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Memento..
My stories in my way..
 

在上一篇中,我们通过SSDS Explorer详细了解了SDS的工作和操作流程。
这一篇,我们会详细讲解如何使用程序员的方法来操作SDS。

SDS提供SOAP和REST两种接口,这里我们是用REST+C#的方法来讲解。SOAP与之殊途同归,请有兴趣的同学自己查阅MSDN。

闲话少说,下面我们以创建Authority为例,给出REST操作SDS的“万能框架”:

public   string  CreateAuthority()
       {
           //步骤一(蓝色部分):通过某种方式,构造要发送到服务的XML数据。显然,这一部分只有在POST方法和PUT方法时才会有,对于GET方法和DELETE方法则不需要。下面示例的是一个创建Authority的XML
       
   const string AuthorityTemplate =
                     @"<s:Authority xmlns:s='http://schemas.microsoft.com/sitka/2008/03/'>
                       <s:Id>{0}</s:Id>
                     </s:Authority>";

           if (String.IsNullOrEmpty(ServiceUri))
           {
               throw new ArgumentOutOfRangeException("ServiceUri");
           }

           string authorityUri = null;
           try
           {

               string requestPayload = string.Format(AuthorityTemplate, authorityId);
              //步骤二:建立用以传送数据的HttpWebRequest对象
              HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(ServiceUri);
              //步骤三:将用户名和密码放置在HttpWebRequest对象的Credentials中
               request.Credentials = new NetworkCredential(userName, password);

              //步骤四(:设置Http方法。HTTP方法与数据操作方法的对照: POST=create; PUT=update; DELETE=delete; GET=retrieve 。在这个例子中,我们需要create,所以选择POST方法。
               request.Method = "POST";

             //步骤五(蓝色部分):传送数据到服务器。显然,这一部分只有在POST方法和PUT方法时才会有,对于GET方法和DELETE方法则不需要。

               UTF8Encoding encoding = new UTF8Encoding();
               request.ContentLength = encoding.GetByteCount(requestPayload);
               request.ContentType = XmlContentType;

               // 传送数据
               using (Stream reqStm = request.GetRequestStream())
               {
                   reqStm.Write(encoding.GetBytes(requestPayload), 0, encoding.GetByteCount(requestPayload));
               }
            
          //步骤六 :获取服务器响应,根据服务器的相应获取操作结果   
       HttpWebResponse response = (HttpWebResponse)request.GetResponse();
               if (response.StatusCode != HttpStatusCode.Created)
               {
                   Console.WriteLine("Failed to create authority");
               }
               authorityUri = "
https://" + authorityId + ".data.database.windows.net/v1/";
           }
           catch (WebException ex)
           {
               Console.Error.WriteLine(ex);
               HttpWebResponse response = ex.Response as HttpWebResponse;
               if (response != null)
               {
                   string errorMsg = ReadResponse(response);
                   Console.WriteLine(string.Format("Error: {0}", errorMsg));
                   Console.WriteLine("Unexpected status code returned: {0} ", response.StatusCode);
               }
           }

           return authorityUri;
       }

很简单吧? 所有的操作与这个“万能框架”相似。例如,我们稍微做一些改动,就可以得到下面这样一个删除Entity的函数:

public   string  DeleteEntity(string entityId)
       {
//由于删除是HTTP中的Delete操作,所以无步骤一和步骤五

string EntityUri = string.Format("https://{0}.data.database.windows.net/v1/{1}/{2}",
                                                    authorityId, containerId, entityId);
         try
         {
//步骤二: WebRequest request = HttpWebRequest.Create(EntityUri);
//步骤三: request.Credentials = new NetworkCredential(userName, password);
//步骤四: request.Method = "DELETE";            
//步骤六:using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
             {
                 if (response.StatusCode != HttpStatusCode.OK)
                 {
                     Console.WriteLine("Failed to delete the entity resource.");
                 }
             }
         }
         catch (WebException ex)
         {
             string errorMsg = ex.Message;
             Console.WriteLine("Deletion failed: {0}", errorMsg);

             if (ex.Response != null)
             {
                 using (HttpWebResponse response = ex.Response as HttpWebResponse)
                 {
                         Console.WriteLine("Unexpected status code returned: {0}", response.StatusCode);
                 }
             }
         }
}

UPDATE的操作和"万能框架"中Create的方法基本雷同,唯一区别是在步骤4的地方,将"POST"改为"PUT"。比如以下这个函数:

读取数据就不用说了吧?呵呵。。那太容易了,就连把URI直接输入浏览器都可以。不过作为编程来说,其实就是在上面给出的DeleteEntity()函数的代码中,步骤四的HTTP方法由DELETE改为GET,再大到HttpWebResponse 中去获取你想要获取的内容。

至此,数据库的四种操作(CRUD,Create,Read,Update,Delete)我们都已经讲过了。对,就是这么容易。

由于时间关系,我只在附件内写出了Authority,Container,Entity三种结构的Create操作。相信读者看完这篇文章后,自己改写成其他操作并非难事。下载地址:https://files.cnblogs.com/azure/BeginningAzureSDS.rar

我正把SDS应用到我目前的项目之中。如果大家有兴趣的话,我争取过段时间提取一部分功能,做成Demo供大家参考。感谢大家的关注!by 流牛木马

posted on 2008-12-21 04:02  流牛木马  阅读(3206)  评论(8编辑  收藏  举报