Shairport Sync Metadata Parser

A simple Node.js (TypeScript) library to parse metadata from Shairport Sync.

This library reads the XML-like metadata stream from standard input, parses it, and emits structured data objects as an RxJS Observable. It is designed to be used in a pipeline with shairport-sync.

This program was originally created by the Gemini CLI, with reference to the C implementation of shairport-sync-metadata-reader.

Features

• Parses shairport-sync metadata from a standard input stream.
• Handles multi-line XML items and Base64 encoded data.
• Provides a clean, easy-to-use RxJS Observable interface.
• Lightweight and has only one dependency (rxjs).

Installation

Once published to npm:

npm install @minoruta/parse-shairport

For now, install directly from GitHub:

npm install git+https://github.com/minoruta/parse-shairport.git

Usage

Create a script (e.g., my-player.js) to import and use the parser.

// my-player.ts
import { parseMetadata, Metadata } from '@minoruta/parse-shairport';

console.log('Metadata parser is running, waiting for data from stdin...');

parseMetadata().subscribe({
  next: (metadata: Metadata) => {
    // Now you can use the structured metadata object
    console.log(metadata);

    // Example: Display track information
    if (metadata.type === 'artist') {
      console.log(`--> Artist: ${metadata.payload}`);
    }
    if (metadata.type === 'title') {
      console.log(`--> Title: ${metadata.payload}`);
    }
  },
  error: (err) => {
    // Errors can occur due to:
    // - Invalid XML format in the metadata stream
    // - Unexpected data encoding issues
    // - stdin stream interruption
    console.error('A critical error occurred in the metadata stream:', err);
  },
  complete: () => {
    console.log('The metadata stream has ended.');
  },
});

Piping from Shairport Sync

To make this work with shairport-sync, you need to configure shairport-sync to output its metadata to standard output and then pipe it to your Node.js script.

ts-node my-player.ts < /tmp/shairport-sync-metadata

or

shairport-sync --metadata-pipename=/dev/stdout | ts-node my-player.ts

API

parseMetadata(): Observable<Metadata>

This is the main function of the library. It takes no arguments.

• Returns: An Observable that emits Metadata objects.
  • It emits a next notification for each piece of metadata parsed from process.stdin.
  • It emits an error notification if there is an error reading the stream.
  • It emits a complete notification when the stdin stream is closed.

Metadata Interface

The Metadata object emitted by the Observable has the following structure:

interface Metadata {
  type: MetadataType;
  payload: string;
}

// Currently supported metadata types
// Note: Additional types may be added in future versions
type MetadataType = 'album' | 'title' | 'artist' | 'session-begin' | 'session-end';

• type: The type of the metadata.
• payload: The string content of the metadata. For session-begin and session-end, this will be an empty string.

Development

To work on this project locally:

1. Clone the repository:

   git clone https://github.com/minoruta/parse-shairport.git
   cd parse-shairport

2. Install dependencies:

   npm install

3. Run example: You can also run the example script directly to see how it works:

   npm run example