gesis.mybinder.org: allow OPTIONS method and do 308 redirection (jupyterhub/mybinder.org-deploy#1344)

Author: bitnik

load_balancer/sites-available/gesis_mybinder

@@ -31,7 +31,7 @@ server {
 
     location / {
         # https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/301
-        limit_except GET {
+        limit_except GET OPTIONS {
             deny  all;
         }
         # https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
@@ -40,11 +40,13 @@ server {
         add_header 'Cache-Control' 'no-cache';
         # https://serverfault.com/questions/426673/nginx-redirect-subdomain-to-sub-directory
         # https://www.nginx.com/resources/wiki/start/topics/tutorials/config_pitfalls/#taxing-rewrites
-        return 301 https://notebooks.gesis.org/binder$request_uri;
+        return 308 https://notebooks.gesis.org/binder$request_uri;
     }
 
     location /build/ {
-        limit_except GET {
+        # add OPTIONS for Preflighted requests: https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
+        # adding OPTIONS is just to be safe, I am not sure if this is preflighted
+        limit_except GET OPTIONS {
             deny  all;
         }
         add_header Access-Control-Allow-Origin $allowed_origin;
@@ -53,7 +55,7 @@ server {
         add_header 'Access-Control-Allow-Headers' 'cache-control';
         add_header 'Content-Type' 'text/event-stream';
         add_header 'Cache-Control' 'no-cache';
-        return 301 https://notebooks.gesis.org/binder$request_uri;
+        # use Permanent Redirect (308) instead of 301, mybinder.org redirects with 307
+        return 308 https://notebooks.gesis.org/binder$request_uri;
     }
 }
-