services.AddSwaggerGen(option =>
 {
 option.SwaggerDoc("sparktodo", new OpenApiInfo
 {
  Version = "v1",
  Title = "SparkTodo API",
  Description = "API for SparkTodo",
  Contact = new OpenApiContact() { Name = "WeihanLi", Email = "weihanli@outlook.com" }
 });
 
 // include document file
 option.IncludeXmlComments(Path.Combine(AppContext.BaseDirectory, $"{typeof(Startup).Assembly.GetName().Name}.xml"), true);
 });

//Enable middleware to serve generated Swagger as a JSON endpoint.
app.UseSwagger();
//Enable middleware to serve swagger-ui (HTML, JS, CSS etc.), specifying the Swagger JSON endpoint
app.UseSwaggerUI(option =>
{
 option.SwaggerEndpoint("/swagger/sparktodo/swagger.json", "sparktodo Docs");

 option.RoutePrefix = string.Empty;
 option.DocumentTitle = "SparkTodo API";
});

services.AddSwaggerGen(option =>
{
 // ...

 // Add security definitions
 option.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme()
 {
 Description = "Please enter into field the word 'Bearer' followed by a space and the JWT value",
 Name = "Authorization",
 In = ParameterLocation.Header,
 Type = SecuritySchemeType.ApiKey,
 });
 option.AddSecurityRequirement(new OpenApiSecurityRequirement
 {
 { new OpenApiSecurityScheme
 {
  Reference = new OpenApiReference()
  {
  Id = "Bearer",
  Type = ReferenceType.SecurityScheme
  }
 }, Array.Empty<string>() }
 });
});

services.AddApiVersioning(options =>
 {
 options.AssumeDefaultVersionWhenUnspecified = true;
 options.DefaultApiVersion = ApiVersion.Default;
 options.ReportApiVersions = true;
 });

services.AddSwaggerGen(option =>
{
 // ...

 option.SwaggerDoc("v1", new OpenApiInfo { Version = "v1", Title = "API V1" });
 option.SwaggerDoc("v2", new OpenApiInfo { Version = "v2", Title = "API V2" });

 option.DocInclusionPredicate((docName, apiDesc) =>
 {
 var versions = apiDesc.CustomAttributes()
  .OfType<ApiVersionAttribute>()
  .SelectMany(attr => attr.Versions);

 return versions.Any(v => $"v{v.ToString()}" == docName);
 });

 option.OperationFilter<RemoveVersionParameterOperationFilter>();
 option.DocumentFilter<SetVersionInPathDocumentFilter>();
});

public class SetVersionInPathDocumentFilter : IDocumentFilter
{
 public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
 {
 var updatedPaths = new OpenApiPaths();

 foreach (var entry in swaggerDoc.Paths)
 {
  updatedPaths.Add(
  entry.Key.Replace("v{version}", swaggerDoc.Info.Version),
  entry.Value);
 }

 swaggerDoc.Paths = updatedPaths;
 }
}

public class RemoveVersionParameterOperationFilter : IOperationFilter
{
 public void Apply(OpenApiOperation operation, OperationFilterContext context)
 {
 // Remove version parameter from all Operations
 var versionParameter = operation.Parameters.Single(p => p.Name == "version");
 operation.Parameters.Remove(versionParameter);
 }
}

//Enable middleware to serve generated Swagger as a JSON endpoint.
app.UseSwagger();
//Enable middleware to serve swagger-ui (HTML, JS, CSS etc.), specifying the Swagger JSON endpoint
app.UseSwaggerUI(option =>
{
 option.SwaggerEndpoint("/swagger/v2/swagger.json", "V2 Docs");
 option.SwaggerEndpoint("/swagger/v1/swagger.json", "V1 Docs");

 option.RoutePrefix = string.Empty;
 option.DocumentTitle = "SparkTodo API";
});