Asp.NetCoreWebApi - RESTful Api

時間 2019-12-11

標籤 asp.netcorewebapi asp netcorewebapi restful api 欄目 ASP 简体版

原文原文鏈接

1. REST
1. 經常使用http動詞
1. WebApi 在 Asp.NetCore 中的實現
- 3.1. 建立WebApi項目.
- 3.2. 集成Entity Framework Core操做Mysql
  - 3.2.1. 安裝相關的包(爲Xxxx.Infrastructure項目安裝)
  - 3.2.2. 創建Entity和Context
  - 3.2.3. ConfigureService中注入EF服務
  - 3.2.4. 遷移數據庫
  - 3.2.5. 數據庫遷移結果
  - 3.2.6. 爲數據庫建立種子數據
1. 支持https
1. 支持HSTS
1. 使用SerilLog
- 6.1. 安裝nuget包
- 6.2. 添加代碼
- 6.3. 自行測試
1. Asp.NetCore配置文件
- 7.1. 默認配置文件
- 7.2. 得到配置
1. 自定義一個異常處理,ExceptionHandler
- 8.1. 弄一個類,寫一個擴展方法處理異常
- 8.2. 在Configuration中使用擴展方法
1. 實現數據接口類(Resource),使用AutoMapper在Resource和Entity中映射
- 9.1. 爲Entity類建立對應的Resource類
- 9.2. 使用 AutoMapper
1. 使用FluentValidation
- 10.1. 安裝Nuget包
- 10.2. 爲每個Resource配置驗證器
1. 實現Http Get(翻頁,過濾,排序)
- 11.1. 資源命名
  - 11.1.1. 資源應該使用名詞,例
  - 11.1.2. 資源命名層次結構
- 11.2. 內容協商
1. 翻頁
- 12.1. 構造翻頁請求參數類
- 12.2. Repository實現支持翻頁請求參數的方法
- 12.3. 搜索(過濾)
- 12.4. 排序
  - 12.4.1. 排序思路
1. 資源塑形(Resource shaping)
1. HATEOAS
- 14.1. 建立供應商特定媒體類型
  - 14.1.1. 判斷Media Type類型

參考 :html

ASP.NET Core Web API 開發-RESTful API實現

理解HTTP冪等性

某站微軟Mvp楊旭的Asp.NetCore WebApi的視頻

1. REST

REST : 具象狀態傳輸(Representational State Transfer,簡稱REST),是Roy Thomas Fielding博士於2000年在他的博士論文 "Architectural Styles and the Design of Network-based Software Architectures" 中提出來的一種萬維網軟件架構風格。
目前在三種主流的Web服務實現方案中，由於REST模式與複雜的SOAP和XML-RPC相比更加簡潔，愈來愈多的web服務開始採用REST風格設計和實現。例如，Amazon.com提供接近REST風格的Web服務執行圖書查詢；mysql

符合REST設計風格的Web API稱爲RESTful API。它從如下三個方面資源進行定義：git

直觀簡短的資源地址：URI，好比：http://example.com/resources/ .
傳輸的資源：Web服務接受與返回的互聯網媒體類型，好比：JSON，XML，YAML等...
對資源的操做：Web服務在該資源上所支持的一系列請求方法（好比：POST，GET，PUT或DELETE）.

PUT和DELETE方法是冪等方法.GET方法是安全方法（不會對服務器端有修改，所以固然也是冪等的）.github

ps 關於冪等方法 :
看這篇理解HTTP冪等性.
簡單說,客戶端屢次請求服務端返回的結果都相同,那麼就說這個操做是冪等的.(我的理解,詳細的看上面給的文章)web

不像基於SOAP的Web服務，RESTful Web服務並無「正式」的標準。這是由於REST是一種架構，而SOAP只是一個協議。雖然REST不是一個標準，但大部分RESTful Web服務實現會使用HTTP、URI、JSON和XML等各類標準。sql

2. 經常使用http動詞

括號中是相應的SQL命令.數據庫

GET(SELECT) : 從服務器取出資源(一項或多項).
POST(CREATE) : 在服務器新建一個資源.
PUT(UPDATE) : 在服務器更新資源(客戶端提供改變後的完整資源).
PATCH(UPDATE) : 在服務器更新資源(客戶端提供改變的屬性).
DELETE(DELETE) : 在服務器刪除資源.

3. WebApi 在 Asp.NetCore 中的實現

這裏以用戶增刪改查爲例.json

3.1. 建立WebApi項目.

參考ASP.NET Core WebAPI 開發-新建WebAPI項目.api

注意,本文創建的Asp.NetCore WebApi項目選擇.net core版本是2.2,不建議使用其餘版本,2.1版本下會遇到依賴文件衝突問題!因此必定要選擇2.2版本的.net core.安全

3.2. 集成Entity Framework Core操做Mysql

3.2.1. 安裝相關的包(爲Xxxx.Infrastructure項目安裝)

Microsoft.EntityFrameworkCore.Design
Pomelo.EntityFrameworkCore.MySql

這裏注意一下,Mysql官方的包是 MySql.Data.EntityFrameworkCore,可是這個包有bug,我在github上看到有人說有替代方案 - Pomelo.EntityFrameworkCore.MySql,通過嘗試,後者比前者好用.全部這裏就選擇後者了.使用前者的話可能會致使數據庫遷移失敗(Update的時候).

PS: Mysql文檔原文:

Install the MySql.Data.EntityFrameworkCore NuGet package.
For EF Core 1.1 only: If you plan to scaffold a database, install the MySql.Data.EntityFrameworkCore.Design NuGet package as well.

EFCore - MySql文檔
Mysql版本要求:
Mysql版本要高於5.7
使用最新版本的Mysql Connector(2019 6/27 目前是8.x).

爲Xxxx.Infrastructure項目安裝EFCore相關的包:

爲Xxxx.Api項目安裝 Pomelo.EntityFrameworkCore.MySql

3.2.2. 創建Entity和Context

ApiUser

namespace ApiStudy.Core.Entities
{
    using System;

    public class ApiUser
    {
        public Guid Guid { get; set; }
        public string Name { get; set; }
        public string Passwd { get; set; }
        public DateTime RegistrationDate { get; set; }
        public DateTime Birth { get; set; }
        public string ProfilePhotoUrl { get; set; }
        public string PhoneNumber { get; set; }
        public string Email { get; set; }
    }
}

UserContext

namespace ApiStudy.Infrastructure.Database
{
    using ApiStudy.Core.Entities;
    using Microsoft.EntityFrameworkCore;

    public class UserContext:DbContext
    {
        public UserContext(DbContextOptions<UserContext> options): base(options)
        {
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<ApiUser>().HasKey(u => u.Guid);

            base.OnModelCreating(modelBuilder);
        }

        public DbSet<ApiUser> ApiUsers { get; set; }
    }
}

3.2.3. ConfigureService中注入EF服務

services.AddDbContext<UserContext>(options =>
            {
                string connString = "Server=Xxx:xxx:xxx:xxx;Database=Xxxx;Uid=root;Pwd=Xxxxx; ";
                options.UseMySQL(connString);
            });

3.2.4. 遷移數據庫

在Tools > NuGet Package Manager > Package Manager Console輸入命令.
Add-Migration Xxx 添加遷移.
PS : 若是遷移不想要,使用 Remove-Migration 命令刪除遷移.
Update-Database 更新到數據庫.

