使用WPF、OwinSelfHost和Swagger创建自托管的Web API

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Web.Http;
using System.Web.Http.Filters;
using System.Xml;
using Microsoft.Owin;
using Microsoft.Owin.Cors;
using MockAPI.Common;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
using Owin;
using Swashbuckle.Application;
using Swashbuckle.Swagger;

[assembly: OwinStartup(typeof(MockAPI.Startup))]

namespace MockAPI
{
    public class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            HttpConfiguration config = new HttpConfiguration();

            JsonSerializerSettings setting = new JsonSerializerSettings()
            {
                //日期类型默认格式化处理
                DateFormatHandling = DateFormatHandling.MicrosoftDateFormat,
                DateFormatString = "yyyy-MM-dd HH:mm:ss",
                //驼峰样式
                ContractResolver = new CamelCasePropertyNamesContractResolver(),
                //空值处理
                //NullValueHandling = NullValueHandling.Ignore,
                //设置序列化的最大层数
                MaxDepth = 10,
                //解决json序列化时的循环引用问题
                ReferenceLoopHandling = ReferenceLoopHandling.Ignore
            };
            config.Formatters.JsonFormatter.SerializerSettings = setting;
            config.Formatters.Remove(config.Formatters.XmlFormatter);

            config.Filters.Add(new HandlerErrorAttribute());
            //config.Routes.MapHttpRoute(
            //    name: "DefaultApi",
            //    routeTemplate: "api/{controller}/{action}/{id}",
            //    defaults: new
            //    {
            //        id = RouteParameter.Optional
            //    }
            //);
            ConfigureSwagger(config);
            //添加路由路径
            config.MapHttpAttributeRoutes();
            app.UseCors(CorsOptions.AllowAll);

            app.Use<LoggingMiddleware>();
            app.UseWebApi(config);

        }
        private static void ConfigureSwagger(HttpConfiguration config)
        {
            var thisAssembly = typeof(Startup).Assembly;
            config.EnableSwagger(c =>
             {
                 c.SingleApiVersion("v1", "MockAPI");

                    //设置接口描述xml路径地址
                    var webApiXmlPath = string.Format(string.Format("{0}/MockAPI.xml", AppDomain.CurrentDomain.BaseDirectory));

                 c.IncludeXmlComments(webApiXmlPath);
                 c.UseFullTypeNameInSchemaIds();
                    //加入控制器描述
                    c.CustomProvider((defaultProvider) => new SwaggerControllerDescProvider(defaultProvider, webApiXmlPath));
             })
             .EnableSwaggerUi(c =>
             {
                 c.DocumentTitle("MockAPI");
                 c.InjectJavaScript(thisAssembly, "MockAPI.Common.Swagger.js");
             });
        }

        public class HandlerErrorAttribute : ExceptionFilterAttribute
        {
            /// <summary>
            /// 控制器方法中出现异常，会调用该方法捕获异常
            /// </summary>
            /// <param name="context">提供使用</param>
            public override void OnException(HttpActionExecutedContext context)
            {
                base.OnException(context);
                LogFile.WriteError(context.Exception.Message);
                throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.OK)
                {
                    Content = new StringContent(
                   JsonConvert.SerializeObject(
                    new
                    {
                        code = -1,
                        data = "xxx",
                        msg = context.Exception.Message
                    }), Encoding.UTF8, "text/json")
                });
            }
        };

        public class SwaggerControllerDescProvider : ISwaggerProvider
        {
            private readonly ISwaggerProvider _swaggerProvider;
            private static ConcurrentDictionary<string, SwaggerDocument> _cache = new ConcurrentDictionary<string, SwaggerDocument>();
            private readonly string _xml;
            /// <summary>
            /// 
            /// </summary>
            /// <param name="swaggerProvider"></param>
            /// <param name="xml">xml文档路径</param>
            public SwaggerControllerDescProvider(ISwaggerProvider swaggerProvider, string xml)
            {
                _swaggerProvider = swaggerProvider;
                _xml = xml;
            }

            public SwaggerDocument GetSwagger(string rootUrl, string apiVersion)
            {

                var cacheKey = string.Format("{0}_{1}", rootUrl, apiVersion);
                SwaggerDocument srcDoc = null;
                //只读取一次
                if (!_cache.TryGetValue(cacheKey, out srcDoc))
                {
                    srcDoc = _swaggerProvider.GetSwagger(rootUrl, apiVersion);

                    srcDoc.vendorExtensions = new Dictionary<string, object> { { "ControllerDesc", GetControllerDesc() } };
                    _cache.TryAdd(cacheKey, srcDoc);
                }
                return srcDoc;
            }

            /// <summary>
            /// 从API文档中读取控制器描述
            /// </summary>
            /// <returns>所有控制器描述</returns>
            public ConcurrentDictionary<string, string> GetControllerDesc()
            {
                string xmlpath = _xml;
                ConcurrentDictionary<string, string> controllerDescDict = new ConcurrentDictionary<string, string>();
                if (File.Exists(xmlpath))
                {
                    XmlDocument xmldoc = new XmlDocument();
                    xmldoc.Load(xmlpath);
                    string type = string.Empty, path = string.Empty, controllerName = string.Empty;

                    string[] arrPath;
                    int length = -1, cCount = "Controller".Length;
                    XmlNode summaryNode = null;
                    foreach (XmlNode node in xmldoc.SelectNodes("//member"))
                    {
                        type = node.Attributes["name"].Value;
                        if (type.StartsWith("T:"))
                        {
                            //控制器
                            arrPath = type.Split('.');
                            length = arrPath.Length;
                            controllerName = arrPath[length - 1];
                            if (controllerName.EndsWith("Controller"))
                            {
                                //获取控制器注释
                                summaryNode = node.SelectSingleNode("summary");
                                string key = controllerName.Remove(controllerName.Length - cCount, cCount);
                                if (summaryNode != null && !string.IsNullOrEmpty(summaryNode.InnerText) && !controllerDescDict.ContainsKey(key))
                                {
                                    controllerDescDict.TryAdd(key, summaryNode.InnerText.Trim());
                                }
                            }
                        }
                    }
                }
                return controllerDescDict;
            }
        }
    }
}