【WebApi】C#创建WebApi学习

Ne0inhk

20 Mar 2026 — 15 min read

1、创建WebApi项目

Prgram.cs代码保留如下

var builder = WebApplication.CreateBuilder(args); // Add services to the container. var app = builder.Build(); // Configure the HTTP request pipeline. app.UseHttpsRedirection(); app.Run();

2、Minmal APIs最小API使用

Prgram.cs中进行最小API使用

var builder = WebApplication.CreateBuilder(args); // Add services to the container. var app = builder.Build(); // Configure the HTTP request pipeline. app.UseHttpsRedirection(); //获取所有衬衫数据列表 app.MapGet("/shirts", () => { return "获取所有衬衫数据列表"; }); //获取指定ID的衬衫数据 app.MapGet("/shirts/{id}", (int id) => { return $"获取ID为 {id} 的衬衫数据"; }); //创建一件新的衬衫 app.MapPost("/shirts", () => { return "创建一件新的衬衫"; }); //更新指定ID的衬衫数据 app.MapPut("/shirts/{id}", (int id) => { return $"更新ID为 {id} 的衬衫数据"; }); //删除指定ID的衬衫数据 app.MapDelete("/shirts/{id}", (int id) => { return $"删除ID为 {id} 的衬衫数据"; }); app.Run();

3、ASP.NET Core中间件管道

app中的Use开头的方法都是中间件组件使用方法

4、Web API控制器实现Web API

方法1：将路由写在方法前面并指定操作动词

using Microsoft.AspNetCore.Mvc; namespace WebApiTest.Controllers { [ApiController] public class ShirtsController : ControllerBase { //获取所有衬衫数据列表 [HttpGet] [Route("api/shirts")] public string GetShirts() { return "获取所有衬衫数据列表"; } //获取指定ID的衬衫数据 [HttpGet] [Route("api/shirts/{id}")] public string GetShirtById(int id) { return $"获取ID为 {id} 的衬衫数据"; } //创建一件新的衬衫 [HttpPost] [Route("api/shirts")] public string CreateShirt() { return "创建一件新的衬衫"; } //更新指定ID的衬衫数据 [HttpPut] [Route("api/shirts/{id}")] public string UpdateShirt(int id) { return $"更新ID为 {id} 的衬衫数据"; } //删除指定ID的衬衫数据 [HttpDelete] [Route("api/shirts/{id}")] public string DeleteShirt(int id) { return $"删除ID为 {id} 的衬衫数据"; } } }

方法2：将路由写在类前面，再在方法前面指定操作动词

using Microsoft.AspNetCore.Mvc; namespace WebApiTest.Controllers { [ApiController] [Route("/api/[controller]")] public class ShirtsController : ControllerBase { //获取所有衬衫数据列表 [HttpGet] public string GetShirts() { return "获取所有衬衫数据列表"; } //获取指定ID的衬衫数据 [HttpGet("{id}")] public string GetShirtById(int id) { return $"获取ID为 {id} 的衬衫数据"; } //创建一件新的衬衫 [HttpPost] public string CreateShirt() { return "创建一件新的衬衫"; } //更新指定ID的衬衫数据 [HttpPut("{id}")] public string UpdateShirt(int id) { return $"更新ID为 {id} 的衬衫数据"; } //删除指定ID的衬衫数据 [HttpDelete("{id}")] public string DeleteShirt(int id) { return $"删除ID为 {id} 的衬衫数据"; } } }

5、基于控制器的Web API的路由

使用注解[Route("/shirts")]设置Web API的URL，可以在方法前使用，也可以在类前使用

方法前

类前

6、模型绑定，将Http请求中的数据映射到操作方法的参数

6.1 从路由绑定，在路由Route("/shirts/{id}")或在操作动词HttpGet("{id}")设置，在方法参数前设置[FromRoute]也可以省略

 [HttpGet("{id}")] public string GetShirtById([FromRoute]int id) { return $"获取ID为 {id} 的衬衫数据"; }

6.2 从查询字符串中绑定，方法参数前使用注解[FromQuery]

http://localhost:5186/api/shirts/1?color=红色

 [HttpGet("{id}")] public string GetShirtById([FromRoute]int id, [FromQuery]string color) { return $"获取ID为 {id} 的衬衫数据"; }