3.2.5. 數據庫遷移結果

3.2.6. 爲數據庫建立種子數據

寫一個建立種子數據的類

UserContextSeed

namespace ApiStudy.Infrastructure.Database
{
    using ApiStudy.Core.Entities;
    using Microsoft.Extensions.Logging;
    using System;
    using System.Linq;
    using System.Threading.Tasks;

    public class UserContextSeed
    {
        public static async Task SeedAsync(UserContext context,ILoggerFactory loggerFactory)
        {
            try
            {
                if (!context.ApiUsers.Any())
                {
                    context.ApiUsers.AddRange(
                        new ApiUser
                        {
                            Guid = Guid.NewGuid(),
                            Name = "la",
                            Birth = new DateTime(1998, 11, 29),
                            RegistrationDate = new DateTime(2019, 6, 28),
                            Passwd = "123587",
                            ProfilePhotoUrl = "https://www.laggage.top/",
                            PhoneNumber = "10086",
                            Email = "yu@outlook.com"
                        },
                        new ApiUser
                        {
                            Guid = Guid.NewGuid(),
                            Name = "David",
                            Birth = new DateTime(1995, 8, 29),
                            RegistrationDate = new DateTime(2019, 3, 28),
                            Passwd = "awt87495987",
                            ProfilePhotoUrl = "https://www.laggage.top/",
                            PhoneNumber = "1008611",
                            Email = "David@outlook.com"
                        },
                        new ApiUser
                        {
                            Guid = Guid.NewGuid(),
                            Name = "David",
                            Birth = new DateTime(2001, 8, 19),
                            RegistrationDate = new DateTime(2019, 4, 25),
                            Passwd = "awt87495987",
                            ProfilePhotoUrl = "https://www.laggage.top/",
                            PhoneNumber = "1008611",
                            Email = "David@outlook.com"
                        },
                        new ApiUser
                        {
                            Guid = Guid.NewGuid(),
                            Name = "Linus",
                            Birth = new DateTime(1999, 10, 26),
                            RegistrationDate = new DateTime(2018, 2, 8),
                            Passwd = "awt87495987",
                            ProfilePhotoUrl = "https://www.laggage.top/",
                            PhoneNumber = "17084759987",
                            Email = "Linus@outlook.com"
                        },
                        new ApiUser
                        {
                            Guid = Guid.NewGuid(),
                            Name = "YouYou",
                            Birth = new DateTime(1992, 1, 26),
                            RegistrationDate = new DateTime(2015, 7, 8),
                            Passwd = "grwe874864987",
                            ProfilePhotoUrl = "https://www.laggage.top/",
                            PhoneNumber = "17084759987",
                            Email = "YouYou@outlook.com"
                        },
                        new ApiUser
                        {
                            Guid = Guid.NewGuid(),
                            Name = "小白",
                            Birth = new DateTime(1997, 9, 30),
                            RegistrationDate = new DateTime(2018, 11, 28),
                            Passwd = "gewa749864",
                            ProfilePhotoUrl = "https://www.laggage.top/",
                            PhoneNumber = "17084759987",
                            Email = "BaiBai@outlook.com"
                        });

                    await context.SaveChangesAsync();
                }
            }
            catch(Exception ex)
            {
                ILogger logger = loggerFactory.CreateLogger<UserContextSeed>();
                logger.LogError(ex, "Error occurred while seeding database");
            }
        }
    }
}

修改Program.Main方法

Program.Main

IWebHost host = CreateWebHostBuilder(args).Build();

using (IServiceScope scope = host.Services.CreateScope())
{
    IServiceProvider provider = scope.ServiceProvider;
    UserContext userContext = provider.GetService<UserContext>();
    ILoggerFactory loggerFactory = provider.GetService<ILoggerFactory>();
    UserContextSeed.SeedAsync(userContext, loggerFactory).Wait();
}

host.Run();

這個時候運行程序會出現異常,打斷點看一下異常信息:Data too long for column 'Guid' at row 1

能夠猜到,Mysql的varbinary(16)放不下C# Guid.NewGuid()方法生成的Guid,因此配置一下數據庫Guid字段類型爲varchar(256)能夠解決問題.

解決方案:
修改 UserContext.OnModelCreating 方法
配置一下 ApiUser.Guid 屬性到Mysql數據庫的映射:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<ApiUser>().Property(p => p.Guid)
        .HasColumnType("nvarchar(256)");
    modelBuilder.Entity<ApiUser>().HasKey(u => u.Guid);
    
    base.OnModelCreating(modelBuilder);
}

4. 支持https

將全部http請求所有映射到https

Startup中:
ConfigureServices方法註冊,並配置端口和狀態碼等:
services.AddHttpsRedirection(…)

services.AddHttpsRedirection(options =>
                {
                    options.RedirectStatusCode = StatusCodes.Status307TemporaryRedirect;
                    options.HttpsPort = 5001;
                });

Configure方法使用該中間件:

app.UseHttpsRedirection()

5. 支持HSTS

ConfigureServices方法註冊
看官方文檔

services.AddHsts(options =>
{
    options.Preload = true;
    options.IncludeSubDomains = true;
    options.MaxAge = TimeSpan.FromDays(60);
    options.ExcludedHosts.Add("example.com");
    options.ExcludedHosts.Add("www.example.com");
});

Configure方法配置中間件管道

app.UseHsts();

注意 app.UseHsts() 方法最好放在 app.UseHttps() 方法以後.

6. 使用SerilLog

有關日誌的微軟官方文檔

SerilLog github倉庫
該github倉庫上有詳細的使用說明.

使用方法:

6.1. 安裝nuget包

Serilog.AspNetCore
Serilog.Sinks.Console

6.2. 添加代碼

Program.Main方法中:

Log.Logger = new LoggerConfiguration()
            .MinimumLevel.Debug()
            .MinimumLevel.Override("Microsoft", LogEventLevel.Information)
            .Enrich.FromLogContext()
            .WriteTo.Console()
            .CreateLogger();

修改Program.CreateWebHostBuilder(...)

