Cookies

Question

Hi friends How does the Cookies work in ASP.NET? thank you

Satyapriya Nayak · Answer

Hi Ankur Normal 0 Cookies : - Cookies are little pieces of information that a server stores on a browser. They are of two types Temporary cookie Persistent cookie Temporary cookie : - They are also known as session cookies. These are volatile in nature. When the browser is shutdown they are erased. Persistent cookie :- These may be called as permanent cookies. These are especially saved in files. It may remain for a month or year. Properties of cookies Some properties of cookie Name: - represent the name of cookie. Name value: - represent a collection of key values of cookie Domain: - represent the domain associated with a specific cookie. Path: - the path associated with a cookie. Expires: - expired time of cookie. Hashkey: - identifies whether the cookie is a cookie dictionary. Secure: - specifies whether the cookie is to be sent in an encrypted connection or not. Working with cookies Cookies are send back and forth between a browser and server. The server creates a cookie by using the set cookie header. Subsequent request from the browser is send to the server in cookie header. Suppose the server create a cookie Set cookie: username=rajkumar; path=1;domain=abc.com; expires=Friday 19th august 20116:30:00GMT The server creates the cookie named as username containing the user information. Path identifies any requested page to the website domain identifies the specific website abc.com expired identifies that this cookie would be expired on the specific data mentioned. After the server creates the cookie the response is send to the server from the browser for each subsequent request to the webpage. The reader sends in the format cookie: username=raj+kumar The server is using set cookie reader. The browser is using reader. Creation and reading session cookies The session cookies can be created by using the response object and can be read by using the request object. The cookies properties of the response and request objects contains instances of Httpcookies collection class. Each cookie is created by using Httpcookie class. For creating cookies Dim cookies1 As New HttpCookie(raj kumar) Response.Cookies.Add(cookies1) For reading cookies Response.Write(request.cookies(cookies1).value) Program Partial Class _Default Inherits System.Web.UI.Page Protected Sub Button1_Click( ByVal sender As Object  ByVal e As System.EventArgs) Handles Button1.Click 'For creating cookies Dim cookies1 As New HttpCookie(TextBox1.Text TextBox2.Text) Response.Cookies.Add(cookies1) clear() End Sub Protected Sub Button2_Click( ByVal sender As Object  ByVal e As System.EventArgs) Handles Button2.Click 'For reading cookies Dim s As String For Each s In Request.Cookies Label1.Text +=   & s Next End Sub Sub clear() TextBox1.Text =  TextBox2.Text =  End Sub End Class Persistence cookies It is saved in a config file.it has a specific expiration date. It is especially used to store information about userid name of authenticated user. For creating persistence cookie Dim pcookie1 as New HttpCookie(user name.ravi kumar) Response.Cookies.Add(pcookie1) pcookie1.expires= #19/06/2011# For reading persistent cookie Response.Write(Request.cookies(user name).Value) Limitation of cookies: - 1.A cookie can store maximum of 4kb of data. 2.A cookie can contain only string values. It can contain objects like dataset object. 3.A cookie is browser dependent. 4.Persistent cookie may be deleted before expiration date by browser. Also Please refer Our recommended articles http://www.c-sharpcorner.com/uploadfile/puranindia/cookies-in-Asp-Net/default.aspx http://www.c-sharpcorner.com/UploadFile/Vipul.Kelkar/working-with-cookies-in-Asp-Net/ http://www.c-sharpcorner.com/uploadfile/annathurai/cookies-in-Asp-Net/default.aspx Thanks

Kunal Vaishya · Answer

A cookie is stored on the client's machine by their web browser software. There are good levels of compatibility in browser implementations so using them is generally hassle-free. When a web server receives an HTTP request it responds with an HTTP response. To set a cookie we include information in an HttpResponse that instructs the browser to save a cookie on the client's system. Future HttpRequests will then include details of this and other cookies. Be very clear about cookies; when you call HttpCookie.Add the cookie is not added to anything except a collection in the HttpResponse that will be sent back to the web browser. The cookie is only stored on the client's machine when the browser has successfully processed the instruction to save the cookie that it received in an HttpResponse. We at the server can only check that cookie has been saved when we receive another HttpRequest as we can then see whether the request includes our cookie.