fix opds, add cors

Author: mekarpeles

docker/web_nginx.conf

@@ -111,19 +111,32 @@ server {
       return 429 '{"status": 429, "message": "Too Many Requests. Consider using https://openlibrary.org/developers/dumps."}';
     }
 
-    location /opds {
+    location /opds/ {
         proxy_pass https://ol-opds.prod.archive.org/;
 
+        add_header Access-Control-Allow-Origin "*" always;
+        add_header Access-Control-Allow-Methods "GET, POST, OPTIONS" always;
+        add_header Access-Control-Allow-Headers "Content-Type, Authorization" always;
+
+        # Handle preflight                                                                                     
+        if ($request_method = OPTIONS) {
+            return 204;
+        }
+
         add_header X-OPDS-Backend "ol-opds.prod.archive.org" always;
+        proxy_ssl_server_name on;
         proxy_set_header Host ol-opds.prod.archive.org;
-        proxy_set_header X-Real-IP $remote_addr;
-        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-	    proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header X-Forwarded-For $remote_addr;
+        proxy_set_header X-Forwarded-Proto $scheme;
 
         # optional but usually needed
         proxy_redirect off;
     }
 
+    location = /opds {
+        return 301 /opds/;
+    }
+
     location / {
         limit_req zone=web_limit burst=100 delay=10;
         limit_req zone=ua_rate_limit burst=25 delay=10;