使用HttpWebResponse编码问题

以下是代码片段:

HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(request.RawUrl);
WebRequest.DefaultWebProxy = null;//Ensure that we will not loop by going again in the proxy
HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();
string charSet = response.CharacterSet;
Encoding encoding;
if (String.IsNullOrEmpty(charSet))
encoding = Encoding.Default;
else
encoding = Encoding.GetEncoding(charSet);

StreamReader resStream = new StreamReader(response.GetResponseStream(), encoding);
return resStream.ReadToEnd();

问题是如果我测试:http://www.google.fr

所有"é"都表现不佳.我试图将ASCII更改为UTF8,但仍然显示错误.我在浏览器中测试了html文件,浏览器显示了html文本,所以我很确定问题出在我用来下载html文件的方法中.

我应该改变什么？

删除了死的ImageShack链接

更新1:代码和测试文件已更改

小智.. 29

如果未在服务器的内容类型标头中指定(与HTML中的"charset"元标记不同),则CharacterSet默认为"ISO-8859-1".我将HttpWebResponse.CharacterSet与HTML的charset属性进行比较.如果它们不同 - 我使用HTML中指定的字符集重新读取页面,但这次使用了正确的编码.

看代码:

    string strWebPage = "";
    // create request
    System.Net.WebRequest objRequest = System.Net.HttpWebRequest.Create(sURL);
    // get response
    System.Net.HttpWebResponse objResponse;
    objResponse = (System.Net.HttpWebResponse)objRequest.GetResponse();
    // get correct charset and encoding from the server's header
    string Charset = objResponse.CharacterSet;
    Encoding encoding = Encoding.GetEncoding(Charset);
    // read response
    using (StreamReader sr = 
           new StreamReader(objResponse.GetResponseStream(), encoding))
    {
        strWebPage = sr.ReadToEnd();
        // Close and clean up the StreamReader
        sr.Close();
    }

    // Check real charset meta-tag in HTML
    int CharsetStart = strWebPage.IndexOf("charset=");
    if (CharsetStart > 0)
    {
        CharsetStart += 8;
        int CharsetEnd = strWebPage.IndexOfAny(new[] { ' ', '\"', ';' }, CharsetStart);
        string RealCharset = 
               strWebPage.Substring(CharsetStart, CharsetEnd - CharsetStart);

        // real charset meta-tag in HTML differs from supplied server header???
        if(RealCharset!=Charset)
        {
            // get correct encoding
            Encoding CorrectEncoding = Encoding.GetEncoding(RealCharset);

            // read the web page again, but with correct encoding this time
            //   create request
            System.Net.WebRequest objRequest2 = System.Net.HttpWebRequest.Create(sURL);
            //   get response
            System.Net.HttpWebResponse objResponse2;
            objResponse2 = (System.Net.HttpWebResponse)objRequest2.GetResponse();
            //   read response
            using (StreamReader sr = 
              new StreamReader(objResponse2.GetResponseStream(), CorrectEncoding))
            {
                strWebPage = sr.ReadToEnd();
                // Close and clean up the StreamReader
                sr.Close();
            }
        }
    }

必须下载两次？ (4认同)

我认为这应该标记为答案.这实际上从任何网页获取编码并正确解码它们.但问题是这在Windows手机中不起作用,因为它的响应实现不支持Response.CharacterSet (2认同)

---

Jon Skeet.. 25

首先,编写该代码的更简单方法是使用StreamReader和ReadToEnd:

HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(myURL);
using (HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse())
{
    using (Stream resStream = response.GetResponseStream())
    {
        StreamReader reader = new StreamReader(resStream, Encoding.???);
        return reader.ReadToEnd();
    }
}

那么"只是"找到正确的编码问题.你是怎么创建这个文件的？如果它是记事本,那么你可能想要Encoding.Default- 但这显然不便携,因为它是你 PC 的默认编码.

在运行良好的Web服务器中,响应将在其标头中指示编码.话虽如此,在某些情况下,响应标题有时会声称一件事,HTML声称另一件事.

1> 小智..：

---

如果未在服务器的内容类型标头中指定(与HTML中的"charset"元标记不同),则CharacterSet默认为"ISO-8859-1".我将HttpWebResponse.CharacterSet与HTML的charset属性进行比较.如果它们不同 - 我使用HTML中指定的字符集重新读取页面,但这次使用了正确的编码.

