CountryData.Globalization.Hosting 1.0.0

CountryData.Globalization

A high-performance .NET library providing comprehensive country data, regions, cultures, currencies, and globalization information. Built for international applications with full country/region support.

Features

• High Performance - O(1) dictionary lookups with lazy-loaded caches
• 250+ Countries - Complete ISO 3166-1 country data
• Administrative Regions - States, provinces, territories
• Currency Information - Symbols, codes, names in multiple languages
• Full Globalization - CultureInfo and RegionInfo integration
• Phone Codes - International dialing codes
• Multi-Language - Support for cultures and localized names
• DI Ready - Built-in dependency injection support
• Thread-Safe - All operations are thread-safe
• Zero Dependencies - Lightweight, no external packages

Installation

Option 1: With Dependency Injection Support (Recommended)

Install both the core package and hosting package:

# Core package
dotnet add package CountryData.Globalization

# Hosting package (for DI support)
dotnet add package CountryData.Globalization.Hosting

Package Manager Console:

Install-Package CountryData.Globalization
Install-Package CountryData.Globalization.Hosting

Option 2: Core Package Only

If you don't need dependency injection support:

dotnet add package CountryData.Globalization

Package Manager Console:

Install-Package CountryData.Globalization

Quick Start

Using With Dependency Injection (Recommended)

Step 1: Register the service

// Program.cs
using CountryData.Globalization.Hosting.Extensions;

var builder = WebApplication.CreateBuilder(args);

// Register CountryData services
builder.Services.AddCountryData();

var app = builder.Build();

Step 2: Inject and use

using CountryData.Globalization.Services;

public class CountryController : ControllerBase
{
    private readonly ICountryDataProvider _countryProvider;

    public CountryController(ICountryDataProvider countryProvider)
    {
        _countryProvider = countryProvider;
    }

    [HttpGet("country/{code}")]
    public IActionResult GetCountry(string code)
    {
        var country = _countryProvider.GetCountryByCode(code);
        if (country == null) return NotFound();

        return Ok(new
        {
            Name = country.CountryName,
            Flag = _countryProvider.GetCountryFlag(code),
            Currency = _countryProvider.GetCurrencySymbol(code),
            PhoneCode = country.PhoneCode,
            IsMetric = _countryProvider.IsMetric(code)
        });
    }
}

Using Without Dependency Injection

If you're not using DI, create the provider directly:

using CountryData.Globalization.Services;

// Simple - just create it (recommended)
var provider = new CountryDataProvider();

// Use the provider
var country = provider.GetCountryByCode("US");
Console.WriteLine($"{country.CountryName} - {provider.GetCountryFlag("US")}");

// Get regions
var states = provider.GetRegionsByCountryCode("US");
foreach (var state in states)
{
    Console.WriteLine($"{state.Name} ({state.ShortCode})");
}

// Get currency info
var symbol = provider.GetCurrencySymbol("US");
Console.WriteLine($"Currency: {symbol}");

Important: Reuse the same provider instance. Don't create new instances repeatedly as it's expensive.

// GOOD - Singleton pattern
public class CountryDataSingleton
{
    private static readonly Lazy<ICountryDataProvider> _instance = 
        new Lazy<ICountryDataProvider>(() => new CountryDataProvider());

    public static ICountryDataProvider Instance => _instance.Value;
}

// Usage
var country = CountryDataSingleton.Instance.GetCountryByCode("US");

API Reference

Country Data Methods

Example:

var country = provider.GetCountryByCode("US");
var flag = provider.GetCountryFlag("JP");
var allCountries = provider.GetAllCountries();

Phone Code Methods

Example:

var phoneCode = provider.GetPhoneCodeByCountryShortCode("GB");  // "+44"
var countries = provider.GetCountriesByPhoneCode("+1");         // US, Canada, etc.

Region Methods

Example:

var states = provider.GetRegionsByCountryCode("US");
var country = provider.GetCountriesByRegion("California").FirstOrDefault();

Currency Methods

Example:

var symbol = provider.GetCurrencySymbol("US");           // "$"
var name = provider.GetCurrencyEnglishName("GB");        // "British Pound"
var euroCountries = provider.GetCountriesByCurrency("EUR");

Culture & Globalization Methods

Example:

var culture = provider.GetCultureInfo("US");             // en-US culture
var cultures = provider.GetAllCulturesForCountry("CA");  // en-CA, fr-CA
var frenchCA = provider.GetSpecificCultureByCountryAndLanguage("CA", "fr");

RegionInfo Methods

Example:

var regionInfo = provider.GetRegionInfo("US");
var isMetric = provider.IsMetric("US");                  // false
var iso3 = provider.GetThreeLetterISORegionName("US");   // "USA"

Common Usage Examples

Example 1: Country Dropdown for Forms

public class CountryDropdownService
{
    private readonly ICountryDataProvider _provider;

    public CountryDropdownService(ICountryDataProvider provider)
    {
        _provider = provider;
    }

    public List<CountryOption> GetCountryOptions()
    {
        return _provider.GetAllCountries()
            .OrderBy(c => c.CountryName)
            .Select(c => new CountryOption
            {
                Code = c.CountryShortCode,
                Name = c.CountryName,
                Flag = _provider.GetCountryFlag(c.CountryShortCode)
            })
            .ToList();
    }
}

