Galène

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.

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).
publicServer: if true, then cross-origin access to the server is allowed. This is safe if the server is on the public Internet, but not necessarily so if it is on a private network.
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.

Examples

A typical group definition file looks like this:

{
    "op":[{"username":"jch","password":"1234"}],
    "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. This particular group does not allow password login for ordinary users, and is suitable if you use invitations (see Stateful Token below) for ordinary users.

In order to allow password login for ordinary users, add a list of users as the entry presenter:

{
    "op": [{"username":"jch","password":"1234"}],
    "presenter": [{"username":"john", "password": "secret"}]
}

If the group is to be publicly accessible, you may allow logins with any username and an empty password:

{
    "op": [{"username":"jch","password":"1234"}],
    "presenter": [{}],
    "public": true
}

The empty dictionary {} is a wildcard entry: it matches any username and any password. Setting public causes the group to be displayed in the list of public groups on the landing page

Reference

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 listed 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/