RadioGaGa

RadioGaGa is a Golang-based backend for a simple Icecast stream frontend, with basic one-on-one chat functionality between listeners and radio staff.

Listeners connect as role=user and can send messages to all connected radio staff. Staff connect as role=radio and can reply directly to specific users.

The backend enforces authentication via JWT for both roles, and requires a shared admin key for role=radio connections.

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Prerequisites

• Go 1.24 or newer
• Environment variables set in the shell
• A WebSocket-capable frontend or tool (e.g. wscat, browser client) to connect to /ws

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Configuration

Variable	Type	Default	Description
PORT	string	:8080	Port for the WebSocket server.
GEWIS_SECRET	string	(none)	Required. HMAC secret for validating JWTs from GEWIS.
RADIO_ADMIN_KEY	string	(none)	Required. Shared key for authenticating role=radio connections.
RADIO_VIDEO_URL	string	https://dwamdstream102.akamaized.net/hls/live/2015525/dwstream102/index.m3u8	URL pointing to the video stream.
RADIO_AUDIO_URL	string	http://rhm1.de:8000	URL pointing to the radio stream.
RADIO_AUDIO_MOUNT_POINT	string	/listen.aac	Mount point for the radio stream.

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Authentication

Users (role=user)

• Must connect with a valid JWT signed with GEWIS_SECRET.

• The JWT must include:

  • lidnr (integer member number)
  • given_name
  • family_name

• These values are stored server-side and sent with each outgoing message.

Radio Staff (role=radio)

• Must connect with both:

  • A valid JWT as above
  • The correct RADIO_ADMIN_KEY provided in the handshake message.

If authentication fails, the server closes the connection immediately.

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Connection Flow

1. Connect to:

   ws://localhost:8080/ws?role=user
   

   or:

   ws://localhost:8080/ws?role=radio
   

2. The first message sent after connecting must be a JSON handshake:

   User handshake

   {
     "token": "<JWT>"
   }

   Radio handshake

   {
     "token": "<JWT>",
     "radioKey": "<RADIO_ADMIN_KEY>"
   }

3. After a successful handshake, you may send chat messages.

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Message Format

Sending

{
  "to": "22222",
  "content": "Hello!"
}

• From users:

  • to is omitted → message goes to all connected radio staff.

• From radio staff:

  • to must be the target user’s lidnr.

Receiving

{
  "from": "12345",
  "to": "22222",
  "content": "Hi there",
  "givenName": "Alice",
  "familyName": "User"
}

• All outgoing messages now include the sender’s given name and family name.

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Session Management

• If the same lidnr connects again, the previous connection is closed with close code 4100.

• Connections without a valid handshake are closed immediately.

• Each connected user is tracked with:

  • lidnr
  • givenName
  • familyName
  • Last activity timestamp
  • Unread message count (for UI indicators)