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>()
                .UseSerilog(); // <-- Add this line;
 }

6.3. 自行測試

7. Asp.NetCore配置文件

7.1. 默認配置文件

默認 appsettings.json
ConfigurationBuilder().AddJsonFile("appsettings.json").Build()-->IConfigurationRoot(IConfiguration)

7.2. 得到配置

IConfiguration[「Key:ChildKey」]
針對」ConnectionStrings:xxx」,可使用IConfiguration.GetConnectionString(「xxx」)

private static IConfiguration Configuration { get; set; }

public StartupDevelopment(IConfiguration config)
{
    Configuration = config;
}

...

Configuration[「Key:ChildKey」]

8. 自定義一個異常處理,ExceptionHandler

8.1. 弄一個類,寫一個擴展方法處理異常

namespace ApiStudy.Api.Extensions
{
    using Microsoft.AspNetCore.Builder;
    using Microsoft.AspNetCore.Http;
    using Microsoft.Extensions.Logging;
    using System;

    public static class ExceptionHandlingExtensions
    {
        public static void UseCustomExceptionHandler(this IApplicationBuilder app,ILoggerFactory loggerFactory)
        {
            app.UseExceptionHandler(
                builder => builder.Run(async context =>
                {
                    context.Response.StatusCode = StatusCodes.Status500InternalServerError;
                    context.Response.ContentType = "application/json";

                    Exception ex = context.Features.Get<Exception>();
                    if (!(ex is null))
                    {
                        ILogger logger = loggerFactory.CreateLogger("ApiStudy.Api.Extensions.ExceptionHandlingExtensions");
                        logger.LogError(ex, "Error occurred.");
                    }
                    await context.Response.WriteAsync(ex?.Message ?? "Error occurred, but cannot get exception message.For more detail, go to see the log.");
                }));
        }
    }
}

8.2. 在Configuration中使用擴展方法

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
{
    app.UseCustomExceptionHandler(loggerFactory);  //modified code

    //app.UseDeveloperExceptionPage();
    app.UseHsts();
    app.UseHttpsRedirection();

    app.UseMvc(); //使用默認路由
}

9. 實現數據接口類(Resource),使用AutoMapper在Resource和Entity中映射

9.1. 爲Entity類建立對應的Resource類

ApiUserResource

namespace ApiStudy.Infrastructure.Resources
{
    using System;

    public class ApiUserResource
    {
        public Guid Guid { get; set; }
        public string Name { get; set; }
        //public string Passwd { get; set; }
        public DateTime RegistrationDate { get; set; }
        public DateTime Birth { get; set; }
        public string ProfilePhotoUrl { get; set; }
        public string PhoneNumber { get; set; }
        public string Email { get; set; }
    }
}

9.2. 使用 AutoMapper

添加nuget包
AutoMapper
AutoMapper.Extensions.Microsoft.DependencyInjection

配置映射
能夠建立Profile
CreateMap<TSource,TDestination>()

MappingProfile

namespace ApiStudy.Api.Extensions
{
    using ApiStudy.Core.Entities;
    using ApiStudy.Infrastructure.Resources;
    using AutoMapper;
    using System;
    using System.Text;

    public class MappingProfile : Profile
    {
        public MappingProfile()
        {
            CreateMap<ApiUser, ApiUserResource>()
                .ForMember(
                d => d.Passwd, 
                opt => opt.AddTransform(s => Convert.ToBase64String(Encoding.Default.GetBytes(s))));

            CreateMap<ApiUserResource, ApiUser>()
                .ForMember(
                d => d.Passwd,
                opt => opt.AddTransform(s => Encoding.Default.GetString(Convert.FromBase64String(s))));
        }
    }
}

注入服務
services.AddAutoMapper()

10. 使用FluentValidation

FluentValidation官網

10.1. 安裝Nuget包

FluentValidation
FluentValidation.AspNetCore

10.2. 爲每個Resource配置驗證器

繼承於AbstractValidator

ApiUserResourceValidator

namespace ApiStudy.Infrastructure.Resources
{
    using FluentValidation;

    public class ApiUserResourceValidator : AbstractValidator<ApiUserResource>
    {
        public ApiUserResourceValidator()
        {
            RuleFor(s => s.Name)
                .MaximumLength(80)
                .WithName("用戶名")
                .WithMessage("{PropertyName}的最大長度爲80")
                .NotEmpty()
                .WithMessage("{PropertyName}不能爲空!");
        }
    }
}

註冊到容器:services.AddTransient<>()
services.AddTransient<IValidator<ApiUserResource>, ApiUserResourceValidator>();

11. 實現Http Get(翻頁,過濾,排序)

基本的Get實現

[HttpGet]
public async Task<IActionResult> Get()
{
    IEnumerable<ApiUser> apiUsers = await _apiUserRepository.GetAllApiUsersAsync();

    IEnumerable<ApiUserResource> apiUserResources = 
        _mapper.Map<IEnumerable<ApiUser>,IEnumerable<ApiUserResource>>(apiUsers);

    return Ok(apiUserResources);
}

[HttpGet("{guid}")]
public async Task<IActionResult> Get(string guid)
{
    ApiUser apiUser = await _apiUserRepository.GetApiUserByGuidAsync(Guid.Parse(guid));

    if (apiUser is null) return NotFound();

    ApiUserResource apiUserResource = _mapper.Map<ApiUser,ApiUserResource>(apiUser);

    return Ok(apiUserResource);
}

11.1. 資源命名

11.1.1. 資源應該使用名詞,例

api/getusers就是不正確的.
GET　api/users就是正確的

11.1.2. 資源命名層次結構

例如api/department/{departmentId}/emoloyees, 這就表示了 department (部門)和員工
(employee)以前是主從關係.
而api/department/{departmentId}/emoloyees/{employeeId},就表示了該部門下的某個員
工.

11.2. 內容協商

ASP.NET Core支持輸出和輸入兩種格式化器.

