Allow IPv4 addresses

.env.example

@@ -3,6 +3,7 @@
 # Technical requirements
 
 export PHX_SERVER=true
+# export PHX_PROTOCOL=ipv4
 export PHX_HOST=localhost
 export PORT=4000
 export SECRET_KEY_BASE=CHANGE_ME

INSTALL.md

@@ -125,6 +125,7 @@ Here is the full list of environment variables you can use to set up Azimutt app
 These are the basic variables you will **need** to set up Azimutt:
 
 - `PHX_SERVER` (optional): if `true`, start the Phoenix server in server mode
+- `PHX_PROTOCOL` (optional, values: `ipv6` or `ipv4`, default: `ipv6`): if `ipv4`, the Phoenix server will listen to IPv4, otherwise IPv6
 - `PHX_HOST` (required): host of the deployed website (ex: `localhost` or `azimutt.app`), it's used to build absolute urls
 - `PORT` (required): the port the server will listen to (ex: `4000`)
 - `SECRET_KEY_BASE` (required): the secret used for server encryption (cookies and others), should be at least 64 bytes and you probably want a random value for it

backend/config/runtime.exs

@@ -64,7 +64,7 @@ if config_env() == :prod || config_env() == :staging do
       # Set it to  {0, 0, 0, 0, 0, 0, 0, 1} for local network only access.
       # See the documentation on https://hexdocs.pm/plug_cowboy/Plug.Cowboy.html
       # for details about using IPv6 vs IPv4 and loopback vs public addresses.
-      ip: {0, 0, 0, 0, 0, 0, 0, 0},
+      ip: if(System.get_env("PHX_PROTOCOL") == "ipv4", do: {0, 0, 0, 0}, else: {0, 0, 0, 0, 0, 0, 0, 0}),
       port: port
     ],
     secret_key_base: System.fetch_env!("SECRET_KEY_BASE")