跨域cookie访问 Easy Cross Domain Cookies (Sharing cookies between domains)

跨域cookie访问

Easy Cross Domain Cookies (Sharing cookies between domains)

 

I own several websites that need memberships to post comments, and recently I wanted the ability to have a single login - so once the user is logged into one site they are automatically logged into the others.

Ideally, I could just write the login cookies for both domains from one location, or somehow share the same login cookie between the domains - but you quickly come up against browser security which (for good reason) doesn’t allow this sort of thing.

There are plenty of ways of solving this problem - but this is the simplest I could find. It uses an IFrame to set cookies on the foreign domain.

In the example, you have Domain A which the visitor is currently on, and Domain B, which you want to set cookies on.

Add a page ‘FrameLogin.aspx’ to your Domain B website.

Public Partial Class FrameLogin

    Inherits System.Web.UI.Page



    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim sUserID As String



        HttpContext.Current.Response.AddHeader(”p3p”, “CP=\”"IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT\”"”)



        sUserID = Request.QueryString(”userid”)



        Dim oCookie As New HttpCookie(”UserID”)

        oCookie.Value = sUserID

        oCookie.Expires = DateTime.Now.AddDays(1000)

        HttpContext.Current.Response.Cookies.Add(oCookie)

        oCookie = Nothing



    End Sub



End Class

Note that the p3p header has been added, this is to allow 3rd party cookies.

To call this page, we insert code into the appropriate ‘Login’ function in your Domain A website.

    Private Function Login(ByVal sUserName As String, ByVal sPassword As String) As Boolean

        Dim iUserID As Integer



        iUserID = CheckLoginOKAndGetUserdID(sUserName, sPassword)



        If iUserID <> 0 Then

            Login = True

            Response.Write(”<IFRAME style=’WIDTH:1px;HEIGHT:1px’ src=’http://www.DomainB.com/FrameLogin.aspx’ frameBorder=’0′></IFRAME>”)

        Else

            Login = False

        End If



    End Function

Once the cookie has been set on Domain B I can use it to auto-login my visitors when they get there.

Also: For simplicity, I am using an IFrame to call a page. If I wanted faster execution I could substitute an iHttpHandler for the page.

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