无法解析“Swashbuckle.AspNetCore.Swagger.ISwaggerProvider”类型的服务

Question

我正在启动一个新的Core Web API，并希望将Swagger 添加到我的应用程序中。

我现在的环境：

• .Net Core 3.0
• Swashbuckle.AspNetCore 5.0.0-rc4

这是我的Startup.cs 类和配置：

public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers();

        //AK: Enable CORS
        //CORS should be configured on host server.
        services.AddCors(setupAction =>
        {
            setupAction.AddPolicy(DevCorsPolicyName,
                builder =>
                {
                    builder.WithOrigins("*").AllowAnyHeader().AllowAnyMethod();
                });
        });

        #region Configuration

        //Configuration File
        services.Configure<AppSettingConfiguration>(Configuration.GetSection("AppSettings"));
        //AutoMapper
        services.AddAutoMapper(AppDomain.CurrentDomain.GetAssemblies());

        //Configure Swagger
        services.ConfigureSwaggerGen(c =>
        {
            c.SwaggerDoc("v3", new OpenApiInfo
            {
                Title = "GTrackAPI",
                Version = "v3"
            });
        });

        #endregion

        #region Dependency Injection

        //Database context and repository
        services.AddDbContext<IGTrackContext, GTrackContext>(builder =>
        {
            builder.UseSqlServer(connectionString: Configuration.GetConnectionString("gtrackConnection"), sqlServerOptionsAction: null);
        });
        services.AddScoped<IGTrackRepository, GTrackRepository>();

        //facade layers
        services.AddScoped<IPersonFacade, PersonFacade>();

        //Service layers
        services.AddScoped<IPersonService, PersonService>();

        #endregion
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        //Enable development environment only settings
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        //AK: Only allow all origins for development environmnet
        app.UseCors(DevCorsPolicyName);

        // 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(c =>
        {
            c.SwaggerEndpoint("/swagger/v1/swagger.json", "GTrackAPI");
            c.RoutePrefix = string.Empty; //Configures swagger to load at application root
        });

        app.UseRouting();

        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });
    }

当我运行我的应用程序时，我收到以下错误：

InvalidOperationException：尝试调用中间件“Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware”时，无法解析“Swashbuckle.AspNetCore.Swagger.ISwaggerProvider”类型的服务。

这里是Stacktrace：

System.InvalidOperationException：尝试调用中间件“Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware”时，无法解析“Swashbuckle.AspNetCore.Swagger.ISwaggerProvider”类型的服务。 在 Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.GetService(IServiceProvider sp, Type type, Type middleware) 在 lambda_method（闭包，对象，HttpContext，IServiceProvider） 在 Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.c__DisplayClass4_1.b__2（HttpContext 上下文） 在 Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.Invoke（HttpContext 上下文，ICorsPolicyProvider corsPolicyProvider） 在 Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.c__DisplayClass4_1.b__2（HttpContext 上下文） 在 Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext 上下文)

很明显，我在这里遗漏了一些东西，不确定到底是什么。任何帮助将不胜感激。

Answer 1

来电

services.AddSwaggerGen();

ConfigureServices 中似乎缺少。

public static IServiceCollection AddSwaggerGen(
    this IServiceCollection services,
    Action<SwaggerGenOptions> setupAction = null)
{
    // Add Mvc convention to ensure ApiExplorer is enabled for all actions
    services.Configure<MvcOptions>(c =>
        c.Conventions.Add(new SwaggerApplicationConvention()));

    // Register generator and it's dependencies
    services.AddTransient<ISwaggerProvider, SwaggerGenerator>();
    services.AddTransient<ISchemaGenerator, SchemaGenerator>();
    services.AddTransient<IApiModelResolver, JsonApiModelResolver>();

    // Register custom configurators that assign values from SwaggerGenOptions (i.e. high level config)
    // to the service-specific options (i.e. lower-level config)
    services.AddTransient<IConfigureOptions<SwaggerGeneratorOptions>, ConfigureSwaggerGeneratorOptions>();
    services.AddTransient<IConfigureOptions<SchemaGeneratorOptions>, ConfigureSchemaGeneratorOptions>();

    // Used by the <c>dotnet-getdocument</c> tool from the Microsoft.Extensions.ApiDescription.Server package.
    services.TryAddSingleton<IDocumentProvider, DocumentProvider>();

    if (setupAction != null) services.ConfigureSwaggerGen(setupAction);

    return services;
}

这就是将ISwaggerProvider 添加到服务集合的原因

您可以将当前代码重构为

//...

//Configure Swagger
services.AddSwaggerGen(c => { //<-- NOTE 'Add' instead of 'Configure'
    c.SwaggerDoc("v3", new OpenApiInfo {
        Title = "GTrackAPI",
        Version = "v3"
    });
});

//...

从源代码中可以看出，它最终会通过设置操作调用ConfigureSwaggerGen。

Answer 2

如果您使用 dotnet CLI 创建了 Web API，并且遇到此错误

错误 NU1100：无法为“net5.0”解析“Swashbuckle.AspNetCore (>= 5.6.3)”

表示dotnet CLI找不到swagger依赖

要解决此问题，您可以运行以下 dotnet CLI 命令

dotnet add package Swashbuckle.AspNetCore.Swagger --version 5.6.3

Answer 3

Minimal API 和 .NET 6 的答案

1. 安装Swashbuckle.AspNetCore NuGet 包
2. 在AddSwaggerGen之前添加AddEndpointsApiExplorer

工作示例：

var builder = WebApplication.CreateBuilder(args);

var services = builder.Services;
services.AddEndpointsApiExplorer();
services.AddSwaggerGen();

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
}

app.UseSwagger();

app.MapGet("/", () => "Hello World!");

app.UseSwaggerUI();
app.Run();