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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.
lets 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 <form> 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, lets send the user
back to the page requested. the variable sreferer
holds the page to go back, if it is empty, we should
redirect the user to our default page.
if sreferer = "" then
response.redirect "index.asp"
else
response.redirect sreferer
end if
else
display the login form
%>
<form action="login.asp<%=sgobackto%>" method="post">
<input type="text" name="txtusername"><br>
<input type="password" name="txtpassword"><br>
<input type="submit" name="cmdlogin"><br>
</form>
<%
end if
%>
testpage.asp
now, all you need to do is setting brequirelogin to true and including the security.asp file.
<%
brequirelogin = true
%>
<!–#include file="security.asp"–>
users should be logged in to see this text.
i hope this sample gives you a quick overview of a simple security system implementation with asp.
you are always welcome to express your feedback!
by hakan eskici