用於輸出的media type放在Accept Header裏,表示客戶端接受這種格式的輸出.
用於輸入的media type放Content-Type Header裏,表示客戶端傳進來的數據是這種格式.
ReturnHttpNotAcceptable設爲true,若是客戶端請求不支持的數據格式,就會返回406.
```
services.AddMvc(options =>
{
    options.ReturnHttpNotAcceptable = true;
});
```
支持輸出XML格式:options.OutputFormatters.Add(newXmlDataContractSerializerOutputFormatter());

12. 翻頁

12.1. 構造翻頁請求參數類

QueryParameters

namespace ApiStudy.Core.Entities
{
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Runtime.CompilerServices;

    public abstract class QueryParameters : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        private const int DefaultPageSize = 10;
        private const int DefaultMaxPageSize = 100;

        private int _pageIndex = 1;
        public virtual int PageIndex
        {
            get => _pageIndex;
            set => SetField(ref _pageIndex, value);
        }

        private int _pageSize = DefaultPageSize;
        public virtual int PageSize
        {
            get => _pageSize;
            set => SetField(ref _pageSize, value);
        }

        private int _maxPageSize = DefaultMaxPageSize;
        public virtual int MaxPageSize
        {
            get => _maxPageSize;
            set => SetField(ref _maxPageSize, value);
        }

        public string OrderBy { get; set; }
        public string Fields { get; set; }

        protected void SetField<TField>(
            ref TField field,in TField newValue,[CallerMemberName] string propertyName = null)
        {
            if (EqualityComparer<TField>.Default.Equals(field, newValue))
                return;
            field = newValue;
            if (propertyName == nameof(PageSize) || propertyName == nameof(MaxPageSize)) SetPageSize();
            
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
            
        }

        private void SetPageSize()
        {
            if (_maxPageSize <= 0) _maxPageSize = DefaultMaxPageSize;
            if (_pageSize <= 0) _pageSize = DefaultPageSize;
            _pageSize = _pageSize > _maxPageSize ? _maxPageSize : _pageSize;
        }
    }
}

ApiUserParameters

namespace ApiStudy.Core.Entities
{
    public class ApiUserParameters:QueryParameters
    {
        public string UserName { get; set; }
    }
}

12.2. Repository實現支持翻頁請求參數的方法

Repository相關代碼

/*----- ApiUserRepository -----*/
public PaginatedList<ApiUser> GetAllApiUsers(ApiUserParameters parameters)
{
    return new PaginatedList<ApiUser>(
        parameters.PageIndex,
        parameters.PageSize,
        _context.ApiUsers.Count(),
        _context.ApiUsers.Skip(parameters.PageIndex * parameters.PageSize)
        .Take(parameters.PageSize));
}

public Task<PaginatedList<ApiUser>> GetAllApiUsersAsync(ApiUserParameters parameters)
{
    return Task.Run(() => GetAllApiUsers(parameters));
}

/*----- IApiUserRepository -----*/
PaginatedList<ApiUser> GetAllApiUsers(ApiUserParameters parameters);
Task<PaginatedList<ApiUser>> GetAllApiUsersAsync(ApiUserParameters parameters);

UserController部分代碼

...

[HttpGet(Name = "GetAllApiUsers")]
public async Task<IActionResult> GetAllApiUsers(ApiUserParameters parameters)
{
    PaginatedList<ApiUser> apiUsers = await _apiUserRepository.GetAllApiUsersAsync(parameters);

    IEnumerable<ApiUserResource> apiUserResources = 
        _mapper.Map<IEnumerable<ApiUser>,IEnumerable<ApiUserResource>>(apiUsers);

    var meta = new
    {
        PageIndex = apiUsers.PageIndex,
        PageSize = apiUsers.PageSize,
        PageCount = apiUsers.PageCount,
        TotalItemsCount = apiUsers.TotalItemsCount,
        NextPageUrl = CreateApiUserUrl(parameters, ResourceUriType.NextPage),
        PreviousPageUrl = CreateApiUserUrl(parameters, ResourceUriType.PreviousPage)
    };
    Response.Headers.Add(
        "X-Pagination",
        JsonConvert.SerializeObject(
            meta, 
            new JsonSerializerSettings
            { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
    return Ok(apiUserResources);
}

...

private string CreateApiUserUrl(ApiUserParameters parameters,ResourceUriType uriType)
{
    var param = new ApiUserParameters
    {
        PageIndex = parameters.PageIndex,
        PageSize = parameters.PageSize
    };
    switch (uriType)
    {
        case ResourceUriType.PreviousPage:
            param.PageIndex--;
            break;
        case ResourceUriType.NextPage:
            param.PageIndex++;
            break;
        case ResourceUriType.CurrentPage:
            break;
        default:break;
    }
    return Url.Link("GetAllApiUsers", parameters);
}

PS注意,爲HttpGet方法添加參數的話,在.net core2.2版本下,去掉那個ApiUserController上的 [ApiController());] 特性,不然參數傳不進來..net core3.0中聽說已經修復這個問題.

12.3. 搜索(過濾)

修改Repository代碼:

public PaginatedList<ApiUser> GetAllApiUsers(ApiUserParameters parameters)
{
    IQueryable<ApiUser> query = _context.ApiUsers.AsQueryable();
    query = query.Skip(parameters.PageIndex * parameters.PageSize)
            .Take(parameters.PageSize);

    if (!string.IsNullOrEmpty(parameters.UserName))
        query = _context.ApiUsers.Where(
            x => StringComparer.OrdinalIgnoreCase.Compare(x.Name, parameters.UserName) == 0);

    return new PaginatedList<ApiUser>(
        parameters.PageIndex,
        parameters.PageSize,
        query.Count(),
        query);
}

12.4. 排序

12.4.1. 排序思路

須要安裝System.Linq.Dynamic.Core

思路:

PropertyMappingContainer
- PropertyMapping(ApiUserPropertyMapping)
  - MappedProperty

MappedProperty

namespace ApiStudy.Infrastructure.Services
{
    public struct MappedProperty
    {
        public MappedProperty(string name, bool revert = false)
        {
            Name = name;
            Revert = revert;
        }

        public string Name { get; set; }
        public bool Revert { get; set; }
    }
}

IPropertyMapping

namespace ApiStudy.Infrastructure.Services
{
    using System.Collections.Generic;

    public interface IPropertyMapping
    {
        Dictionary<string, List<MappedProperty>> MappingDictionary { get; }
    }
}

PropertyMapping

namespace ApiStudy.Infrastructure.Services
{
    using System.Collections.Generic;

    public abstract class PropertyMapping<TSource,TDestination> : IPropertyMapping
    {
        public Dictionary<string, List<MappedProperty>> MappingDictionary { get; }

        public PropertyMapping(Dictionary<string, List<MappedProperty>> MappingDict)
        {
            MappingDictionary = MappingDict;
        }
    }
}

IPropertyMappingContainer

namespace ApiStudy.Infrastructure.Services
{
    public interface IPropertyMappingContainer
    {
        void Register<T>() where T : IPropertyMapping, new();
        IPropertyMapping Resolve<TSource, TDestination>();
        bool ValidateMappingExistsFor<TSource, TDestination>(string fields);
    }
}

