Say if I have link1.aspx and link2.aspx. Within link1.aspx, I redirect the user to link2.aspx.
What is the most efficient way of checking that link2.aspx is only accessed via link1.aspx?
For example, something like:
link2.aspx:
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
if page is not accessed via link1.aspx
{
Response.Redirect("~/portal.aspx");
}
}
}
I could use a query string but are there any other ways?
You can use UrlReferrer. However, it is not a secure way of detecting where the user comes from.
For example,
if (string.Equals(Request.UrlReferrer.AbsoluteUri,
"YOUR_REFERRER_URL",
StringComparison.InvariantCultureIgnoreCase))
{
}
If it is redirecting between pages inside your application, I would like to suggest to use SessionState which is more secure and robust than UrlReferrer.
private bool IsValidUrl
{
set { Session["IsValidUrl"] = true; }
}
protected void Button1_Click(object sender, EventArgs e)
{
IsValidUrl = true;
Response.Redirect("link2.aspx");
}
private bool IsValidUrl
{
get
{
if (Session["IsValidUrl"] != null)
return Convert.ToBoolean(Session["IsValidUrl"]);
return false;
}
set { Session["IsValidUrl"] = value; }
}
protected void Page_Load(object sender, EventArgs e)
{
if (IsValidUrl)
{
// user comes from valid url.
// .... Do somthing
// Reset session state value
IsValidUrl = false;
}
}
You could use the Request.UrlReferrer property to check what page the user is coming from.
