.NET Micro Framework 開發 DPWS 裝置服務完整實作指南

DPWS (Device Profile for Web Services) 是 Windows Rally 技術子集，針對資源受限裝置定義最小化安全 Web Service 介面集。Windows Vista 內建 WSDAPI 客戶端，支援 DPWS 裝置自動發現於網路鄰居。本文完整示範在 .NET Micro Framework v3.0 上建立 DPWS Host 與 Client，於 Windows Vista 環境執行驗證。

DPWS 架構與類庫總覽

DPWS Host 類庫 (MFDpwsDevice.dll、MFWsStack.dll)

DPWS Client 類庫 (MFDpwsClient.dll)

完整開發流程實作

步驟 1：定義 Web Service WSDL

建立 ASP.NET Web Service 專案，定義 Add 方法：

[WebService(Namespace = "https://fox23.cnblogs.com/")]
public class Service1 : System.Web.Services.WebService {
    [WebMethod]
    public int Add(int a, int b) { return a + b; }
}

瀏覽服務取得 WSDL，另存為 AddService.wsdl。

步驟 2：MfSvcUtil.exe 產生輔助類別

SDK 工具目錄執行：

MfSvcUtil AddService.wsdl

產生三個檔案：

• AddService.cs - 資料合約類別
• AddServiceHostedService.cs - 主機服務基類
• AddServiceClientProxy.cs - 客戶端 Proxy

步驟 3：建立 Device Host Service

新增 .NET Micro Framework Console 專案，引用四個組件，加入產生的三個類別。

using System;
using Microsoft.SPOT;
using Dpws.Device;
using fox.cnblogs.com; // 產生類別命名空間

public class Program {
    public static void Main() {
        // 設定裝置端點 (必須 urn:uuid 格式)
        Device.EndpointAddress = "urn:uuid:587066b0-440f-4652-8395-ec20cca0ec91";

        // 裝置中繼資料配置
        Device.ThisModel.Manufacturer = "Freesc Huang";
        Device.ThisModel.ManufacturerUrl = "https://fox23.cnblogs.com/";
        Device.ThisModel.ModelName = "Freesc Dpws Test Device";
        Device.ThisModel.ModelNumber = "1.0";
        Device.ThisModel.ModelUrl = "https://fox23.cnblogs.com/";
        Device.ThisModel.PresentationUrl = "https://fox23.cnblogs.com/";
        Device.ThisDevice.FriendlyName = "Service1Soap";
        Device.ThisDevice.FirmwareVersion = "alpha";
        Device.ThisDevice.SerialNumber = "12345678";

        // 實作服務介面
        public class AddServiceImplementation : IService1Soap {
            public AddResponse Add(Add req) {
                AddResponse response = new AddResponse();
                response.AddResult = req.a + req.b;
                return response;
            }
        }

        // 註冊並啟動服務
        Device.HostedServices.Add(new Service1Soap(new AddServiceImplementation()));
        Device.Start();
        
        Debug.Print("Device started!");
        Thread.Sleep(Timeout.Infinite);
    }
}

步驟 4：建立 Device Client Consumer

public class Program {
    public static void Main() {
        // 發現裝置
        DpwsServiceDescription resolveMatch = Discover.DiscoveryClient.Resolve(
            "urn:uuid:587066b0-440f-4652-8395-ec20cca0ec91");
        
        // 取得裝置中繼資料並尋找服務端點
        var deviceMetadata = Discover.MexClient.Get(deviceEndpointURI);
        string serviceEndpoint = null;
        if (deviceMetadata.Relationship.HostedServices != null) {
            for (int i = 0; i < deviceMetadata.Relationship.HostedServices.Count; ++i) {
                if (deviceMetadata.Relationship.HostedServices[i].ServiceID == 
                    "urn:uuid:2c7ea8f1-d812-402d-afa8-6ca9fa03a2f0") {
                    serviceEndpoint = deviceMetadata.Relationship.HostedServices[i]
                        .EndpointRefs[0].Address.AbsoluteUri;
                }
            }
        }

        // 呼叫服務
        Service1SoapClientProxy soapProxy = new Service1SoapClientProxy();
        soapProxy.ServiceEndpoint = serviceEndpoint;
        soapProxy.IgnoreRequestFromThisIP = false;
        
        Add request = new Add { a = 2, b = 5 };
        AddResponse response = soapProxy.Add(request);
        Debug.Print("mResponse.AddResult: " + response.AddResult); // 輸出 7
    }
}

步驟 5：執行驗證

雙 Visual Studio 分別對模擬器偵錯，先啟 Host 再啟 Client：

HOST:
urn:uuid:587066b0-440f-4652-8395-ec20cca0ec91
Device started!

CLIENT:
Device endpoint found: https://192.168.1.101:8084/587066b0-440f-4652-8395-ec20cca0ec91
Found device:
ModelName: Freesc Dpws Test Device
ModelNumber: 1.0
FirmwareVersion: alpha
FriendlyName: Service1Soap
SerialNumber: 12345678
Service endpoint found: https://192.168.1.101:8084/2c7ea8f1-d812-402d-afa8-6ca9fa03a2f0
mResponse.AddResult: 7

首次執行 Vista 防火牆會詢問，選擇 Unblock 即可。

總結與展望

DPWS 讓資源受限裝置輕鬆公開/消費 Web Service，隨支援裝置增加應用將更普及。.NET MF 團隊正努力與桌面 WCF 整合，未來將構建裝置與 PC 組成的服務網絡，帶來更豐富應用場景。