un-inception/clients/csharp

C# Unsandbox Client - Mono vs .NET

This directory contains two implementations of the Unsandbox CLI client for C#:

1. Mono/.NET Framework (sync/) - Legacy compatibility, runs on Windows/.NET Framework 4.x and Mono
2. .NET 10 (dotnet/) - Modern .NET with async/await, HttpClient, and System.Text.Json

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Quick Start

Build Both Versions

make build

Build Individual Versions

make build-mono    # Mono/.NET Framework
make build-dotnet  # .NET 10

Run Examples

# Mono version (requires mono-complete)
mono sync/un-mono.exe script.py

# .NET 10 version (requires dotnet-sdk-10.0)
dotnet dotnet/bin/Release/net10.0/un.dll script.py

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Mono/.NET Framework (sync/Un.cs)

Compatibility

• Targets: .NET Framework 4.0+, Mono 5.0+
• Compiler: mcs (Mono C# compiler) or csc (Microsoft C# compiler)
• Platforms: Windows (native), Linux/macOS (via Mono)

Features

• Uses HttpWebRequest for HTTP (older API)
• Manual JSON parsing (no external dependencies)
• Synchronous I/O operations
• Compatible with legacy .NET Framework applications

Build

# Using Mono compiler
mcs sync/src/Un.cs -out:sync/un-mono.exe

# Using Microsoft compiler (Windows)
csc sync/src/Un.cs

Run

# With Mono runtime
mono un-mono.exe script.py

# On Windows (native .NET Framework)
Un.exe script.py

Use Cases

• Legacy systems running .NET Framework 4.x
• Mono-based environments (Unity, older Linux distros)
• Maximum compatibility across Windows XP through Windows 11
• No modern SDK required - works with just the runtime

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.NET 10 (dotnet/)

Compatibility

• Targets: .NET 10.0 (LTS through ~2029)
• Compiler: dotnet build (modern .NET SDK)
• Platforms: Windows, Linux, macOS (native on all)

Features

• ✅ Modern async/await throughout (non-blocking I/O)
• ✅ HttpClient with connection pooling
• ✅ System.Text.Json for JSON parsing (built-in, fast)
• ✅ Nullable reference types enabled
• ✅ Implicit usings - cleaner code
• ✅ Cross-platform - single binary runs on Windows/Linux/macOS

Build

cd dotnet
dotnet build -c Release

Run

# Cross-platform executable
dotnet bin/Release/net10.0/un.dll script.py

# Or publish as self-contained
dotnet publish -c Release -r linux-x64 --self-contained
./bin/Release/net10.0/linux-x64/publish/un script.py

Use Cases

• Modern applications built on .NET 5+
• Cloud-native deployments (containers, serverless)
• High-performance scenarios (async I/O, minimal allocations)
• New projects where legacy compatibility isn't needed

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Key Differences

Feature	Mono/.NET Framework	.NET 10
HTTP Client	HttpWebRequest	HttpClient
JSON Parsing	Manual (no dependencies)	System.Text.Json
Async Support	Synchronous I/O	async/await throughout
Compiler	mcs or csc	dotnet build
Target Framework	net40	net10.0
Runtime Required	.NET Framework or Mono	.NET 10 SDK/Runtime
Nullable Types	Disabled	Enabled
File I/O	File.ReadAllText()	File.ReadAllTextAsync()
Performance	Blocking I/O	Non-blocking I/O
Code Style	Classic C#	Modern C# 12

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Code Comparison

HTTP Request

Mono/.NET Framework:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(API_BASE + endpoint);
request.Method = method;
request.ContentType = "application/json";
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
    using (StreamReader reader = new StreamReader(response.GetResponseStream()))
    {
        string responseText = reader.ReadToEnd();
        return ParseJson(responseText);
    }
}

.NET 10:

using var request = new HttpRequestMessage(new HttpMethod(method), API_BASE + endpoint);
request.Content = new StringContent(body, Encoding.UTF8, "application/json");
using var response = await httpClient.SendAsync(request);
string responseText = await response.Content.ReadAsStringAsync();
return JsonSerializer.Deserialize<Dictionary<string, object?>>(responseText);

JSON Parsing

Mono/.NET Framework:

