@elbowz, thanks for your PR! By analyzing the history of the files in this pull request, we identified @mmaret, @fabaff and @balloob to be potential reviewers.

Can you give/add some context about/to your change? At least on a default installation of Debian with Apache it seems that a2enmod is not available.

about the Apache module: https://httpd.apache.org/docs/2.4/mod/mod_proxy_wstunnel.html

The command is executed on Ubuntu 16.04...I thought that could run also on debian

Debian jessie provides the file in the apache2 package. (https://packages.debian.org/jessie/amd64/apache2/filelist)

@elbowz, I was more thinking about why a user need to enable this module.

Debian jessie provides the file in the apache2 package.

Wired. Have to check it again.

By the module description (https://httpd.apache.org/docs/2.4/mod/mod_proxy_wstunnel.html), it looks like the ProxyPass directive used in the Apache configuration need this module when used with websocket.
But, on my configuration, I do not need this. May be, this is required on ubuntu because of some compilation configuration...
IMO, describing the error or the context that may lead you to enable this module in the documentation could be interesting

By the module description (https://httpd.apache.org/docs/2.4/mod/mod_proxy_wstunnel.html), it looks like the ProxyPass directive used in the Apache configuration need this module when used with websocket.

Exact!

But, on my configuration, I do not need this. May be, this is required on ubuntu because of some compilation configuration...
IMO, describing the error or the context that may lead you to enable this module in the documentation could be interesting

What I can say is that, after the latest update of hass, apache proxy stop working for web socket and I need refresh page (F5) for get update. Enabling the proxy_wstunnel apache module, all was revert back