# i login
# o logout
+
+# in cook and par,
+# a, aN anything including -
+# t, tN temporary value (in our db, no logged in user yet)
+# y, yN value corresponds to logged-in user
+# n, nN value not in our db
+# x, xN t or y
+# - no value supplied
+# if N differs the case applies only when the two values differ
+# (eg, a1 y2 does not apply when the logged-in value is supplied twice)
+
+# "stale session" means request originates from a page from a login
+# session which has been revoked (eg by logout); "cleared session"
+# means request originates from a browser which has a different (or
+# no) cookie.
+
# Case analysis, cookie mode, app promises re mutate:
# cook par meth form
#
- # y y GET nr fine, show page or send data
+ # any - POST nrmuoi bug or attack, fail
+ # any - GET rmuoi bug or attack, fail
+ # any any GET muoi bug or attack, fail
+ # any t any nrmuo bug or attack, fail
#
- # y - GET n cross-site link
- # show data
- # y1 y2 GET n intra-site link
- # from session no longer known to browser
- # do not revoke y2 as not a POST so not RESTful
- # treat as cross-site link, show data
- # y n GET n intra-site link from stale session,
- # treat as cross-site link, show data
+ # a1 a2 POST o logout
+ # if a1 is valid, revoke it
+ # if a2 is valid, revoke it
+ # delete cookie
+ # redirect to "just logged out" page
+ # (which contains link to login form)
#
- # y - GET r bug or attack, fail
- # y1 y2 GET r intra-site data request
- # from session no longer known to browser
- # do not revoke y2 as not a POST so not RESTful
- # fail
- # y n GET r intra-site data request from stale session
- # fail
+ # - t POST i complain about cookies being disabled
#
- # - y GET n CLEAR COOKIES TO LOGOUT OPTION
+ # - n POST i complain about stale login form
+ # show new login form
#
- # -/n any GET n cross-site link but user not logged in
- # show login form
+ # x1 x2 POST i login (or switch user)
+ # revoke x1 if it was valid and !=x2
+ # upgrade x2 to y2 in our db (setting username)
+ # set cookie to x2
+ # redirect to GET of remaining params
#
- # -/n any GET r data request from stale session
- # fail
+ # t1 a2 ANY nrmu treat as - a2 ANY
#
- # any any GET muoi bug or attack, fail
+ # y - GET n cross-site link
+ # show data
#
+ # y y GET nr fine, show page or send data
# y y POST nrmu mutation is OK, do operation
- # y y POST o logout
- # y y POST i login, redirect to GET of remaining params
#
- # any - POST bug or xsrf attack, fail
+ # y1 y2 GET nr request from stale page
+ # do not revoke y2 as not RESTful
+ # treat as y1 n GET
#
- # n/y1 y2 POST r intra-site form submission
- # from session no longer known to browser
+ # y1 y2 POST nrmu request from stale page
# revoke y2
+ # treat as y1 n POST
+ #
+ # y n GET n intra-site link from stale page,
+ # treat as cross-site link, show data
+ #
+ # y n POST n m intra-site form submission from stale page
# show "session interrupted"
- # n/y1 y2 POST m intra-site js operation
- # from session no longer known to browser
- # revoke y2
+ # with link to main data page
+ #
+ # y n GET r intra-site request from stale page
# fail
- # y n POST r intra-site form submission from stale session
- # show "session interrupted"
- # y n POST m intra-site form submission from stale session
+ #
+ # y n POST r u intra-site request from stale page
# fail
#
- # - y2 GET intra-site link or data request
- # from session no longer known to browser
+ # -/n y2 GET nr intra-site link from cleared session
+ # do not revoke y2 as not RESTful
+ # treat as -/n n GET
+ #
+ # -/n y2 POST nrmu request from cleared session
+ # revoke y2
+ # treat as -/n n POST
+ #
+ # -/n n GET n cross-site link but user not logged in
+ # show login form with redirect to orig params
+ #
+ # -/n n GET rmu user not logged in
# fail
-
- # - y2 any req from old session y2, del y2, show login
- # y1 y2 any req from old session y2, del y2, show y1 main
-
- # y1 any GET non-mut cross-site link
- # y1 any GET non-mut no mutation, show page providing new par
#
- # A B any page from old session or cross-site request
- # any y2 POST logout do logout y2
-
-
- # any any GET mutate bug or attack, forbidden, call die
+ # -/n n POST nrmu user not logged in
+ # fail
my $dbh = $r->{Dbh};
my ($nusername, $nlast) =