6.3 从请求头Header中绑定，方法参数前使用注解[FromHeader]

 [HttpGet("{id}")] public string GetShirtById([FromRoute]int id, [FromQuery]string color, [FromHeader]int size) { return $"获取ID为 {id} 的衬衫数据，衬衫颜色为{color}，大小为{size}"; }

6.4 从请求体Body JSON格式中绑定，方法参数前使用注解[FromBody]

 [HttpPost] public string CreateShirt([FromBody]Shirt shirt) { return $"创建一件新的衬衫，{shirt.Id}, {shirt.Name}, {shirt.Color}, {shirt.Gender}, {shirt.Price}"; }

6.5 从请求体Body 表单中绑定，方法参数前使用注解[FromForm]

 [HttpPost] public string CreateShirt([FromForm]Shirt shirt) { return $"创建一件新的衬衫，{shirt.Id}, {shirt.Name}, {shirt.Color}, {shirt.Gender}, {shirt.Price}"; }

7、数据注解模型验证

8、ValidationAtteibute模型验证，继承ValidationAttribute

创建脚本Shirt_EnsureCorrectSizingAttribute.cs

using System.ComponentModel.DataAnnotations; using WebApiDemo.Models; namespace WebApiTest.Models.Validations { public class Shirt_EnsureCorrectSizingAttribute : ValidationAttribute { protected override ValidationResult? IsValid(object? value, ValidationContext validationContext) { var shirt = validationContext.ObjectInstance as Shirt; if(shirt != null && !string.IsNullOrEmpty(shirt.Gender)) { if(shirt.Gender.Equals("men", StringComparison.OrdinalIgnoreCase) && shirt.Size < 8) { return new ValidationResult("男性衬衫的尺码必须大于或等于8。"); } else if (shirt.Gender.Equals("women", StringComparison.OrdinalIgnoreCase) && shirt.Size < 6) { return new ValidationResult("女性衬衫的尺码必须大于或等于6。"); } } return ValidationResult.Success; } } }

在属性前添加注解

9、Web API返回类型

返回类型使用IActionResult

正确返回使用 Ok(返回数据)

未找到使用 NotFound()

错误响应使用 BadRequest()

 [HttpGet("{id}")] public IActionResult GetShirtById([FromRoute]int id, [FromQuery]string color, [FromHeader]int size) { if(id <= 0) { //错误响应 return BadRequest(); } else if(id > 10) { //未找到 return NotFound(); } //正确响应 return Ok($"获取ID为 {id} 的衬衫数据，衬衫颜色为{color}，大小为{size}"); }

10、操作过滤器进行模型验证，继承ActionFilterAttribute

用户输入传递的id可能不符合规范，可以通过操作过滤器进行模型验证对id进行验证

创建脚本Shirt_ValidateShirtIdFilterAttribute

using Microsoft.AspNetCore.Mvc; using Microsoft.AspNetCore.Mvc.Filters; namespace WebApiTest.Filters.ActionFilters { public class Shirt_ValidateShirtIdFilterAttribute : ActionFilterAttribute { public override void OnActionExecuting(ActionExecutingContext context) { base.OnActionExecuting(context); var id = context.ActionArguments["id"] as int?; if (id.HasValue) { if(id.Value <= 0) { context.ModelState.AddModelError("Id", "衬衫ID必须大于0。"); var problemDetails = new Microsoft.AspNetCore.Mvc.ValidationProblemDetails(context.ModelState) { Status = 400, Title = "请求参数错误", }; context.Result = new BadRequestObjectResult(problemDetails); } } } } }

