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asp.net core 使用protobuf
在一些性能要求很高的应用中，使用protocol buffer序列化，优于Json。而且protocol buffer向后兼容的能力比较好。
由于Asp.net core 采用了全新的MiddleWare方式，因此使用protobuf序列化，只需要使用Protobuf-net修饰需要序列化的对象，并在MVC初始化的时候增加相应的Formatter就可以了。
MVC Controller 的Action返回对象时，MVC回根据用户的Request Header里面的MIME选择对应的Formater来序列化返回对象( Serialize returned object)。MVC具有默认的Json Formater，这个可以不用管。
这里有一个直接可以运行的例子，具有Server和Client代码 https://github.com/damienbod/AspNetMvc6ProtobufFormatters
但是，这里面有一个很严重的问题。 看下面的例子。
例如我们需要序列化的对象时ApparatusType，服务端的定义(使用了EntityFramework)是这样的：
using System;using System.Collections.Generic;using System.ComponentModel.DataAnnotations;using ProtoBuf;namespace Hammergo.Data{ [ProtoContract] public partial class ApparatusType { public ApparatusType() { this.Apps = new List<App>(); } [ProtoMember(1)] public System.Guid Id { get; set; } [ProtoMember(2)] [MaxLength(20)] public string TypeName { get; set; } [ProtoIgnore] public virtual ICollection<App> Apps { get; set; } }}
属于ProtoBuf 的三个修饰为
[ProtoContract] [ProtoMember(1)]
[ProtoMember(2)]
其他的不用管，在客户端定义是这样的
using System;using System.Collections.Generic;using ProtoBuf;namespace Hammergo.Poco{ [ProtoContract] public class ApparatusType { [ProtoMember(1)] public virtual System.Guid Id { get; set; } [ProtoMember(2)] public virtual string TypeName { get; set; } }}这里使用了Virtual关键字，是为了生成POCO的代理类，以跟踪状态，没有这个要求可以不使用。
如果使用https://github.com/damienbod/AspNetMvc6ProtobufFormatters 的方案就会发现
如果ASP.NET 的action返回List<AppratusType>，在客户端使用
var result = response.Content.ReadAsAsync<List<Hammergo.Poco.ApparatusType>>(new[] { new ProtoBufFormatter() }).Result;
就会抛出异常，ReadAsAsync ProtoBuf Formatter No MediaTypeFormatter is available to read
大意是没有 相应的MediaTypeFormatter来供ReadAsAsync来使用，
检查https://github.com/damienbod/AspNetMvc6ProtobufFormatters 的方案，发现它调用了https://github.com/WebApiContrib/WebApiContrib.Formatting.ProtoBuf里面的ProtoBufFormatter.cs ，这个里面有一个错误。
using System;using System.IO;using System.Linq;using System.Net;using System.Net.Http;using System.Net.Http.Formatting;using System.Net.Http.Headers;using System.Reflection;using System.Threading.Tasks;using ProtoBuf;using ProtoBuf.Meta;namespace WebApiContrib.Formatting{ public class ProtoBufFormatter : MediaTypeFormatter { private static readonly MediaTypeHeaderValue mediaType = new MediaTypeHeaderValue("application/x-protobuf"); private static Lazy<RuntimeTypeModel> model = new Lazy<RuntimeTypeModel>(CreateTypeModel); public static RuntimeTypeModel Model { get { return model.Value; } } public ProtoBufFormatter() { SupportedMediaTypes.Add(mediaType); } public static MediaTypeHeaderValue DefaultMediaType { get { return mediaType; } } public override bool CanReadType(Type type) { return CanReadTypeCore(type); } public override bool CanWriteType(Type type) { return CanReadTypeCore(type); } public override Task<object> ReadFromStreamAsync(Type type, Stream stream, HttpContent content, IFormatterLogger formatterLogger) { var tcs = new TaskCompletionSource<object>(); try { object result = Model.Deserialize(stream, null, type); tcs.SetResult(result); } catch (Exception ex) { tcs.SetException(ex); } return tcs.Task; } public override Task WriteToStreamAsync(Type type, object value, Stream stream, HttpContent content, TransportContext transportContext) { var tcs = new TaskCompletionSource<object>(); try { Model.Serialize(stream, value); tcs.SetResult(null); } catch (Exception ex) { tcs.SetException(ex); } return tcs.Task; } private static RuntimeTypeModel CreateTypeModel() { var typeModel = TypeModel.Create(); typeModel.UseImplicitZeroDefaults = false; return typeModel; } private static bool CanReadTypeCore(Type type) { return type.GetCustomAttributes(typeof(ProtoContractAttribute)).Any(); } }}
