Cookies

What is a cookie?
Cookies are small text files that are added to a users browser by a web application to store session/user specific data. A web application is able to read the contents of a cookie(s) on each subsequent visit a user makes to a website.

Security considerations
Cookies are unsuitable for storing secure information such as passwords.

Adding a cookie
A cookie may contain a number of name/value pairs when it is added to the browser. The expiry date of a cookie defines how long the cookie should remain in the browser for.

Response.Cookies("userInfo")("userName") = "straximo"
Response.Cookies("userInfo")("lastVisit") = DateTime.Now.ToString()
Response.Cookies("userInfo").Expires = DateTime.Now.AddDays(1)

Use the Response (outgoing) object to add a cookie.

Modifying a cookie
A cookie may be modified simply by overwriting it.

Response.Cookies("userInfo")("userName") = "straximo4"
Response.Cookies("userInfo")("lastVisit") = DateTime.Now.ToString()
Response.Cookies("userInfo").Expires = DateTime.Now.AddDays(1)

Use the Response (outgoing) object to modify a cookie.

Removing a cookie
A cookie is removed by setting the expiry date to a time in the past.

Response.Cookies("userInfo").Expires = DateTime.Now.AddDays(-1)

Use the Response (outgoing) object to remove a cookie.

Reading a cookie
After checking that a cookie exists, a cookie value may be read & used just like any other value.

If Not Request.Cookies("userInfo") Is Nothing Then
  Label1.Text = Request.Cookies("userName")("userName")
  Label2.Text = Request.Cookies("userName")("lastVisit")End If

Use the Request (outgoing) object to read a cookie.