Redirect user back to the original action after login

Question

The sequence of actions that I am trying to accomplish is below.

Context: user can add products to its own account.

1. User tries to add a specific product. (He/she is not login at this point.)
2. In the code behind, I need to redirect the user to login page before I can add the product to user's account.
3. After login, how do I take the system back to the logic to finish up the action in step 1.

Thanks.

Answer 1

When you redirect to the login page, add the original URL in the querystring.
After a successful login, send a to the URL from the querystring.

Answer 2

Assuming you are using FormsAuthentication, if you are not, or don't know what to use, check it out here: http://msdn.microsoft.com/en-us/library/xdt4thhy.aspx

OK, so when your user tries to access a page that is protected (ie they have to be logged it), ASP.NET's forms authentication will send them to the login page, which is best set up in the web config:

<authentication mode="Forms">
   <forms loginUrl="~/Public/Login.aspx" defaultUrl="~/Public/Default.aspx"/>
</authentication>

It will also attach a ReturnUrl query string parameter to the that, so the login page knows where they came from: http://www.example.com/Public/Login.aspx ?ReturnUrl=%2fprivate%2forderproduct.aspx

Then, in your login page, assuming that they have successfully authenticated, you set the authentication cookie and redirect them back from whence they came:

FormsAuthentication.SetAuthCookie(someUserIdentifier,isRememberMeSet);
FormsAuthentication.RedirectFromLoginPage(someUserIdentifier, isRememberMeSet);

Of course, if you don't want to use FormsAuthentication, you can still use the concept of the return URL. Forms authentication just gives you a lot of that for free.