private static bool CanReadTypeCore(Type type)这个有问题，它只能识别有ProtoContract的类，没法识别其对应的IEnumerable<T>，修改这个方法就可以了。如下：
private static bool CanReadTypeCore(Type type) { bool isCan = type.GetCustomAttributes(typeof(ProtoContractAttribute)).Any(); if (!isCan && typeof(IEnumerable).IsAssignableFrom(type)) { var temp = type.GetGenericArguments().FirstOrDefault(); isCan = temp.GetCustomAttributes(typeof(ProtoContractAttribute)).Any(); } return isCan; }
下面我给出，关键的代码片段：
使用了一个辅助Library，结构如下图：
DateTimeOffsetSurrogate.cs的代码如下：
using System;using System.Collections.Generic;using System.Linq;using System.Threading.Tasks;using ProtoBuf;namespace ProtoBufHelper{ [ProtoContract] public class DateTimeOffsetSurrogate { [ProtoMember(1)] public long DateTimeTicks { get; set; } [ProtoMember(2)] public short OffsetMinutes { get; set; } public static implicit operator DateTimeOffsetSurrogate(DateTimeOffset value) { return new DateTimeOffsetSurrogate { DateTimeTicks = value.Ticks, OffsetMinutes = (short)value.Offset.TotalMinutes }; } public static implicit operator DateTimeOffset(DateTimeOffsetSurrogate value) { return new DateTimeOffset(value.DateTimeTicks, TimeSpan.FromMinutes(value.OffsetMinutes)); } }}
ProtoBufFormatter.cs 的代码如下：
using System;using System.Collections;using System.IO;using System.Linq;using System.Net;using System.Net.Http;using System.Net.Http.Formatting;using System.Net.Http.Headers;using System.Reflection;using System.Threading.Tasks;using ProtoBuf;using ProtoBuf.Meta;namespace ProtoBufHelper{ public class ProtoBufFormatter : MediaTypeFormatter { private static readonly MediaTypeHeaderValue mediaType = new MediaTypeHeaderValue("application/x-protobuf"); private static Lazy<RuntimeTypeModel> model = new Lazy<RuntimeTypeModel>(CreateTypeModel); public static RuntimeTypeModel Model { get { return model.Value; } } public ProtoBufFormatter() { SupportedMediaTypes.Add(mediaType); } public static MediaTypeHeaderValue DefaultMediaType { get { return mediaType; } } public override bool CanReadType(Type type) { var temp = CanReadTypeCore(type); return temp; } public override bool CanWriteType(Type type) { return CanReadTypeCore(type); } public override Task<object> ReadFromStreamAsync(Type type, Stream stream, HttpContent content, IFormatterLogger formatterLogger) { var tcs = new TaskCompletionSource<object>(); try { object result = Model.Deserialize(stream, null, type); tcs.SetResult(result); } catch (Exception ex) { tcs.SetException(ex); } return tcs.Task; } public override Task WriteToStreamAsync(Type type, object value, Stream stream, HttpContent content, TransportContext transportContext) { var tcs = new TaskCompletionSource<object>(); try { Model.Serialize(stream, value); tcs.SetResult(null); } catch (Exception ex) { tcs.SetException(ex); } return tcs.Task; } private static RuntimeTypeModel CreateTypeModel() { var typeModel = TypeModel.Create(); typeModel.UseImplicitZeroDefaults = false; typeModel.Add(typeof(DateTimeOffset), false).SetSurrogate(typeof(DateTimeOffsetSurrogate)); return typeModel; } private static bool CanReadTypeCore(Type type) { bool isCan = type.GetCustomAttributes(typeof(ProtoContractAttribute)).Any(); if (!isCan && typeof(IEnumerable).IsAssignableFrom(type)) { var temp = type.GetGenericArguments().FirstOrDefault(); isCan = temp.GetCustomAttributes(typeof(ProtoContractAttribute)).Any(); } return isCan; } }}
这样就可以设置ASP.NET Core端的代码：
添加ProtobufInputFormatter.cs 和 ProtobufOutputFormatter.cs 代码分别如下：