需要使用验证的方法前添加注解

11、异常过滤器实现异常处理

更新衬衫之前可能其他请求把该衬衫已经删掉，更新时可能会报错，模拟该情景

创建脚本Shirt_HandleUpdateExceptionFilterAttribute

using Microsoft.AspNetCore.Mvc; using Microsoft.AspNetCore.Mvc.Filters; namespace WebApiTest.Filters.ExceptionFilters { public class Shirt_HandleUpdateExceptionFilterAttribute : ExceptionFilterAttribute { public int?[] shirtsId = new int?[] { 1, 2, 3, 4, 5 }; public override void OnException(ExceptionContext context) { base.OnException(context); //判断衬衫ID是否存在 暂时假设shirtsId为数据库中已有的衬衫ID列表 var strShirtId = context.RouteData.Values["id"] as string; if (int.TryParse(strShirtId, out int shirtId)) { if (shirtsId.FirstOrDefault(x => x == shirtId) == null) { context.ModelState.AddModelError("Id", $"衬衫已经不存在"); var problemDetails = new ValidationProblemDetails(context.ModelState) { Status = StatusCodes.Status404NotFound, }; context.Result = new NotFoundObjectResult(problemDetails); } } } } }

在需要异常处理的方法前使用

12、Web API操作数据库

案例使用SqlServer数据库

12.1 下载安装Sql Server Developer Edition和SQL Server Management Studio

Sql Server Developer Edition

SQL Server Management Studio

打开SQL Server Management Studio连接本地数据库

12.2 安装需要使用的包

EntityFrameworkCore
EntityFrameworkCore.Design
EntityFrameworkCore.Tools
EntityFrameworkCore.SqlServer

1）打开管理NuGet程序包

2）搜索安装指定的包

3）双击查看是否安装成功

12.3 创建数据库上下文

1）创建脚本ApplicationDbContext

using Microsoft.EntityFrameworkCore; using WebApiDemo.Models; namespace WebApiTest.Data { public class ApplicationDbContext : DbContext { public DbSet<Shirt> Shirts { get; set; } protected override void OnModelCreating(ModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); //数据播种 modelBuilder.Entity<Shirt>().HasData( new Shirt { Id = 1, Name = "衬衫1", Color = "red", Gender = "men", Size = 10, Price = 100 }, new Shirt { Id = 2, Name = "衬衫2", Color = "blue", Gender = "men", Size = 12, Price = 140 }, new Shirt { Id = 3, Name = "衬衫3", Color = "黑色", Gender = "wemen", Size = 11, Price = 132 }, new Shirt { Id = 4, Name = "衬衫4", Color = "白色", Gender = "wemen", Size = 7, Price = 151 } ); } } }

12.4 执行数据库迁移

1）添加连接字符串

2）获取连接字符串，视图->服务器资源管理器->数据连接

//需要将master替换为需要创建的数据库名称 Data Source=(local);Initial Catalog=master;Integrated Security=True;Trust Server Certificate=True

3）数据库上下文中创建构造函数指定连接数据库位置

using Microsoft.EntityFrameworkCore; using WebApiDemo.Models; namespace WebApiTest.Data { public class ApplicationDbContext : DbContext { public ApplicationDbContext(DbContextOptions options) : base(options) { } public DbSet<Shirt> Shirts { get; set; } protected override void OnModelCreating(ModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); //数据播种 modelBuilder.Entity<Shirt>().HasData( new Shirt { Id = 1, Name = "衬衫1", Color = "red", Gender = "men", Size = 10, Price = 100 }, new Shirt { Id = 2, Name = "衬衫2", Color = "blue", Gender = "men", Size = 12, Price = 140 }, new Shirt { Id = 3, Name = "衬衫3", Color = "黑色", Gender = "wemen", Size = 11, Price = 132 }, new Shirt { Id = 4, Name = "衬衫4", Color = "白色", Gender = "wemen", Size = 7, Price = 151 } ); } } }

4）在Progam.cs添加运行EntityFrameworkCore所需的服务

builder.Services.AddDbContext<ApplicationDbContext>(options => { options.UseSqlServer(builder.Configuration.GetConnectionString("ShirtStoreManagement")); });

5）创建迁移代码并进行迁移

控制台运行命令Add-Migration Init（Init可以替换为该次进行操作说明）

运行成功会创建在迁移文件夹下创建迁移代码

在控制台运行迁移代码，Update-Database Init（Init为迁移代码名称，不指定会执行最新的代码）

执行成功可以在查看数据库创建成功

12.5 使用EF Core实现Get端点

在ShirtsController构造函数中依赖注入Db上下文

 //获取所有衬衫数据列表 [HttpGet] public IActionResult GetShirts() { return Ok(db.Shirts.ToList()); }

