lmxopcua/tools/opcuacli-dotnet/Commands/WriteCommand.cs

using CliFx;
using CliFx.Attributes;
using CliFx.Infrastructure;
using Opc.Ua;
using Opc.Ua.Client;

namespace OpcUaCli.Commands;

[Command("write", Description = "Write a value to a node")]
public class WriteCommand : ICommand
{
    /// <summary>
    /// Gets the OPC UA endpoint URL to connect to before issuing the write.
    /// </summary>
    [CommandOption("url", 'u', Description = "OPC UA server endpoint URL", IsRequired = true)]
    public string Url { get; init; } = default!;

    [CommandOption("username", 'U', Description = "Username for authentication")]
    public string? Username { get; init; }

    [CommandOption("password", 'P', Description = "Password for authentication")]
    public string? Password { get; init; }

    /// <summary>
    /// Gets the node identifier that should receive the write.
    /// </summary>
    [CommandOption("node", 'n', Description = "Node ID (e.g. ns=2;s=MyNode)", IsRequired = true)]
    public string NodeId { get; init; } = default!;

    /// <summary>
    /// Gets the textual value supplied on the command line before type conversion.
    /// </summary>
    [CommandOption("value", 'v', Description = "Value to write", IsRequired = true)]
    public string Value { get; init; } = default!;

    /// <summary>
    /// Connects to the OPC UA endpoint, converts the supplied value, and writes it to the target node.
    /// </summary>
    /// <param name="console">The console used to report the write result.</param>
    public async ValueTask ExecuteAsync(IConsole console)
    {
        using var session = await OpcUaHelper.ConnectAsync(Url, Username, Password);

        var node = new NodeId(NodeId);
        var current = await session.ReadValueAsync(node);
        var typedValue = OpcUaHelper.ConvertValue(Value, current.Value);

        var writeValue = new WriteValue
        {
            NodeId = node,
            AttributeId = Attributes.Value,
            Value = new DataValue(new Variant(typedValue))
        };

        var request = new WriteValueCollection { writeValue };
        var response = await session.WriteAsync(null, request, CancellationToken.None);

        if (StatusCode.IsGood(response.Results[0]))
            await console.Output.WriteLineAsync($"Write successful: {NodeId} = {typedValue}");
        else
            await console.Output.WriteLineAsync($"Write failed: {response.Results[0]}");
    }
}