webrtc-server

An OTP application to make video calls using WebRTC. It includes a STUN/TURN server using processone/stun.

Configuration

authentication

An authentication function needs to be provided to the app environment as which will be used to authenticate both the websocket connections to the signaling server and the turn connections.

Example:

{auth_fun, {module, function}}

The function will ba called like module:function(Username), and should return the expected password for the given Username. The password will compared to the one sent by the clients. Auth will be considered failed if the result value is not a binary or the function throws an error.

The implementation of this function will depend on how this application is expected to be deployed. It could just return a fixed password from configuration, encode the username using a secret shared with the application server, lookup the password on a common datastore, etc.

callbacks

webrtc_server allows to define callback functions that will be triggered when users enter or leave a room. This can be useful to track conversation state (such as when a call starts or end), without needing extra work in the clients.

{create_callback, {module, function}}
{join_callback, {module, function}}
{leave_callback, {module, function}}

The three callbacks receive the same arguments: * Room: name of the room used to connect. * Username: username provided by the client executing the action. * OtherUsers: list of the rest of the usernames currently in the room.

Websockets API for signaling

TODO

Run in development

make dev

The app will run on https://localhost:8443/:room

Run in production

Configuration

Update the configuration in conf/sys.config:

• port: set to 443 for HTTPS.
• certfile: absolute path to the certificate file.
• keyfile: absolute path to the key file.
• hostname: name of the host where the app will be deployed. Will be used as the auth_realm for stun and to lookup the turn_ip
• turn_ip: IP of the server where the app will be deployed. If not provided, will default to the first result of inet_res:lookup(Hostname, in, a)

Build a release

make release

Unpack the generated tar and bin/webrtc_server start.

Firewall setup for STUN/TURN

iptables -A INPUT -p tcp --dport 3478 -j ACCEPT
iptables -A INPUT -p udp --dport 3478 -j ACCEPT
iptables -A INPUT -p tcp --dport 5349 -j ACCEPT
iptables -A INPUT -p udp --dport 5349 -j ACCEPT
iptables -A INPUT -p udp --dport 49152:65535 -j ACCEPT

Mac build error

This error while building on mac OS:

_build/default/lib/fast_tls/c_src/fast_tls.c:21:10: fatal error: 'openssl/err.h' file not found

Is solved by exporting some openssl flags:

export LDFLAGS="-L/usr/local/opt/openssl/lib"
export CFLAGS="-I/usr/local/opt/openssl/include/"
export CPPFLAGS="-I/usr/local/opt/openssl/include/"