galene/README

Galene is a videoconferencing server that is easy to deploy and requires
moderate server resources.  It is described at <https://galene.org>.


# Installation

See the file INSTALL in this directory for installation instructions.


# Usage

## Locations

There is a landing page at the root of the server.  It contains a form
for typing the name of a group, and a clickable list of public groups.

Groups are available under `/group/groupname/`.  You may share this URL
with others, there is no need to go through the landing page.

Recordings can be accessed under `/recordings/groupname/`.  This is only
available to the administrator of the group.

Some statistics are available under `/stats.json`, with a human-readable
version at `/stats.html`.  This is only available to the server administrator.


## Main interface

After logging in, the user is confronted with the main interface.

### Buttons

There are up to three buttons at the top.  The *Enable*/*Disable* button
enables either or both the camera and the microphone (depending on the
options set in the side menu, see below).  The *Mute* button mutes or
unmutes the microphone.  The *Share Screen* button shares the screen or
a window.

### Side menu

There is a menu on the right of the user interface.  This allows choosing
the camera and microphone and setting the video throughput.  The
*Blackboard mode* checkbox increases resolution and sacrifices framerate
in favour of image quality.  The *Play local file* dialog allows streaming
a video from a local file.

### User list

There is a user list on the left.  Clicking on a user opens a menu with
actions that can be applied to that user.  Clicking on ones own username
opens a menu with actions that are global to the group.

### Text box

Typing a string in the text box at the bottom of the chat pane sends
a broadcast message to all of the users in the group.

Typing a line starting with a slash `/` in the text box causes a command
to be sent to the server.  Type `/help` to get the list of available
commands; the output depends on whether you are an operator or not.


# The global configuration file

The server may be configured in the JSON file `data/config.json`.  This
file may look as follows:

    {
        "admin":[{"username":"root","password":"secret"}]
        "canonicalHost": "galene.example.org",
    }

The fields are as follows:

- `admin` defines the users allowed to look at the `/stats.html` file; it
  has the same syntax as user definitions in groups (see below).
- `proxyURL`: if running behind a reverse proxy, this specifies the
  address of the proxy.
- `canonicalHost`: the canonical name of the host running the server; this
  will cause clients to be redirected if they use a different hostname to
  access the server.


# Group definitions

Groups are defined by files in the `./groups` directory (this may be
configured by the `-groups` command-line option, try `./galene -help`).
The definition for the group called *groupname* is in the file
`groups/groupname.json`; it does not contain the group name, which makes
it easy to copy or link group definitions.  You may use subdirectories:
a file `groups/teaching/networking.json` defines a group called
*teaching/networking*.

A typical group definition file looks like this:

    {
        "op":[{"username":"jch","password":"1234"}],
        "presenter":[{}],
        "allow-recording": true,
        "allow-subgroups": true
    }

This defines a group with the operator (administrator) username *jch* and
password *1234*, empty username and password for presenters (ordinary
users with the right to enable their camera and microphone).  The
`allow-recording` entry says that the operator is allowed to record videos
to disk, and the `allow-subgroups` entry says that subgroups will be
created automatically.

More precisely, every group definition file contains a single JSON
directory (a list of entries between `{' and `}').  All fields are
optional, but unless you specify at least one user definition (`op`,
`presenter`, or `other`), nobody will be able to join the group.  The
following fields are allowed:

 - `op`, `presenter`, `other`: each of these is an array of user
   definitions (see *Authorisation* below) and specifies the users allowed
   to connect respectively with operator privileges, with presenter
   privileges, and as passive listeners;
 - `authKeys`, `authServer` and `authPortal`: see *Authorisation* below;
 - `public`: if true, then the group is visible on the landing page;
 - `displayName`: a human-friendly version of the group name;
 - `description`: a human-readable description of the group; this is
   displayed on the landing page for public groups;
 - `contact`: a human-readable contact for this group, such as an e-mail
   address;
 - `comment`: a human-readable string;
 - `max-clients`: the maximum number of clients that may join the group at
   a time;
 - `max-history-age`: the time, in seconds, during which chat history is
   kept (default 14400, i.e. 4 hours);
 - `allow-recording`: if true, then recording is allowed in this group;
 - `unrestricted-tokens`: if true, then ordinary users (without the "op"
   privilege) are allowed to create tokens;
 - `allow-anonymous`: if true, then users may connect with an empty username;
 - `allow-subgroups`: if true, then subgroups of the form `group/subgroup`
   are automatically created when first accessed;
 - `autolock`: if true, the group will start locked and become locked
   whenever there are no clients with operator privileges;
 - `autokick`: if true, all clients will be kicked out whenever there are
   no clients with operator privileges; this is not recommended, prefer
   the `autolock` option instead;
 - `redirect`: if set, then attempts to join the group will be redirected
   to the given URL; most other fields are ignored in this case;
 - `codecs`: this is a list of codecs allowed in this group.  The default
   is `["vp8", "opus"]`.
   
