Silverlight_Rest_WCF系列之四：Rest调用者,RestInvoker.

还记得上篇文章中的PUT调用Rest服务的代码吗？不记得没关系，下面就是它的代码。

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#region  使用WebRequest

            WebRequest webRequest  = WebRequestCreator.ClientHttp.Create(
                 new  Uri( " http://localhost:19598/ProductService.svc/Product " ));
            webRequest.ContentType  =   " application/json " ;
            webRequest.Method  =   " PUT " ;
            webRequest.BeginGetRequestStream(requestAsyncCallback  =>
                {
                    Stream requestStream  =  webRequest.EndGetRequestStream(requestAsyncCallback);

                    JsonObject jo  =   new  JsonObject();
                    jo[ " Id " ]  =  Guid.NewGuid().ToString();
                    jo[ " Name " ]  =   " test " ;

                     string  jsonString  =  jo.ToString();
                     byte [] buffer  =  System.Text.Encoding.Unicode.GetBytes(jsonString);
                    requestStream.Write(buffer,  0 , buffer.Length);
                    requestStream.Close();

                    webRequest.BeginGetResponse(responseAsyncCallback  =>
                        {
                            WebResponse webResponse  =  webRequest.EndGetResponse(responseAsyncCallback);
                             using  (StreamReader reader  =   new  StreamReader(webResponse.GetResponseStream()))
                            {
                                 string  result  =  reader.ReadToEnd();
                                 // MessageBox.Show(result);
                                 this .Dispatcher.BeginInvoke(()  =>
                                {
                                    MessageBox.Show(result);
                                });
                            }
                        },  null );
                },  null );

             #endregion

如果说每次调用服务都需要写这么多代码的话，那估计程序员会疯的。所以我决定对他进行包装。

在这段代码中有几个地方可以封装。

1：创建WebRequest的代码可以封装。

WebRequest webRequest  = WebRequestCreator.ClientHttp.Create(
                 new  Uri( " http://localhost:19598/ProductService.svc/Product " ));
            webRequest.ContentType  =   " application/json " ;
            webRequest.Method  =   " PUT " ;

 

 2：序列化数据到requestStream对象中可以封装。

 Stream requestStream  =  webRequest.EndGetRequestStream(requestAsyncCallback);

                    JsonObject jo  =   new  JsonObject();
                    jo[ " Id " ]  =  Guid.NewGuid().ToString();
                    jo[ " Name " ]  =   " test " ;

                     string  jsonString  =  jo.ToString();
                     byte [] buffer  =  System.Text.Encoding.Unicode.GetBytes(jsonString);
                    requestStream.Write(buffer,  0 , buffer.Length);
                    requestStream.Close();

3：对返回结果执行的操作可以封装。

WebResponse webResponse  =  webRequest.EndGetResponse(responseAsyncCallback);
                             using  (StreamReader reader  =   new  StreamReader(webResponse.GetResponseStream()))
                            {
                                 string  result  =  reader.ReadToEnd();
                                 // MessageBox.Show(result);
                                 this .Dispatcher.BeginInvoke(()  =>
                                {
                                    MessageBox.Show(result);
                                });
                            }

 

按照1，2，3的方式我们先从1开始。代码如下：

1:使用GetWebRequest函数获取WebRequest对象，当然了你也可以用factory，但是在目前而言，一个函数就足够了。

///   <summary>
         ///  获取WebRequest对象
         ///   </summary>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="httpMethod"> 请求的方法：GET,PUT,POST,DELETE </param>
         ///   <param name="contentType"> 请求的类型，json:"application/json" </param>
         ///   <returns></returns>
         public   static  HttpWebRequest GetWebRequest( string  requestUriString,
                                                     string  httpMethod,
                                                     string  contentType)
        {
            HttpWebRequest request  =  (HttpWebRequest)WebRequestCreator.ClientHttp.Create( new  Uri(requestUriString));
            request.Method  =  httpMethod;
            
             if  ( ! string .IsNullOrWhiteSpace(contentType))
            {
                request.ContentType  =  contentType;
            }

             return  request;
        }

2:封装序列化到RequestStream的过程。

Stream requestStream  =  webRequest.EndGetRequestStream(requestAsyncResult);
                SerializeDataToRequestStream(data,requestStream);
                requestStream.Close();

