2021-02-10

.Net WebClient调用WebService

WebClient调用WebService

(文末下载完整代码)

先上代码:

  object[] inObjects = new[] { "14630, 14631" };  HttpWebClient wc = new HttpWebClient(2300);  var result1 = WebServiceClientHelper.InvokeWebService("ESBService_TEST", "", "QueryVocabSet", inObjects, wc);  WriteLine(result1.ToString());

 public class HttpWebClient : WebClient {  /// <summary>  /// 初始化需要设置超时时间,以毫秒为单位  /// </summary>  /// <param name="timeout">毫秒为单位</param>  public HttpWebClient(int timeout)  {   Timeout = timeout;  }  public int Timeout { get; set; }  /// <summary>  /// 重写 GetWebRequest,添加 WebRequest 对象超时时间  /// </summary>  protected override WebRequest GetWebRequest(Uri address)  {   HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);   request.Timeout = Timeout;   request.ReadWriteTimeout = Timeout;   return request;  } }

  HttpWebRequest 改造依据:

WebClient

HttpWebRequest

提供用于将数据发送到由 URI 标识的资源及从这样的资源接收数据的常用方法。

public class HttpWebRequest : WebRequest, ISerializable

Assembly location:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\System.dll

Assembly location:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\System.dll

 protected virtual WebRequest GetWebRequest(Uri address) {  WebRequest request = WebRequest.Create(address);  this.CopyHeadersTo(request);  if (this.Credentials != null)  request.Credentials = this.Credentials;  if (this.m_Method != null)  request.Method = this.m_Method;  if (this.m_ContentLength != -1L)  request.ContentLength = this.m_ContentLength;  if (this.m_ProxySet)  request.Proxy = this.m_Proxy;  if (this.m_CachePolicy != null)  request.CachePolicy = this.m_CachePolicy;  return request; } protected virtual WebResponse GetWebResponse(WebRequest request) {  WebResponse response = request.GetResponse();  this.m_WebResponse = response;  return response; }

 

 

 public class HttpWebClient : WebClient {  /// <summary>  /// 初始化需要设置超时时间,以毫秒为单位  /// </summary>  /// <param name="timeout">毫秒为单位</param>  public HttpWebClient(int timeout)  {   Timeout = timeout;  }  public int Timeout { get; set; }  /// <summary>  /// 重写 GetWebRequest,添加 WebRequest 对象超时时间  /// </summary>  protected override WebRequest GetWebRequest(Uri address)  {   HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);   request.Timeout = Timeout;   request.ReadWriteTimeout = Timeout;   return request;  } }

 

  调用服务处理:

  public static object InvokeWebService(string providerName, string url, string methodName, object[] args, WebClient wc = null)  {   object result = null;   if (wc == null) wc = new WebClient();   using (wc)   {    using (Stream wsdl = wc.OpenRead(url))    {     var client = GetClient(wsdl, url, methodName, providerName);     client.SetValue("Timeout", wsdl.ReadTimeout);     result = client.InvokeService(args);    }   }   return result;  }

