C# WebRequest.BeginGetResponse方法代码示例

    public void BeginProcessRequest(Site site)
    {
        string sql = "";
        int iResult = 0;
        this.Site = site;

        oDataIO = new DataIO();
        SqlConnection Conn = new SqlConnection();
        Conn = oDataIO.GetDBConnection("ProfilesDB");
        sqlCmd = new SqlCommand();
        sqlCmd.Connection = Conn;

        site.IsDone = false;
        _request = WebRequest.Create(site.URL);

        // Enter log record
        sql = "insert into FSLogOutgoing(FSID,SiteID,Details,SentDate,QueryString) "
             + " values ('" + site.FSID.ToString() + "'," + site.SiteID.ToString() + ",0,GetDate()," + cs(site.SearchPhrase) + ")";
        sqlCmd.CommandText = sql;
        sqlCmd.CommandType = System.Data.CommandType.Text;
        iResult = sqlCmd.ExecuteNonQuery();

        if (sqlCmd.Connection.State == System.Data.ConnectionState.Open)
            sqlCmd.Connection.Close();

        _request.BeginGetResponse(new AsyncCallback(EndProcessRequest), site);
    }

 void DoWithResponse(WebRequest request, Action<HttpWebResponse> responseAction)
 {
     Action wrapperAction = () =>
     {
         request.BeginGetResponse(new AsyncCallback((iar) =>
                                                    {
             var response = (HttpWebResponse)((HttpWebRequest)iar.AsyncState).EndGetResponse(iar);
             responseAction(response);
         }), request);
     };
     wrapperAction.BeginInvoke(new AsyncCallback((iar) =>
                                                 {
         var action = (Action)iar.AsyncState;
         action.EndInvoke(iar);
     }), wrapperAction);
 }

 // 在此方法中开始你的异步操作
 // 执行后立即返回
 // HttpApplication 对象此时可以立即返回到池中
 private IAsyncResult BeginProcess(object sender, EventArgs e, AsyncCallback cb, object extraData)
 {
     _request = HttpWebRequest.Create("http://www.sina.com.cn");
     return _request.BeginGetResponse(cb, extraData);
 }

    public void runNetLoop()
    {
        ManualResetEvent http_response_sync = new ManualResetEvent(false);
        HttpWebResponse resp = null;

        int registeredHandle = 0;
        try
        {
            conn = HttpWebRequest.Create(url);//todomt (HttpConnection)Connector.open(url);
            //System.Net.ServicePointManager.Expect100Continue = false;

            if (method == 0) conn.Method = "GET";
            else conn.Method = "POST";

            if (updateTime != null && updateTime.Trim().Length > 0) {
                conn.Headers["IfModifiedSince"] = updateTime;
            }

            registeredHandle = CRunTime.registerObject(conn);

        }
        catch (Exception e)
        {
            quit = true;
            Logger.log(e.ToString());
            UIWorker.addUIEventLog("Async Net : Exception opening URL " + e);
        }

        int handle = registeredHandle;

        UIWorker.addUIEventValid(c_do_async_connect_cb, handle, cb_addr, context, 0, false, this);
        if (quit) return;

        while (!quit)
        {
            lock (conn)
            {
                if (!do_read)
                {
                    try
                    {
                        Monitor.Wait(conn);
                    }
                    catch (SynchronizationLockException e)
                    {
                    }
                    if (quit) return;
                    if (!do_read) continue;
                }
            }

            try
            {
                if (Stream == null)
                {
                    resp = null;
                    Exception exp = null;
                    try
                    {
                        http_response_sync.Reset();
                        conn.BeginGetResponse(delegate(IAsyncResult result)
                        {
                            try
                            {
                                Logger.log("downloading " + conn.RequestUri);
                                resp = (HttpWebResponse)conn.EndGetResponse(result);
                                http_response_sync.Set();
                            }
                            catch (Exception we)
                            {
                                resp = null;
                                exp = we;
                                http_response_sync.Set();
                            }
                        }, null);
                    }
                    catch (Exception ioe)
                    {
                        resp = null;
                        exp = ioe;
                        http_response_sync.Set();
                    }

                    http_response_sync.WaitOne();

                    if (resp != null)
                    {
                        Stream = resp.GetResponseStream();
                        int status = (int)resp.StatusCode;
                        long data_size = resp.ContentLength;
                        string lastModifiedStr = resp.Headers["Last-Modified"];
                        //Logger.log("Java header, s is " + lastModifiedStr);

                        /*
                         * We need to send c a complete header string, so we fake it by creating the
                         * res string. More header fields can be added later on besides the content length and last-modified
                         *
                         */
                        string res = "HTTP/1.1 " + status + " OK\r\nContent-Length: " + data_size + "\r\n";
                        if (lastModifiedStr != null)
//.........这里部分代码省略.........

	/// <summary>
	/// Equivalent of webRequest.GetResponse, but using our own RequestState.
	/// This can or should be used along with web async instance's isResponseCompleted parameter
	/// inside a IEnumerator method capable of yield return for it, although it's mostly for clarity.
	/// Here's an usage example:
	/// 
	/// WebAsync webAsync = new WebAsync(); StartCoroutine( webAsync.GetReseponse(webRequest) );
	/// while (! webAsync.isResponseCompleted) yield return null;
	/// RequestState result = webAsync.requestState;
	/// 
	/// </summary>
	/// <param name='webRequest'>
	/// A System.Net.WebRequest instanced var.
	/// </param>
	public IEnumerator GetResponse (WebRequest webRequest) {
		isResponseCompleted = false;
		requestState = new RequestState();
		
		// Put the request into the state object so it can be passed around
		requestState.webRequest = webRequest;
		
		// Do the actual async call here
		IAsyncResult asyncResult = (IAsyncResult) webRequest.BeginGetResponse(
			new AsyncCallback(RespCallback), requestState);
		
		// WebRequest timeout won't work in async calls, so we need this instead
		ThreadPool.RegisterWaitForSingleObject(
			asyncResult.AsyncWaitHandle,
			new WaitOrTimerCallback(ScanTimeoutCallback),
			requestState,
			(TIMEOUT *1000), // obviously because this is in miliseconds
			true
			);
		
		// Wait until the the call is completed
		while (!asyncResult.IsCompleted) { yield return null; }
		
		// Help debugging possibly unpredictable results
		if (requestState != null) {
			if (requestState.errorMessage != null) {
				// this is not an ERROR because there are at least 2 error messages that are expected: 404 and NameResolutionFailure - as can be seen on CheckForMissingURL
				Debug.Log("[WebAsync] Error message while getting response from request '"+ webRequest.RequestUri.ToString() +"': "+ requestState.errorMessage);
			}
		}
		
		isResponseCompleted = true;
	}