代码例子 - Ask For Login

The need for a security system is obvious if your pages include sensitive information.
This sample shows you how to setup some of your pages to ask for login if the user has not logged in yet.
2eNetWorX/dev site uses this kind of protection for interactive pages and file downloads.
Let's assume that we have a page where the visitors can ask questions. We want to make sure that the user has logged in before being able to ask a question.
If the user has not logged in yet, we will ask for a login. After a successful login, we will redirect the user to the page requested.
First, we will have a common file to check for login. You need to include this file into all the pages that require login.
security.asp
<%
bLoggedIn = (len(session("UserName")) > 0)
if bRequireLogin then
'Login required
if Not bLoggedIn then
'Not logged in, ask for login
response.redirect "login.asp?comebackto=" & _
request.servervariables("script_name") & "?" & _
server.urlencode(request.querystring)
'Note how we construct the page to come back
end if
end if
%>
login.asp
First thing to do in our login.asp page is to get the page where the user is redirected from. The variable sReferer is used to redirect back to the page the user has come from.
sGoBackTo variable will used in the

tag for persisting this location when we submit the login form.
<%
if request("comebackto") <> "" then
sReferer = request("comebackto")
sGoBackTo = "?" & request.querystring
end if
if request("cmdLogin") <> "" then
'Login Form submitted
sUserName = request("txtUserName")
sPassword = request("txtPassword")
'Check for username and password
if sUserName = "bill" And sPassword = "gates" then
bLoginSuccessful = True
end if
session("UserName") = sUserName
'After a successful login, let's send the user