C# 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", "http://localhost/ESBService/VitalSign.svc?wsdl", "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 http://192.168.2.100:8090/services/dududuTest?wsdl 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"><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"><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 XmlSchema) sdi.Schemas.Add((XmlSchema)osd);
                }

                //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.XML.dll");
                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 http://localhost/ESBService/VitalSign.svc?wsdl 的内容,返回了一段服务中的方法说明 xml,

  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/

http:// 开头

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:

http://192.168.8.100:9000/empId=<EmployeeId>&jobId=<JobId>

get 方式,相当于有这样一个格式的服务地址,可以返回一个超文本内容(网页)或者一些某种格式的数据。

(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)

http://172.18.99.100:8080/yyzx/index.action?userName=<userName>&passWord=<passWord>

有些网址中这样是等价的,应该是哪里(服务配置、架构配置等)处理到了这个逻辑:

http://192.168.29.100:8081/emr/index.php/index/emr/getemr?personid=7321446

http://192.168.29.100:8081/emr/index.php/index/emr/getemr/personid/7321446

 

附:点击下载完整代码

 

posted @ 2021-02-09 20:48  Carcar019  阅读(77)  评论(0编辑  收藏