Enclose wss proxy directives in IfModule

So it should work even if mod_proxy_wstunnel isn't available (socket.io should fallback to another method like xhr-polling)

conf/httpd_alias.conf

@@ -1,5 +1,7 @@
-ProxyPass /socket.io/1/websocket ws://localhost:8888/socket.io/1/websocket
-ProxyPassReverse /socket.io/1/websocket ws://localhost:8888/socket.io/1/websocket
+<IfModule mod_proxy_wstunnel.so>
+  ProxyPass /socket.io/1/websocket ws://localhost:8888/socket.io/1/websocket
+  ProxyPassReverse /socket.io/1/websocket ws://localhost:8888/socket.io/1/websocket
+</IfModule>
 ProxyPass /socket.io/ http://localhost:8888/socket.io/
 ProxyPassReverse /socket.io/ http://localhost:8888/socket.io/
 AliasMatch ^/vroom/([a-z]{2}/)?(\d{10}/)?((js|css|img|fonts|snd)/.*) /opt/vroom/public/$3

conf/httpd_vhost.conf

@@ -8,8 +8,10 @@
     ServerName vroom.example.com
     SSLEngine on
     DocumentRoot /opt/vroom/public
+    <IfModule mod_proxy_wstunnel.so>
       ProxyPass /socket.io/1/websocket ws://localhost:8889/socket.io/1/websocket
       ProxyPassReverse /socket.io/1/websocket ws://localhost:8888/socket.io/1/websocket
+    </IfModule>
     ProxyPass /socket.io/ http://localhost:8888/socket.io/
     ProxyPassReverse /socket.io/ http://localhost:8888/socket.io/
     AliasMatch ^/([a-z]{2}/)?(\d{10}/)?((js|css|img|fonts|snd)/.*) /opt/vroom/public/$3