PropertyMappingContainer

namespace ApiStudy.Infrastructure.Services
{
    using System;
    using System.Linq;
    using System.Collections.Generic;

    public class PropertyMappingContainer : IPropertyMappingContainer
    {
        protected internal readonly IList<IPropertyMapping> PropertyMappings = new List<IPropertyMapping>();

        public void Register<T>() where T : IPropertyMapping, new()
        {
            if (PropertyMappings.Any(x => x.GetType() == typeof(T))) return;
            PropertyMappings.Add(new T());
        }

        public IPropertyMapping Resolve<TSource,TDestination>()
        {
            IEnumerable<PropertyMapping<TSource, TDestination>> result = PropertyMappings.OfType<PropertyMapping<TSource,TDestination>>();
            if (result.Count() > 0)
                return result.First();
            throw new InvalidCastException(
               string.Format( "Cannot find property mapping instance for {0}, {1}", typeof(TSource), typeof(TDestination)));
        }

        public bool ValidateMappingExistsFor<TSource, TDestination>(string fields)
        {
            if (string.IsNullOrEmpty(fields)) return true;

            IPropertyMapping propertyMapping = Resolve<TSource, TDestination>();

            string[] splitFields = fields.Split(',');

            foreach(string property in splitFields)
            {
                string trimmedProperty = property.Trim();
                int indexOfFirstWhiteSpace = trimmedProperty.IndexOf(' ');
                string propertyName = indexOfFirstWhiteSpace <= 0 ? trimmedProperty : trimmedProperty.Remove(indexOfFirstWhiteSpace);
                
                if (!propertyMapping.MappingDictionary.Keys.Any(x => string.Equals(propertyName,x,StringComparison.OrdinalIgnoreCase))) return false;
            }
            return true;
        }
    }
}

QueryExtensions

namespace ApiStudy.Infrastructure.Extensions
{
    using ApiStudy.Infrastructure.Services;
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Linq.Dynamic.Core;

    public static class QueryExtensions
    {
        public static IQueryable<T> ApplySort<T>(
           this IQueryable<T> data,in string orderBy,in IPropertyMapping propertyMapping)
        {
            if (data == null) throw new ArgumentNullException(nameof(data));
            if (string.IsNullOrEmpty(orderBy)) return data;

            string[] splitOrderBy = orderBy.Split(',');
            foreach(string property in splitOrderBy)
            {
                string trimmedProperty = property.Trim();
                int indexOfFirstSpace = trimmedProperty.IndexOf(' ');
                bool desc = trimmedProperty.EndsWith(" desc");
                string propertyName = indexOfFirstSpace > 0 ? trimmedProperty.Remove(indexOfFirstSpace) : trimmedProperty;
                propertyName = propertyMapping.MappingDictionary.Keys.FirstOrDefault(
                    x => string.Equals(x, propertyName, StringComparison.OrdinalIgnoreCase)); //ignore case of sort property

                if (!propertyMapping.MappingDictionary.TryGetValue(
                    propertyName, out List<MappedProperty> mappedProperties))
                    throw new InvalidCastException($"key mapping for {propertyName} is missing");

                mappedProperties.Reverse();
                foreach(MappedProperty mappedProperty in mappedProperties)
                {
                    if (mappedProperty.Revert) desc = !desc;
                    data = data.OrderBy($"{mappedProperty.Name} {(desc ? "descending" : "ascending")} ");
                }
            }
            return data;
        }
    }
}

UserController 部分代碼

[HttpGet(Name = "GetAllApiUsers")]
public async Task<IActionResult> GetAllApiUsers(ApiUserParameters parameters)
{
    if (!_propertyMappingContainer.ValidateMappingExistsFor<ApiUserResource, ApiUser>(parameters.OrderBy))
        return BadRequest("can't find fields for sorting.");

    PaginatedList<ApiUser> apiUsers = await _apiUserRepository.GetAllApiUsersAsync(parameters);

    IEnumerable<ApiUserResource> apiUserResources =
        _mapper.Map<IEnumerable<ApiUser>, IEnumerable<ApiUserResource>>(apiUsers);

    IEnumerable<ApiUserResource> sortedApiUserResources =
        apiUserResources.AsQueryable().ApplySort(
            parameters.OrderBy, _propertyMappingContainer.Resolve<ApiUserResource, ApiUser>());

    var meta = new
    {
        apiUsers.PageIndex,
        apiUsers.PageSize,
        apiUsers.PageCount,
        apiUsers.TotalItemsCount,
        PreviousPageUrl = apiUsers.HasPreviousPage ? CreateApiUserUrl(parameters, ResourceUriType.PreviousPage) : string.Empty,
        NextPageUrl = apiUsers.HasNextPage ? CreateApiUserUrl(parameters, ResourceUriType.NextPage) : string.Empty,
    };
    Response.Headers.Add(
        "X-Pagination",
        JsonConvert.SerializeObject(
            meta,
            new JsonSerializerSettings
            { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
    return Ok(sortedApiUserResources);
}

private string CreateApiUserUrl(ApiUserParameters parameters, ResourceUriType uriType)
{
    var param = new {
        parameters.PageIndex,
        parameters.PageSize
    };
    switch (uriType)
    {
        case ResourceUriType.PreviousPage:
            param = new
            {
                PageIndex = parameters.PageIndex - 1,
                parameters.PageSize
            };
            break;
        case ResourceUriType.NextPage:
            param = new
            {
                PageIndex = parameters.PageIndex + 1,
                parameters.PageSize
            };
            break;
        case ResourceUriType.CurrentPage:
            break;
        default: break;
    }
    return Url.Link("GetAllApiUsers", param);
}

13. 資源塑形(Resource shaping)

返回資源的指定字段

ApiStudy.Infrastructure.Extensions.TypeExtensions

namespace ApiStudy.Infrastructure.Extensions
{
    using System;
    using System.Collections.Generic;
    using System.Reflection;

    public static class TypeExtensions
    {
        public static IEnumerable<PropertyInfo> GetProeprties(this Type source, string fields = null)
        {
            List<PropertyInfo> propertyInfoList = new List<PropertyInfo>();
            if (string.IsNullOrEmpty(fields))
            {
                propertyInfoList.AddRange(source.GetProperties(BindingFlags.Public | BindingFlags.Instance));
            }
            else
            {
                string[] properties = fields.Trim().Split(',');
                foreach (string propertyName in properties)
                {
                    propertyInfoList.Add(
                        source.GetProperty(
                        propertyName.Trim(),
                        BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase));
                }
            }
            return propertyInfoList;
        }
    }
}

ApiStudy.Infrastructure.Extensions.ObjectExtensions

namespace ApiStudy.Infrastructure.Extensions
{
    using System.Collections.Generic;
    using System.Dynamic;
    using System.Linq;
    using System.Reflection;

    public static class ObjectExtensions
    {
        public static ExpandoObject ToDynamicObject(this object source, in string fields = null)
        {
            List<PropertyInfo> propertyInfoList = source.GetType().GetProeprties(fields).ToList();

