ZenohDotNet.Native 0.1.0

ZenohDotNet.Native

Low-level Zenoh FFI bindings for .NET with embedded runtime.

Overview

ZenohDotNet.Native provides P/Invoke bindings to the Zenoh C library, allowing .NET applications to use Zenoh's distributed messaging capabilities. The native Zenoh runtime is embedded in the NuGet package, so no separate installation is required.

Features

• Embedded Runtime: Zenoh C library is included in the package
• Cross-Platform: Supports Windows, Linux, and macOS on x64 and ARM64
• Mobile Support: Android (arm64-v8a, armeabi-v7a, x86_64) and iOS (arm64)
• Memory Safe: Proper IDisposable implementation for resource management
• .NET Standard 2.1: Compatible with .NET Core 3.0+, .NET 5+, and Unity 2021.2+
• Liveliness API: Monitor resource presence with liveliness tokens
• Attachments: Send key-value metadata alongside payloads

Supported Platforms

• Windows (x64, ARM64)
• Linux (x64, ARM64)
• macOS (x64, ARM64)
• Android (arm64-v8a, armeabi-v7a, x86_64)
• iOS (arm64)

Installation

dotnet add package ZenohDotNet.Native

Usage

Creating a Session

using ZenohDotNet.Native;

// Open a session with default configuration
using var session = new Session();

// Or with custom JSON configuration
var config = "{\"mode\":\"peer\"}";
using var session = new Session(config);

Publishing Data

using var session = new Session();
using var publisher = session.DeclarePublisher("demo/example/test");

// Publish a string
publisher.Put("Hello, Zenoh!");

// Publish bytes
byte[] data = { 1, 2, 3, 4 };
publisher.Put(data);

// Publish with encoding
publisher.Put(data, PayloadEncoding.ApplicationJson);

Publishing with Attachments

// Attachments are key-value metadata sent alongside the payload
var attachment = new Dictionary<string, string>
{
    ["sender"] = "device-001",
    ["priority"] = "high"
};
session.Put("demo/example/test", "Hello!", attachment);

Subscribing to Data

using var session = new Session();
using var subscriber = session.DeclareSubscriber("demo/example/**", sample =>
{
    Console.WriteLine($"Received on {sample.KeyExpression}: {sample.GetPayloadAsString()}");
});

// Keep the application running to receive messages
Console.ReadLine();

Query/Queryable (Request-Response)

// Queryable (server)
using var queryable = session.DeclareQueryable("demo/query", query =>
{
    Console.WriteLine($"Query received: {query.Selector}");
    query.Reply("demo/query", "Response data");
});

// Query (client)
session.Get("demo/query", sample =>
{
    Console.WriteLine($"Reply: {sample.GetPayloadAsString()}");
});

Liveliness API

Monitor resource presence using liveliness tokens:

// Declare a liveliness token (resource is "alive" while token exists)
using var token = session.DeclareLivelinessToken("my/resource/path");

// Subscribe to liveliness changes
using var liveSub = session.DeclareLivelinessSubscriber("my/**", (keyExpr, isAlive) =>
{
    if (isAlive)
        Console.WriteLine($"{keyExpr} is now alive");
    else
        Console.WriteLine($"{keyExpr} has died");
});

Delete

// Delete a key expression
session.Delete("demo/example/test");

API Reference

Session

• Session() - Opens a session with default configuration
• Session(string configJson) - Opens a session with JSON configuration
• DeclarePublisher(string keyExpr) - Creates a publisher
• DeclarePublisher(string keyExpr, PublisherOptions options) - Creates a publisher with options
• DeclareSubscriber(string keyExpr, Action<Sample> callback) - Creates a subscriber
• DeclareQueryable(string keyExpr, Action<Query> callback) - Creates a queryable
• DeclareQuerier(string keyExpr) - Creates a querier for repeated queries
• Get(string selector, Action<Sample> callback) - Performs a query
• Put(string keyExpr, byte[] data) - Direct put without publisher
• Put(string keyExpr, byte[] data, IDictionary<string, string> attachment) - Put with attachment
• Delete(string keyExpr) - Delete a key expression
• DeclareLivelinessToken(string keyExpr) - Declare a liveliness token
• DeclareLivelinessSubscriber(string keyExpr, Action<string, bool> callback) - Subscribe to liveliness changes
• GetZenohId() - Gets the session's Zenoh ID

Publisher

• Put(byte[] data) - Publishes binary data
• Put(string value) - Publishes a UTF-8 string
• Put(byte[] data, PayloadEncoding encoding) - Publishes with encoding
• KeyExpression - Gets the key expression

Subscriber

• Automatically receives data via callback
• Callback receives Sample objects

Sample

• KeyExpression - The key expression of the sample
• Payload - Raw byte array payload
• Kind - Sample kind (Put or Delete)
• Encoding - Payload encoding
• Timestamp - Optional timestamp
• GetPayloadAsString() - Converts payload to UTF-8 string

Query

• Selector - The query selector
• Payload - Optional query payload
• Reply(string keyExpr, byte[] data) - Reply to the query
• Reply(string keyExpr, string value) - Reply with a string

LivelinessToken

• KeyExpression - The token's key expression
• Disposing the token signals the resource is no longer alive

LivelinessSubscriber

• Receives (string keyExpr, bool isAlive) callbacks
• isAlive = true when a token is declared
• isAlive = false when a token is dropped

Building from Source

See the main repository README for build instructions.

License

This project is licensed under the MIT License.