Load native DLLs

Some .NET packages require platform-specific native files: .dll on Windows, .so on Linux, or .dylib on macOS. Include them in the node library ZIP so the Worker can find them.

Directory layout

Paths are relative to the directory containing MyFlowNodes.dll:

MyFlowNodes-1.0.0.zip
└─ MyFlowNodes-1.0.0/
   ├─ MyFlowNodes.dll
   ├─ MyFlowNodes.deps.json
   └─ runtimes/
      ├─ win-x64/native/device.dll
      └─ linux-x64/native/libdevice.so

Include files needed by the Worker's OS and architecture. Do not mix binaries for different architectures in the same directory.

Fixed dependencies: declare a directory

If every use of the library needs the native files, add an assembly attribute in a file such as NativeLibraryManifest.cs:

using SereinFlow.Core.Api;

[assembly: NativeLibraryDirectory(
    "runtimes/{rid}/native",
    Recursive = false,
    Required = true)]

{rid} is replaced by the Worker's runtime identifier, such as win-x64. The attribute can instead be put on one node class. Recursive defaults to true; Required also defaults to true. SereinFlow.OpenCvLibrary currently declares this directory at assembly level, non-recursively and as required.

Conditional loading: inject the loader

When a dependency is needed only for one node, inject IFlowNativeLibraryLoader:

using SereinFlow.Core.Api;
using SereinFlow.Library;

[FlowLibrary("Device tools")]
public sealed class DeviceNodes
{
    public DeviceNodes(IFlowNativeLibraryLoader native)
    {
        native.LoadNativeLibraryDirectory(
            "vendor/native/{rid}", recursive: true, required: true);
    }

    [FlowNode(AnotherName = "Read device")]
    public string Read() => "Device ready";
}

Use native.LoadNativeLibrary("vendor/native/{rid}/device.dll") for one file; it returns false if absent. Repeated loads within a run are safe. With required: false, missing or empty directories are skipped and file load failures are logged in Worker diagnostics. Required failures throw FlowNativeLibraryException.

Troubleshooting

1. Inspect the ZIP and verify the path relative to the main assembly.
2. Match {rid} to the actual Worker OS and architecture.
3. Include transitive native dependencies, not only the top-level DLL.
4. Inspect FlowNativeLibraryException.Code, RelativePath, and its message.

Paths must stay inside the uploaded package. Do not use absolute paths or ... Preserve subdirectories in the ZIP and confirm project referencing in Package and upload.