[hunchentoot-devel] A simple way to handle logins?

[Toby]

Vamsee Kanakala wrote:
> set the user object when the user logs in, and check for it at the
> beginning of a function
> 
> However, most of my functions would require the login-check method to
> be run before they display the page.

Here's how I do it:

(declaim (special %current-user%))

(defmacro with-current-user (&body body)
 `(let ((%current-user% (session-value current-user)))
    (unless %current-user% (redirect "/login"))
    , at body))

(defun my-protected-page-handler ()
  (with-current-user
    (with-html-output-to-string (*standard-output* nil :prologue t)
      (:html
        ...

I use this pattern a lot: a session value, a related special variable,
and a macro that binds one to the other, taking action if the session
value is not set.

By the way, special variables bound by (let) forms are thread-specific,
at least on SBCL, so all is well.

You might also find this useful:

(defmacro with-session-values (declarations &body body)
  "with-session-values ({session-value | (var session-value)}*) declaration* form*"
  `(let ,(loop for decl in declarations
               if (listp decl)
                 collect `(,(first decl) (session-value (quote ,(second decl))))
               else
                 collect `(,decl (session-value (quote ,decl))))
     , at body))


Toby