Supported video codecs include:

 - `"vp8"` (compatible with all supported browsers);
 - `"vp9"` (better video quality, but incompatible with Safari);
 - `"av1"` (even better video quality, only supported by some browsers,
   recording is not supported, SVC is not supported);
 - `"h264"` (incompatible with Debian and with some Android devices, SVC
   is not supported).

Supported audio codecs include `"opus"`, `"g722"`, `"pcmu"` and `"pcma"`.
Only Opus can be recorded to disk.  There is no good reason to use
anything except Opus.


## Client Authorisation

Galene implements three authorisation methods: a simple username/password
authorisation scheme, a scheme using stateful tokens and a mechanism based
on cryptographic tokens that are generated by an external server.  The
former two mechanism are intended to be used in standalone installations,
while the server-based mechanism is designed to allow easy integration
with an existing authorisation infrastructure (such as LDAP, OAuth2, or
even Unix passwords).

### Password authorisation

When password authorisation is used, authorised usernames and password are
defined directly in the group configuration file, in the `op`, `presenter`
and `other` arrays.  Each member of the array is a dictionary, that may
contain the fields `username` and `password`:

 - if `username` is present, then the entry only matches clients that
   specify this exact username; otherwise, any username matches;
 - if `password` is present, then the entry only matches clients that
   specify this exact password; otherwise, any password matches.

For example, the entry

    {"username": "jch", "password": "1234"}
    
specifies username *jch* with password *1234*, while

    {"password": "1234"}
    
allows any username with password *1234*, and

    {}
    
allows any username with any password.

By default, empty usernames are forbidden; set the `allow-anonymous`
option to allow empty usernames.  By default, recording is forbidden;
specify the `allow-recording` option to allow operators to record.


### Hashed passwords

If you don't wish to store cleartext passwords on the server, you may
generate hashed passwords with the `galene-password-generator` utility.  A
user entry with a hashed password looks like this:

    {
        "username": "jch",
        "password": {
            "type": "pbkdf2",
            "hash": "sha-256",
            "key": "f591c35604e6aef572851d9c3543c812566b032b6dc083c81edd15cc24449913",
            "salt": "92bff2ace56fe38f",
            "iterations": 4096
        }
    }

### Stateful tokens

Stateful tokens allow to temporarily grant access to a user.  In order to
generate a stateful token, the group administrator types

    /invite user period

where `user` is the username granted to the temporary user, and `period`
is the time period for which the token will be valid (for example `2d`
meaning 2 days).  The server replies with a link, valid the given time
period, that may be sent to the temporary user for example by e-mail.

Tokens may also be granted without imposing a specific username:

    /invite '' 2d

Stateful tokens are revokable (use the `/revoke` command) and their
lifetime may be extended (use the `/reinvite` command).


### Authorisation servers

Galene is able to delegate authorisation decisions to an external
authorisation server.  This makes it possible to integrate Galene with an
existing authentication and authorisation infrastructure, such as LDAP,
OAuth2 or even Unix passwords.

When an authorisation server is used, the group configuration file
specifies one or more public keys in JWK format.  In addition, it may
specify either an authorisation server or an authorisation portal.

    {
        "authKeys": [{
            "kty": "oct",
            "alg": "HS256",
            "k": "MYz3IfCq4Yq-UmPdNqWEOdPl4C_m9imHHs9uveDUJGQ",
            "kid": "20211030"
        }, {
            "kty": "EC",
            "alg": "ES256",
            "crv": "P-256",
            "x": "dElK9qBNyCpRXdvJsn4GdjrFzScSzpkz_I0JhKbYC88",
            "y": "pBhVb37haKvwEoleoW3qxnT4y5bK35_RTP7_RmFKR6Q",
            "kid": "20211101"
        }]
        "authServer": "https://auth.example.org",
    }

The `kid` field serves to distinguish among multiple keys, and must match
the value provided by the authorisation server.  If the server doesn't
provide a `kid`, the first key with a matching `alg` field will be used.

If an authorisation server is specified, then the default client, after it
prompts for a password, will request a token from the authorisation server
and will join the group using token authentication.  The password is never
communicated to the server.

If an authorisation portal is specified, then the default client will
redirect initial client connections to the authorisation portal.  The
authorisation portal is expected to authorise the client and then redirect
it to Galene with the `username` and `token` query parameters set.


# Further information

Galène's web page is at <https://galene.org>.

Answers to common questions and issues are at <https://galene.org/faq.html>.


-- Juliusz Chroboczek <https://www.irif.fr/~jch/>