canary: a music streaming server/client

canary is a package of a music streaming server and its companion iOS client that run upon DAAP. Employing DAAP for streaming and mDNS/DNS-SD for service advertisement let canary work perfectly with iTunes.

This document explains the server. See the files in the client directory for the client.

The server supports, among other things:

• Apple Music/iTunes as a client,
• rescan of songs based on a schedule,
  • it cleverly does nothing unless files or directories change
• authorization via a password,
• delievery of mp3/ogg files if your client can play them and
• multiple paths to contain your songs

but does not support yet:

• adding or editing smart playlists and
• what I don't know yet but you do
  • please let me know about them!

The initial scan of songs is fairly fast thanks to high performance of the music-metadata module; about 7 mins with 5,000+ songs on my Gentoo machine with Intel Atom D525, 4GB RAM and a 5400-rpm HDD. Once the database has been built, rescanning is even faster; about 1 min on the same condition. The server remembers the mtime, modification time of files and reads only added or modified files.

Prerequisites

• Nothing; MongoDB is no longer necessary!

The only thing you need to run canary is a node.js environment. canary started to support a stand-alone DB, NeDB as well as MongoDB. You better depend on MongoDB, however, if a huge number of songs need to be served, because NeDB stores all its indexed data on memory.

canary can run with avahi or dns-sd, or launch its own instance of mDNS/DNS-SD service implemented in pure JavaScript (node-mdns-js) when you have neither installed.

Having more than one instance of mDNS/DNS-SD service on the same machine confuses the service to prevent it from properly working.

The value for mdns in server.conf (see below) chooses a service for mDNS publication.

• avahi: avahi-publish-service is probed to execute;
• dns-sd: dns-sd is probed to execute;
• mdns-js: mdns-js is launched without probing the two above;
• auto: canary tries to execute either of avahi-publish-service or dns-sd, and launches mdns-js on failure. This is the default behavior;
• off: no service advertisement activated.

If your system have avahi or dns-sd, please make sure that avahi-publish-service or dns-sd is accessible without specifying a path from the location canary runs.

Whenever avahi or dns-sd fails to start, mdns-js is selected as a fallback.

If you are not able to get the service advertisement to work with any of these options, please let me know to help you.

Configuration

Two configuration files need to be provided for the server, one for its database and the other for the server itself.

The server configuration, config/server.json looks like:

{
    "name":     "canary music",
    "port":     3689,
    "runAs": {
        "uid": "userid",
        "gid": "groupid"
    },
    "password": "password",
    "scan": {
        "path":  [ "/path/to/mp3/files" ],
        "cycle": [ "17:00:00" ],
        "utc":   false
    },
    "db":    "neDB",
    "mdns":  "auto",
    "debug": false
}

• the name of the server will be published and broadcast. If your client knows DNS-SD, it will appear on it;
• the server will run on port; it must be set to the default port 3689 for iTunes to find the server;
• runAs, if specified, makes the server drop privileges by changing its uid and gid to the given ones, which is useful when the server initially runs as root, for example, by an init.d script. If not specified, running the server as root will be warned;
• if password has a non-empty string, the server requires a client to send the password on every request. This, for example, forces iTunes ask a password on its initial connection to the server;
• scan specifies the schedule for rescanning files:
  • path is an array of directories of music files to serve;
  • cycle and utc: clear what these mean from their names but you can refer to ontime for how to specify the rescanning schedule. canary-server accepts other options for ontime except single that is always set to true;
• db selects a DB to store metadata of scanned songs. neDB and mongoDB (case-insensitive) are supported;
• mdns selects a service for mDNS advertisement. Possible values are auto, avahi, dns-sd, mdns-js and off. See Prerequisites section above;
• debug controls the server's log level. Setting this to true makes the server verbose.

One of config/db.ne.json and config/db.mongo.json is used depending on the setting of the db field above; both files must exist and be syntactically correct.

config/db.mongo.json contains:

{
    "host":          "localhost",
    "port":          27017,
    "db":            "canary",
    "user":          "user",
    "password":      "password",
    "reconnectTime": 2
}

The options from host to password inclusive specify basic information for DB connection. If no authentication is required, user and password can be omitted.

reconnectTime specifies a time interval in seconds for which the server waits before trying to reconnect when disconnected from the DB.

config/db.ne.json looks like:

{
    "path": "db"
}

to specify a path into which persistent DB files go.

How to run

As other node.js programs, you can run canary-server with

node server.js -c config/

where the -c option (or --config) specifies a configuration directory the server will use.

Since version 0.2.2, canary extracts cover images from media files. If you have database built by a previous version, the --rebuild option will help cover images be prepared.

Clients tested

The following DAAP clients have been tested with canary-server. If your favorite client is not on the list or does not work with the server, please open a new issue to describe the problem concisely.

• iTunes (Windows)
• Apple Music (Mac)
• Simple DAAP Client (iOS)
• DAAP Media Player (Android)
• Music Pump DAAP Player Demo (Android)
• SharePlay (Android)
• Diapente Music Stream Player (Android)

Help needed

canary-server is implemented in a very short time. It already works well but needs many improvements that include, but not limited to:

• testing for files with various and sometimes weird meta data; metadata of my files are normalized so not enough samples to push the server's metadata handling.

INSTALL.md explains how to build and install the library. For the copyright issues, see the accompanying LICENSE.md file.

If you have a question or suggestion, do not hesitate to contact me via email (woong.jun at gmail.com) or web (http://code.woong.org/).