加载XmlDocument时“解析EntityName时发生错误”

Question

I have written some code to parse RSS feeds for a ASP.NET C# application and it works fine for all RSS feeds that I have tried, until I tried Facebook.

My code fails at the last line below...

WebRequest request = WebRequest.Create(url);
WebResponse response = request.GetResponse();
Stream rss = response.GetResponseStream();
XmlDocument xml = new XmlDocument();
xml.Load(rss);

...with the error "An error occurred while parsing EntityName. Line 12, position 53."

It is hard to work out what is at thhat position of the XML file as the entire file is all in one line, but it is straight from Facebook and all characters appear to be encoded properly except possibly one character (♥).

I don't particularly want to rewrite my RSS parser to use a different method. Any suggestions for how to bypass this error? Is there a way of turning off checking of the file?

Answer 1

Look at the downloaded stream. It doesn't contain the RSS feed, but a HTML page with message about incompatible browser. That's because when downloading the URL like this, the user agent header is not set. If you do that, your code should work:

var request = (HttpWebRequest)WebRequest.Create(url);
request.UserAgent = "MyApplication";

var xml = new XmlDocument();

using (var response = request.GetResponse())
using (var rss = response.GetResponseStream())
{
    xml.Load(rss);
}