using System;using System.Threading.Tasks;using Microsoft.AspNetCore.Mvc;using Microsoft.AspNetCore.Mvc.Formatters;using Microsoft.Net.Http.Headers;using ProtoBuf.Meta;using ProtoBufHelper;namespace DamService{ public class ProtobufInputFormatter : InputFormatter { private static Lazy<RuntimeTypeModel> model = new Lazy<RuntimeTypeModel>(CreateTypeModel); public static RuntimeTypeModel Model { get { return model.Value; } } public override Task<InputFormatterResult> ReadRequestBodyAsync(InputFormatterContext context) { var type = context.ModelType; var request = context.HttpContext.Request; MediaTypeHeaderValue requestContentType = null; MediaTypeHeaderValue.TryParse(request.ContentType, out requestContentType); object result = Model.Deserialize(context.HttpContext.Request.Body, null, type); return InputFormatterResult.SuccessAsync(result); } public override bool CanRead(InputFormatterContext context) { return true; } private static RuntimeTypeModel CreateTypeModel() { var typeModel = TypeModel.Create(); typeModel.UseImplicitZeroDefaults = false; typeModel.Add(typeof(DateTimeOffset), false).SetSurrogate(typeof(DateTimeOffsetSurrogate)); return typeModel; } }}
using System;using System.Text;using System.Threading.Tasks;using Microsoft.AspNetCore.Mvc.Formatters;using Microsoft.Net.Http.Headers;using ProtoBuf.Meta;using ProtoBufHelper;namespace DamService{ public class ProtobufOutputFormatter : OutputFormatter { private static Lazy<RuntimeTypeModel> model = new Lazy<RuntimeTypeModel>(CreateTypeModel); public string ContentType { get; private set; } public static RuntimeTypeModel Model { get { return model.Value; } } public ProtobufOutputFormatter() { ContentType = "application/x-protobuf"; SupportedMediaTypes.Add(MediaTypeHeaderValue.Parse("application/x-protobuf")); //SupportedEncodings.Add(Encoding.GetEncoding("utf-8")); } private static RuntimeTypeModel CreateTypeModel() { var typeModel = TypeModel.Create(); typeModel.UseImplicitZeroDefaults = false; typeModel.Add(typeof(DateTimeOffset), false).SetSurrogate(typeof(DateTimeOffsetSurrogate)); return typeModel; } public override Task WriteResponseBodyAsync(OutputFormatterWriteContext context) { var response = context.HttpContext.Response; Model.Serialize(response.Body, context.Object); return Task.FromResult(response); } }}
在Startup.cs中
public void ConfigureServices(IServiceCollection services) 方法中这样添加MVC中间件
services.AddMvc(options =>
{
options.InputFormatters.Add(new ProtobufInputFormatter());
options.OutputFormatters.Add(new ProtobufOutputFormatter());
options.FormatterMappings.SetMediaTypeMappingForFormat("protobuf", MediaTypeHeaderValue.Parse("application/x-protobuf"));
});
整个Startup.cs代码
using System;using System.Collections.Generic;using System.Linq;using System.Threading.Tasks;using Microsoft.AspNetCore.Builder;using Microsoft.AspNetCore.Hosting;using Microsoft.AspNetCore.Identity.EntityFrameworkCore;using Microsoft.EntityFrameworkCore;using Microsoft.Extensions.Configuration;using Microsoft.Extensions.DependencyInjection;using Microsoft.Extensions.Logging;using DamService.Data;using DamService.Models;using DamService.Services;using System.Net;using Microsoft.AspNetCore.Diagnostics;using Microsoft.AspNetCore.Http;using Microsoft.Net.Http.Headers;namespace DamService{ public class Startup { public Startup(IHostingEnvironment env) { var builder = new ConfigurationBuilder() .SetBasePath(env.ContentRootPath) .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true) .