LuskiServer/LuskiServer/ConfigureSwaggerOptions.cs

using Asp.Versioning;

namespace LuskiServer;

using Asp.Versioning.ApiExplorer;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using Microsoft.OpenApi.Models;
using Swashbuckle.AspNetCore.SwaggerGen;
using System.Text;

/// <summary>
/// Configures the Swagger generation options.
/// </summary>
/// <remarks>This allows API versioning to define a Swagger document per API version after the
/// <see cref="IApiVersionDescriptionProvider"/> service has been resolved from the service container.</remarks>
public class ConfigureSwaggerOptions : IConfigureOptions<SwaggerGenOptions>
{
    private readonly IApiVersionDescriptionProvider provider;

    /// <summary>
    /// Initializes a new instance of the <see cref="ConfigureSwaggerOptions"/> class.
    /// </summary>
    /// <param name="provider">The <see cref="IApiVersionDescriptionProvider">provider</see> used to generate Swagger documents.</param>
    public ConfigureSwaggerOptions(IApiVersionDescriptionProvider provider) => this.provider = provider;

    /// <inheritdoc />
    public void Configure(SwaggerGenOptions options)
    {
        // add a swagger document for each discovered API version
        // note: you might choose to skip or document deprecated API versions differently
        foreach (ApiVersionDescription description in provider.ApiVersionDescriptions)
        {
            options.SwaggerDoc(description.GroupName, CreateInfoForApiVersion(description));
        }
    }

    private static OpenApiInfo CreateInfoForApiVersion(ApiVersionDescription description)
    {
        StringBuilder text = new StringBuilder("A simple way to view nice information to understand API v" + description.ApiVersion + ".");
        OpenApiInfo info = new OpenApiInfo()
        {
            Title = "Luski Server API",
            Version = description.ApiVersion.ToString(),
            //Contact = new OpenApiContact() { Name = "Bill Mei", Email = "bill.mei@somewhere.com" },
            //License = new OpenApiLicense() { Name = "MIT", Url = new Uri( "https://opensource.org/licenses/MIT" ) }
        };

        if (description.IsDeprecated)
        {
            text.Append(" This API version has been deprecated.");
        }

        if (description.SunsetPolicy is { } policy)
        {
            if (policy.Date.HasValue)
            {
                text.Append(" The API will be sunset on ")
                    .Append(policy.Date.Value.Date.ToShortDateString())
                    .Append('.');
            }

            if (policy.HasLinks)
            {
                text.AppendLine();

                for (int i = 0; i < policy.Links.Count; i++)
                {
                    LinkHeaderValue link = policy.Links[i];

                    if (link.Type == "text/html")
                    {
                        text.AppendLine();

                        if (link.Title.HasValue)
                        {
                            text.Append(link.Title.Value).Append(": ");
                        }

                        text.Append(link.LinkTarget.OriginalString);
                    }
                }
            }
        }

        info.Description = text.ToString();

        return info;
    }
}