Using WebClient in C# is there a way to get the UR

2019-01-06 14:03发布

Using the WebClient class I can get the title of a website easily enough:

WebClient x = new WebClient();    
string source = x.DownloadString(s);
string title = Regex.Match(source, 
    @"\<title\b[^>]*\>\s*(?<Title>[\s\S]*?)\</title\>",
    RegexOptions.IgnoreCase).Groups["Title"].Value;

I want to store the URL and the page title. However when following a link such as:

http://tinyurl.com/dbysxp

I'm clearly going to want to get the Url I'm redirected to.

QUESTIONS

Is there a way to do this using the WebClient class?

How would I do it using HttpResponse and HttpRequest?

标签: c# .net regex http
8条回答
家丑人穷心不美
2楼-- · 2019-01-06 14:31

HttpWebRequest.AllowAutoRedirect can be set to false. Then you'd have to manually http status codes in the 300 range.

// Create a new HttpWebRequest Object to the mentioned URL.
HttpWebRequest myHttpWebRequest=(HttpWebRequest)WebRequest.Create("http://www.contoso.com");    
myHttpWebRequest.MaximumAutomaticRedirections=1;
myHttpWebRequest.AllowAutoRedirect=true;
HttpWebResponse myHttpWebResponse=(HttpWebResponse)myHttpWebRequest.GetResponse();  
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3楼-- · 2019-01-06 14:37

If I understand the question, it's much easier than people are saying - if you want to let WebClient do all the nuts and bolts of the request (including the redirection), but then get the actual response URI at the end, you can subclass WebClient like this:

class MyWebClient : WebClient
{
    Uri _responseUri;

    public Uri ResponseUri
    {
        get { return _responseUri; }
    }

    protected override WebResponse GetWebResponse(WebRequest request)
    {
        WebResponse response = base.GetWebResponse(request);
        _responseUri = response.ResponseUri;
        return response;
    }
}

Just use MyWebClient everywhere you would have used WebClient. After you've made whatever WebClient call you needed to do, then you can just use ResponseUri to get the actual redirected URI. You'd need to add a similar override for GetWebResponse(WebRequest request, IAsyncResult result) too, if you were using the async stuff.

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