netCore WebAPI基础1

Restfule

特点

• 无状态
• 面向资源，即访问地址时使用的是名词形式
• 使用HTTP动词
  

使用情况

• 适用：面向资源，如增删改查
• 不适用：面向过程，如登陆

Restfule成熟度

1. L0:只需要api访问即可
2. L1:面向资源
   写成api/touristRoutes而不是api/getTouristRoutes
3. L2:使用HTTP动词
   利用GET\POST\PUT\PATCH\DELETE来区分操作
4. L3:超媒体控制
   api的自我发现，即返回一个资源时，附带着返回对这条资源操作的相关链接

状态码

级别	常见状态码
1xx	不常用
2xx	200：ok,201:created,201:No Content
3xx	301/302:Moved Permanently,304:Not Modified
4xx	400:Bad Request,401:Unauthorized,403:Forbidden,404:Not Found
5xx	500:Internal Servel Error,502:Gateway

内容协商

浏览器会在头文件中的Accept下协商内容的格式，如application/json。
.netCore默认是返回Json格式可以在program中修改：

builder.Services.AddControllers(opt => {
    opt.ReturnHttpNotAcceptable = true;//默认是false，即只识别和返回json类型
    opt.OutputFormatters.Add(new XmlDataContractSerializerOutputFormatter());//可以返回xml类型，老方法，已经弃用
}).AddXmlDataContractSerializerFormatters();//新方法，可以输入和输入xml格式的内容

DTO

数据模型（Model）包含了很多不需要展示的信息。将需要展示的信息提取形成DTO模型对象

1. Nuget安装AutoMapper.Extensions.Microsoft.DependencyInjection
2. 创建Dto对象

   //模型对象
   public class TouristRoute
   {
       [Key]
       public Guid Id { get; set; }
       [Required]
       [MaxLength(100)]
       public string Title { get; set; }
       [Required]
       [MaxLength(1500)]
       public string Description { get; set; }
       [Column(TypeName = "decimal(18, 2)")]
       public decimal OriginalPrice { get; set; }
       [Range(0.0, 1.0)]
       public double? DiscountPresent { get; set; }
       public DateTime CreateTime { get; set; }
       public DateTime? UpdateTime { get; set; }
       public DateTime? DepartureTime { get; set; }
       [MaxLength]
       public string Features { get; set; }
       [MaxLength]
       public string Fees { get; set; }
       [MaxLength]
       public string Notes { get; set; }
       public double? Rating { get; set; }
       public TravelDays? TravelDays { get; set; }
       public TripType? TripType { get; set; }
       public DepartureCity? DepartureCity { get; set; }
   }
   //DTO对象
   public class TouristRouteDto
   {
       public Guid Id { get; set; }
       public string Title { get; set; }
       public string Description { get; set; }
       public decimal Price { get; set; }// 计算方式：原价 * 折扣
       public DateTime CreateTime { get; set; }
       public DateTime? UpdateTime { get; set; }
       public DateTime? DepartureTime { get; set; }
       public string Features { get; set; }
       public string Fees { get; set; }
       public string Notes { get; set; }
       public double? Rating { get; set; }
       public string TravelDays { get; set; }// 枚举变成了string
       public string TripType { get; set; }// 枚举变成了string
       public string DepartureCity { get; set; }// 枚举变成了string
   }

3. 注册AutoMapper

   //会自动扫描Profiles文件夹，对里面的映射设置进行处理
   //扫描程序集中所有包含映射关系的profile文件并加载
   builder.Services.AddAutoMapper(AppDomain.CurrentDomain.GetAssemblies());

4. 创建Profiles文件夹，并在里面增加映射文件

   public class TouristRouteProfile:Profile
   {
       public TouristRouteProfile()
       {
           //默认自动匹配名称相同的字段
           CreateMap<TouristRoute, TouristRouteDto>()
               //其他需要的映射
               .ForMember(dest => dest.Price,
                          opt => opt.MapFrom(src => src.OriginalPrice * (decimal)(src.DiscountPresent ?? 1)))
               .ForMember(dest => dest.TravelDays,
                          opt => opt.MapFrom(src => src.TravelDays.ToString()))
               .ForMember(dest => dest.TripType,
                          opt => opt.MapFrom(src => src.TripType.ToString()))
               .ForMember(dest => dest.DepartureCity,
                          opt => opt.MapFrom(src => src.DepartureCity.ToString())
               );
       }
   }

5. 在控制器中使用

   [Route("api/[controller]")]
   [ApiController]
   public class TouristRoutesController : ControllerBase
   {
       private ITourisTouteRepository _tourisTouteRepository;
       private readonly IMapper _mapper;//增加注入
       public TouristRoutesController(ITourisTouteRepository tourisTouteRepository, IMapper mapper)
       {
           _tourisTouteRepository = tourisTouteRepository;
           _mapper = mapper;
       }
       [HttpGet]
       public IActionResult GetTouristRoutes()
       {
           var routes = _tourisTouteRepository.GetTourisRoutes();
           if (routes == null || routes.Count()<=0)
           {
               return NotFound("没有旅游路线");
           }
           //使用映射
           var touristRouteDto = _mapper.Map<IEnumerable<TouristRouteDto>>(routes);
           return Ok(touristRouteDto);
       }
   }