ScriptReferenceExecutor

my_earth

于 2008-05-26 18:54:00 发布

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CC 4.0 BY-SA版权

分类专栏： asp.net ajax2.0 文章标签： function null string action button timer

本文链接：https://blog.youkuaiyun.com/my_earth/article/details/2483489

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1 篇文章

订阅专栏

本文介绍了一种利用异步通信层进行前后端交互的方法，包括客户端JavaScript代码发送请求及服务器端处理请求的过程。通过不同的操作（如正常、错误、超时）演示了如何处理各种响应情况。

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2_UseAsyncCommLayer.aspx

<head runat="server">
    <title>Use Async Communication Layer</title>

    <script language="javascript" type="text/javascript">
  var webRequest = null;

  function sendRequest(action)
  {

   webRequest = new Sys.Net.WebRequest();
   webRequest.set_url("Handlers/ScriptReferenceExecutor.ashx");
   webRequest.get_headers()["action"] = action;
   webRequest.set_body("Hello World!");
   webRequest.set_timeout(3000);
    debugger;
   webRequest.set_executor(new Sys.Net.ScriptReferenceExecutor());

   webRequest.add_completed(onCompleted);
   webRequest.invoke();
  }

  function onCompleted(response, eventArgs)
  {
   if (response.get_aborted())
   {
    alert("Request aborted!");
   }
   else if (response.get_responseAvailable())
   {
    var statusCode = response.get_statusCode();
    if ((statusCode < 200) || (statusCode >= 300))
    {
     alert("Error occurred!");
    }
    else
    {
     alert(response.get_responseData());
    }
   }
   else if (response.get_timedOut())
   {
    alert("Request timed out!");
   }
   else
   {
    alert("Error occurred!");
   }
  }
    </script>
</head>
<body>
    <form id="form1" runat="server">
  <asp:ScriptManager ID="ScriptManager1" runat="server" ScriptMode="Debug">
      <Scripts>
          <asp:ScriptReference Path="ScriptReferenceExecutor.js" />
      </Scripts>
  </asp:ScriptManager>

  <input type="button" value="Normal" onclick="sendRequest('normal');" />
  <input type="button" value="Error" onclick="sendRequest('error');" />
  <input type="button" value="Timeout" onclick="sendRequest('abc')" />
  <input type="button" value="Abort" onclick="webRequest.get_executor().abort()" />
    </form>
</body>

ScriptReferenceExecutor.js

Sys.Net.ScriptReferenceExecutor = function()
{
Sys.Net.ScriptReferenceExecutor.initializeBase(this);

    this._responseAvailable = false;
    this._timedOut = false;
    this._aborted = false;
    this._started = false;
    this._responseData = null;
    this._statusCode = 0;
    this._statusText = null;

    this._uniqueKey = null;
    this._timer = null;
    this._scriptElement = null;

}
Sys.Net.ScriptReferenceExecutor.prototype =
{
    get_responseAvailable : function()
    {
        return this._responseAvailable;
    },

    get_timedOut : function()
    {
        return this._timedOut;
    },

    get_aborted : function()
    {
        return this._aborted;
    },

    get_started : function()
    {
        return this._started;
    },

    get_responseData : function()
    {
        return this._responseData;
    },

    get_statusCode : function()
    {
        return this._statusCode;
    },

    get_statusText : function()
    {
        return this._statusText;
    },

    get_xml : function()
    {
        return new XMLDOM(this.get_responseData());
    },

    executeRequest : function()
    {
        this._started = true;

        var request = this.get_webRequest();
        var serializer = Sys.Serialization.JavaScriptSerializer;

        var scriptUrl = request.get_url() + "?";
        scriptUrl += (("headers=") + encodeURIComponent(serializer.serialize(request.get_headers())));
        scriptUrl += ("&body=" + encodeURIComponent(serializer.serialize(request.get_body())));

        var uniqueKey = this._uniqueKey = this._generateUniqueKey();
        scriptUrl += ("&uniqueKey=" + encodeURIComponent(serializer.serialize(uniqueKey)));
        Sys.Net.ScriptReferenceExecutor._executors[uniqueKey] = this;

        var scriptElement = this._scriptElement = document.createElement("script");
        scriptElement.type = "text/javascript";
        scriptElement.language = "javascript";
        scriptElement.src = scriptUrl;
        document.getElementsByTagName("head")[0].appendChild(scriptElement);

        var timeout = request.get_timeout();
        if (timeout > 0)
        {
            this._timer = window.setTimeout(
                Function.createDelegate(this, this._onTimeout), timeout);
        }

    },

    _onTimeout : function()
    {
        this.complete(null, null, null, false, true, false);
    },

    abort : function()
    {
        this.complete(null, null, null, false, false, true);
    },

    _generateUniqueKey : function()
    {
        return Math.random().toString();
    },

    complete : function(statusCode, statusText, body, responseAvailable, timedOut, aborted)
    {
        this._statusCode = statusCode;
        this._statusText = statusText;
        this._responseData = body;
        this._responseAvailable = responseAvailable;
        this._timedOut = timedOut;
        this._aborted = aborted;

        if (this._timer)
        {
            window.clearTimeout(this._timer);
        }
        document.getElementsByTagName("head")[0].removeChild(this._scriptElement);
        delete Sys.Net.ScriptReferenceExecutor._executors[this._uniqueKey];

        this.get_webRequest().completed(Sys.EventArgs.Empty);
    }
}
Sys.Net.ScriptReferenceExecutor.registerClass("Sys.Net.ScriptReferenceExecutor", Sys.Net.WebRequestExecutor);
Sys.Net.ScriptReferenceExecutor._executors = new Object();
Sys.Net.ScriptReferenceExecutor.complete = function(uniqueKey, statusCode, statusText, body)
{
    var executor = Sys.Net.ScriptReferenceExecutor._executors[uniqueKey];
    if (executor)
    {
        executor.complete(statusCode, statusText, body, true, false, false);
    }
}

ScriptReferenceExecutor.ashx

<%@ WebHandler Language="C#" Class="ScriptReferenceExecutor" %>

using System;
using System.Web;
using System.Collections.Generic;
using System.Web.Script.Serialization;

public class ScriptReferenceExecutor : IHttpHandler {

    public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "text/plain";

// context.Response.Write("alert('Message Received!');");

        JavaScriptSerializer serializer = new JavaScriptSerializer();
        Dictionary<string, string> headers = serializer.Deserialize<Dictionary<string, string>>(
            context.Request.QueryString["headers"]);
        string body = serializer.Deserialize<string>(context.Request.QueryString["body"]);
        string uniqueKey = serializer.Deserialize<string>(context.Request.QueryString["uniqueKey"]);

        string action = headers["action"];
        if (action == "normal")
        {
            this.SendResponse(context, uniqueKey, 200, "OK", "You've send: " + body);
        }
        else if (action == "error")
        {
            this.SendResponse(context, uniqueKey, 500, "Error", null);
        }
        else
        {
            System.Threading.Thread.Sleep(5000);
        }
    }

    private void SendResponse(HttpContext context, string uniqueKey, int statusCode, string statusText, string body)
    {
        context.Response.Write("Sys.Net.ScriptReferenceExecutor.complete('" + uniqueKey + "', ");
        context.Response.Write("'" + statusCode + "', ");
        context.Response.Write("'" + statusText + "', ");
        context.Response.Write(new JavaScriptSerializer().Serialize(body) + ");");
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}