 SerializeDataToRequestStream方法可以对JsonObject,匿名类，DataContract修饰的类进行序列化。

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private   static   void  SerializeDataToRequestStream < T > (T data, Stream requestStream)
        {
             if  (data.GetType()  ==   typeof (System.Json.JsonObject))
            {
                 string  jsonString  =  data.ToString();
                 byte [] buffer  =  System.Text.Encoding.Unicode.GetBytes(jsonString);
                requestStream.Write(buffer,  0 , buffer.Length);
            }
             else   if (data.GetType().FullName.Contains( " AnonymousType " ))  // 如果是匿名类
            {
                 #region  使用反射获取属性和值，可以使用FastInvoker来优化。

                PropertyInfo[] pis  =  data.GetType().GetProperties();
                System.Json.JsonObject jo  =   new  System.Json.JsonObject();
                 foreach (PropertyInfo pi  in  pis)
                {
                    jo[pi.Name]  =  pi.GetValue(data,  null ).ToString();
                }

                 #endregion

                 string  jsonString  =  jo.ToString();
                 byte [] buffer  =  System.Text.Encoding.Unicode.GetBytes(jsonString);
                requestStream.Write(buffer,  0 , buffer.Length);
            }
             else
            {
                DataContractJsonSerializer serializer  =   new  DataContractJsonSerializer( typeof (T));
                serializer.WriteObject(requestStream, data);
            }
        }

 

 3：处理WebResponse。如果T是String类型则直接返回Json的string，否则使用DataContractJsonSerializer 反序列化成对象进行操作。

  ///   <summary>
         ///  处理WebResponse
         ///   </summary>
         ///   <typeparam name="T"> WebResponse返回结果的类型 </typeparam>
         ///   <param name="webResponse"> webResponse对象 </param>
         ///   <param name="action"> 对结果的操作 </param>
         private   static   void  HandleWebResponse < T > (WebResponse webResponse, Action < T >  action)
        {
             using  (Stream responseStream  =  webResponse.GetResponseStream())
            {
                DataContractJsonSerializer serializer  =   new  DataContractJsonSerializer( typeof (T));
                 if  ( typeof (T)  ==   typeof ( string ))
                {
                    T responseObject  =  (T)( object )GetStringFromStream(responseStream);
                    action(responseObject);
                }
                 else
                {
                    T responseObject  =  (T)serializer.ReadObject(responseStream);
                    action(responseObject);
                }

            }
        }

好了，基本框架已经搭建好了，尝试下调用GET服务吧。

///   <summary>
         ///  调用GET方法
         ///   </summary>
         ///   <typeparam name="T"> 结果的类型 </typeparam>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="action"> 对结果的操作 </param>
         public   static   void  InvokeGet < T > ( string  requestUriString, Action < T >  action)
        {
            HttpWebRequest webRequest  =  GetWebRequest(requestUriString,  " GET " ,  string .Empty);
            webRequest.BeginGetResponse((asyncResult)  =>
            {
                WebResponse response  =  webRequest.EndGetResponse(asyncResult);
                HandleWebResponse(response, action);                
            },  null );
        }

调用GET服务比较简单，使用GET从指定的URL下载数据就可以了，那么调用POST,PUT,DELETE呢？

其实原理都比较简单，就是GetRequestStream--->写数据到RequestStream--->GetResponse。

所以可以写一个通用方法来调用PUT，POST，DELETE。

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///   <summary>
         ///  调用PUT/POST/DELETE方法
         ///   </summary>
         ///   <typeparam name="TData"> 请求数据的类型 </typeparam>
         ///   <typeparam name="TResult"> 结果的类型 </typeparam>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="data"> 请求的数据 </param>
         ///   <param name="action"> 对结果的操作 </param>
         ///   <param name="httpMethod"> 请求的具体方法，PUT/POST/DELETE </param>
         public   static   void  InvokePutPostDelete < TData, TResult > ( string  requestUriString, TData data, Action < TResult >  action,  string  httpMethod)
        {
            HttpWebRequest webRequest  =  GetWebRequest(requestUriString, httpMethod,  " application/json " );

            webRequest.BeginGetRequestStream((requestAsyncResult)  =>
            {
                Stream requestStream  =  webRequest.EndGetRequestStream(requestAsyncResult);
                SerializeDataToRequestStream(data,requestStream);
                requestStream.Close();

                webRequest.BeginGetResponse((responseAsyncResult)  =>
                {
                    WebResponse response  =  webRequest.EndGetResponse(responseAsyncResult);
                    HandleWebResponse(response, action);
                },  null );
            },  null );
        }

