A Subsonic API proxy server that transparently integrates Deezer as a music source. When a song is not available in your local Navidrome library, it is automatically fetched from Deezer, downloaded, and served to your Subsonic-compatible client.

Why "Octo-Fiesta"?

The name was randomly generated by GitHub when creating the repository. We found it amusing and somewhat fitting for a music application — after all, "fiesta" evokes a party atmosphere, which goes well with music streaming. So we kept it!

Features

Transparent Proxy: Acts as a middleware between Subsonic clients (like Aonsoku, Sublime Music, etc.) and your Navidrome server
Deezer Integration: Seamlessly searches and streams music from Deezer when not available locally
Automatic Downloads: Songs are downloaded on-the-fly and cached for future use
Full Metadata Embedding: Downloaded files include complete ID3 tags (title, artist, album, track number, year, genre, BPM, ISRC, etc.) and embedded cover art
Organized Library: Downloads are saved in a clean Artist/Album/Track.mp3 folder structure
Artist Deduplication: Merges local and Deezer artists to avoid duplicates in search results
Album Enrichment: Local albums are enriched with missing tracks from Deezer
Cover Art Proxy: Serves cover art for external content transparently

Architecture

┌─────────────────┐     ┌──────────────────┐     ┌─────────────────┐
│  Subsonic       │────▶│   Octo-Fiesta    │────▶│   Navidrome     │
│  Client         │◀────│   (Proxy)        │◀────│   Server        │
│  (Aonsoku)      │     │                  │     │                 │
└─────────────────┘     └────────┬─────────┘     └─────────────────┘
                                 │
                                 ▼
                        ┌─────────────────┐
                        │   Deezer API    │
                        │   (Metadata +   │
                        │    Downloads)   │
                        └─────────────────┘

Requirements

.NET 9.0 SDK
A running Navidrome server
A Deezer ARL token (for downloading)

Installation

Clone the repository

git clone https://github.com/your-username/octo-fiesta.git
cd octo-fiesta

Restore dependencies
```
dotnet restore
```

Configure the application

Edit octo-fiesta/appsettings.json:

{
  "Subsonic": {
    "Url": "http://your-navidrome-server:4533"
  },
  "Library": {
    "DownloadPath": "./downloads"
  },
  "Deezer": {
    "Arl": "your-deezer-arl-token",
    "ArlFallback": ""
  }
}

Run the server
```
cd octo-fiesta
dotnet run
```
The proxy will start on http://localhost:5274 by default.
Configure your Subsonic client

Point your Subsonic client to http://localhost:5274 instead of your Navidrome server directly.

Configuration

Subsonic Settings

Setting	Description
`Subsonic:Url`	URL of your Navidrome/Subsonic server

Library Settings

Setting	Description
`Library:DownloadPath`	Directory where downloaded songs are stored

Deezer Settings

Setting	Description
`Deezer:Arl`	Your Deezer ARL token (required for downloads)
`Deezer:ArlFallback`	Backup ARL token if primary fails

Getting a Deezer ARL Token

Log in to Deezer in your browser
Open Developer Tools (F12)
Go to Application > Cookies > https://www.deezer.com
Find the arl cookie and copy its value

Note

: ARL tokens expire periodically and need to be refreshed.

API Endpoints

The proxy implements the Subsonic API and adds transparent Deezer integration to:

Endpoint	Description
`GET /rest/search3`	Merged search results from Navidrome + Deezer
`GET /rest/stream`	Streams audio, downloading from Deezer if needed
`GET /rest/getSong`	Returns song details (local or Deezer)
`GET /rest/getAlbum`	Returns album with tracks from both sources
`GET /rest/getArtist`	Returns artist with albums from both sources
`GET /rest/getCoverArt`	Proxies cover art for external content

All other Subsonic API endpoints are passed through to Navidrome unchanged.

External ID Format

External (Deezer) content uses typed IDs:

Type	Format	Example
Song	`ext-deezer-song-{id}`	`ext-deezer-song-123456`
Album	`ext-deezer-album-{id}`	`ext-deezer-album-789012`
Artist	`ext-deezer-artist-{id}`	`ext-deezer-artist-259`

Legacy format ext-deezer-{id} is also supported (assumes song type).

Download Folder Structure

Downloaded music is organized as:

downloads/
├── Artist Name/
│   ├── Album Title/
│   │   ├── 01 - Track One.mp3
│   │   ├── 02 - Track Two.mp3
│   │   └── ...
│   └── Another Album/
│       └── ...
└── Another Artist/
    └── ...

Metadata Embedding

Downloaded files include:

Basic: Title, Artist, Album, Album Artist
Track Info: Track Number, Total Tracks, Disc Number
Dates: Year, Release Date
Audio: BPM, Duration
Identifiers: ISRC (in comments)
Credits: Contributors/Composers
Visual: Embedded cover art (high resolution)
Rights: Copyright, Label

Development

Build

dotnet build

Run Tests

dotnet test

Project Structure

octo-fiesta/
├── Controllers/
│   └── SubsonicController.cs    # Main API controller
├── Models/
│   ├── MusicModels.cs           # Song, Album, Artist, etc.
│   └── SubsonicSettings.cs      # Configuration model
├── Services/
│   ├── DeezerDownloadService.cs # Deezer download & decryption
│   ├── DeezerMetadataService.cs # Deezer API integration
│   ├── IDownloadService.cs      # Download interface
│   ├── IMusicMetadataService.cs # Metadata interface
│   └── LocalLibraryService.cs   # Local file management
├── Program.cs                   # Application entry point
└── appsettings.json             # Configuration

octo-fiesta.Tests/
├── DeezerDownloadServiceTests.cs
├── DeezerMetadataServiceTests.cs
└── LocalLibraryServiceTests.cs

Dependencies

BouncyCastle.Cryptography - Blowfish decryption for Deezer streams
TagLibSharp - ID3 tag and cover art embedding
Swashbuckle.AspNetCore - Swagger/OpenAPI documentation

Limitations

Playlist Search: Subsonic clients like Aonsoku filter playlists client-side from a cached getPlaylists call. Deezer playlists appear in global search (search3) but not in the Playlists tab filter.
Region Restrictions: Some Deezer tracks may be unavailable depending on your region.
ARL Expiration: Deezer ARL tokens expire and need periodic refresh.

License

MIT

Acknowledgments

Navidrome - The excellent self-hosted music server
Deezer - Music streaming service
Subsonic API - The API specification