asp.net core 3.0 中使用 swagger

Intro#

上次更新了 asp.net core 3.0 简单的记录了一下 swagger 的使用 ,详细可以参考asp.net core3.0更新简记，那个项目的 api 比较简单，都是匿名接口不涉及到认证以及 api 版本控制，最近把另外一个 api 项目升级到了 3.0，还是遇到了一些问题，这里单独写一篇文章介绍，避免踩坑。

Swagger 基本使用#

安装 nuget 包 Swashbuckle.AspNetCore，需要使用 5.0.x 版本，使用最新的 5.0.0-rc 版本（还没发稳定版，需要显示预览版本才能看到）

swagger 服务注册：

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);
    });

中间件配置：

//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";
});

为 Swagger 添加 Bearer Token 认证#

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>() }
    });
});

支持多个 ApiVersion#

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>();
});

自定义 Api version 相关的 OperationFilter:

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);
    }
}

中间件配置：

//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";
});

最终 swagger 效果