In Apache how do I configure a sub-url redirection to socket.io?

I got a simple node.js websocket server:

var io = require('socket.io')(12345);

io.on('connection', function(socket){
  console.log('a user connected');
  socket.on('disconnect', function(){
    console.log('user disconnected');
  });

  socket.on('test', function(msg){
    console.log('test msg: ' + msg);
    io.emit('test', 'Test answer');
  });
});

I connect to it, and it responds correctly with iocat:

me@whatever:~/prj/client$ iocat --socketio ws://localhost:12345 -e test
> adsa
> [ 'Test answer' ]

so now I want to configure apache server's ssl to redirect a certain sub-url from my project to this websocket

I have apache configured to serve my project in https://localhost/prj

I want the websocket to be avaiable in https://localhost/prj/socket

So searching the web and SO I found 2 possible ways to do this:

1 - ProxyPass alone

<Location /prj/socket>
    ProxyPass ws://localhost:12345
    ProxyPassReverse ws://localhost:12345
</Location>

2- ProxyPass with rewriting

<Location /agora/socket>
         RewriteEngine On
         RewriteCond %{REQUEST_URI}  ^/agora/socket/socket.io           [NC]
         RewriteCond %{QUERY_STRING} transport=websocket    [NC]
         RewriteRule ^/agora/socket/(.*)           "ws://localhost:12345/$1" [P,L]

         ProxyPass        /agora/socket/socket.io  ws://localhost:12345/socket.io
         ProxyPassReverse /agora/socket/socket.io  ws://localhost:12345/socket.io
</Location>

But none of them worked. The connection is established but the server doesn't respond:

me@whatever:~/prj/client$ iocat --socketio https://localhost/prj/socket -e teste
> asdfasd
> asdasd
> 

Pages where I got this info:

https://github.com/socketio/socket.io/issues/1696

https://stackoverflow.com/questions/27526281/websockets-and-apache-proxy-how-to-configure-mod-proxy-wstunnel

There is no error in the logs, it just wouldn't work. So increased the Apache LogLevel to see how the rules where being rewritten. I set it to LogLevel alert rewrite:trace6. After that I got this log in webserver connection:

[Tue Aug 01 13:22:14.510992 2017] [rewrite:trace2] [pid 28400] mod_rewrite.c(476): [client 127.0.0.1:36004] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] init rewrite engine with requested uri /socket.io/
[Tue Aug 01 13:22:14.511023 2017] [rewrite:trace3] [pid 28400] mod_rewrite.c(476): [client 127.0.0.1:36004] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] applying pattern '^/agora/socket/(.*)' to uri '/socket.io/'
[Tue Aug 01 13:22:14.511029 2017] [rewrite:trace1] [pid 28400] mod_rewrite.c(476): [client 127.0.0.1:36004] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] pass through /socket.io/
[Tue Aug 01 13:22:14.922563 2017] [rewrite:trace2] [pid 28401] mod_rewrite.c(476): [client 127.0.0.1:36010] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] init rewrite engine with requested uri /socket.io/
[Tue Aug 01 13:22:14.922607 2017] [rewrite:trace3] [pid 28401] mod_rewrite.c(476): [client 127.0.0.1:36010] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] applying pattern '^/agora/socket/(.*)' to uri '/socket.io/'
[Tue Aug 01 13:22:14.922616 2017] [rewrite:trace1] [pid 28401] mod_rewrite.c(476): [client 127.0.0.1:36010] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] pass through /socket.io/
[Tue Aug 01 13:22:15.609710 2017] [rewrite:trace2] [pid 28403] mod_rewrite.c(476): [client 127.0.0.1:36014] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] init rewrite engine with requested uri /socket.io/
[Tue Aug 01 13:22:15.609755 2017] [rewrite:trace3] [pid 28403] mod_rewrite.c(476): [client 127.0.0.1:36014] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] applying pattern '^/agora/socket/(.*)' to uri '/socket.io/'
[Tue Aug 01 13:22:15.609766 2017] [rewrite:trace1] [pid 28403] mod_rewrite.c(476): [client 127.0.0.1:36014] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] pass through /socket.io/
[Tue Aug 01 13:22:15.950666 2017] [rewrite:trace2] [pid 28402] mod_rewrite.c(476): [client 127.0.0.1:36020] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] init rewrite engine with requested uri /socket.io/
[Tue Aug 01 13:22:15.950714 2017] [rewrite:trace3] [pid 28402] mod_rewrite.c(476): [client 127.0.0.1:36020] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] applying pattern '^/agora/socket/(.*)' to uri '/socket.io/'
[Tue Aug 01 13:22:15.950724 2017] [rewrite:trace1] [pid 28402] mod_rewrite.c(476): [client 127.0.0.1:36020] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] pass through /socket.io/
[Tue Aug 01 13:22:18.329478 2017] [rewrite:trace2] [pid 28399] mod_rewrite.c(476): [client 127.0.0.1:36024] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] init rewrite engine with requested uri /socket.io/
[Tue Aug 01 13:22:18.329512 2017] [rewrite:trace3] [pid 28399] mod_rewrite.c(476): [client 127.0.0.1:36024] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] applying pattern '^/agora/socket/(.*)' to uri '/socket.io/'
[Tue Aug 01 13:22:18.329519 2017] [rewrite:trace1] [pid 28399] mod_rewrite.c(476): [client 127.0.0.1:36024] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] pass through /socket.io/
[Tue Aug 01 13:22:18.668606 2017] [rewrite:trace2] [pid 28424] mod_rewrite.c(476): [client 127.0.0.1:36030] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] init rewrite engine with requested uri /socket.io/
[Tue Aug 01 13:22:18.668649 2017] [rewrite:trace3] [pid 28424] mod_rewrite.c(476): [client 127.0.0.1:36030] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] applying pattern '^/agora/socket/(.*)' to uri '/socket.io/'
[Tue Aug 01 13:22:18.668658 2017] [rewrite:trace1] [pid 28424] mod_rewrite.c(476): [client 127.0.0.1:36030] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78520a0/initial] pass through /socket.io/

and this when I try to send a message:

[Tue Aug 01 13:26:55.653675 2017] [rewrite:trace2] [pid 28400] mod_rewrite.c(476): [client 127.0.0.1:37454] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] init rewrite engine with requested uri /socket.io/
[Tue Aug 01 13:26:55.653723 2017] [rewrite:trace3] [pid 28400] mod_rewrite.c(476): [client 127.0.0.1:37454] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] applying pattern '^/agora/socket/(.*)' to uri '/socket.io/'
[Tue Aug 01 13:26:55.653734 2017] [rewrite:trace1] [pid 28400] mod_rewrite.c(476): [client 127.0.0.1:37454] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] pass through /socket.io/
[Tue Aug 01 13:26:55.987130 2017] [rewrite:trace2] [pid 28402] mod_rewrite.c(476): [client 127.0.0.1:37460] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] init rewrite engine with requested uri /socket.io/
[Tue Aug 01 13:26:55.987173 2017] [rewrite:trace3] [pid 28402] mod_rewrite.c(476): [client 127.0.0.1:37460] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] applying pattern '^/agora/socket/(.*)' to uri '/socket.io/'
[Tue Aug 01 13:26:55.987182 2017] [rewrite:trace1] [pid 28402] mod_rewrite.c(476): [client 127.0.0.1:37460] 127.0.0.1 - - [localhost/sid#7f48e6578ae0][rid#7f48d78500a0/initial] pass through /socket.io/

AFAIU the rewrite rule is being applyied. Anyone knows why the server isn't responding ?

Any help appreciated. Thanks.