Bug 1771774: Allow override of externallogin redirect

When trying to hit a non homepage page where login is required

behatnotneeded

Change-Id: Ia52dff12c16dd58304bbe9251723311e3b18325e
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>

htdocs/auth/lib.php

@@ -1385,7 +1385,7 @@ function auth_draw_login_page($message=null, Pieform $form=null) {
     }
 
     $externallogin = get_config('externallogin');
-    if ($externallogin) {
+    if ($externallogin && !param_alphanum('override', false)) {
         $externallogin = preg_replace('/{shorturlencoded}/', urlencode(get_relative_script_path()), $externallogin);
         $externallogin = preg_replace('/{wwwroot}/', get_config('wwwroot'), $externallogin);
         redirect($externallogin);

htdocs/lib/config-defaults.php

@@ -397,6 +397,10 @@ $cfg->sslproxy = false;
  *
  * A point to note about the example below. Moodle doesn't strip the trailing slash from wwwroot
  * Bug MDL-30042 fixes this, if this patch isn't applied, just hard code the login url you want instead
+ *
+ * Another point to note is if you need some system to render the local login page when accessing a restricted page
+ * rather than automatically redirect to externallogin you can override this by adding a 'override=1' to the URL of the page you are
+ * trying to access.
  */
 // $cfg->externallogin = 'http://moodle.example.com/auth/mnet/jump.php?hostwwwroot={wwwroot}&wantsurl={shorturlencoded}';