[Windows 8 App]HttpWebRequest翻譯應用(下)

2014-01-15

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Windows 8 控制項
2014-01-29

這裡是關於 AdmaAuthentication 的程式碼如下：


        public class AdmaAuthentication
        {
            public static readonly string DatamarketAccessUri = "https://datamarket.accesscontrol.windows.net/v2/OAuth2-13";
            private string clientId;
            private string clientSecret;
            private string request;
            public AdmaAuthentication(string clientId, string clientSecret)
            {
                this.clientId = clientId;
                this.clientSecret = clientSecret;
                this.request = string.Format("grant_type = client_creadentials&client_id={0}&client_secret={1}&scope=http://api.microsofttranslator.com", System.Net.WebUtility.UrlEncode(clientId), System.Net.WebUtility.UrlEncode(clientSecret));
            }
            public Task<AdmAccessToken> GetAccessToken()
            {
                return HttpPost(DatamarketAccessUri, this.request);
            }

            private async Task<AdmAccessToken> HttpPost(string DatamarketAccessUri, string requestDetails)
            {
                WebRequest webRequest = WebRequest.Create(DatamarketAccessUri);
                webRequest.ContentType = "application/x-www-form-urlencoded";
                webRequest.Method = "POST";
                byte[] bytes = Encoding.UTF8.GetBytes(requestDetails);
                using (Stream outputStream = await webRequest.GetRequestStreamAsync())
                {
                    outputStream.Write(bytes, 0, bytes.Length);
                }
                using (WebResponse webResponse = await webRequest.GetResponseAsync())
                {
                    DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(AdmAccessToken));
                    AdmAccessToken token = (AdmAccessToken)serializer.ReadObject(webResponse.GetResponseStream());
                    return token;
                }
            }
        }

由於AdmaAuthentication 類別是來自微軟官方，這裡我們就不對其做詳細的解釋

接下來看一下，翻譯按鈕的Click事件是如何實現的

此按鈕透過HTTP請求將要翻譯的英文送給翻譯伺服器，並接收服務器的回應數據

關於 BtnTranslate_Click 的程式碼如下：


        private async void BtnTranslate_Click(object sender, RoutedEventArgs e)
        {
            string text = TxtEnglish.Text;

            string from = "en";

            string to = "zh-TW";

            string uri = "https://api.datamarket.azure.com/Bing/MicrosoftTranslator/v1/Translate?Text=" + System.Net.WebUtility.UrlEncode(text) + "&from" + from + "&to" + to;
            string authToken = "Bearer" + " " + token.access_token;

            HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(uri);

            httpWebRequest.Headers["Authorization"] = authToken;

            WebResponse response = null;
            try
            {
                response = await httpWebRequest.GetResponseAsync();
                using (Stream stream = response.GetResponseStream())
                {
                    System.Runtime.Serialization.DataContractSerializer dcs = new System.Runtime.Serialization.DataContractSerializer(Type.GetType("System.String"));
                    string translation = (string)dcs.ReadObject(stream);
                    TxtChinese.Text = translation;
                }
            }
            catch (Exception ex)
            {
                TxtMessage.Text = ex.Message;
            }
        }

上面的程式碼中，首先取得輸入的英文語句，並定義請求字符串 uri

以 uri 為參數呼叫非同步方法 WebRequest.Create 建立HTTP請求 httpWebRequest

由於翻譯需要使用到權限的驗證

所以這裡使用了在前面獲得的客戶端 token 來請求 Headers 中的 Authorization 鍵賦值

最後，將翻譯出來的字符串輸出到文字方塊中

專案執行的畫面如下：

這是初始畫面

這是翻譯 apple 蘋果的結果

這是翻譯歡迎來到微軟

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