Host:Port Parsing Feature

This document describes the automatic host:port parsing functionality added to the SoundTouch CLI, which allows users to specify both host and port in a single -host flag.

Overview

The SoundTouch CLI now supports parsing host and port combinations in the -host flag, making it more user-friendly and following common CLI patterns. Users can specify either just a host (using the default or -port flag) or a complete host:port combination.

Usage Examples

Basic Host:Port Format

# Specify host and port together
soundtouch-cli -host 192.0.2.100:8090 -info
soundtouch-cli -host 192.0.2.10:8090 -play
soundtouch-cli -host soundtouch.local:8090 -pause

Traditional Separate Flags (Still Supported)

# Traditional separate host and port flags
soundtouch-cli -host 192.0.2.100 -port 8090 -info
soundtouch-cli -host 192.0.2.10 -port 8090 -play

Precedence Rules

When both formats are used, the port specified in the host:port format takes precedence:

# Uses port 8090 from host:port, ignores -port 9999
soundtouch-cli -host 192.0.2.100:8090 -port 9999 -info

Supported Formats

IPv4 Addresses

# Standard IPv4 with port
soundtouch-cli -host 192.0.2.100:8090 -info

# IPv4 without port (uses default 8090)
soundtouch-cli -host 192.0.2.100 -info

Hostnames

# Hostname with port
soundtouch-cli -host soundtouch.local:8090 -info
soundtouch-cli -host bose-kitchen:9000 -play

# Hostname without port (uses default)
soundtouch-cli -host soundtouch.local -info

IPv6 Addresses

# IPv6 with port (requires brackets)
soundtouch-cli -host [::1]:8090 -info
soundtouch-cli -host [2001:db8::1]:8090 -play

# IPv6 without port
soundtouch-cli -host ::1 -info

Implementation Details

Parsing Function

The parseHostPort() function handles the parsing logic:

func parseHostPort(hostPort string, defaultPort int) (string, int)

Parsing Rules

1. Contains colon: Attempts to split using net.SplitHostPort()
2. Valid port: Port must be numeric and in range 1-65535
3. Invalid port: Falls back to original host and default port
4. No colon: Returns original input as host with default port
5. Parse error: Returns original input as host with default port

Error Handling

The parser is designed to be forgiving and always return usable values:

• Invalid port numbers: Fall back to default port
• Malformed input: Return original input as host
• Empty input: Handle gracefully
• Multiple colons: Handled by net.SplitHostPort() error handling

Test Coverage

Unit Tests

Comprehensive test coverage in cmd/soundtouch-cli/main_test.go:

• ✅ IPv4 addresses with and without ports
• ✅ Hostnames with and without ports
• ✅ IPv6 addresses with and without ports
• ✅ Invalid port handling
• ✅ Edge cases (empty strings, malformed input)
• ✅ Real-world SoundTouch scenarios

Integration Tests

Tested with real SoundTouch devices:

• ✅ SoundTouch 10 (192.0.2.11:8090)
• ✅ SoundTouch 20 (192.0.2.10:8090)

Benefits

User Experience

• Simplified syntax: host:port is more intuitive than separate flags
• Consistent with other tools: Follows common CLI patterns
• Backward compatible: Existing scripts continue to work
• Copy-paste friendly: Can copy host:port from discovery output

Development Benefits

• Robust parsing: Handles edge cases gracefully
• Comprehensive tests: Well-tested functionality
• Clean implementation: Uses Go standard library
• Error resilience: Falls back to sensible defaults

Examples with Real Devices

Discovery + Direct Usage

# Discover devices to find host:port
$ soundtouch-cli -discover
Found SoundTouch devices:
  My SoundTouch Device (192.0.2.10:8090) - SoundTouch 20

# Use discovered host:port directly
$ soundtouch-cli -host 192.0.2.10:8090 -play

Different Port Scenarios

# Standard SoundTouch port
soundtouch-cli -host 192.0.2.100:8090 -info

# Custom port (if device configured differently)
soundtouch-cli -host 192.0.2.100:9000 -info

# Default port fallback
soundtouch-cli -host 192.0.2.100 -info  # Uses 8090

Error Scenarios

# Invalid port - uses default 8090
soundtouch-cli -host 192.0.2.100:invalid -info

# Out of range port - uses default 8090  
soundtouch-cli -host 192.0.2.100:99999 -info

# Malformed input - treats as hostname
soundtouch-cli -host "malformed::input" -info

CLI Help Output

The help text has been updated to reflect the new functionality:

Options:
  -host <ip>        SoundTouch device IP address (or host:port)
  -port <port>      SoundTouch device port (default: 8090)

Examples:
  soundtouch-cli -host 192.0.2.100 -info
  soundtouch-cli -host 192.0.2.100:8090 -info
  soundtouch-cli -host 192.0.2.100:8090 -pause
  soundtouch-cli -host 192.0.2.100:8090 -preset 1

Technical Implementation

Function Signature

// parseHostPort splits a host:port string into separate host and port components
// If no port is specified, returns the original host and the provided default port
func parseHostPort(hostPort string, defaultPort int) (string, int)

Key Features

• Uses Go’s net.SplitHostPort() for robust parsing
• Validates port range (1-65535)
• Handles IPv6 addresses correctly with brackets
• Graceful fallback for all error conditions
• Preserves original host for malformed input

Integration Points

The parsed values are used throughout the CLI:

• Device info commands
• Now playing queries
• Source management
• Key control commands
• All API endpoint interactions

Future Enhancements

Potential improvements for the future:

1. URL Format Support: Support full URLs like http://192.0.2.100:8090
2. Service Discovery: Auto-detect port via service discovery protocols
3. Configuration File: Save frequently used host:port combinations
4. Environment Variables: Support SOUNDTOUCH_HOST with host:port format
5. Validation: More sophisticated host validation (DNS lookup, ping)

Reference

• Implementation: cmd/soundtouch-cli/main.go (parseHostPort function)
• Tests: cmd/soundtouch-cli/main_test.go
• Go Documentation: net.SplitHostPort() for parsing logic
• Standards: Follows RFC 3986 for host:port format