12.6 使用EF Core实现Get by Id端点

修改Shirt_ValidateShirtIdFilterAttribute，实现验证ID在数据库是否存在

using Microsoft.AspNetCore.Mvc; using Microsoft.AspNetCore.Mvc.Filters; using WebApiTest.Data; namespace WebApiTest.Filters.ActionFilters { public class Shirt_ValidateShirtIdFilterAttribute : ActionFilterAttribute { private readonly ApplicationDbContext db; public Shirt_ValidateShirtIdFilterAttribute(ApplicationDbContext db) { this.db = db; } public override void OnActionExecuting(ActionExecutingContext context) { base.OnActionExecuting(context); var id = context.ActionArguments["id"] as int?; if (id.HasValue) { if(id.Value <= 0) { context.ModelState.AddModelError("Id", "衬衫ID必须大于0。"); var problemDetails = new ValidationProblemDetails(context.ModelState) { Status = 400, Title = "请求参数错误", }; context.Result = new BadRequestObjectResult(problemDetails); } else { var shirt = db.Shirts.Find(id.Value); if(shirt == null) { context.ModelState.AddModelError("Id", $"ID为{id.Value}的衬衫在数据库不存在"); var problemDetails = new ValidationProblemDetails(context.ModelState) { Status = 400, Title = "衬衫ID不存在", }; context.Result = new NotFoundObjectResult(problemDetails); } else { context.HttpContext.Items["shirt"] = shirt; } } } } } }

在操作过滤器中查询数据库存在ID衬衫在context.HttpContext.Items中进行存在，然后在控制器中获取，避免重复进行数据库查询减少性能开销

控制器查询代码

 //获取指定ID的衬衫数据 [HttpGet("{id}")] [TypeFilter(typeof(Shirt_ValidateShirtIdFilterAttribute))] public IActionResult GetShirtById([FromRoute]int id) { //正确响应 return Ok(HttpContext.Items["shirt"]); }

12.7 使用EF Core实现Post端点

 //创建一件新的衬衫 [HttpPost] public IActionResult CreateShirt([FromBody]Shirt shirt) { this.db.Shirts.Add(shirt); this.db.SaveChanges(); return CreatedAtAction(nameof(GetShirtById), new { id = shirt.Id}, shirt); }

12.8 使用EF Core实现Put端点

修改代码Shirt_HandleUpdateExceptionFilterAttribute，实现验证当前ID数据是否还存在，可能存在当前操作之前数据被删除的可能

using Microsoft.AspNetCore.Mvc; using Microsoft.AspNetCore.Mvc.Filters; using WebApiTest.Data; namespace WebApiTest.Filters.ExceptionFilters { public class Shirt_HandleUpdateExceptionFilterAttribute : ExceptionFilterAttribute { private readonly ApplicationDbContext db; public Shirt_HandleUpdateExceptionFilterAttribute(ApplicationDbContext db) { this.db = db; } public override void OnException(ExceptionContext context) { base.OnException(context); //判断衬衫ID是否存在 暂时假设shirtsId为数据库中已有的衬衫ID列表 var strShirtId = context.RouteData.Values["id"] as string; if (int.TryParse(strShirtId, out int shirtId)) { if (this.db.Shirts.FirstOrDefault(x => x.Id == shirtId) == null) { context.ModelState.AddModelError("Id", $"衬衫已经在数据库不存在，可能在此之前被删除了"); var problemDetails = new ValidationProblemDetails(context.ModelState) { Status = StatusCodes.Status404NotFound, }; context.Result = new NotFoundObjectResult(problemDetails); } } } } }

控制器更新代码

 //更新指定ID的衬衫数据 [HttpPut("{id}")] [TypeFilter(typeof(Shirt_ValidateShirtIdFilterAttribute))] [TypeFilter(typeof(Shirt_HandleUpdateExceptionFilterAttribute))] public IActionResult UpdateShirt(int id, [FromBody]Shirt shirt) { var shirtToUpdate = HttpContext.Items["shirt"] as Shirt; shirtToUpdate.Name = shirt.Name; shirtToUpdate.Size = shirt.Size; shirtToUpdate.Color = shirt.Color; shirtToUpdate.Gender = shirt.Gender; shirtToUpdate.Price = shirt.Price; this.db.SaveChanges(); return Ok($"ID为{id}衬衫更新成功"); }