 

RestInvoker的完整代码如下：

 

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public   class  RestInvoker
    {
         ///   <summary>
         ///  获取WebRequest对象
         ///   </summary>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="httpMethod"> 请求的方法：GET,PUT,POST,DELETE </param>
         ///   <param name="contentType"> 请求的类型，json:"application/json" </param>
         ///   <returns></returns>
         public   static  HttpWebRequest GetWebRequest( string  requestUriString,
                                                     string  httpMethod,
                                                     string  contentType)
        {
            HttpWebRequest request  =  (HttpWebRequest)WebRequestCreator.ClientHttp.Create( new  Uri(requestUriString));
            request.Method  =  httpMethod;
            
             if  ( ! string .IsNullOrWhiteSpace(contentType))
            {
                request.ContentType  =  contentType;
            }

             return  request;
        }

         ///   <summary>
         ///  调用GET方法
         ///   </summary>
         ///   <typeparam name="T"> 结果的类型 </typeparam>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="action"> 对结果的操作 </param>
         public   static   void  InvokeGet < T > ( string  requestUriString, Action < T >  action)
        {
            HttpWebRequest webRequest  =  GetWebRequest(requestUriString,  " GET " ,  string .Empty);
            webRequest.BeginGetResponse((asyncResult)  =>
            {
                WebResponse response  =  webRequest.EndGetResponse(asyncResult);
                HandleWebResponse(response, action);                
            },  null );
        }

         ///   <summary>
         ///  调用PUT方法
         ///   </summary>
         ///   <typeparam name="TData"> 请求数据的类型 </typeparam>
         ///   <typeparam name="TResult"> 结果的类型 </typeparam>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="data"> 请求的数据 </param>
         ///   <param name="action"> 对结果的操作 </param>
         public   static   void  InvokePut < TData,TResult > ( string  requestUriString, TData data, Action < TResult >  action)
        {
            InvokePutPostDelete(requestUriString, data, action,  " PUT " );
        }

         ///   <summary>
         ///  调用POST方法
         ///   </summary>
         ///   <typeparam name="TData"> 请求数据的类型 </typeparam>
         ///   <typeparam name="TResult"> 结果的类型 </typeparam>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="data"> 请求的数据 </param>
         ///   <param name="action"> 对结果的操作 </param>
         public   static   void  InvokePost < TData, TResult > ( string  requestUriString, TData data, Action < TResult >  action)
        {
            InvokePutPostDelete(requestUriString, data, action,  " POST " );
        }

         ///   <summary>
         ///  调用DELETE方法
         ///   </summary>
         ///   <typeparam name="TData"> 请求数据的类型 </typeparam>
         ///   <typeparam name="TResult"> 结果的类型 </typeparam>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="data"> 请求的数据 </param>
         ///   <param name="action"> 对结果的操作 </param>
         public   static   void  InvokeDelete < TData, TResult > ( string  requestUriString, TData data, Action < TResult >  action)
        {
            InvokePutPostDelete(requestUriString, data, action,  " DELETE " );
        }

         ///   <summary>
         ///  调用PUT/POST/DELETE方法
         ///   </summary>
         ///   <typeparam name="TData"> 请求数据的类型 </typeparam>
         ///   <typeparam name="TResult"> 结果的类型 </typeparam>
         ///   <param name="requestUriString"> 请求的地址 </param>
         ///   <param name="data"> 请求的数据 </param>
         ///   <param name="action"> 对结果的操作 </param>
         ///   <param name="httpMethod"> 请求的具体方法，PUT/POST/DELETE </param>
         public   static   void  InvokePutPostDelete < TData, TResult > ( string  requestUriString, TData data, Action < TResult >  action,  string  httpMethod)
        {
            HttpWebRequest webRequest  =  GetWebRequest(requestUriString, httpMethod,  " application/json " );

            webRequest.BeginGetRequestStream((requestAsyncResult)  =>
            {
                Stream requestStream  =  webRequest.EndGetRequestStream(requestAsyncResult);
                SerializeDataToRequestStream(data,requestStream);
                requestStream.Close();

                webRequest.BeginGetResponse((responseAsyncResult)  =>
                {
                    WebResponse response  =  webRequest.EndGetResponse(responseAsyncResult);
                    HandleWebResponse(response, action);
                },  null );
            },  null );
        }

