Session and cookies,get and post methods

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session and cookiesget and post methods

Introduction

Web appcation work on HTTPprotocolHTTP protocol is a stateless protocolIt does not maintain the state between

requests

cookies

• A cookie is often used to identify a user.• A cookie is a small file that the server embeds

on the user's computer.• Common use of cookies is to remember users

between visits.

Uses of cookies

• Identification of a user session, user's preferences.

• Cookies can also be used for travelling of data from one page to another.

• Shopping cart contents • Authentication

Ways of creating cookies

By using HttpCookies class

HttpCookie StudentCookies = new HttpCookie("StudentCookies"); StudentCookies.Value = TextBox1.Text; StudentCookies.Expires = DateTime.Now.AddHours(1);

Response.Cookies.Add(StudentCookies);

By using Response directly

Response.Cookies["StudentCookies"].Value = TextBox1.Text; Response.Cookies["StudentCookies"].ExpiresDateTime.Now.AddDays(1);

multiple values in same cookie

Response.Cookies["StudentCookies"]["RollNumber"] = TextBox1.Text; Response.Cookies["StudentCookies"]["FirstName"] = "Anu"; Response.Cookies["StudentCookies"]["LastName"] = "Menon"; Response.Cookies["StudentCookies"].Expires = DateTime.Now.AddDays(1);

How to Retrieve a Cookie Value?For httpcookie class and response directly

method:string val = Request.Cookies["StudentCookies"].Value;

For multiple cookies: string val; val = Request.Cookies["StudentCookies"]["RollNumber"]; val= val+ " " + Request.Cookies["StudentCookies"]["FirstName"]; val = val+ " " +Request.Cookies["StudentCookies"]["LastName"]; Label1.Text = val;

Example program: protected void Page_Load(object sender, EventArgs e) { HttpCookie cookie = Request.Cookies["cookie"]; if (cookie == null) { HttpCookie userCookie = new HttpCookie("cookie"); userCookie["Name"] = "sanila"; userCookie.Expires = DateTime.Now.AddSeconds(8); Response.Cookies.Add(userCookie); Label1.Text = "Cookie created at: " + DateTime.Now.ToString() + "<br /><br />"; } else { string name = cookie["Name"]; Label1.Text += "Welcome " + name; } } demo

Deleting cookies

For deleting cookies:

if (Request.Cookies["StudentCookies"] != null) { Response.Cookies["StudentCookies"].Expires =

DateTime.Now.AddDays(-1); }

session

Session serve the same purpose of cookies that is sessions are used to maintain the state in between requests

Creating session variable

Session["FirstName"] = TextBox.Text; Session["LastName"] = TextBox1.Text;

How to receive session variable

if (Session["UserName"] != null) {

label1.Text = "Welcome : " + Session[“username"]; } else { label1.Text= “please check your username” ; }

Destroying the session itself

• Session.clear(); //clears all the session variables

• Session.Abandon(); //destroys the whole session

Example program

Difference between session and cookies

cookies session

cookies are stored in the user's browser Sessions are stored in server

A cookie can keep information in the user's browser until deleted by user or set as per the timer. It will not be destroyed even if you close the browser.

A session is available as long as the browser is opened. Usercant disable the session. It will be destroyed if you close the browser

Cookies can only store string Can store any object

we can save cookie for future reference Session can’t be.

HTTP methods

HTTP methods is used for send the data from client side to server side.

GET METHODPOST METHOD

comparison GET METHOD POST METHOD

Data will be arranged in HTTP header by appending to the URL as query string

Data will be arranged in HTTP message body.

Data is in query string so user can view the data

Data is not shown to user

Less secured compared to POST method because data is in query string so it will be saved in browser history and web server logs

safer than GET method because data is not saved in history or web server logs.

As data is saved in URL so its saves only 2048 bytes data

We can used any amount of data and any format

Hacking will be easy Hacking is difficult

Only ASCII character data type allowed No restrictions. Allows binary data also

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Disclaimer: This presentation is prepared by trainees of baabtra as a part of mentoring program. This is not official document of baabtra –Mentoring PartnerBaabtra-Mentoring Partner is the mentoring division of baabte System Technologies Pvt . Ltd

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