从WebApi 1迁移到WebAPI 2要改变配置代码如下：
WebApi 1：
protected void Application_Start()
{
// WARNING - Not compatible with attribute routing.
WebApiConfig.Register(GlobalConfiguration.Configuration);
}
WebAPI 2：
protected void Application_Start()
{
// Pass a delegate to the Configure method.
GlobalConfiguration.Configure(WebApiConfig.Register);
}
添加一个Route Attributes
public class OrdersController : ApiController
{
[Route("customers/{customerId}/orders")]
[HttpGet]
public IEnumerable<Order> FindOrdersByCustomer(int customerId) { ... }
}
可以匹配一下URL：
- http://localhost/customers/1/orders
- http://localhost/customers/bob/orders
- http://localhost/customers/1234-5678/orders
匹配http post请求的CreateBook
[Route("api/books")]
[HttpPost]
public HttpResponseMessage CreateBook(Book book) { ... }
[Route("api/books")]
[AcceptVerbs("MKCOL")]
public void MakeCollection() {
Route Prefixes
对于同一个controller路由有相同的前缀， 此时可以使用 [RoutePrefix] attribute
[RoutePrefix("api/books")]
public class BooksController : ApiController
{
// GET api/books
[Route("")]
public IEnumerable<Book> Get() { ... }
// GET api/books/5
[Route("{id:int}")]
public Book Get(int id) { ... }
// POST api/books
[Route("")]
public HttpResponseMessage Post(Book book) { ... }
}
可以在方法的attribute中使用（~）重写路由前缀
[RoutePrefix("api/books")]
public class BooksController : ApiController
{
// GET /api/authors/1/books
[Route("~/api/authors/{authorId:int}/books")]
public IEnumerable<Book> GetByAuthor(int authorId) { ... }
// ...
}
路由前缀中可以包含参数
[RoutePrefix("customers/{customerId}")]
public class OrdersController : ApiController
{
// GET customers/1/orders
[Route("orders")]
public IEnumerable<Order> Get(int customerId) { ... }
}
路由约束
路由约束用于严格匹配路由中的参数，通用语法是{参数:约束}，如下：
[Route("users/{id:int}"]
public User GetUserById(int id) { ... }
[Route("users/{name}"]
public User GetUserByName(string name) { ... }
支持的约束如下表所示：
| Constraint | Description | Example |
|---|---|---|
| alpha | Matches uppercase or lowercase Latin alphabet characters (a-z, A-Z) | {x:alpha} |
| bool | Matches a Boolean value. | {x:bool} |
| datetime | Matches a DateTime value. | {x:datetime} |
| decimal | Matches a decimal value. | {x:decimal} |
| double | Matches a 64-bit floating-point value. | {x:double} |
| float | Matches a 32-bit floating-point value. | {x:float} |
| guid | Matches a GUID value. | {x:guid} |
| int | Matches a 32-bit integer value. | {x:int} |
| length | Matches a string with the specified length or within a specified range of lengths. | {x:length(6)} {x:length(1,20)} |
| long | Matches a 64-bit integer value. | {x:long} |
| max | Matches an integer with a maximum value. | {x:max(10)} |
| maxlength | Matches a string with a maximum length. | {x:maxlength(10)} |
| min | Matches an integer with a minimum value. | {x:min(10)} |
| minlength | Matches a string with a minimum length. | {x:minlength(10)} |
| range | Matches an integer within a range of values. | {x:range(10,50)} |
| regex | Matches a regular expression. | {x:regex(^\d{3}-\d{3}-\d{4}$)} |
注意：带括号的约束，如"min"，可以对路由中的参数应用多个约束，用冒号分割约束
[Route("users/{id:int:min(1)}")]
public User GetUserById(int id) { ... }
自定义路由约束
public class NonZeroConstraint : IHttpRouteConstraint
{
public bool Match(HttpRequestMessage request, IHttpRoute route, string parameterName,
IDictionary<string, object> values, HttpRouteDirection routeDirection)
{
object value;
if (values.TryGetValue(parameterName, out value) && value != null)
{
long longValue;
if (value is long)
{
longValue = (long)value;
return longValue != ;
} string valueString = Convert.ToString(value, CultureInfo.InvariantCulture);
if (Int64.TryParse(valueString, NumberStyles.Integer,
CultureInfo.InvariantCulture, out longValue))
{
return longValue != ;
}
}
return false;
}
} 修改WebAPIConfig.cs
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
var constraintResolver = new DefaultInlineConstraintResolver();
constraintResolver.ConstraintMap.Add("nonzero", typeof(NonZeroConstraint)); config.MapHttpAttributeRoutes(constraintResolver);
}
} 实际应用：
[Route("{id:nonzero}")]
public HttpResponseMessage GetNonZero(int id) { ... }
可选的URI参数和默认值
第一种方式，默认值直接分配给了方法参数，因此参数获得的是精确的值
第二种方式，默认值通过model-binding进行处理，默认的model-binder将字符串类型的默认值"1033"转为int形的1033，对于model-binder可能有所不同。
第一种写法
public class BooksController : ApiController
{
[Route("api/books/locale/{lcid:int?}")]
public IEnumerable<Book> GetBooksByLocale(int lcid = ) { ... }
} 第二种写法
public class BooksController : ApiController
{
[Route("api/books/locale/{lcid:int=1033}")]
public IEnumerable<Book> GetBooksByLocale(int lcid) { ... }
}
Route Names
web api中每个路由有一个name，Route names可以用来生成links
public class BooksController : ApiController
{
[Route("api/books/{id}", Name="GetBookById")]
public BookDto GetBook(int id)
{
// Implementation not shown...