         ///   <summary>
         ///  序列化对象到RequestStream中
         ///   </summary>
         ///   <typeparam name="T"> 请求数据的类型 </typeparam>
         ///   <param name="data"> 请求的数据 </param>
         ///   <param name="requestStream"> RequestStream </param>
         private   static   void  SerializeDataToRequestStream < T > (T data, Stream requestStream)
        {
             if  (data.GetType()  ==   typeof (System.Json.JsonObject))
            {
                 string  jsonString  =  data.ToString();
                 byte [] buffer  =  System.Text.Encoding.Unicode.GetBytes(jsonString);
                requestStream.Write(buffer,  0 , buffer.Length);
            }
             else   if (data.GetType().FullName.Contains( " AnonymousType " ))  // 如果是匿名类
            {
                 #region  使用反射获取属性和值，可以使用FastInvoker来优化。

                PropertyInfo[] pis  =  data.GetType().GetProperties();
                System.Json.JsonObject jo  =   new  System.Json.JsonObject();
                 foreach (PropertyInfo pi  in  pis)
                {
                    jo[pi.Name]  =  pi.GetValue(data,  null ).ToString();
                }

                 #endregion

                 string  jsonString  =  jo.ToString();
                 byte [] buffer  =  System.Text.Encoding.Unicode.GetBytes(jsonString);
                requestStream.Write(buffer,  0 , buffer.Length);
            }
             else
            {
                DataContractJsonSerializer serializer  =   new  DataContractJsonSerializer( typeof (T));
                serializer.WriteObject(requestStream, data);
            }
        }

         ///   <summary>
         ///  处理WebResponse
         ///   </summary>
         ///   <typeparam name="T"> WebResponse返回结果的类型 </typeparam>
         ///   <param name="webResponse"> webResponse对象 </param>
         ///   <param name="action"> 对结果的操作 </param>
         private   static   void  HandleWebResponse < T > (WebResponse webResponse, Action < T >  action)
        {
             using  (Stream responseStream  =  webResponse.GetResponseStream())
            {
                DataContractJsonSerializer serializer  =   new  DataContractJsonSerializer( typeof (T));
                 if  ( typeof (T)  ==   typeof ( string ))
                {
                    T responseObject  =  (T)( object )GetStringFromStream(responseStream);
                    action(responseObject);
                }
                 else
                {
                    T responseObject  =  (T)serializer.ReadObject(responseStream);
                    action(responseObject);
                }

            }
        }

         ///   <summary>
         ///  从Stream中获取String
         ///   </summary>
         ///   <param name="stream"></param>
         ///   <returns></returns>
         public   static   string  GetStringFromStream(Stream stream)
        {
             byte [] buffer  =   new   byte [ 32768 ];
            stream.Position  =   0 ;  // 重置读取位置
             while  ( true )
            {
                 int  read  =  stream.Read(buffer,  0 , buffer.Length);
                 if  (read  <=   0 )
                     break ;
            }

             return  System.Text.Encoding.UTF8.GetString(buffer,  0 , ( int )stream.Length);
        }

         ///   <summary>
         ///  复制流
         ///   </summary>
         ///   <param name="input"> 输入流 </param>
         ///   <param name="output"> 输出流 </param>
         private   static   void  CopyStream(Stream input, Stream output)
        {
             byte [] buffer  =   new   byte [ 32768 ];
            input.Position  =   0 ;  // 重置读取位置
             while  ( true )
            {
                 int  read  =  input.Read(buffer,  0 , buffer.Length);
                 if  (read  <=   0 )
                     return ;
                output.Write(buffer,  0 , read);
            }
        }

    }

 

但是我们还没有解决跨线程问题，还记得上篇文章中的this.Dispatcher.BeginInvoker吗？

但是在某些特定情况下，客户端不想调用BeginInvoker。

我们下回要修改RestInvoker,让它可以跨线程。 下回分解。。。