            ExpandoObject expandoObject = new ExpandoObject();
            foreach (PropertyInfo propertyInfo in propertyInfoList)
            {
                try
                {
                    (expandoObject as IDictionary<string, object>).Add(
                    propertyInfo.Name, propertyInfo.GetValue(source));
                }
                catch { continue; }
            }
            return expandoObject;
        }

        internal static ExpandoObject ToDynamicObject(this object source, in IEnumerable<PropertyInfo> propertyInfos, in string fields = null)
        {
            ExpandoObject expandoObject = new ExpandoObject();
            foreach (PropertyInfo propertyInfo in propertyInfos)
            {
                try
                {
                    (expandoObject as IDictionary<string, object>).Add(
                    propertyInfo.Name, propertyInfo.GetValue(source));
                }
                catch { continue; }
            }
            return expandoObject;
        }
    }
}

ApiStudy.Infrastructure.Extensions.IEnumerableExtensions

namespace ApiStudy.Infrastructure.Extensions
{
    using System;
    using System.Collections.Generic;
    using System.Dynamic;
    using System.Linq;
    using System.Reflection;

    public static class IEnumerableExtensions
    {
        public static IEnumerable<ExpandoObject> ToDynamicObject<T>(
            this IEnumerable<T> source,in string fields = null)
        {
            if (source == null) throw new ArgumentNullException(nameof(source));

            List<ExpandoObject> expandoObejctList = new List<ExpandoObject>();
            List<PropertyInfo> propertyInfoList = typeof(T).GetProeprties(fields).ToList();
            foreach(T x in source)
            {
                expandoObejctList.Add(x.ToDynamicObject(propertyInfoList, fields));
            }
            return expandoObejctList;
        }
    }
}

ApiStudy.Infrastructure.Services.TypeHelperServices

namespace ApiStudy.Infrastructure.Services
{
    using System.Reflection;

    public class TypeHelperServices : ITypeHelperServices
    {
        public bool HasProperties<T>(string fields)
        {
            if (string.IsNullOrEmpty(fields)) return true;

            string[] splitFields = fields.Split(',');
            foreach(string splitField in splitFields)
            {
                string proeprtyName = splitField.Trim();
                PropertyInfo propertyInfo = typeof(T).GetProperty(
                    proeprtyName, BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);
                if (propertyInfo == null) return false;
            }
            return true;
        }
    }
}

UserContext.GetAllApiUsers(), UserContext.Get()

[HttpGet(Name = "GetAllApiUsers")]
public async Task<IActionResult> GetAllApiUsers(ApiUserParameters parameters)
{
    //added code
    if (!_typeHelper.HasProperties<ApiUserResource>(parameters.Fields))
        return BadRequest("fields not exist.");

    if (!_propertyMappingContainer.ValidateMappingExistsFor<ApiUserResource, ApiUser>(parameters.OrderBy))
        return BadRequest("can't find fields for sorting.");

    PaginatedList<ApiUser> apiUsers = await _apiUserRepository.GetAllApiUsersAsync(parameters);

    IEnumerable<ApiUserResource> apiUserResources =
        _mapper.Map<IEnumerable<ApiUser>, IEnumerable<ApiUserResource>>(apiUsers);

    IEnumerable<ApiUserResource> sortedApiUserResources =
        apiUserResources.AsQueryable().ApplySort(
            parameters.OrderBy, _propertyMappingContainer.Resolve<ApiUserResource, ApiUser>());

    //modified code
    IEnumerable<ExpandoObject> sharpedApiUserResources =
        sortedApiUserResources.ToDynamicObject(parameters.Fields);

    var meta = new
    {
        apiUsers.PageIndex,
        apiUsers.PageSize,
        apiUsers.PageCount,
        apiUsers.TotalItemsCount,
        PreviousPageUrl = apiUsers.HasPreviousPage ? CreateApiUserUrl(parameters, ResourceUriType.PreviousPage) : string.Empty,
        NextPageUrl = apiUsers.HasNextPage ? CreateApiUserUrl(parameters, ResourceUriType.NextPage) : string.Empty,
    };
    Response.Headers.Add(
        "X-Pagination",
        JsonConvert.SerializeObject(
            meta,
            new JsonSerializerSettings
            { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
    //modified code
    return Ok(sharpedApiUserResources);
}

配置返回的json名稱風格爲CamelCase

StartupDevelopment.ConfigureServices

services.AddMvc(options =>
    {
        options.ReturnHttpNotAcceptable = true;
        options.OutputFormatters.Add(new XmlDataContractSerializerOutputFormatter());
    })
        .AddJsonOptions(options =>
        {
            //added code
            options.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
        });

14. HATEOAS

REST裏最複雜的約束,構建成熟RESTAPI的核心

可進化性,自我描述
超媒體(Hypermedia,例如超連接)驅動如何消
費和使用API

UserContext

private IEnumerable<LinkResource> CreateLinksForApiUser(string guid,string fields = null)
{
    List<LinkResource> linkResources = new List<LinkResource>();
    if (string.IsNullOrEmpty(fields))
    {
        linkResources.Add(
            new LinkResource(Url.Link("GetApiUser", new { guid }), "self", "get"));
    }
    else
    {
        linkResources.Add(
            new LinkResource(Url.Link("GetApiUser", new { guid, fields }), "self", "get"));
    }

    linkResources.Add(
            new LinkResource(Url.Link("DeleteApiUser", new { guid }), "self", "Get"));
    return linkResources;
}

private IEnumerable<LinkResource> CreateLinksForApiUsers(ApiUserParameters parameters,bool hasPrevious,bool hasNext)
{
    List<LinkResource> resources = new List<LinkResource>();

    resources.Add(
            new LinkResource(
                CreateApiUserUrl(parameters,ResourceUriType.CurrentPage),
                "current_page", "get"));
    if (hasPrevious)
        resources.Add(
            new LinkResource(
                CreateApiUserUrl(parameters, ResourceUriType.PreviousPage),
                "previous_page", "get"));
    if (hasNext)
        resources.Add(
            new LinkResource(
                CreateApiUserUrl(parameters, ResourceUriType.NextPage),
                "next_page", "get"));

    return resources;
}

[HttpGet(Name = "GetAllApiUsers")]
public async Task<IActionResult> GetAllApiUsers(ApiUserParameters parameters)
{
    if (!_typeHelper.HasProperties<ApiUserResource>(parameters.Fields))
        return BadRequest("fields not exist.");

    if (!_propertyMappingContainer.ValidateMappingExistsFor<ApiUserResource, ApiUser>(parameters.OrderBy))
        return BadRequest("can't find fields for sorting.");

