keyed-service

modul-connect/naming-conventions/keyed-service

C# Keyed Service Naming Convention

Rule Definition

When generating or refactoring C# constructors using the [FromKeyedServices] attribute, the parameter name must be derived from the Key Argument rather than the Interface Type.

Logic & Transformation

1. Source of Truth: Use the value inside [FromKeyedServices(...)] (e.g., ModulConnect.Queries.Postgres.Backoffice).
2. Identifier Extraction: Take the last segment of the Key (e.g., Backoffice).
3. Contextual Suffixing: - If the namespace contains .Queries., append Query.

• If the namespace contains .Commands., append Command.

1. Casing: Convert the result to camelCase for the parameter and _camelCase for the private field.

Examples

✅ Correct (Key-Derived)

public class OrderProcessor(
    [FromKeyedServices(ModulConnect.Queries.Postgres.Backoffice)] 
    IDataAccess backofficeQuery) 
{
    private readonly IDataAccess _backofficeQuery = backofficeQuery;
}

❌ Incorrect (Type-Derived)

// DO NOT use the interface name "dataAccess"
public class OrderProcessor(
    [FromKeyedServices(ModulConnect.Queries.Postgres.Backoffice)] 
    IDataAccess dataAccess) 
{ 
    /* ... */ 
}

Rationale

In a modular architecture, the interface (e.g., IDataAccess) defines the contract, but the Key defines the instance's specific responsibility. Naming the parameter after the Key prevents naming collisions when multiple implementations of the same interface are injected and provides immediate semantic clarity.