webapi的方法可以返回的类型有:void
、httpresponsemessage
、IHttpActionResult
、自定义
public class ValuesController : ApiController { public void Post() { } }
HTTP响应
HTTP/1.1 204 No Content Server: Microsoft-IIS/8.0 Date: Mon, 27 Jan 2014 02:13:26 GMT
可直接创建返回的HttpResponseMessage,包括exception。
public class ValuesController : ApiController { public HttpResponseMessage Get() { HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.OK, "value"); response.Content = new StringContent("hello", Encoding.Unicode); response.Headers.CacheControl = new CacheControlHeaderValue() { MaxAge = TimeSpan.FromMinutes(20) }; return response; } }
响应
HTTP/1.1 200 OK Cache-Control: max-age=1200 Content-Length: 10 Content-Type: text/plain; charset=utf-16 Server: Microsoft-IIS/8.0 Date: Mon, 27 Jan 2014 08:53:35 GMT hello
也可以直接在HttpResponseMessage包含域模型的数据
public HttpResponseMessage Get() { // 生成自定义数据 IEnumerable<Product> products = GetProductsFromDB(); // 将数据直接赋值给HttpResponseMessage HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.OK, products); return response; }
这个是异步执行操作。IHttpActionResult接口的定义
public interface IHttpActionResult { Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken); }
实现接口的类
public class TextResult : IHttpActionResult { string _value; HttpRequestMessage _request; public TextResult(string value, HttpRequestMessage request) { _value = value; _request = request; } public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken) { var response = new HttpResponseMessage() { Content = new StringContent(_value), RequestMessage = _request }; return Task.FromResult(response); } }
控制器
public class ValuesController : ApiController { public IHttpActionResult Get() { return new TextResult("hello", Request); } }
响应
HTTP/1.1 200 OK Content-Length: 5 Content-Type: text/plain; charset=utf-8 Server: Microsoft-IIS/8.0 Date: Mon, 27 Jan 2014 08:53:35 GMT hello
另外,系统会有一些内置的IHttpActionResult 实现类,包括:NotFound、Ok等。具体可参考MSDN:内置实现
public IHttpActionResult Get (int id) { Product product = _repository.Get (id); if (product == null) { return NotFound(); // Returns a NotFoundResult } return Ok(product); // Returns an OkNegotiatedContentResult }
这个就是自定义的类型。
这里面就包含了:1、内容协商;2、异常处理(HttpResponseException )。异常处理可参见MSDN中的资料。异常处理资料