12.9 使用EF Core实现Delete端点

 //删除指定ID的衬衫数据 [HttpDelete("{id}")] [TypeFilter(typeof(Shirt_ValidateShirtIdFilterAttribute))] public IActionResult DeleteShirt(int id) { var shirtToDelete = HttpContext.Items["shirt"] as Shirt; this.db.Shirts.Remove(shirtToDelete); this.db.SaveChanges(); return Ok(shirtToDelete); }

13、Web Api安全机制，使用JWT生成令牌和验证令牌

1）创建应用程序信息类，Application.cs

namespace WebApiDemo.Authority { public class Application { public int ApplicationId { get; set; } public string? ApplicationName { get; set; } public string? ClientId { get; set; } public string? Secret { get; set; } public string? Scopes { get; set; } } }

2）创建应用内容存储，AppPepository.cs，替代已存储数据库的应用程序注册信息

namespace WebApiDemo.Authority { public static class AppPepository { private static List<Application> _applications = new List<Application> { new Application { ApplicationId = 1, ApplicationName = "MVCWebApp", ClientId = "53D3C1E6-4587-4AD5-8C6E-A8E4BD59940E", Secret = "0673FC70-0514-4011-B4A3-DF9BC03201BC", Scopes = "read,write,delete" } }; public static Application? GetApplicationByClientId(string clientId) { return _applications.FirstOrDefault(app => app.ClientId == clientId); } } }

3）创建应用凭证类，AppCredential.cs，用于接受认证请求参数

namespace WebApiDemo.Authority { public class AppCredential { public string? ClientId { get; set; } = string.Empty; public string? Secret { get; set; } = string.Empty; } }

4）创建应用认证控制器接口，AuthorityController.cs

using Microsoft.AspNetCore.Mvc; using Microsoft.IdentityModel.JsonWebTokens; using Microsoft.IdentityModel.Tokens; using System.Text; using WebApiDemo.Authority; namespace WebApiDemo.Controllers { [ApiController] public class AuthorityController : ControllerBase { private readonly IConfiguration configuration; public AuthorityController(IConfiguration configuration) { this.configuration = configuration; } [HttpPost("auth")] public IActionResult Authenticate([FromBody] AppCredential credential) { if (Authenticator.Authenticate(credential.ClientId, credential.Secret)) { var expiresAt = DateTime.UtcNow.AddMinutes(10); return Ok(new { access_token = Authenticator.CreateToken(credential.ClientId, expiresAt, configuration["SecurityKey"] ?? string.Empty), expores_at = expiresAt }); } else { ModelState.AddModelError("Unanthorized", "未被授权"); var problemDetails = new ValidationProblemDetails(ModelState) { Status = StatusCodes.Status401Unauthorized, }; return new UnauthorizedObjectResult(problemDetails); } } } }