    PaginatedList<ApiUser> apiUsers = await _apiUserRepository.GetAllApiUsersAsync(parameters);

    IEnumerable<ApiUserResource> apiUserResources =
        _mapper.Map<IEnumerable<ApiUser>, IEnumerable<ApiUserResource>>(apiUsers);

    IEnumerable<ApiUserResource> sortedApiUserResources =
        apiUserResources.AsQueryable().ApplySort(
            parameters.OrderBy, _propertyMappingContainer.Resolve<ApiUserResource, ApiUser>());

    IEnumerable<ExpandoObject> shapedApiUserResources =
        sortedApiUserResources.ToDynamicObject(parameters.Fields);

    IEnumerable<ExpandoObject> shapedApiUserResourcesWithLinks = shapedApiUserResources.Select(
        x =>
        {
            IDictionary<string, object> dict = x as IDictionary<string, object>;
            if(dict.Keys.Contains("guid"))
                dict.Add("links", CreateLinksForApiUser(dict["guid"] as string));
            return dict as ExpandoObject;
        });

    var result = new
    {
        value = shapedApiUserResourcesWithLinks,
        links = CreateLinksForApiUsers(parameters, apiUsers.HasPreviousPage, apiUsers.HasNextPage)
    };

    var meta = new
    {
        apiUsers.PageIndex,
        apiUsers.PageSize,
        apiUsers.PageCount,
        apiUsers.TotalItemsCount,
        //PreviousPageUrl = apiUsers.HasPreviousPage ? CreateApiUserUrl(parameters, ResourceUriType.PreviousPage) : string.Empty,
        //NextPageUrl = apiUsers.HasNextPage ? CreateApiUserUrl(parameters, ResourceUriType.NextPage) : string.Empty,
    };
    Response.Headers.Add(
        "X-Pagination",
        JsonConvert.SerializeObject(
            meta,
            new JsonSerializerSettings
            { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
    return Ok(result);
}

14.1. 建立供應商特定媒體類型

application/vnd.mycompany.hateoas+json
- vnd是vendor的縮寫，這一條是mime type的原則，表示這個媒體類型是供應商特定的
- 自定義的標識，也可能還包括額外的值，這裏我是用的是公司名，隨後是hateoas表示返回的響應裏面要
  包含連接
- 「+json」
在Startup裏註冊.

14.1.1. 判斷Media Type類型

[FromHeader(Name = "Accept")] stringmediaType

//Startup.ConfigureServices 中註冊媒體類型
services.AddMvc(options =>
    {
        options.ReturnHttpNotAcceptable = true;
        //options.OutputFormatters.Add(new XmlDataContractSerializerOutputFormatter());
        JsonOutputFormatter formatter = options.OutputFormatters.OfType<JsonOutputFormatter>().FirstOrDefault();
        formatter.SupportedMediaTypes.Add("application/vnd.laggage.hateoas+json");
    })

// get方法中判斷媒體類型
if (mediaType == "application/json") 
    return Ok(shapedApiUserResources);
else if (mediaType == "application/vnd.laggage.hateoas+json")
{
    ...
    return;
}

注意,要是的 Action 認識 application/vnd.laggage.hateoss+json ,須要在Startup.ConfigureServices中註冊這個媒體類型,上面的代碼給出了具體操做.

UserContext

[HttpGet(Name = "GetAllApiUsers")]
public async Task<IActionResult> GetAllApiUsers(ApiUserParameters parameters,[FromHeader(Name = "Accept")] string mediaType)
{
    if (!_typeHelper.HasProperties<ApiUserResource>(parameters.Fields))
        return BadRequest("fields not exist.");

    if (!_propertyMappingContainer.ValidateMappingExistsFor<ApiUserResource, ApiUser>(parameters.OrderBy))
        return BadRequest("can't find fields for sorting.");

    PaginatedList<ApiUser> apiUsers = await _apiUserRepository.GetAllApiUsersAsync(parameters);

    IEnumerable<ApiUserResource> apiUserResources =
        _mapper.Map<IEnumerable<ApiUser>, IEnumerable<ApiUserResource>>(apiUsers);

    IEnumerable<ApiUserResource> sortedApiUserResources =
        apiUserResources.AsQueryable().ApplySort(
            parameters.OrderBy, _propertyMappingContainer.Resolve<ApiUserResource, ApiUser>());

    IEnumerable<ExpandoObject> shapedApiUserResources =
        sortedApiUserResources.ToDynamicObject(parameters.Fields);

    if (mediaType == "application/json") return Ok(shapedApiUserResources);
    else if (mediaType == "application/vnd.laggage.hateoas+json")
    {
        IEnumerable<ExpandoObject> shapedApiUserResourcesWithLinks = shapedApiUserResources.Select(
            x =>
            {
                IDictionary<string, object> dict = x as IDictionary<string, object>;
                if (dict.Keys.Contains("guid"))
                    dict.Add("links", CreateLinksForApiUser(dict["guid"] as string));
                return dict as ExpandoObject;
            });

        var result = new
        {
            value = shapedApiUserResourcesWithLinks,
            links = CreateLinksForApiUsers(parameters, apiUsers.HasPreviousPage, apiUsers.HasNextPage)
        };

        var meta = new
        {
            apiUsers.PageIndex,
            apiUsers.PageSize,
            apiUsers.PageCount,
            apiUsers.TotalItemsCount,
        };
        Response.Headers.Add(
            "X-Pagination",
            JsonConvert.SerializeObject(
                meta,
                new JsonSerializerSettings
                { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
        return Ok(result);
    }
    return NotFound($"Can't find resources for the given media type: [{mediaType}].");
}

[HttpGet("{guid}",Name = "GetApiUser")]
public async Task<IActionResult> Get(string guid, [FromHeader(Name = "Accept")] string mediaType , string fields = null)
{
    if (!_typeHelper.HasProperties<ApiUserResource>(fields))
        return BadRequest("fields not exist.");

    ApiUser apiUser = await _apiUserRepository.GetApiUserByGuidAsync(Guid.Parse(guid));

    if (apiUser is null) return NotFound();
    ApiUserResource apiUserResource = _mapper.Map<ApiUser, ApiUserResource>(apiUser);

    ExpandoObject shapedApiUserResource = apiUserResource.ToDynamicObject(fields);
    if (mediaType == "application/json") return Ok(shapedApiUserResource);

    else if(mediaType == "application/vnd.laggage.hateoas+json")
    {

    
    IDictionary<string, object> shapedApiUserResourceWithLink = shapedApiUserResource as IDictionary<string, object>;
    shapedApiUserResourceWithLink.Add("links", CreateLinksForApiUser(guid, fields));

    return Ok(shapedApiUserResourceWithLink);
    }
    return NotFound(@"Can't find resource for the given media type: [{mediaType}].");
}

自定義Action約束.

