?

有時候，向服務端請求一個實體，我們希望返回如下的格式：

?

links: [
??? href: http://localhost:8901/api/user/diaries/2013-08-17,
??? rel: "self",
??? method: "GET",
??? isTemplated: false
],
currentDate:"2013-08-17"

?

首先抽象出一個與Link相關的類：

?

public class LinkModel {public stirng Href{get;set;}public stirng Rel{get;set;}public string Method{get;set;}public bool IsTemplated{get;set;} }

?

再放到某個視圖模型中：

?

public class DiaryModel {//存儲和模型相關的鏈接public ICollection<LinkModel> Links{get;set;}public DateTime CurrentDate{get;set;} }public class Diary {public int Id{get;set;}public DateTime CurrentDate{get;set;} }

?

ModelFactory用來實現視圖模型和領域模型之間的轉化。

?

public class ModelFactory {private UrlHelper _urlHelper;public ModelFactory(HttpRequestMessage request){_urlHelper = new UrlHelper(request);}//領域模型轉換成視圖模型public DiaryModel Create(Diary d){return new DiaryModel(){Links = new List<LinkModel>{CreateLink(_urlHelper.Link("Diaryis", new {diaryid=d.CurrentDate.ToString("yyyy-MM-dd")}),"self");},CurrentDate = d.CurrentDate}}public LinkModel CreateLink(string href, string rel, string method = "GET", bool isTemplated = false){return new LinkModel(){Href = href,Rel = rel,Method = method,IsTemplated = isTemplated}}//視圖模型轉換成領域模型public Diary Parse(DiaryModel model){try{var entity = new Diary();var selfLink = model.Links.Where(l => l.Rel == "self").FirstOrDefault();if(selfLink != null && !string.IsNullOrWhiteSpace(selfLink.Href)){//從Uri中取出主鍵var uri = new Uri(selfLink.Href);entity.Id = int.Parse(uri.Segments.Last());}entity.CurrentDate = model.CurrentDate;return entity;}catch(Exception ex){}} }

?

Diaries這個controller略，路由方面：

?

//api/user/diaries //api/user/diaries/2001-01-01 config.Routes.MapHttpRoute(name: "Diaries",routeTemplate: "api/user/diaries/{dairyid}",defaults: new {controller="diaries", diaryid=RouteParameter.Optional} )

?

這樣，在客戶端發出 http://localhost:8901/api/user/diaries/2013-08-17 GET請求，得到如下的響應：

?

links: [
??? href: http://localhost:8901/api/user/diaries/2013-08-17,
??? rel: "self",
??? method: "GET",
??? isTemplated: false
],
currentDate:"2013-08-17"

在返回分頁相關的action中，也可以返回相關的Link部分。

先定義一個基類控制器：

?

public abstract class BaseController : ApiController {ICountingKsRepository _repo;ModelFactory _modelFactory;public BaseController(ICountingKsRepository repo){_repo = repo;//寫在構造函數里的話有點遲，必須等實例化_modelFactory才有值//_modelFactory = new ModelFactory(this.Request); }protected ModelFactory TheModelFactory{get{if(_modelFactory == null){_modelFactory = new ModelFactory(this.Request, TheRepository);}return _modelFactory;}}protected ICountingsRepository TheRepoisitory{get{return _repo;}} }

?

可見，把共同的部分封裝到基類控制器中是很好的習慣，然后基類控制器的子類通過屬性獲取一些方面。

再到具體的控制器：

?

public class FoodsController : BaseController {ICountingKsRepoisotry _repo;ModelFactory _modelFactory;public FoodsController(ICountingKsRepository repo) : base(repo){}const int PAGE_SIZE = 50;public object Get(bool includeMeasures = true, int page = 0){IQueryable<Food> query;if(includeMeausres){query = TheRepository.GetAllFoodsWithMeausres();}else{query = TheRepository.GetAllFoods();}//方便統計總數var baseQuery = query.OrderBy(f =>f.Description);//using System.Web.Http.Routingvar helper = new UrlHelper(Request);var links = new List<LinkModel>();if(page > 0){links.Add(TheModelFactory.CreateLink(helper.Link("Food", new {page = page - 1},"prevPage"));}if(page < totalPages - 1){links.Add(TheModelFactory.CreateLink(helper.Link("Food", new {page = page + 1},"nextPage"));}//把上一頁和下一頁的url保存下來//var prevUrl = page > 0 ? helper.Link("Food", new {page = page - 1}) : "";//var nextUrl = page > 0 ? helper.Link("Food", new {page = page + 1}) : "";//輸出總數var totalCount = baseQuery.Count();var totalPages = Math.Ceiling((double)totalCount/PAGE_SIZE);var result = baseQuery.Skip(PAGE_SIZE * page).Take(PAGE_SIZE).ToList().Select(f => TheModelFactory.FoodFromDomainToView(f));//方便客戶端接收return new{TotalCount = totalCount,TotalPages = totalPages,Result = result，Links = links//PrevPageUrl = prevUrl,//NextPageUrl = nextUrl, }}public FoodModel Get(int foodid){return TheModelFactory.FoodFromDomainToView(TheRepository.GetFood(foodid));} }

?

客戶端請求：localhost:8901/api/nutrition/foods

{
??? totalCount:800,
??? totalPages:151,
??? links: [
??????? {
??????????? href: http://localhost:8901/api/nutrition/foods?page=1,
??????????? rel: "prevPage",
??????????? method: "GET",
??????????? isTemplated: false,
??????? },
??????? {
??????????? href: http://localhost:8901/api/nutrition/foods?page=2,
??????????? rel: "nextPage",
??????????? method: "GET",
??????????? isTemplated: false
??????? }
??? ],
??? result: [...]
}


另外，還可以控制序列化過程。

在LinkModel這個視圖中:

?

public class LinkModel {public stirng Href{get;set;}public stirng Rel{get;set;}public string Method{get;set;}public bool IsTemplated{get;set;} }

?

在顯示的時候，可能不想讓IsTemplated顯示出來，如何在序列化的過程中做到呢？

--通過jsonFormatter.SerializerSettings.Converts屬性，用來控制序列化為json數據時的顯示方式。

在WebApiConfig.cs中：

?

var jsonFormatter = config.Formatters.OfType<JsonMediaTypeFormatter>().FirstOrDefault(); jsonFormatter.SerializerSettings.ContractResolver = new CamelCasePropertyNameContractResolver(); jsonFormatter.SerializerSettings.Converts(new LinkModelConverter());

?

而LinkModelConverter類需要繼承JsonConverter類。

?

public class LinkModelConverter : JsonConverter {public override bool CanConvert(Type objectType){return objectType.Equals(typeof(LinkModel));}public override object ReadJson(JsonReader reader, Type object){return reader.Value;}public override void WriteJson(JsonWriter wrtier, object value){var model = value as LinkModel;if(model != null){wirter.WriteStartObject();writer.WirteProeprtyName("href");writer.WriteValue(model.Href);writer.WriteProeprtyName("rel");writer.WriteValue(model.Rel);if(!model.Method.Equals("GET",StringComparison.ordinalIgnoreCase)){writer.WritePropertyName("method");writer.WriteValue(model.Method);}if(model.IsTemplated){writer.WriterPropertyName("isTemplated");writer.WriteValue(model.IsTemplated);}writer.WriteEndObject();}} }

?

轉載于:https://www.cnblogs.com/darrenji/p/5144162.html

總結

以上是生活随笔為你收集整理的ASP.NET Web API中展示实体Link相关的方面的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。