DocumentService/DocumentService.API/Configuration/SwaggerConfiguration.cs

using Microsoft.Extensions.Options;
using Microsoft.OpenApi.Models;
using System.Reflection;

namespace DocumentService.API.Configuration
{
    /// <summary>
    /// Provides extension methods for configuring Swagger/OpenAPI documentation.
    /// </summary>
    public static class SwaggerConfiguration
    {
        /// <summary>
        /// Adds Swagger documentation generation to the service collection.
        /// </summary>
        /// <param name="services">The service collection to add Swagger to.</param>
        /// <param name="configuration">Configuration to read SwaggerSettings from.</param>
        /// <returns>The modified service collection.</returns>
        public static IServiceCollection AddSwaggerDocumentation(
            this IServiceCollection services,
            IConfiguration configuration)
        {
            var swaggerSettings = configuration.GetSection(SwaggerSettings.SectionName).Get<SwaggerSettings>()
                ?? new SwaggerSettings();

            services.AddSwaggerGen(options =>
            {
                options.SwaggerDoc(swaggerSettings.Version, new OpenApiInfo
                {
                    Title = swaggerSettings.Title,
                    Version = swaggerSettings.Version,
                    Description = swaggerSettings.Description
                });

                // Resolve conflicting actions: Keep first variant
                // DualInputDocumentFilter will merge both variants into single operation
                options.ResolveConflictingActions(apiDescriptions => apiDescriptions.First());

                // Add document filter to merge operations with different content types
                options.DocumentFilter<DualInputDocumentFilter>();

                // XML-Kommentare einbinden
                var xmlFile = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
                var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);
                options.IncludeXmlComments(xmlPath);
            });

            return services;
        }
    }
}