application state (variable)

• Application state is a global storage mechanism that saves data that can be accessed from every web page in a web application. The data that is saved in the application variable is maintained between every request that is sent to the server.
• The application state is maintained in the HTTP Application class implemented as a directory. The application variable holds data that is global for the web application and is not associated with a specific user. Placing the data in the application state gives you a single access point for shared application data. The data that you save in the application state isn't permanent and is cleaned whenever the application restarts.
• It should be noted that many users might be accessing the application state simultaneously so any call to the application state object needs to be thread-safe. This can be easily done in ASP.NET using the lock keyword on the statements that are accessing application state objects.

Session state (variable)

• A session is a series of requests made by the client. A new session starts when a user sends the first request to the web application. This means that every user of the web application will have a separate session state. The session state is used to store and retrieve information about the user as the user navigates from one page to another page in ASP.NET web applications.
• The session has a timeout period and after the timeout the session data is lost and a new session is created for the user. The timeout occurs when the user is no longer active for some time. The session object is implemented as a key/value dictionary that is represented by an instance of the HTTP Session object.
• The session is used for the following scenarios.
  • To track user sessions.
  • Rise session management event.
  • Store session-specific data.
• Session objects are one of the intrinsic objects supported by ASP.NET. They provide a developer with a complete web session management solution.