Spring Boot using Stomp over WebSocket: Handshake failed due to invalid Upgrade header: null

Question

I am using ws (non secured WebSocket) in a Spring Boot application. Once the client tries to connect to the server the following error appears:

Handshake failed due to invalid Upgrade header: null

The spring boot app runs on an Ubuntu server behind an Apache proxy. Apache is configured as follows:

<VirtualHost *:80>
    DocumentRoot /var/www/myapp/public/
    ServerAdmin webmaster@localhost
    ServerName  app.myapp.biz

    RewriteEngine       On
    RewriteCond         %{HTTP:Upgrade}^websocket$ [NC,OR]
    RewriteCond         %{HTTP:Connection}^upgrade$ [NC]
    RewriteRule         .* "ws:/127.0.0.1:8096/$1" [P,QSA,L]

    ProxyPreserveHost   On
    ProxyRequests       Off
    ProxyPass           / http://127.0.0.1:8096/
    ProxyPassReverse    / http://127.0.0.1:8096/
    RequestHeader       set X-Forwarded-Proto http
    RequestHeader       set X-Forwarded-Port 80

    SetEnv mongo_username           aUser
    SetEnv mongo_password           aPassword
</VirtualHost>

The application.properties for the Spring app are as follows:

debug=false
server.port=8096
server.address=127.0.0.1

server.forward-headers-strategy=native
server.tomcat.use-relative-redirects=true
server.tomcat.remoteip.protocol-header=x-forwarded-proto
server.tomcat.remoteip.remote-ip-header=x-forwarded-for
server.tomcat.remoteip.port-header=x-forwarded-port

When running the app on my developer machine everything works just fine. Once deployed on the server the aforementioned error occurs. I’ve googled a lot but couldn’t find something specific for this problem. I hope someone can help.

Info: The frontend app trying to connect is an Angular app using ng2-stompjs.

Answer 1

I finally managed to find the error. The order of statements in the apache.conf does matter! The working conf file looks like so:

<VirtualHost *:80>
    ServerAdmin webmaster@localhost
    ServerName  app.myapp.biz

    ProxyPreserveHost   On
    ProxyRequests       Off
    ProxyPass           / http://127.0.0.1:8096/
    ProxyPassReverse    / http://127.0.0.1:8096/

    RewriteEngine       On
    RewriteCond         %{HTTP:Upgrade} websocket [NC]
    RewriteCond         %{HTTP:Connection} upgrade [NC]
    RewriteRule         ^/?(.*) "ws://127.0.0.1:8096/$1" [P,L]

    SetEnv mongo_username           aUser
    SetEnv mongo_password           aPassword
</VirtualHost>