} [Route("api/books")]
public HttpResponseMessage Post(Book book)
{
// Validate and add book to database (not shown) var response = Request.CreateResponse(HttpStatusCode.Created); // Generate a link to the new book and set the Location header in the response.
string uri = Url.Link("GetBookById", new { id = book.BookId });
response.Headers.Location = new Uri(uri);
return response;
}
}
Route Order
通过设置RouteOrder属性在route attribute上，可以指定Route的顺序，值越小先被计算，默认顺序对应的值是0
路由顺序的选择：
- 比较RouteOrder属性
- 对于URI部分按如下进行排序
- URI的固定部分（literal segments）
- 带约束的路由参数
- 不带约束的路由参数
- 带约束的通配符
- 不带约束的通配符
- route的排序不区分大小写的
[RoutePrefix("orders")]
public class OrdersController : ApiController
{
[Route("{id:int}")] // constrained parameter
public HttpResponseMessage Get(int id) { ... }
[Route("details")] // literal
public HttpResponseMessage GetDetails() { ... }
[Route("pending", RouteOrder = )]
public HttpResponseMessage GetPending() { ... }
[Route("{customerName}")] // unconstrained parameter
public HttpResponseMessage GetByCustomer(string customerName) { ... }
[Route("{*date:datetime}")] // wildcard
public HttpResponseMessage Get(DateTime date) { ... }
}
路由排序如下：
- orders/{details}
- orders/{id}
- orders/{customreName}
- orders/{*date}
- orders/pending
Route Attribute的使用完整例子：
using BooksAPI.DTOs;
using BooksAPI.Models;
using System;
using System.Data.Entity;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;
using System.Web.Http;
using System.Web.Http.Description; namespace BooksAPI.Controllers
{
[RoutePrefix("api/books")]
public class BooksController : ApiController
{
private BooksAPIContext db = new BooksAPIContext(); // Typed lambda expression for Select() method.
private static readonly Expression<Func<Book, BookDto>> AsBookDto =
x => new BookDto
{
Title = x.Title,
Author = x.Author.Name,
Genre = x.Genre
}; // GET api/Books
[Route("")]
public IQueryable<BookDto> GetBooks()
{
return db.Books.Include(b => b.Author).Select(AsBookDto);
} // GET api/Books/5
[Route("{id:int}")]
[ResponseType(typeof(BookDto))]
public async Task<IHttpActionResult> GetBook(int id)
{
BookDto book = await db.Books.Include(b => b.Author)
.Where(b => b.BookId == id)
.Select(AsBookDto)
.FirstOrDefaultAsync();
if (book == null)
{
return NotFound();
} return Ok(book);
} [Route("{id:int}/details")]
[ResponseType(typeof(BookDetailDto))]
public async Task<IHttpActionResult> GetBookDetail(int id)
{
var book = await (from b in db.Books.Include(b => b.Author)
where b.AuthorId == id
select new BookDetailDto
{
Title = b.Title,
Genre = b.Genre,
PublishDate = b.PublishDate,
Price = b.Price,
Description = b.Description,
Author = b.Author.Name
}).FirstOrDefaultAsync(); if (book == null)
{
return NotFound();
}
return Ok(book);
} [Route("{genre}")]
public IQueryable<BookDto> GetBooksByGenre(string genre)
{
return db.Books.Include(b => b.Author)
.Where(b => b.Genre.Equals(genre, StringComparison.OrdinalIgnoreCase))
.Select(AsBookDto);
} [Route("~api/authors/{authorId}/books")]
public IQueryable<BookDto> GetBooksByAuthor(int authorId)
{
return db.Books.Include(b => b.Author)
.Where(b => b.AuthorId == authorId)
.Select(AsBookDto);
} [Route("date/{pubdate:datetime:regex(\\d{4}-\\d{2}-\\d{2})}")]
[Route("date/{*pubdate:datetime:regex(\\d{4}/\\d{2}/\\d{2})}")]
public IQueryable<BookDto> GetBooks(DateTime pubdate)
{
return db.Books.Include(b => b.Author)
.Where(b => DbFunctions.TruncateTime(b.PublishDate)
== DbFunctions.TruncateTime(pubdate))
.Select(AsBookDto);
} protected override void Dispose(bool disposing)
{
db.Dispose();
base.Dispose(disposing);
}
}
}
其中以下路由中的匹配符*的作用：
[Route("date/{pubdate:datetime:regex(\\d{4}-\\d{2}-\\d{2})}")]
[Route("date/{pubdate:datetime:regex(\\d{4}/\\d{2}/\\d{2})}")] // new
public IQueryable<BookDto> GetBooks2(DateTime pubdate)
{
/*
* 路由中的*匹配符的作用，是为了告诉route engine占位符{pubdate}应该匹配剩余的URI，
* 默认情况下，一个模板参数仅仅匹配一个URI。
* This tells the routing engine that {pubdate} should match the rest of the URI. By default,
* a template parameter matches a single URI segment. In this case, we want {pubdate} to
* span several URI segments:
*/
}