Any way to check a url

[Henry Jia]

Hi,

Does there has any easy way to check if a specified url is a valid one (both the format should be valid but also the specified path / file is available)?

Thanks in advance!

Henry

[Scott Allen]

Re: Any way to check a url

You could always pop the url into a System.Net.WebC lient object. If
the url is invalid, or the url is unreachable, the object will throw a
WebException. Of course, this doesn't distinguish between a bad URL
and a bad network connection, for that you would need some additional
tests, perhaps fetching from a known good URL.

HTH,

--
Scott

http://www.OdeToCode.com

On Tue, 27 Apr 2004 11:46:53 +0800, "Henry Jia" <jia_h@hotmail. com>
wrote:
[color=blue]
>Hi,
>
> Does there has any easy way to check if a specified url is a valid one (both the format should be valid but also the specified path / file is available)?
>
> Thanks in advance!
>
>Henry[/color]

[Henry Jia]

Re: Any way to check a url

What's the meaning of "pop the url"? and how about the time used for check?

Thank you!

"Scott Allen" <bitmask@[nospam].fred.net> wrote in message news:00or80hvsa 9sqsshtt8qdqvi6 8ipq2ei09@4ax.c om...
You could always pop the url into a System.Net.WebC lient object. If
the url is invalid, or the url is unreachable, the object will throw a
WebException. Of course, this doesn't distinguish between a bad URL
and a bad network connection, for that you would need some additional
tests, perhaps fetching from a known good URL.

HTH,

--
Scott

http://www.OdeToCode.com

On Tue, 27 Apr 2004 11:46:53 +0800, "Henry Jia" <jia_h@hotmail. com>
wrote:
[color=blue]
>Hi,
>
> Does there has any easy way to check if a specified url is a valid one (both the format should be valid but also the specified path / file is available)?
>
> Thanks in advance!
>
>Henry[/color]

[Morten Wennevik]

Re: Any way to check a url

Hi Henry,

So far this method has worked for me, it connects to a DNS server and
checks the name. I strip any http:// headers or folder structures before
passing it to ValidateURL.

// check to see if we can find the url
private bool ValidateURL(str ing u)
{
try
{
Dns.GetHostByNa me(u);
}
catch
{
try // maybe we passed an ip address
{
Dns.GetHostByAd dress(u);
}
catch
{
return false;
}
}
return true;
}


Happy coding!
Morten Wennevik [C# MVP]

[Scott Allen]

Re: Any way to check a url

Hi Henry,

Sorry for the slang.

Here is a sample:

WebClient wc = new WebClient();
Stream stream = wc.OpenRead("ht tp://www.microsoft.c om");
stream.ReadByte ();
stream.Close();

If you pass the URL into the OpenRead method, and the code executes
without an exception, then you can be sure that the URL is well formed
and valid, that the server is reachable, and that the path and
filename exist on the server.

As for timing, it won't be as fast as verifying the URL format with a
regular expression, but the only way to be sure you have a valid path
to a file that exists on a remote server is to go to the server and
ask for the file.

HTH,

On Tue, 27 Apr 2004 13:24:08 +0800, "Henry Jia" <jia_h@hotmail. com>
wrote:
[color=blue]
>What's the meaning of "pop the url"? and how about the time used for check?
>
>Thank you!
>
> "Scott Allen" <bitmask@[nospam].fred.net> wrote in message news:00or80hvsa 9sqsshtt8qdqvi6 8ipq2ei09@4ax.c om...
> You could always pop the url into a System.Net.WebC lient object. If
> the url is invalid, or the url is unreachable, the object will throw a
> WebException. Of course, this doesn't distinguish between a bad URL
> and a bad network connection, for that you would need some additional
> tests, perhaps fetching from a known good URL.
>
> HTH,
>
> --
> Scott
> http://www.OdeToCode.com
>
> On Tue, 27 Apr 2004 11:46:53 +0800, "Henry Jia" <jia_h@hotmail. com>
> wrote:
>[color=green]
> >Hi,
> >
> > Does there has any easy way to check if a specified url is a valid one (both the format should be valid but also the specified path / file is available)?
> >
> > Thanks in advance!
> >
> >Henry[/color][/color]

--
Scott

http://www.OdeToCode.com