看代码:

    string strWebPage = "";
    // create request
    System.Net.WebRequest objRequest = System.Net.HttpWebRequest.Create(sURL);
    // get response
    System.Net.HttpWebResponse objResponse;
    objResponse = (System.Net.HttpWebResponse)objRequest.GetResponse();
    // get correct charset and encoding from the server's header
    string Charset = objResponse.CharacterSet;
    Encoding encoding = Encoding.GetEncoding(Charset);
    // read response
    using (StreamReader sr = 
           new StreamReader(objResponse.GetResponseStream(), encoding))
    {
        strWebPage = sr.ReadToEnd();
        // Close and clean up the StreamReader
        sr.Close();
    }

    // Check real charset meta-tag in HTML
    int CharsetStart = strWebPage.IndexOf("charset=");
    if (CharsetStart > 0)
    {
        CharsetStart += 8;
        int CharsetEnd = strWebPage.IndexOfAny(new[] { ' ', '\"', ';' }, CharsetStart);
        string RealCharset = 
               strWebPage.Substring(CharsetStart, CharsetEnd - CharsetStart);

        // real charset meta-tag in HTML differs from supplied server header???
        if(RealCharset!=Charset)
        {
            // get correct encoding
            Encoding CorrectEncoding = Encoding.GetEncoding(RealCharset);

            // read the web page again, but with correct encoding this time
            //   create request
            System.Net.WebRequest objRequest2 = System.Net.HttpWebRequest.Create(sURL);
            //   get response
            System.Net.HttpWebResponse objResponse2;
            objResponse2 = (System.Net.HttpWebResponse)objRequest2.GetResponse();
            //   read response
            using (StreamReader sr = 
              new StreamReader(objResponse2.GetResponseStream(), CorrectEncoding))
            {
                strWebPage = sr.ReadToEnd();
                // Close and clean up the StreamReader
                sr.Close();
            }
        }
    }

---

必须下载两次？

---

我认为这应该标记为答案.这实际上从任何网页获取编码并正确解码它们.但问题是这在Windows手机中不起作用,因为它的响应实现不支持Response.CharacterSet

2> Jon Skeet..：

---

首先,编写该代码的更简单方法是使用StreamReader和ReadToEnd:

HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(myURL);
using (HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse())
{
    using (Stream resStream = response.GetResponseStream())
    {
        StreamReader reader = new StreamReader(resStream, Encoding.???);
        return reader.ReadToEnd();
    }
}

那么"只是"找到正确的编码问题.你是怎么创建这个文件的？如果它是记事本,那么你可能想要Encoding.Default- 但这显然不便携,因为它是你 PC 的默认编码.

在运行良好的Web服务器中,响应将在其标头中指示编码.话虽如此,在某些情况下,响应标题有时会声称一件事,HTML声称另一件事.

3> 小智..：

---

如果您不想两次下载页面,我会使用如何将WebResponse放入内存流中稍微修改Alex的代码？.这是结果

public static string DownloadString(string address)
{
    string strWebPage = "";
    // create request
    System.Net.WebRequest objRequest = System.Net.HttpWebRequest.Create(address);
    // get response
    System.Net.HttpWebResponse objResponse;
    objResponse = (System.Net.HttpWebResponse)objRequest.GetResponse();
    // get correct charset and encoding from the server's header
    string Charset = objResponse.CharacterSet;
    Encoding encoding = Encoding.GetEncoding(Charset);

    // read response into memory stream
    MemoryStream memoryStream;
    using (Stream responseStream = objResponse.GetResponseStream())
    {
        memoryStream = new MemoryStream();

        byte[] buffer = new byte[1024];
        int byteCount;
        do
        {
            byteCount = responseStream.Read(buffer, 0, buffer.Length);
            memoryStream.Write(buffer, 0, byteCount);
        } while (byteCount > 0);
    }

    // set stream position to beginning
    memoryStream.Seek(0, SeekOrigin.Begin);

    StreamReader sr = new StreamReader(memoryStream, encoding);
    strWebPage = sr.ReadToEnd();

    // Check real charset meta-tag in HTML
    int CharsetStart = strWebPage.IndexOf("charset=");
    if (CharsetStart > 0)
    {
        CharsetStart += 8;
        int CharsetEnd = strWebPage.IndexOfAny(new[] { ' ', '\"', ';' }, CharsetStart);
        string RealCharset =
               strWebPage.Substring(CharsetStart, CharsetEnd - CharsetStart);

        // real charset meta-tag in HTML differs from supplied server header???
        if (RealCharset != Charset)
        {
            // get correct encoding
            Encoding CorrectEncoding = Encoding.GetEncoding(RealCharset);

            // reset stream position to beginning
            memoryStream.Seek(0, SeekOrigin.Begin);

            // reread response stream with the correct encoding
            StreamReader sr2 = new StreamReader(memoryStream, CorrectEncoding);

            strWebPage = sr2.ReadToEnd();
            // Close and clean up the StreamReader
            sr2.Close();
        }
    }

    // dispose the first stream reader object
    sr.Close();

    return strWebPage;
}

---

.NET 4及更高版本应该有一个Stream.CopyTo(Stream)方法来简化它.