读取一个 JavaScript 文件并通过 HttpHandler 输出回来

Question

你知道 Twitter 没有通过 https 提供它的小部件 javascript 文件，所以我决定通过 httphandler 提供它，到目前为止，我迷路了！

这是我到目前为止所做的：

public void ProcessRequest(HttpContext context) {

    context.Response.ContentType = "application/javascript";

    WebRequest request = WebRequest.Create("http://widgets.twimg.com/j/2/widget.js");
    request.Method = "GET";
    request.ContentType = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";

    using (WebResponse response = request.GetResponse()) {

        using (Stream requestStream = response.GetResponseStream()) {

            Stream outStream = context.Response.OutputStream;
            byte[] buffer = new byte[1024];
            int len = (int)response.ContentLength, bytes;

            while (len > 0 && (bytes =
                requestStream.Read(buffer, 0, buffer.Length)) > 0) {

                outStream.Write(buffer, 0, bytes);
                len -= bytes;
            }
        }
    }
}

我没有收到任何错误，但是当我调试代码时，我看到 response.ContentLength 以 -1 的形式返回。我在这里错过了什么？

更新

也尝试了下面的代码，看看它是否有任何区别并且也没有工作：

public void ProcessRequest(HttpContext context) {

    context.Response.ContentType = "application/x-javascript";

    HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://widgets.twimg.com/j/2/widget.js");
    request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
    request.Method = "GET";

    using (WebResponse response = request.GetResponse()) {

        using (Stream requestStream = response.GetResponseStream()) {

            Stream outStream = context.Response.OutputStream;
            byte[] buffer = new byte[1024];
            int len = (int)response.ContentLength, bytes;

            while (len > 0 && (bytes =
                requestStream.Read(buffer, 0, buffer.Length)) > 0) {

                outStream.Write(buffer, 0, bytes);
                len -= bytes;
            }
        }
    }
}

Answer 1

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
    public override void ProcessRequest(HttpContext context)
    {
        int bytesProcessed = 0;
        Stream remoteStream = null;
        Stream localStream = null;
        context.Response.ContentType = "application/octet-stream";

        WebRequest request = WebRequest.Create("http://widgets.twimg.com/j/2/widget.js");
    //    request.Method = "GET";
        request.ContentType = "application/octet-stream";

        using (WebResponse response = request.GetResponse())
        {

            using (Stream requestStream = response.GetResponseStream())
            {
                localStream = File.Create(@"c:\1.y2yy");

                // Allocate a 1k buffer
                byte[] buffer = new byte[1024];
                int bytesRead;

                // Simple do/while loop to read from stream until
                // no bytes are returned
                do
                {
                    // Read data (up to 1k) from the stream
                    bytesRead = requestStream.Read(buffer, 0, buffer.Length);

                    // Write the data to the local file
                    localStream.Write(buffer, 0, bytesRead);

                    // Increment total bytes processed
                    bytesProcessed += bytesRead;
                } while (bytesRead > 0);
                localStream.Close();
            }
        }
    }
    protected void Page_Load(object sender, EventArgs e)
    {

    }
}

Answer 2

我用下面的代码解决了我的问题。不确定这是否是正确的做法：

    public void ProcessRequest(HttpContext context) {

        context.Response.ContentType = "application/x-javascript";

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://widgets.twimg.com/j/2/widget.js");
        request.Accept = "application/javascript";
        request.KeepAlive = false;
        request.Method = "GET";

        HttpWebResponse webresponse = (HttpWebResponse)request.GetResponse();

        Encoding enc = System.Text.Encoding.GetEncoding(1252);
        StreamReader loResponseStream = new
          StreamReader(webresponse.GetResponseStream(), enc);

        string Response = loResponseStream.ReadToEnd();

        context.Response.Write(Response);
    }

Answer 3

除了您始终假定编码为 1252 之外，您的代码没有问题。因此，如果您知道它是没有问题的。在完美的世界中，服务器的响应将在其标头中指示编码。但情况并非总是如此。查看此question 了解有关该主题的更多信息。

我稍微修改了你的代码。

 public void ProcessRequest(HttpContext context)
 {           
        WebRequest request = WebRequest.Create("http://widgets.twimg.com/j/2/widget.js");
        request.Method = "GET";
        request.ContentType = "application/javascript";

        using (HttpWebResponse response = (HttpWebResponse) request.GetResponse())
        {
            Encoding enc = String.IsNullOrEmpty(response.CharacterSet) ? 
                Encoding.GetEncoding(1252) : Encoding.GetEncoding(response.CharacterSet);

            using (var reader = new StreamReader(response.GetResponseStream(), enc))
            {
                var jsContent = reader.ReadToEnd();

                if (!String.IsNullOrEmpty(jsContent)) {
                    context.Response.ContentType = "application/javascript";
                    context.Response.Write(jsContent);
                }                    
            }
        }
 }