Your first node

Build a node that calculates a pass rate from the number of passing and tested items.

1. Create a class library

The current SereinFlow.Library targets .NET 10. From the SereinFlow repository root:

dotnet new classlib -n MyFlowNodes -f net10.0
Set-Location MyFlowNodes
dotnet add reference ..\src\SereinFlow.Library\SereinFlow.Library.csproj

Outside this repository you can reference the SereinFlow.Library package instead. Match the server version; this repository currently specifies 1.2.0.

2. Add a method

Create QualityNodes.cs:

using SereinFlow.Core.Api;

namespace MyFlowNodes;

[FlowLibrary("Quality checks")]
public sealed class QualityNodes
{
    [FlowNode(AnotherName = "Calculate pass rate", Desc = "Percentage of passing items")]
    public decimal PassRate(
        [NodeParam(Name = "Passing items")] int passed,
        [NodeParam(Name = "Total items")] int total)
    {
        if (total <= 0)
            throw new ArgumentOutOfRangeException(nameof(total), "Total must be positive");

        return Math.Round((decimal)passed / total * 100m, 2);
    }
}

[FlowLibrary] marks the class as a node library. [FlowNode] exposes PassRate in the canvas catalog. AnotherName, Desc, and [NodeParam] set user-visible labels. The returned decimal is the node result.

3. Publish and use it

Add <EnableDynamicLoading>true</EnableDynamicLoading> to the <PropertyGroup> in MyFlowNodes.csproj, so publication includes dynamic-loading dependencies. From the project directory:

dotnet publish .\MyFlowNodes.csproj -c Release -o ..\artifacts\MyFlowNodes-1.0.0
Compress-Archive -Path ..\artifacts\MyFlowNodes-1.0.0 `
  -DestinationPath ..\artifacts\MyFlowNodes-1.0.0.zip -Force

The ZIP must contain a top-level MyFlowNodes-1.0.0 directory with MyFlowNodes.dll inside. Upload it in the console, add the library to a project, then place Calculate pass rate on the canvas. Enter both numbers, mark it as the entry, save, and run. See Package and upload for structure and troubleshooting.

Stable IDs

Ordinary nodes can omit FlowNode.Id and NodeParam.Id; the current API derives them from library, method, and parameter names. If existing flows use a node, plan renames carefully. Explicit IDs and NodeParam.Aliases support an intentional migration.