OpcSharp.Tool 0.3.1

OpcSharp

A pure C# OPC UA client SDK with zero external OPC UA dependencies. Implements the OPC UA Binary Protocol from scratch.

Documentation: patdhlk.com/OpcSharp

Targets: netstandard2.0 · net8.0 · net9.0 · net10.0

Installation

dotnet add package OpcSharp.Client

Individual layers can be referenced separately if needed:

dotnet add package OpcSharp.Types
dotnet add package OpcSharp.Encoding
dotnet add package OpcSharp.Transport
dotnet add package OpcSharp.Transport.Http
dotnet add package OpcSharp.Transport.WebSocket
dotnet add package OpcSharp.Security
dotnet add package OpcSharp.Protocol
dotnet add package OpcSharp.Services

Architecture

Layered stack where each layer depends only on layers below it:

OpcSharp.Client        ← High-level API, fluent builder, DI integration
OpcSharp.Services      ← Attribute, Browse, Method, Subscription, Discovery
OpcSharp.Protocol      ← Session + SecureChannel management
OpcSharp.Security      ← Security policies, crypto, certificates, user identity
OpcSharp.Transport.WebSocket ← WebSocket transport (opc.wss://, opc.ws://)
OpcSharp.Transport.Http← HTTPS transport
OpcSharp.Transport     ← TCP transport, Hello/ACK, chunking
OpcSharp.Encoding      ← Binary encoder/decoder for all OPC UA types
OpcSharp.Types         ← NodeId, StatusCode, DataValue, Variant, etc.

Quick Start

var client = new OpcSharpClientBuilder()
    .WithEndpoint("opc.tcp://localhost:4840")
    .Build();

await client.ConnectAsync();

var results = await client.ReadAsync(new[]
{
    new ReadValueId
    {
        NodeId = new NodeId(0, 2258),
        AttributeId = AttributeIds.Value
    }
});

Console.WriteLine(results[0].Value);
await client.DisconnectAsync();

Connect via WebSocket

Use opc.wss:// for secure WebSocket or opc.ws:// for plain WebSocket — the same API works across all transports:

var client = new OpcSharpClientBuilder()
    .WithEndpoint("opc.wss://server.example.com/opcua")
    .Build();

await client.ConnectAsync();
// Read, Write, Browse, Subscribe — identical to TCP

Security

Supported policies: None, Basic128Rsa15, Basic256, Basic256Sha256, Aes128_Sha256_RsaOaep, Aes256_Sha256_RsaPss, and ECC policies (NET8+).

User identity: Anonymous, UserName/Password, X509 Certificate, Issued Token (SAML/JWT).

CLI Tool

Explore and diagnose OPC UA servers from the command line:

dotnet tool install -g OpcSharp.Tool

opcsharp discover opc.tcp://localhost:4840
opcsharp browse opc.tcp://localhost:4840
opcsharp read opc.tcp://localhost:4840 -n "i=2258"
opcsharp health opc.tcp://localhost:4840

See the CLI documentation for the full command reference.

Build & Test

dotnet build OpcSharp.sln
dotnet test OpcSharp.sln

Integration tests require Docker:

docker compose -f docker/docker-compose.yml up -d --build
dotnet test tests/OpcSharp.Integration.Tests

License

See LICENSE for details.