Improve Connection header for WebSocket reverse proxy (#217)

* Improve Connection header for WebSocket reverse proxy

reference: https://nginx.org/en/docs/http/websocket.html

* Move map to http context

src/nginxconfig/generators/conf/nginx.conf.js

@@ -190,6 +190,15 @@ export default (domains, global) => {
         }
     }
 
+    // Connection header for WebSocket reverse proxy
+    if (domains.some(d => d.reverseProxy.reverseProxy.computed)) {
+        config.http.push(['# Connection header for WebSocket reverse proxy', '']);
+        config.http.push(['map $http_upgrade $connection_upgrade', {
+            'default': 'upgrade',
+            '""': 'close',
+        }]);
+    }
+
     // Configs!
     config.http.push(['# Load configs', '']);
     config.http.push(['include', [

src/nginxconfig/generators/conf/proxy.conf.js

@@ -32,7 +32,7 @@ export default global => {
 
     config['# Proxy headers'] = '';
     config['proxy_set_header Upgrade'] = '$http_upgrade';
-    config['proxy_set_header Connection'] = '"upgrade"';
+    config['proxy_set_header Connection'] = '$connection_upgrade';
     config['proxy_set_header Host'] = '$host';
     config['proxy_set_header X-Real-IP'] = '$remote_addr';
     config['proxy_set_header X-Forwarded-For'] = '$proxy_add_x_forwarded_for';