構建 RESTful 服務

1.設計須知

• 您需要什麼樣的資源？
• 將使用哪些 URI 表示這些資源？
• 每個 URI 將支援統一介面的哪些部件（HTTP 動詞）

2.下面設計uri

3.建立一個wcf工程StudentService，刪除裏面的所有代碼

3.1 建立一些使用到的類 IssuesCollection

    public class IssuesCollection
    {
        public string SchoolName { get; set; }
        public List<IssuesData> IssuesDatas;
    }

    public class IssuesData
    {
        public string Issues { set; get; }

        public int Year { set; get; }
    }

    public class Student
    {
        public int ID { get; set; }
        public string Name { get; set; }
        public Nullable<int> Score { get; set; }
        public string State { get; set; }
    }

    public class Department
    {
        public string SchoolName { get; set; }
        public string DepartmentName { get; set; }
        public List<Student> Students { get; set; }
    }

3.2 建立Service類，主要處理類

    [ServiceContract]
    [AspNetCompatibilityRequirements(RequirementsMode
        = AspNetCompatibilityRequirementsMode.Allowed)]
    public class Service
    {
        [OperationContract]
        [WebGet(UriTemplate = "/")]
        public IssuesCollection GetAllIssues()
        {
            //Iniissues();
            //return issues;
            IssuesCollection issues1 = new IssuesCollection();
            issues1.SchoolName = "gsw";
            issues1.IssuesDatas = new List<IssuesData>();
            for (int i = 0; i < 10; i++)
            {
                IssuesData item = new IssuesData() { Issues = "gsw" + i.ToString(), Year = 2010 + i };
                issues1.IssuesDatas.Add(item);
            }
            return issues1;
        }

        [OperationContract]
        [WebGet(UriTemplate = "Service/GetDepartment")]
        public Department GetDepartment()
        {
            Department department = new Department
            {
                SchoolName = "北京大學",
                DepartmentName = "學生處",
                Students = new List<Student>()
            };

            return department;
        }

        [OperationContract]
        [WebGet(UriTemplate = "Service/GetAStudent({id})")]
        public Student GetAStudent(string id)
        {
            Random rd = new Random();
            Student aStudent = new Student
                {
                    ID = System.Convert.ToInt16(id), 
                    Name = "Name No. " + id,
                    Score = Convert.ToInt16(60 + rd.NextDouble() * 40),
                    State = "GA"
                };

            return aStudent;
        }

        [OperationContract]
        [WebInvoke(Method ="POST", UriTemplate = "Service/AddStudentToDepartment",
            BodyStyle = WebMessageBodyStyle.WrappedRequest)]
        public Department
            AddStudentToDepartment(Department department, Student student)
        {
            List<Student> Students = department.Students;
            Students.Add(student);

            return department;
        }
    }

3.3 設置配置文件web.config

<?xml version="1.0"?>
<configuration>

  <system.web>
    <compilation debug="true" targetFramework="4.0" />
  </system.web>

  <system.serviceModel>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true"
      multipleSiteBindingsEnabled="true" />
    <standardEndpoints>
      <webHttpEndpoint>
        <standardEndpoint name="" helpEnabled="true" automaticFormatSelectionEnabled="true" />
      </webHttpEndpoint>
    </standardEndpoints>
  </system.serviceModel>
  
 <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
  </system.webServer>
  
</configuration>

3.4 在Global.asax 中加入事件

public class Global : System.Web.HttpApplication
    {
        protected void Application_Start(object sender, EventArgs e)
        {
            RouteTable.Routes.Add(new ServiceRoute("", new WebServiceHostFactory(), typeof(Service)));
        }

        protected void Application_BeginRequest(object sender, EventArgs e)
        {

                HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
                HttpContext.Current.Response.Cache.SetNoStore();
                