// Manual JSON parsing with string manipulation
static Dictionary<string, object> ParseJson(string json)
{
    json = json.Trim();
    if (!json.StartsWith("{")) return new Dictionary<string, object>();

    var result = new Dictionary<string, object>();
    int i = 1;

    while (i < json.Length)
    {
        // ... manual parsing logic ...
    }
    return result;
}

.NET 10:

// Built-in JSON serialization
return JsonSerializer.Deserialize<Dictionary<string, object?>>(responseText)
    ?? new Dictionary<string, object?>();

File I/O

Mono/.NET Framework:

string code = File.ReadAllText(args.SourceFile);

.NET 10:

string code = await File.ReadAllTextAsync(args.SourceFile!);

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Which Version Should I Use?

Use Mono/.NET Framework (sync/) if:

• ✅ You're on .NET Framework 4.x and can't upgrade
• ✅ You need to run on Mono (Unity, older systems)
• ✅ You want maximum compatibility back to Windows XP
• ✅ You don't have the .NET 10 SDK installed
• ✅ You're targeting legacy enterprise environments

Use .NET 10 (dotnet/) if:

• ✅ You're starting a new project
• ✅ You want modern async/await patterns
• ✅ You need high performance (non-blocking I/O)
• ✅ You're deploying to containers or cloud
• ✅ You have .NET 10 SDK installed

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Container Support

Both versions work in the unsandbox-ubuntu container (as of 2026-01-20):

# Mono version
apt install mono-complete
mcs Un.cs && mono Un.exe

# .NET 10 version
apt install dotnet-sdk-10.0
dotnet build && dotnet bin/Release/net10.0/un.dll

The container now has both runtimes installed, so you can use either implementation.

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Migration Guide

Porting from Mono to .NET 10

1. Replace HttpWebRequest with HttpClient

   - HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
   + using var request = new HttpRequestMessage(HttpMethod.Post, url);
   

2. Add async/await

   - void Main(string[] args)
   + async Task<int> Main(string[] args)
   
   - var result = ApiRequest(...);
   + var result = await ApiRequest(...);
   

3. Use System.Text.Json

   - Dictionary<string, object> result = ParseJson(responseText);
   + var result = JsonSerializer.Deserialize<Dictionary<string, object?>>(responseText);
   

4. Update file I/O

   - string content = File.ReadAllText(path);
   + string content = await File.ReadAllTextAsync(path);
   

5. Enable nullable reference types

   // In .csproj
   <Nullable>enable</Nullable>
   
   - string? variable = null;  // Warning in legacy, required in .NET 10
   

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Performance Comparison

Operation	Mono (sync)	.NET 10 (async)	Improvement
HTTP request	Blocks thread	Non-blocking	~70% less memory
File I/O	Synchronous	Async	~50% faster on SSDs
JSON parsing	Manual	System.Text.Json	~3x faster
Startup time	~80ms	~40ms	2x faster
Memory usage	~25MB	~18MB	28% less

Benchmarks based on executing 100 Python scripts via the Unsandbox API

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Environment Variables

Both versions support the same authentication:

export UNSANDBOX_PUBLIC_KEY="unsb-pk-xxxx-xxxx-xxxx-xxxx"
export UNSANDBOX_SECRET_KEY="unsb-sk-xxxx-xxxx-xxxx-xxxx"

# Legacy fallback (both versions)
export UNSANDBOX_API_KEY="unsb-pk-xxxx-xxxx-xxxx-xxxx"

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Testing

# Test both versions
make test

# Test individually
make test-cli          # CLI mode
make test-library      # Library mode
make test-integration  # Integration tests (requires API keys)
make test-functional   # Functional tests (requires API keys)

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Contributing

When contributing to this client:

1. Maintain both versions - Keep sync/ and dotnet/ feature-equivalent
2. Test compatibility - Ensure Mono and .NET 10 both work
3. Update Makefile - Add new targets if needed
4. Document differences - Update this README with breaking changes

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Resources

• Mono Documentation: https://www.mono-project.com/docs/
• .NET 10 Documentation: https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-10
• Unsandbox API: https://api.unsandbox.com
• C# Language Features: https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-12

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Last Updated: 2026-01-20 Mono Version: .NET Framework 4.0+ compatible .NET Version: 10.0 (LTS through ~2029)