  形如这样 的地址,

  返回的是 dududuTest 服务下公开的方法,以流的形式,

  代码处理里面需要解读这种流,目前看到的一种方式是,把这个流解读编译成一个动态的dll,利用反射,动态调用方法。

 /// <summary>为从具有 <see cref="T:System.String" /> 指定的 URI 的资源下载的数据打开一个可读的流。</summary> /// <returns>一个 <see cref="T:System.IO.Stream" />,用于从资源读取数据。</returns> /// <param name="address">以 <see cref="T:System.String" /> 形式指定的 URI,将从中下载数据。</param> public Stream OpenRead(string address) {  if (address == null)  throw new ArgumentNullException(nameof (address));  return this.OpenRead(this.GetUri(address)); } /// <summary>为从具有 <see cref="T:System.Uri" /> 指定的 URI 的资源下载的数据打开一个可读的流</summary> /// <returns>一个 <see cref="T:System.IO.Stream" />,用于从资源读取数据。</returns> /// <param name="address">以 <see cref="T:System.Uri" /> 形式指定的 URI,将从中下载数据。</param> public Stream OpenRead(Uri address) {  if (Logging.On)  Logging.Enter(Logging.Web, (object) this, nameof (OpenRead), (object) address);  if (address == (Uri) null)  throw new ArgumentNullException(nameof (address));  WebRequest request = (WebRequest) null;  this.ClearWebClientState();  try  {  request = this.m_WebRequest = this.GetWebRequest(this.GetUri(address));  Stream responseStream = (this.m_WebResponse = this.GetWebResponse(request)).GetResponseStream();  if (Logging.On)   Logging.Exit(Logging.Web, (object) this, nameof (OpenRead), (object) responseStream);  return responseStream;  }  catch (Exception ex)  {  Exception innerException = ex;  if (innerException is ThreadAbortException || innerException is StackOverflowException || innerException is OutOfMemoryException)  {   throw;  }  else  {   if (!(innerException is WebException) && !(innerException is SecurityException))   innerException = (Exception) new WebException(SR.GetString("net_webclient"), innerException);   WebClient.AbortRequest(request);   throw innerException;  }  }  finally  {  this.CompleteWebClientState();  } }

View Code

  类 DefaultWebServiceClient 定义:

 public class DefaultWebServiceClient {  Type _type;  MethodInfo _method;  object _obj;  public object InvokeService(object[] args)  {   object proxy = GetProxy();   return _method.Invoke(proxy, args);  }  public void SetValue(string fieldName, object value)  {   object proxy = GetProxy();   PropertyInfo field = _type.GetProperty(fieldName);   if (field != null)    field.SetValue(proxy, value);  }  public object GetProxy()  {   if (_obj == null)    _obj = Activator.CreateInstance(_type);   return _obj;  }  public MethodInfo MethodInfo  {   get { return _method; }  }  public DefaultWebServiceClient(Stream wsdl, string url, string methodname, string providerName)  {   if (wsdl == null || (wsdl.CanWrite && wsdl.Length == 0))    throw new Exception("Wsdl为空");   try   {    ServiceDescription sd = ServiceDescription.Read(wsdl);    ServiceDescriptionImporter sdi = new ServiceDescriptionImporter();    sdi.AddServiceDescription(sd, "", "");    CodeNamespace cn = new CodeNamespace(string.Format("DefaultWebServiceClient_{0}_{1}", providerName, wsdl.GetHashCode().ToString()));    DiscoveryClientProtocol dcp = new DiscoveryClientProtocol();    dcp.DiscoverAny(url);    dcp.ResolveAll();    foreach (object osd in dcp.Documents.Values)    {     if (osd is ServiceDescription) sdi.AddServiceDescription((ServiceDescription)osd, null, null); ;     if (osd is //生成客户端代理类代码     CodeCompileUnit ccu = new CodeCompileUnit();    ccu.Namespaces.Add(cn);    sdi.Import(cn, ccu);    CSharpCodeProvider csc = new CSharpCodeProvider();    ICodeCompiler icc = csc.CreateCompiler();    //设定编译器的参数     CompilerParameters cplist = new CompilerParameters();    cplist.GenerateExecutable = false;    cplist.GenerateInMemory = true;    cplist.ReferencedAssemblies.Add("System.dll");    cplist.ReferencedAssemblies.Add("System.");    cplist.ReferencedAssemblies.Add("System.Web.Services.dll");    cplist.ReferencedAssemblies.Add("System.Data.dll");    //编译代理类     CompilerResults cr = icc.CompileAssemblyFromDom(cplist, ccu);    if (true == cr.Errors.HasErrors)    {     System.Text.StringBuilder sb = new StringBuilder();     foreach (CompilerError ce in cr.Errors)     {      sb.Append(ce.ToString());      sb.Append(System.Environment.NewLine);     }     throw new Exception(sb.ToString());    }    //生成代理实例,并调用方法     Assembly assembly = cr.CompiledAssembly;    Type type = null;    foreach (Type t in assembly.GetExportedTypes())    {     if (t.GetCustomAttributes(typeof(System.Web.Services.WebServiceBindingAttribute), false).Count() > 0)     {      type = t;      break;     }    }    MethodInfo mi = null;    if (type == null)    {     throw new Exception("从Wsdl中找不到可调用的类型");    }    mi = type.GetMethod(methodname);    if (mi == null)    {     throw new Exception(string.Format("从Wsdl中找不到可调用的方法{0}.{1}", type.Name, methodname));    }    _type = type;    _method = mi;   }   catch (Exception ex)   {    throw new Exception("创建WebService客户端失败!", ex);   }  } }