                EnableCrossDmainAjaxCall();
        }

        private void EnableCrossDmainAjaxCall()
        {
            HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", "*");
            if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
            {
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "GET, POST");
                HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Content-Type, Accept");
                HttpContext.Current.Response.AddHeader("Access-Control-Max-Age", "1728000");
                HttpContext.Current.Response.End();
            }
        }
    }

通過以上步驟，就建立了wcf rest，可以測試使用。運行工程http://localhost:4305/help，介面如下：

 

和我們上面設置的資源是一樣的。

4.代碼解讀

4.1    [ServiceContract] 定義服務

4.2   [WebGet(UriTemplate = "/")] ，使用網站根路徑，得到相應內容，基本是get方法。

我們輸入 http://localhost:4305/，頁面會輸出

gsw02010gsw12011gsw22012gsw32013gsw42014gsw52015gsw62016gsw72017gsw82018gsw92019gsw

這個正好是GetAllIssues方法返回的內容。

http://localhost:4305/Service/GetDepartment,會顯示 學生處北京大學

4.3 UriTemplate 指定uri。

4.4 WebGetAttribute 告訴調度程式方法應該回應 HTTP GET 請求。 WebInvokeAttribute 預設映射為 HTTP POST，但可將 WebInvokeAttribute.Method 屬性設置為支援所有其他 HTTP 動詞（PUT 和 DELETE 是最常用的兩個）。 URI 預設由方法的名稱確定（添加到端點的基礎 URI 之上）。

4.5 可以指定輸出類型

5. 客戶端調用

5.1 代碼調用

5.1.1 get 語句

   HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create("http://localhost:4305/Service/GetDepartment");
            HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
             DataContractJsonSerializer json = new DataContractJsonSerializer(typeof(Department));
             object o = json.ReadObject(resp.GetResponseStream());
             Department d = (Department)o;

5.1.2 post 語句

 修改服務器端uri，這個方法，只是提交Department，返回Department類型，並且設置

 department.SchoolName = "test";

    [OperationContract]
        [WebInvoke(Method ="POST", UriTemplate = "Service/AddStudentToDepartment",
            RequestFormat = WebMessageFormat.Json,BodyStyle = WebMessageBodyStyle.Bare
            ,ResponseFormat=WebMessageFormat.Json)]
        public Department
            AddStudentToDepartment(Department department)
        {
            //List<Student> Students = department.Students;
            //Students.Add(student);
            department.SchoolName = "test";
            return department;
        }

客戶端調用：

  WebClient clent = new WebClient();
            Department department = new Department();
            department.DepartmentName = "學生會";
            department.SchoolName = "天津大學";
            department.Students = new List<Student>();
            department.Students.Add(new Student() { ID = 12, Name = "gsw", Score = 34, State = "查" });
            MemoryStream ms = new MemoryStream();
            DataContractJsonSerializer serializerToupdata = new DataContractJsonSerializer(typeof(Department));
            serializerToupdata.WriteObject(ms, department);
  
            clent.Headers["Content-type"] = "application/json";
            //提交數據，並且返回數據
             byte[] bytes= clent.UploadData("http://localhost:4305/Service/AddStudentToDepartment", "POST", ms.ToArray());

             ms = new MemoryStream(bytes);
             serializerToupdata = new DataContractJsonSerializer(typeof(Department));

             object o = serializerToupdata.ReadObject(ms);
             Department d = (Department)o;

最好的到的d對象，SchoolName是“test”，說明提交成功，讀取成功。

 

5.2 jquery調用

<script type="text/javascript">
    $(document).ready(function () {
        $.ajax({
            cache: false,
            type: "GET",
            async: false,
            dataType: "json",
            url: "http://localhost:4305/",
            success: function (department1) {
            //返回名稱
                alert(department1.SchoolName);
            },
            error: function (xhr) {
                alert(xhr.responseText);
            }
        });
    });
</script>

調用 http://localhost:4305/方法，返回IssuesCollection類型，輸出     alert(department1.SchoolName);