FluentAAS – Fluent C# Library for the Asset Administration Shell (AAS)

License: MIT
NuGet: coming soon
Status: Active development

FluentAAS is a modular Fluent API for creating, validating, serializing, and packaging Asset Administration Shell (AAS 3.0) models in C#.
It serves as a developer-friendly abstraction over the official AAS Core meta-model, enabling both flexible generic modeling and highly structured, specification-compliant supported submodel templates.

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Key Features

Fluent Builder API

Create Asset Administration Shells, Submodels, and Submodel Elements using a clean, expressive DSL.

Immutable AAS Model

All AAS graph elements are immutable C# records, ideal for TDD and snapshot tests.

Full AAS Validation

Includes a standalone IValidationService with detailed validation reports.

JSON / AASX Serialization

Serialize and deserialize environments using FluentAAS.IO.

Supported Submodel Templates

Includes prebuilt builders for frequently used AAS Submodels such as:

• Digital Nameplate V2_0
• …more templates coming soon

These templates ensure developers produce specification-compliant submodels with minimal effort.

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📦 Project Structure

Package	Responsibility
FluentAAS.Core	Immutable AAS meta-model types
FluentAAS.Builder	Fluent builders for AAS entities + submodel templates
FluentAAS.Validation	Rule-based meta-model validation
FluentAAS.IO	JSON + AASX serialization/deserialization helpers

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Getting Started

Installation

dotnet add package FluentAAS

(If not yet available, clone the repository and reference the projects directly.)

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How to Build AAS Models with FluentAAS

FluentAAS offers two different ways to build submodels:

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1. Using Supported Submodel Templates

(Recommended when your submodel is covered by an official spec)

These builders:

• enforce required fields
• automatically apply semantic IDs
• ensure correct AAS element hierarchy
• dramatically reduce boilerplate

Example: Building a Digital Nameplate Submodel (V2.0)

Based on your integration test:

var environment = AasBuilder.Create()
    .AddShell("urn:aas:example:my-shell", "MyShell")
    .WithGlobalAssetId("urn:asset:example:my-asset")
    .AddDigitalNameplate("urn:submodel:example:digital-nameplate:V2_0")
        .WithManufacturerName("de", "Muster AG")
        .WithManufacturerName("en", "Sample Corp")
        .WithManufacturerProductDesignation("de", "Super-Antriebseinheit XS")
        .WithManufacturerProductDesignation("en", "Super Drive Unit XS")
        .WithSerialNumber("SN-000123")
        .Build()    // finish the Digital Nameplate
    .Done()        // return to shell builder
    .Build();      // finish AAS environment

Serialize / Deserialize

string json = AasJsonSerializer.ToJson(environment);
var env2 = AasJsonSerializer.FromJson(json);

Export to AASX

environment.ToAasx("./example.aasx", "/aas/env.json");

This is the easiest and safest way to build complex spec-conformant submodels.

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2. Using the Generic Submodel Builder

(Recommended when no official FluentAAS template exists yet)

Use this when creating:

• your own custom submodels
• unofficial AAS extensions
• submodels not yet added to FluentAAS.Templates

Example: Creating a Custom Submodel

var environment = AasBuilder.Create()
    .AddShell("urn:aas:example:my-shell", "MyShell")
    .WithGlobalAssetId("urn:asset:example:my-asset")
    .AddSubmodel("urn:aas:example:generic-submodel:1", "GenericSubmodel")
        .WithSemanticId(new Reference(
            ReferenceTypes.ExternalReference,
            [
                new Key(KeyTypes.Submodel, "urn:aas:example:generic-submodel:semantic-id")
            ]))
        .AddMultiLanguageProperty(
            "GenericMultiLanguageProperty",
            ls => ls.Add("en", "Example value")
                    .Add("de", "Beispielwert"))
        .AddElement("GenericProperty", "example value")
    .Done()
    .Build();

This approach gives you full control, mirroring the raw AAS 3.0 capabilities.

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Supported Submodels vs Generic Submodels

Type	When to Use	Advantages
Supported Submodels (Templates)	You need official AAS-compliant submodels (e.g., Digital Nameplate)	Automatic semantic IDs, required field checks, cleaner API
Generic Submodels	Custom extensions, early drafts, unsupported specs	Total flexibility, full AAS feature surface

Philosophy

FluentAAS lets you:

• Be productive quickly when using known AAS submodels
• Be fully expressive when building anything custom

This duality is one of the core design goals of the library.

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🤝 Contributing

Pull requests are welcome for:

• Additional official submodel templates
• Improved validation rules
• Useful builder extensions
• Performance improvements