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true); if (env.IsDevelopment()) { // For more details on using the user secret store see http://go.microsoft.com/fwlink/?LinkID=532709 builder.AddUserSecrets(); } builder.AddEnvironmentVariables(); Configuration = builder.Build(); } public IConfigurationRoot Configuration { get; } // This method gets called by the runtime. Use this method to add services to the container. public void ConfigureServices(IServiceCollection services) { // Add framework services. services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"))); services.AddScoped(provider => new Hammergo.Data.DamWCFContext(Configuration.GetConnectionString("OdataDBConnectionString"))); services.AddIdentity<ApplicationUser, IdentityRole>() .AddEntityFrameworkStores<ApplicationDbContext>() .AddDefaultTokenProviders(); services.AddMvc(options => { options.InputFormatters.Add(new ProtobufInputFormatter()); options.OutputFormatters.Add(new ProtobufOutputFormatter()); options.FormatterMappings.SetMediaTypeMappingForFormat("protobuf", MediaTypeHeaderValue.Parse("application/x-protobuf")); }); // Add application services. //services.AddTransient<IEmailSender, AuthMessageSender>(); //services.AddTransient<ISmsSender, AuthMessageSender>(); } // This method gets called by the runtime. Use this method to configure the HTTP request pipeline. public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory) { loggerFactory.AddConsole(Configuration.GetSection("Logging")); loggerFactory.AddDebug(); //if (env.IsDevelopment()) //{ // app.UseDeveloperExceptionPage(); // app.UseDatabaseErrorPage(); // app.UseBrowserLink(); //} //else //{ // app.UseExceptionHandler("/Home/Error"); //} app.UseExceptionHandler(_exceptionHandler); app.UseStaticFiles(); app.UseIdentity(); // Add external authentication middleware below. To configure them please see http://go.microsoft.com/fwlink/?LinkID=532715 app.UseMvc(routes => { routes.MapRoute( name: "default", template: "{controller=Home}/{action=Index}/{id?}"); }); } private void _exceptionHandler(IApplicationBuilder builder) { builder.Run( async context => { context.Response.StatusCode = (int)HttpStatusCode.InternalServerError; context.Response.ContentType = "text/plain"; var error = context.Features.Get<IExceptionHandlerFeature>(); if (error != null) { await context.Response.WriteAsync(error.Error.Message).ConfigureAwait(false); } }); } }}上面的
services.AddScoped(provider => new Hammergo.Data.DamWCFContext(Configuration.GetConnectionString("OdataDBConnectionString")));是我自己的数据库连接，可以使用自己的，也可以不用，我用的是EntityFrameWork 6.1.3 不是core，目前core还有一些功能没有，暂时不使用。 添加一个测试用的Controller，
using System;using System.Linq;using Microsoft.AspNetCore.Mvc;using Microsoft.Extensions.Logging;using Hammergo.Data;using System.Linq.Expressions;using System.Data.Entity;using System.Collections.Generic;using System.Threading.Tasks;namespace DamService.Controllers{ public class AppsController : Controller { private readonly DamWCFContext _dbContext; private readonly ILogger _logger; public AppsController( DamWCFContext dbContext, ILoggerFactory loggerFactory) { _dbContext = dbContext; _logger = loggerFactory.CreateLogger<AccountController>(); } [HttpGet] public async Task<List<App>> Top10() { return await _dbContext.Apps.Take(10).ToListAsync(); } }}客户端测试代码：
var client = new HttpClient { BaseAddress = new Uri("http://localhost.Fiddler:40786/") }; client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-protobuf")); HttpResponseMessage response = null; //test top 10 string uri = "Apps/Top10"; Trace.WriteLine("\n Test {0}.", uri); response = client.GetAsync(uri).Result; if (response.IsSuccessStatusCode) { var result = response.Content.ReadAsAsync<List<Hammergo.Poco.App>>(new[] { new ProtoBufFormatter() }).Result; Assert.AreEqual(result.Count, 10, "反序列化失败"); Console.WriteLine("{0} test success!", uri); } else { var message = response.Content.ReadAsStringAsync().Result; Console.WriteLine("{0} ({1})\n message: {2} ", (int)response.StatusCode, response.ReasonPhrase, message); }
http://localhost.Fiddler:40786/ 这里40786为服务端口，Fiddler表示使用了Fiddler代理，这样在使用时需要开启Fiddler，如果不使用Fidller，将URI修改为：
http://localhost:40786/
asp.net core 使用protobuf
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