nginx http auth module query

[karanj]

One additional question here -

In this as I understand it redirects to error_page on receiving a 4xx
status code. Is it possible that nginx reads the value of error page
from a custom header which comes along with the response (with 4xx
status code) and then assign the value of error_page to that value.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,222520,222536#msg-222536