Example 2: Phone Number Formatting

public class PhoneNumberService
{
    private readonly ICountryDataProvider _provider;

    public PhoneNumberService(ICountryDataProvider provider)
    {
        _provider = provider;
    }

    public string FormatPhoneNumber(string countryCode, string localNumber)
    {
        var phoneCode = _provider.GetPhoneCodeByCountryShortCode(countryCode);
        return $"{phoneCode} {localNumber}";
    }
}

// Usage: FormatPhoneNumber("US", "555-1234") returns "+1 555-1234"

Example 3: Address Form with Dynamic Regions

public class AddressFormService
{
    private readonly ICountryDataProvider _provider;

    public AddressFormService(ICountryDataProvider provider)
    {
        _provider = provider;
    }

    public List<RegionOption> GetRegionsForCountry(string countryCode)
    {
        return _provider.GetRegionsByCountryCode(countryCode)
            .Select(r => new RegionOption
            {
                Code = r.ShortCode,
                Name = r.Name
            })
            .OrderBy(r => r.Name)
            .ToList();
    }
}

Example 4: Currency Display

public class CurrencyService
{
    private readonly ICountryDataProvider _provider;

    public CurrencyService(ICountryDataProvider provider)
    {
        _provider = provider;
    }

    public CurrencyInfo GetCurrencyInfo(string countryCode)
    {
        return new CurrencyInfo
        {
            Symbol = _provider.GetCurrencySymbol(countryCode),
            EnglishName = _provider.GetCurrencyEnglishName(countryCode),
            NativeName = _provider.GetCurrencyNativeName(countryCode)
        };
    }
}

Example 5: Multi-Language Support

public class LocalizationService
{
    private readonly ICountryDataProvider _provider;

    public LocalizationService(ICountryDataProvider provider)
    {
        _provider = provider;
    }

    public string GetLocalizedCountryName(string countryCode, string languageCode)
    {
        var culture = new CultureInfo(languageCode);
        return _provider.GetDisplayName(countryCode, culture) 
            ?? _provider.GetCountryByCode(countryCode)?.CountryName 
            ?? "Unknown";
    }
}

// Usage: 
// GetLocalizedCountryName("JP", "fr-FR") returns "Japon"
// GetLocalizedCountryName("JP", "es-ES") returns "Japón"

Architecture & Performance

Performance Characteristics

Caching Strategy

All caches use lazy initialization with thread-safe Lazy<T>:

1. Country Dictionary - Built at construction (~50ms)
2. RegionInfo Cache - Built on first currency/region access (~50-100ms)
3. CultureInfo Cache - Built on first culture access (~100-150ms)
4. Phone Code Index - Built on first phone query (<10ms)
5. Currency Index - Built on first currency query (~50-100ms)
6. Language Index - Built on first language query (~100-150ms)

Memory Footprint: ~2-5 MB for all caches combined

Thread Safety

100% Thread-Safe

• Immutable data collections
• Thread-safe lazy initialization via Lazy<T>
• No mutable state
• Safe for concurrent access from multiple threads
• Registered as Singleton by default

Data Models

Country Model

public class Country
{
    public string CountryName { get; set; }        // "United States"
    public string CountryShortCode { get; set; }   // "US"
    public string PhoneCode { get; set; }          // "+1"
    public List<Region> Regions { get; set; }      // States/Provinces
}

Region Model

public class Region
{
    public string Name { get; set; }         // "California"
    public string? ShortCode { get; set; }   // "CA" (optional)
}

Best Practices

Recommended Usage

// GOOD - With DI (Recommended)
builder.Services.AddCountryData();

public class MyService
{
    private readonly ICountryDataProvider _provider;
    
    public MyService(ICountryDataProvider provider)
    {
        _provider = provider;
    }
}

// GOOD - Without DI (Simple instantiation)
var provider = new CountryDataProvider();

// GOOD - Without DI (Singleton pattern)
public class CountryDataSingleton
{
    private static readonly Lazy<ICountryDataProvider> _instance = 
        new Lazy<ICountryDataProvider>(() => new CountryDataProvider());

    public static ICountryDataProvider Instance => _instance.Value;
}

Anti-Patterns to Avoid

// BAD - Creating new instances repeatedly
foreach (var item in items)
{
    var provider = new CountryDataProvider();  // Expensive!
    var country = provider.GetCountryByCode(item.Code);
}

// GOOD - Reuse single instance
var provider = new CountryDataProvider();
foreach (var item in items)
{
    var country = provider.GetCountryByCode(item.Code);
}

// BAD - Calling GetCountriesByRegion in loops
foreach (var region in regions)
{
    var country = provider.GetCountriesByRegion(region).FirstOrDefault();  // O(n×m)!
}

// GOOD - Build your own index for repeated lookups
var regionIndex = provider.GetAllCountries()
    .SelectMany(c => c.Regions.Select(r => new { Region = r.Name, Country = c }))
    .ToDictionary(x => x.Region, x => x.Country, StringComparer.OrdinalIgnoreCase);

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Country data based on ISO 3166-1 standards
• Culture and region information from .NET CultureInfo and RegionInfo
• Flag emojis using Unicode regional indicator symbols