C＃：处理WebClient“违反协议” [英] C#: Handling WebClient "protocol violation"

问题描述

我需要读取路由器中的一个位置，但是出现以下异常-

I need to read a location in my Router, but I get the following exception -

ServerProtocolViolation "The server committed a protocol violation. 
                        Section=ResponseHeader Detail=CR must be followed by LF"

当我使用 .DownloadString（url）函数时。有什么方法可以使 WebClient 忽略协议违规？ Google中的搜索告诉我，应该在某处设置 useUnsafeHeaderParsing 选项。我可以通过程序吗？

This occurs when I use the .DownloadString(url) function. Is there any way to make WebClient ignore protocol violation? Searches in Google tell me I should set the useUnsafeHeaderParsing option somewhere. Can I do it through program? What's the catch if I use it?

编辑：附加代码-

    public Readlog() {
        WebClient wc = new WebClient();

        string url = @"http://192.168.0.1/setup.cgi?next_file=log.htm&todo=cfg_init";
        Console.WriteLine(url);
        try {
            //wc.Headers.Add("User-Agent", "Mozilla/5.0(Windows; U; Windows NT 5.2; rv:1.9.2) Gecko/20100101 Firefox/3.6");
            wc.Credentials = new NetworkCredential("admin", "admin");
            //Next line causes exception System.Net.WebException
            //Message - "The server committed a protocol violation. Section=ResponseHeader Detail=CR must be followed by LF"
            //May be I need to use useUnsafeHeaderParsing somehow to avoid that
            string result = wc.DownloadString(url);
            Console.WriteLine(result);
        } catch (WebException we) {
            System.Diagnostics.Trace.WriteLine(we.ToString());
        }
    }

推荐答案

外观例如，最简单的方法是在应用程序中包含一个.config文件，其中包含以下内容：

Looks like the easiest way is including a .config file with your app containing the following:

<system.net>
<settings>
<httpWebRequest useUnsafeHeaderParsing = "true"/>
</settings>
</system.net>

但是也可以在代码中完成，但这似乎有些混乱：

However it's also possible to do it within the code but it seems a little messy:

http://social.msdn.microsoft.com/Forums/en-US/netfxnetcom/thread/ff098248-551c-4da9-8ba5-358a9f8ccc57

还要注意，该属性的MSDN定义是

Also note that the MSDN definition of that property is

设置此属性会忽略
期间发生的$$验证错误b $ b HTTP解析。

Setting this property ignores validation errors that occur during HTTP parsing.

http://msdn.microsoft.com/zh-cn/library/system.net.configuration.httpwebrequestelement.useunsafeheaderparsing.aspx

所以我说它相当安全，尽管它确实提到只为了向后兼容才使用它。

So I'd say it's fairly safe to use, although it does mention to only use it for backwards compatibility.

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