View Code

  WebClient 是一个操作 WebRequest 的类型,相当于一个 worker,它把服务器能提供的内容(资源)都以流的形式返回来,供我们调用,

  解读这种流,需要 ServiceDescription 类实例,再将每项加载入 ServiceDescriptionImporter 类的实例中,

  再把它编译成能本地使用的组件,动态地调用,相当于运行时加载了一个dll。

  (注:三种方法调用 webService https://www.jb51.net/article/190211.htm)

 

 

验证 1

验证 2

 

新建了一个webClient(服务代理),

它请求的处理对象默认是webRequest,

因为webRequest没有TimeOut属性,于是我继承了webCLient,override处理对象为HttpWebRequest

(注,HttpWebRequest 是 WebRequest的子类)

新建了一个webClient,

它请求的处理对象默认是webRequest

 

结果

在完成整个调用当中charles获取了2次http请求,其中:

第一次:在获取wsdl流的时候,请求包是http请求的get方式;

第二次:加载动态dll反射调用方法时,请求包是http请求的post方式;

同左

webClient真的是一个代理,像一个worker,代码上看似在本地动态引用了第三方的dll,但实际上还是http请求

就算不写死类型为 HttpWebRequest,识别出来的对象仍然是HttpWebRequest 的实例,这个服务本质提供的就是 http 请求

待证

 

识别为http请求应该是url的前缀是http的原因,如果是ftp://...那么识别出来就应该是ftpWebRequest

  这种 WebClient 的方式应该只适用于取 wsdl 来处理,

  我尝试直接用 HttpWebRequest 用 get 方法取  的内容,返回了一段服务中的方法说明

  而我试过直接照着第二次包的请求内容来发 HttpWebRequest,并不能成功(报错500内部服务器出错),可能是我入参处理不对。

  WebClient 方式和直接发 HttpWebRequest 方式应该是互通的,可以互相转换的,

  不过 WebClient 使用 Httpwebrequest 的方式封装了别的处理,某些程度上减少了程序员的工作,总归是数据结构整合的问题,这块就不多研究了。

 

  WebClient封装 HttpWebRequest 的部分内容(头部等),它还提供了一些方法,

  这里有一个示例,是异步请求,得到响应后触发事件的适用,不过这个实例比较久远了,2008年的:

https://docs.microsoft.com/zh-cn/archive/blogs/silverlight_sdk/using-webclient-and-httpwebrequest

 

  .Net当中,WebRequest 与 HttpWebRequest 区别,从名字感觉很相似,反编译结果确实是。

由客服端构建的(不同协议的)请求发给服务器

WebRequest

FtpWebRequest

FileWebRequest

HttpWebRequest

WebSocket

抽象基类

继承于WebRequest

继承于WebRequest

继承于WebRequest

抽象基类

与WebResponse成对存在

ftp:// 开头

file:// 开头,一般是打开本机文件,

形如:

file:///C:/Users/dududu/0209.pdf

file://dududu/Share2021/

ws:// 开头

wss:// 

 

 

 

Websocket主要是javaScript在页面中使用,不需要像http请求那样等待一整个页面文件返回,只取业务数据。

点击看看参考


 

   放一些地址给观察观察,感知请求和接受的运作模式,各有性格,殊途同归:

(我比较好奇是服务器怎么响应网络,光知道配置总显得苍白)








原文转载:http://www.shaoqun.com/a/542588.html

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WebClient调用WebService(文末下载完整代码)先上代码:object[]inObjects=new[]{"14630,14631"};HttpWebClientwc=newHttpWebClient(2300);varresult1=WebServiceClientHelper.InvokeWebService("ESBService_TEST&quo
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