C#, Is there a better way to verify URL formatting than IsWellFormedUriString?
Is there a better/more accurate/stricter method/way to find out if a URL is properly formatted?
Using:
bool IsGoodUrl = Uri.IsWellFormedUriString(url, UriKind.Absolute);
Doesn't catch everything. If I type htttp://www.google.com and run that filter, it passes. Then I get a NotSupportedException later when calling WebRequest.Create .
This bad url will also make it past the following code (which is the only other filter I could find):
Uri nUrl = null;
if (Uri.TryCreate(url, UriKind.Absolute, out nUrl))
{
url = nUrl.ToString();
}
The reason Uri.IsWellFormedUriString("htttp://www.google.com", UriKind.Absolute) returns true is because it is in a form that could be a valid Uri. URI and URL are not the same.
See: What's the difference between a URI and a URL?
In your case, I would check that new Uri("htttp://www.google.com").Scheme was equal to http or https .
Technically, htttp://www.google.com is a properly formatted URL, according the URL specification. The NotSupportedException was thrown because htttp isn't a registered scheme. If it was a poorly-formatted URL, you would have gotten a UriFormatException . If you just care about HTTP(S) URLs, then just check the scheme as well.
@Greg's solution is correct. However you can steel using URI and validate all protocols (scheme) that you want as valid.
public static bool Url(string p_strValue)
{
if (Uri.IsWellFormedUriString(p_strValue, UriKind.RelativeOrAbsolute))
{
Uri l_strUri = new Uri(p_strValue);
return (l_strUri.Scheme == Uri.UriSchemeHttp || l_strUri.Scheme == Uri.UriSchemeHttps);
}
else
{
return false;
}
}