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DependencyInjectionExtensions

Namespace: RA.Utilities.OpenApi.Extensions

The DependencyInjectionExtensions class provides a set of convenient extension methods for OpenApiOptions to simplify the registration of the various document transformers and filters included in this package.

These helpers streamline the setup process in Program.cs, making the code cleaner and more readable.

AddDefaultsDocumentTransformer()​

This is the recommended starting point. It registers a sensible default set of document transformers with a single call.

What it does:

  • DocumentInfoTransformer: Populates the API's title, version, and description from appsettings.json.
  • BearerSecurityDocumentTransformer: Automatically adds the "Authorize" button and JWT security scheme if Bearer authentication is detected.
  • HeadersParameterTransformer: Adds common request and response headers (like x-request-id) to all API operations based on configuration.

Usage​

// In Program.cs
builder.Services.AddOpenApi()
    .AddDefaultsDocumentTransformer();

AddFluentValidationRules()​

This extension registers the FluentValidationSchemaTransformer, which automatically enriches the OpenAPI schema with constraints derived from your FluentValidation rules.

Usage​

// In Program.cs
builder.Services.AddOpenApi(options =>
{
    options.AddFluentValidationRules();
});

AddEnumXmlDescriptionTransformer(string xmlPath)​

This extension registers the EnumXmlSchemaTransformer, which reads your project's XML documentation file to add descriptive markdown tables to your enum schemas.

Usage​

// In Program.cs
var xmlFile = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);

builder.Services.AddOpenApi(options =>
{
    options.AddEnumXmlDescriptionTransformer(xmlPath);
});

AddDefaultResponsesOperationTransformer()​

This extension registers the DefaultResponsesOperationTransformer, which automatically adds a standardized 500 Internal Server Error response to every API operation.

Usage​

// In Program.cs
builder.Services.AddOpenApi()
    .AddDefaultResponsesOperationTransformer();

AddPolymorphismDocumentTransformer<T>()​

This extension registers the PolymorphismDocumentTransformer to correctly document polymorphic types (a base class with several derived classes) using the oneOf and discriminator keywords.

Usage​

You provide the base type T and a dictionary mapping discriminator values to the derived types.

// In Program.cs
builder.Services.AddOpenApi()
    .AddPolymorphismDocumentTransformer<ErrorResponse>(new()
    {
        { "NotFound", typeof(NotFoundResponse) },
        { "Conflict", typeof(ConflictResponse) },
    });

Individual Transformer Extensions​

For more granular control, you can also register each of the default transformers individually.

Usage​

// In Program.cs
builder.Services.AddOpenApi()
    .AddDocumentInfoTransformer()
    .AddBearerSecurityDocumentTransformer();
    // ... and so on