![EXAMPLE:
Session["Name"] = “textName”;
Response.Write(Session[“Name"]);
Code Explanation:-
• The first line of code takes the value of the Name textbox
control and stores it in the Session object. By specifying the
code of Session["Name"] , we are giving the property a name
called "Name." By specifying a name for the property, it
becomes easier to retrieve it at a later point in time.
• The next line of code retrieves the stored value from the
Session object. It then writes this value via the
'Response.Write' method back to the client.](https://image.slidesharecdn.com/sessionscookies-190205165658/85/Sessions-cookies-4-320.jpg)
Sessions&cookies
- 1. SESSIONS & COOKIES Are state management techniques (used to maintain the state of the application since http is a stateless protocol).
- 2. Basic about State Management in ASP.NET • ASP.NET framework provides various ways to preserve states at various stage. • Controlstate, viewstate, sessions, cookies etc. • This can be categorised as client side and server side state management techniques.
- 3. SESSIONS • Session stores variables on the Server Side. • Session will allocates memory in the web server and for every user server will allocates memory, so Session is per user based. • Sessions are generally used to maintain state when you navigate through a website. However, they can also be used to hold commonly accessed objects. • Every session is identified by a unique session id. • Sessions are not reliant on the user allowing a cookie. They work instead like a token allowing access and passing information while the user has their browser open. • The problem with sessions is that when you close your browser you also lose the session. So, if you had a site requiring a login, this couldn't be saved as a session like it could as a cookie, and the user would be forced to re-login every time they visit.
- 4. EXAMPLE: Session["Name"] = “textName”; Response.Write(Session[“Name"]); Code Explanation:- • The first line of code takes the value of the Name textbox control and stores it in the Session object. By specifying the code of Session["Name"] , we are giving the property a name called "Name." By specifying a name for the property, it becomes easier to retrieve it at a later point in time. • The next line of code retrieves the stored value from the Session object. It then writes this value via the 'Response.Write' method back to the client.
- 5. ADVANTAGES AND DISADVANTAGES • Advantages: Session provide us a way to maintain user data, all over the applications. We can store any type of object in it. Session is secure and transparent from the user. • Disadvantages: Performance overhead in case of large volumes of user, because data is stored in server memory.
- 6. COOKIES • Basically a cookie is Client Side variable and will store data either in browser or in system hard disk. • Cookies are stored per-user on the users machine. A cookie is usually just a bit of information. • You can never fully trust that a cookie has not been tampered with by a user or outside source however if security is a big concern and you must use cookies then you can either encrypt your cookies or set them to only be transmitted. • A user can clear there cookies at any time or not allow cookies altogether so you cannot count on them being there just because a user has visited your site in the past. • A cookie can keep information in the user's browser until deleted. If a person has a login and password, this can be set as a cookie in their browser so they do not have to re-login to your website every time they visit. • You can store almost anything in a browser cookie. • The trouble is that a user can block cookies or delete them at any time. If, for example, your website's shopping cart utilized cookies, and a person had their browser set to block them, then they could not shop at your website.
- 7. EXAMPLE: <% Response.Cookies("firstname")=“mlsu”; Response.Cookies("firstname").Expires=#May 10,2019#; %> Code Explanation:- • Here we will create a cookie named "firstname" and assign the value “mlsu" to it. And in the second line we are setting a date, when the cookie should expire. <% fname=Request.Cookies("firstname"); Response.Write("Firstname=" & fname); %> Code Explanation:- • We retrieve the value of the cookie named "firstname" and display it on a page.
- 8. ADVANTAGES AND DISADVANTAGES • Advantages: It is very simple to use and implement. Browser is in-charge of sending data. For multiple sites with cookies, the browser automatically arranges them. • Disadvantages: It stores data in simple text format, so it’s not secure at all. There is a size limit for cookies data(4KB). Most browsers provide limits for number of cookies at a time which is 20.
- 9. DIFFERENCE BETWEEN COOKIES AND SESSION Note: You can of course get the best of both worlds! Once you know what each does, you can use a combination of cookies and sessions to make your site work exactly the way you want it to. 1. Client-side state management technique, stored in on client's browser. 2. Can store text data. 3. Not suggestible for storing critical information. 4. Cookie doesn't have a self- expiry time. 1. Server-side state management technique, stored in server. 2. Can stored an object. 3. Can be used for storing critical information. 4. Session expires after 20 minutes by default. Cookies Sessions
- 10. THANK YOU
Editor's Notes
- #10: the main difference between cookies and sessions is that cookies are stored in the user's browser, and sessions are not. This difference determines what each is best used for.