RequestHeaderMatchingMediaTypeAttribute

[AttributeUsage(AttributeTargets.All, Inherited = true, AllowMultiple = true)]
public class RequestHeaderMatchingMediaTypeAttribute : Attribute, IActionConstraint
{
    private readonly string _requestHeaderToMatch;
    private readonly string[] _mediaTypes;

    public RequestHeaderMatchingMediaTypeAttribute(string requestHeaderToMatch, string[] mediaTypes)
    {
        _requestHeaderToMatch = requestHeaderToMatch;
        _mediaTypes = mediaTypes;
    }

    public bool Accept(ActionConstraintContext context)
    {
        var requestHeaders = context.RouteContext.HttpContext.Request.Headers;
        if (!requestHeaders.ContainsKey(_requestHeaderToMatch))
        {
            return false;
        }

        foreach (var mediaType in _mediaTypes)
        {
            var mediaTypeMatches = string.Equals(requestHeaders[_requestHeaderToMatch].ToString(),
                mediaType, StringComparison.OrdinalIgnoreCase);
            if (mediaTypeMatches)
            {
                return true;
            }
        }

        return false;
    }

    public int Order { get; } = 0;
}

UserContext

[HttpGet(Name = "GetAllApiUsers")]
[RequestHeaderMatchingMediaType("Accept",new string[] { "application/vnd.laggage.hateoas+json" })]
public async Task<IActionResult> GetHateoas(ApiUserParameters parameters)
{
    if (!_typeHelper.HasProperties<ApiUserResource>(parameters.Fields))
        return BadRequest("fields not exist.");

    if (!_propertyMappingContainer.ValidateMappingExistsFor<ApiUserResource, ApiUser>(parameters.OrderBy))
        return BadRequest("can't find fields for sorting.");

    PaginatedList<ApiUser> apiUsers = await _apiUserRepository.GetAllApiUsersAsync(parameters);

    IEnumerable<ApiUserResource> apiUserResources =
        _mapper.Map<IEnumerable<ApiUser>, IEnumerable<ApiUserResource>>(apiUsers);

    IEnumerable<ApiUserResource> sortedApiUserResources =
        apiUserResources.AsQueryable().ApplySort(
            parameters.OrderBy, _propertyMappingContainer.Resolve<ApiUserResource, ApiUser>());

    IEnumerable<ExpandoObject> shapedApiUserResources =
        sortedApiUserResources.ToDynamicObject(parameters.Fields);

    IEnumerable<ExpandoObject> shapedApiUserResourcesWithLinks = shapedApiUserResources.Select(
            x =>
            {
                IDictionary<string, object> dict = x as IDictionary<string, object>;
                if (dict.Keys.Contains("guid"))
                    dict.Add("links", CreateLinksForApiUser(dict["guid"] as string));
                return dict as ExpandoObject;
            });

    var result = new
    {
        value = shapedApiUserResourcesWithLinks,
        links = CreateLinksForApiUsers(parameters, apiUsers.HasPreviousPage, apiUsers.HasNextPage)
    };

    var meta = new
    {
        apiUsers.PageIndex,
        apiUsers.PageSize,
        apiUsers.PageCount,
        apiUsers.TotalItemsCount,
    };
    Response.Headers.Add(
        "X-Pagination",
        JsonConvert.SerializeObject(
            meta,
            new JsonSerializerSettings
            { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
    return Ok(result);
}

[HttpGet(Name = "GetAllApiUsers")]
[RequestHeaderMatchingMediaType("Accept",new string[] { "application/json" })]
public async Task<IActionResult> Get(ApiUserParameters parameters)
{
    if (!_typeHelper.HasProperties<ApiUserResource>(parameters.Fields))
        return BadRequest("fields not exist.");

    if (!_propertyMappingContainer.ValidateMappingExistsFor<ApiUserResource, ApiUser>(parameters.OrderBy))
        return BadRequest("can't find fields for sorting.");

    PaginatedList<ApiUser> apiUsers = await _apiUserRepository.GetAllApiUsersAsync(parameters);

    IEnumerable<ApiUserResource> apiUserResources =
        _mapper.Map<IEnumerable<ApiUser>, IEnumerable<ApiUserResource>>(apiUsers);

    IEnumerable<ApiUserResource> sortedApiUserResources =
        apiUserResources.AsQueryable().ApplySort(
            parameters.OrderBy, _propertyMappingContainer.Resolve<ApiUserResource, ApiUser>());

    IEnumerable<ExpandoObject> shapedApiUserResources =
        sortedApiUserResources.ToDynamicObject(parameters.Fields);

    return Ok(shapedApiUserResources);
}

[HttpGet("{guid}", Name = "GetApiUser")]
[RequestHeaderMatchingMediaType("Accept", new string[] { "application/vnd.laggage.hateoas+json" })]
public async Task<IActionResult> GetHateoas(string guid, string fields = null)
{
    if (!_typeHelper.HasProperties<ApiUserResource>(fields))
        return BadRequest("fields not exist.");

    ApiUser apiUser = await _apiUserRepository.GetApiUserByGuidAsync(Guid.Parse(guid));

    if (apiUser is null) return NotFound();
    ApiUserResource apiUserResource = _mapper.Map<ApiUser, ApiUserResource>(apiUser);

    ExpandoObject shapedApiUserResource = apiUserResource.ToDynamicObject(fields);

    IDictionary<string, object> shapedApiUserResourceWithLink = shapedApiUserResource as IDictionary<string, object>;
    shapedApiUserResourceWithLink.Add("links", CreateLinksForApiUser(guid, fields));

    return Ok(shapedApiUserResourceWithLink);
}

[HttpGet("{guid}", Name = "GetApiUser")]
[RequestHeaderMatchingMediaType("Accept", new string[] { "application/json" })]
public async Task<IActionResult> Get(string guid,  string fields = null)
{
    if (!_typeHelper.HasProperties<ApiUserResource>(fields))
        return BadRequest("fields not exist.");

    ApiUser apiUser = await _apiUserRepository.GetApiUserByGuidAsync(Guid.Parse(guid));

    if (apiUser is null) return NotFound();
    ApiUserResource apiUserResource = _mapper.Map<ApiUser, ApiUserResource>(apiUser);

    ExpandoObject shapedApiUserResource = apiUserResource.ToDynamicObject(fields);

    return Ok(shapedApiUserResource);
}

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