5）设置密钥

6）创建应用认证身份验证逻辑类，Authenticator.cs

using Microsoft.IdentityModel.JsonWebTokens; using Microsoft.IdentityModel.Tokens; using System.Security.Claims; namespace WebApiDemo.Authority { public static class Authenticator { public static bool Authenticate(string clientId, string secret) { var app = AppPepository.GetApplicationByClientId(clientId); if (app == null) return false; return (app.ClientId == clientId && app.Secret == secret); } public static string CreateToken(string clientId, DateTime expiresAt, string strSecretKey) { //安全算法 //签名密钥 //负载（声明） //生成签名 //算法 var signingCredentials = new SigningCredentials( new SymmetricSecurityKey(System.Text.Encoding.UTF8.GetBytes(strSecretKey)), SecurityAlgorithms.HmacSha256Signature); //负载（声明） var app = AppPepository.GetApplicationByClientId(clientId); var clamsDictionary = new Dictionary<string, object> { { "AppName", app?.ApplicationName??string.Empty }, //{ "Read", (app?.Scopes??string.Empty).Contains("read") ? "true" : "false" }, //{ "Write", (app?.Scopes??string.Empty).Contains("write") ? "true" : "false" } }; var scopes = app?.Scopes?.Split(',') ?? Array.Empty<string>(); if(scopes.Length > 0) { foreach(var scope in scopes) { clamsDictionary.Add(scope.Trim().ToLower(), "true"); } } var tokenDescriptor = new SecurityTokenDescriptor { SigningCredentials = signingCredentials, Claims = clamsDictionary, Expires = expiresAt, NotBefore = DateTime.UtcNow, }; var tokenHandler = new JsonWebTokenHandler(); return tokenHandler.CreateToken(tokenDescriptor); } public static async Task<IEnumerable<Claim>?> VerifyTokenAsync(string tokenString, string securityKey) { if(string.IsNullOrWhiteSpace(tokenString) || string.IsNullOrWhiteSpace(securityKey)) { return null; } var keyBytes = System.Text.Encoding.UTF8.GetBytes(securityKey); var tokenHandle = new JsonWebTokenHandler(); var validationParameters = new TokenValidationParameters { ValidateIssuer = false, IssuerSigningKey = new SymmetricSecurityKey(keyBytes), ValidateIssuerSigningKey = false, ValidateAudience = false, ValidateLifetime = true, ClockSkew = TimeSpan.Zero }; try { var result = await tokenHandle.ValidateTokenAsync(tokenString, validationParameters); if(result.SecurityToken != null) { var tokenObject = tokenHandle.ReadJsonWebToken(tokenString); return tokenObject.Claims ?? Enumerable.Empty<Claim>(); } else { return null; } } catch (SecurityTokenMalformedException) { return null; } catch (SecurityTokenExpiredException) { return null; } catch (SecurityTokenInvalidSignatureException) { return null; } catch (Exception) { throw; } } } }

7）通过过滤器方式实现JWT令牌验证

using Microsoft.AspNetCore.Mvc; using Microsoft.AspNetCore.Mvc.Filters; using WebApiDemo.Attributes; using WebApiDemo.Authority; namespace WebApiDemo.Filters.AuthFilters { public class JwtTokenAuthFilterAttribute : Attribute, IAsyncAuthorizationFilter { public async Task OnAuthorizationAsync(AuthorizationFilterContext context) { //1. 从请求头中获取授权标识 if (!context.HttpContext.Request.Headers.TryGetValue("Authorization", out var authHeader)) { context.Result = new UnauthorizedResult(); return; } string tokenString = authHeader.ToString(); //2. 去掉Bearer前缀 if (tokenString.StartsWith("Bearer ", StringComparison.OrdinalIgnoreCase)) { tokenString = tokenString.Substring("Bearer ".Length).Trim(); } else { context.Result = new UnauthorizedResult(); return; } //3. 获取配置和安全密钥 var configuration = context.HttpContext.RequestServices.GetService<IConfiguration>(); var securityKey = configuration?["SecurityKey"] ?? string.Empty; //4. 验证令牌 并且 提取声明 //if(!await Authenticator.VerifyTokenAsync(tokenString, securityKey)) //{ // context.Result = new UnauthorizedResult(); //} var claims = await Authenticator.VerifyTokenAsync(tokenString, securityKey); if (claims == null) { context.Result = new UnauthorizedResult(); // 无效令牌 401 } else { //5. 获取声明需求 var requiredClaism = context.ActionDescriptor.EndpointMetadata .OfType<RequiredClaimAttribute>() .ToList(); if(requiredClaism != null && !requiredClaism.All(rc => claims.Any(c => c.Type.Equals(rc.ClaimType, StringComparison.OrdinalIgnoreCase) && c.Value.Equals(rc.ClaimValue, StringComparison.OrdinalIgnoreCase)))) { context.Result = new StatusCodeResult(403); // 权限不足 403 } } } } }

8）授权、权限作用域校验类，RequiredClaimAttribute.cs

namespace WebApiDemo.Attributes { [AttributeUsage(AttributeTargets.Method | AttributeTargets.Class,AllowMultiple = true)] public class RequiredClaimAttribute : Attribute { public string ClaimType { get; } public string ClaimValue { get; } public RequiredClaimAttribute(string claimType, string claimValue) { this.ClaimType = claimType; this.ClaimValue = claimValue; } } }