Proposal to make `:redirect-on-auth?` dynamic

friend.clj.diff

diff --git a/src/cemerick/friend.clj b/src/cemerick/friend.clj
index 0c8dda5..0731a64 100644
--- a/src/cemerick/friend.clj
+++ b/src/cemerick/friend.clj
@@ -154,6 +154,7 @@ Equivalent to (complement current-authentication)."}
           resp (response/redirect-after-post
                  (or unauthorized-uri
                      (and (string? redirect) redirect)
+                     (and (fn? redirect) (redirect authentication-map request))
                       (str (:context request) (-> request ::auth-config :default-landing-uri ))))]
       (if unauthorized-uri
         (-> resp

The redirect value you're proposing checking to be a function or not is not coming from the configuration to friend/authenticate; it's a value that is attached to the authentication map's metadata, as returned by your workflow.

You can achieve what you want now by modifying the responses of the workflow(s) you use to add in the user's home URL as the :cemerick.friend/redirect in the authentication map's metadata.

That said, providing a way to dynamically control redirects without providing custom or wrapped workflows would make things easier (and simpler, if multiple workflows are in play). Please file an issue, but the proposed change here is not correct.