How to check whether the URL is valid or not

Question

I have one textbox in that user enter the URL, but if want to check that URL while page rendering then what to do?

Here is my code:

protected void btnRender_Click(object sender, EventArgs e)
{
    string strResult = string.Empty;
    WebResponse objResponse;
    WebRequest objRequest = System.Net.HttpWebRequest.Create(urltxt.Text);
    objResponse = objRequest.GetResponse();
    using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
    {
        strResult = sr.ReadToEnd();
        sr.Close();
    }
    strResult = strResult.Replace("<form id='form1' method='post' action=''>", "");
    strResult = strResult.Replace("</form>", "");          
    TextBox1.Text = strResult.Trim();
    div.InnerHtml = strResult.Trim();
}

I have this code to check whether URL is valid or not, so can you please tell me where to call this? {if i want to also check https also then how can i do in this code}

 protected bool CheckUrlExists(string url)
    {
        // If the url does not contain Http. Add it.
      // if i want to also check for https how can i do.this code is only for http not https
        if (!url.Contains("http://"))
        {
            url = "http://" + url;
        }
        try
        {
            var request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "HEAD";
            using (var response = (HttpWebResponse)request.GetResponse())
            {
                return response.StatusCode == HttpStatusCode.OK;
            }
         }
         catch
         {
             return false;
         }
     }

The TextBox name is urltxt

There is much more stuff to validate, have a look at this [Python question](http://stackoverflow.com/questions/827557/how-do-you-validate-a-url-with-a-regular-expression-in-python) — oleksii, Apr 18 '13 at 09:52
@oleksii i have put that regular expressio but doesn't check that is valid or not or it exist or not — hitarth, Apr 18 '13 at 09:54
If you need to know whether it is active/exists, you should access it. That's the only way to tell, and even that is not guaranteed (you may be faced with a paywall for wifi access, for example, or a proxy server's 404 page - or there may be network issues which prevent you from reaching the URL you are attempting to visit) — penguat, Apr 18 '13 at 10:33

MSTdev · Answer 1 · 2013-04-18T10:26:49.480

3

Try this uriName(your desired URI)

  bool Uriresult = Uri.TryCreate(uriName, UriKind.Absolute, out uriResult) && uriName.Scheme == Uri.UriSchemeHttp;

as per your code

string uriName = urltxt.Text; bool Uriresult = Uri.TryCreate(uriName, UriKind.Absolute, out uriResult) && uriName.Scheme == Uri.UriSchemeHttp;

edited Apr 18 '13 at 10:26

answered Apr 18 '13 at 09:57

MSTdev

4,507
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can you please edit your code according to my code...because uri name doesnt exist – hitarth Apr 18 '13 at 10:00
ok sure `string uriName = urltxt.Text; bool Uriresult = Uri.TryCreate(uriName, UriKind.Absolute, out uriResult) && uriName.Scheme == Uri.UriSchemeHttp;` – MSTdev Apr 18 '13 at 10:18
can you please tell me what is uriResult in out uriResult – Sivajith Jan 09 '15 at 06:56

score 3 · Accepted Answer · edited Apr 18 '13 at 10:36

3

Try like below, It will help you....

     protected void btnRender_Click(object sender, EventArgs e)
        {
            if(CheckUrlExists(urltxt.Text))
            {
                string strResult = string.Empty;
                WebResponse objResponse;
                WebRequest objRequest = System.Net.HttpWebRequest.Create(urltxt.Text);
                objResponse = objRequest.GetResponse();
                using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
                {
                    strResult = sr.ReadToEnd();
                    sr.Close();
                }
                strResult = strResult.Replace("<form id='form1' method='post' action=''>", "");
                strResult = strResult.Replace("</form>", "");
                TextBox1.Text = strResult.Trim();
                div.InnerHtml = strResult.Trim();
            }
            else
            {
                MessageBox.Show("Not a Valid URL");
            }
        }

edited Apr 18 '13 at 10:36

hitarth

317
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answered Apr 18 '13 at 10:07

Pandian

8,848
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thanks alot bro....its working ........i got problem just see edit – hitarth Apr 18 '13 at 10:33
hey @pandian if want to also check the mail and https whether they are valid or not..how can i do in this code so i can check whether it is working or not if (!url.Contains("http://")) { url = "http://" + url; } try { var request = WebRequest.Create(url) as HttpWebRequest; request.Method = "HEAD"; using (var response = (HttpWebResponse)request.GetResponse()) { return response.StatusCode == HttpStatusCode.OK; } } catch { return false; } } – hitarth Apr 23 '13 at 06:30
Pandian how to do that...thanks in advance in bro – hitarth Apr 23 '13 at 06:47

How to check whether the URL is valid or not

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