c# - Autorest/Swagger 为返回文件的 Web Api Controller 生成代码

Question

在我的 ASP.NET Web API 应用程序中，我有一个这样的 Controller :

    [RoutePrefix("api/ratings")]
    public class RateCostumerController : ApiController
    { 

        [AllowAnonymous]  
        [Route("Report/GetReport")]  
        [HttpGet]
        public HttpResponseMessage ExportReport([FromUri] string costumer)  

        {  
            var rd = new ReportDocument();  

           /*No relevant code here*/

            var result = new HttpResponseMessage(HttpStatusCode.OK)
            {
                Content = new ByteArrayContent(ms.ToArray())
            };
            result.Content.Headers.ContentDisposition =
                new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment")
                {
                    FileName = "Reporte.pdf"
                };
            result.Content.Headers.ContentType =
                new MediaTypeHeaderValue("application/octet-stream");

            return result;
        }
}

因此，当我使用客户参数发出简单的 GET 请求时，我在浏览器中得到一个 pdf 文件作为响应。一些响应 header :

内容处理:附件； filename=Reporte.pdf内容长度:22331内容类型:应用程序/八位字节流

在我的 Xamarin PCL 项目中设置 swagger、生成 json 元数据文件并生成 C# 代码后，我尝试使用该服务。但它失败了，因为在生成的代码中试图反序列化 json，但不是 json 结果!

这是生成的代码失败的部分:

[...]
var _result = new Microsoft.Rest.HttpOperationResponse<object>();
            _result.Request = _httpRequest;
            _result.Response = _httpResponse;
            // Deserialize Response
            if ((int)_statusCode == 200)
            {
                _responseContent = await _httpResponse.Content.ReadAsStringAsync().ConfigureAwait(false);
                try
                {
                    _result.Body = Microsoft.Rest.Serialization.SafeJsonConvert.DeserializeObject<object>(_responseContent, this.Client.DeserializationSettings);
                }
                catch (Newtonsoft.Json.JsonException ex)
                {
                    _httpRequest.Dispose();
                    if (_httpResponse != null)
                    {
                        _httpResponse.Dispose();
                    }
                    throw new Microsoft.Rest.SerializationException("Unable to deserialize the response.", _responseContent, ex);
                }
            }
            if (_shouldTrace)
            {
                Microsoft.Rest.ServiceClientTracing.Exit(_invocationId, _result);
            }
            return _result;
[...]

当我调试时，我发现文件的内容在正文中，所以反序列化把它搞砸了。由于不建议编辑这个生成的类文件，我需要在我的 API 中更改什么才能正确生成应用程序/八位字节流内容响应的代码？

Answer 1

创建返回文件的自定义过滤器:

 [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false)]
    public sealed class SwaggerFileResponseAttribute : SwaggerResponseAttribute
    {
        public SwaggerFileResponseAttribute(HttpStatusCode statusCode) : base(statusCode)
        {
        }

        public SwaggerFileResponseAttribute(HttpStatusCode statusCode, string description = null, Type type = null)  : base(statusCode, description, type)
        {
        }
        public SwaggerFileResponseAttribute(int statusCode) : base(statusCode)
        {
        }

        public SwaggerFileResponseAttribute(int statusCode, string description = null, Type type = null) : base(statusCode, description, type)
        {
        }
    }

还有这个自定义的 ResponseTypeFilter 类:

public sealed class UpdateFileResponseTypeFilter : IOperationFilter
    {
        public void Apply(Operation operation, SchemaRegistry schemaRegistry, ApiDescription apiDescription)
        {
            if (apiDescription.GetControllerAndActionAttributes<SwaggerResponseRemoveDefaultsAttribute>().Any())
            {
                operation.responses.Clear();
            }
            var responseAttributes = apiDescription.GetControllerAndActionAttributes<SwaggerFileResponseAttribute>()
                .OrderBy(attr => attr.StatusCode);

            foreach (var attr in responseAttributes)
            {
                var statusCode = attr.StatusCode.ToString();

                Schema responseSchema = new Schema { format = "byte", type = "file" };

                operation.produces.Clear();
                operation.produces.Add("application/octet-stream");

                operation.responses[statusCode] = new Response
                {
                    description = attr.Description ?? InferDescriptionFrom(statusCode),
                    schema = responseSchema
                };
            }
        }

        private string InferDescriptionFrom(string statusCode)
        {
            HttpStatusCode enumValue;
            if (Enum.TryParse(statusCode, true, out enumValue))
            {
                return enumValue.ToString();
            }
            return null;
        }
    }

然后在SwaggerConfig文件中注册:

c.OperationFilter<UpdateFileResponseTypeFilter>();

要使用这个过滤器，只需像这样在每个 Action Controller 中添加它:

 [Route("Report/GetReport/{folio}")]
        [SwaggerFileResponse(HttpStatusCode.OK, "File Response")]
        [HttpGet]
        public HttpResponseMessage ExportReport(string folio)
        {
...

因此，当 swagger 生成 json 元数据时，autorest 将正确创建一个返回任务的方法 < Microsoft.Rest.HttpOperationResponse< System.IO.Stream >>