There are the Uri.IsWellFormedUriString
and Uri.TryCreate
methods, but they seem to return true
for file paths etc.
How do I check whether a string is a valid (not necessarily active) HTTP URL for input validation purposes?
This question is related to
c#
.net
validation
url
uri
All the answers here either allow URLs with other schemes (e.g., file://
, ftp://
) or reject human-readable URLs that don't start with http://
or https://
(e.g., www.google.com
) which is not good when dealing with user inputs.
Here's how I do it:
public static bool ValidHttpURL(string s, out Uri resultURI)
{
if (!Regex.IsMatch(s, @"^https?:\/\/", RegexOptions.IgnoreCase))
s = "http://" + s;
if (Uri.TryCreate(s, UriKind.Absolute, out resultURI))
return (resultURI.Scheme == Uri.UriSchemeHttp ||
resultURI.Scheme == Uri.UriSchemeHttps);
return false;
}
Usage:
string[] inputs = new[] {
"https://www.google.com",
"http://www.google.com",
"www.google.com",
"google.com",
"javascript:alert('Hack me!')"
};
foreach (string s in inputs)
{
Uri uriResult;
bool result = ValidHttpURL(s, out uriResult);
Console.WriteLine(result + "\t" + uriResult?.AbsoluteUri);
}
Output:
True https://www.google.com/
True http://www.google.com/
True http://www.google.com/
True http://google.com/
False
Uri uri = null;
if (!Uri.TryCreate(url, UriKind.Absolute, out uri) || null == uri)
return false;
else
return true;
Here url
is the string you have to test.
public static bool CheckURLValid(this string source)
{
Uri uriResult;
return Uri.TryCreate(source, UriKind.Absolute, out uriResult) && uriResult.Scheme == Uri.UriSchemeHttp;
}
Usage:
string url = "htts://adasd.xc.";
if(url.CheckUrlValid())
{
//valid process
}
UPDATE: (single line of code) Thanks @GoClimbColorado
public static bool CheckURLValid(this string source) => Uri.TryCreate(source, UriKind.Absolute, out Uri uriResult) && uriResult.Scheme == Uri.UriSchemeHttps;
Usage:
string url = "htts://adasd.xc.";
if(url.CheckUrlValid())
{
//valid process
}
Try that:
bool IsValidURL(string URL)
{
string Pattern = @"^(?:http(s)?:\/\/)?[\w.-]+(?:\.[\w\.-]+)+[\w\-\._~:/?#[\]@!\$&'\(\)\*\+,;=.]+$";
Regex Rgx = new Regex(Pattern, RegexOptions.Compiled | RegexOptions.IgnoreCase);
return Rgx.IsMatch(URL);
}
It will accept URL like that:
This would return bool:
Uri.IsWellFormedUriString(a.GetAttribute("href"), UriKind.Absolute)
After Uri.TryCreate
you can check Uri.Scheme
to see if it HTTP(s).
bool passed = Uri.TryCreate(url, UriKind.Absolute, out Uri uriResult) && (uriResult.Scheme == Uri.UriSchemeHttp || uriResult.Scheme == Uri.UriSchemeHttps)
This method works fine both in http and https. Just one line :)
if (Uri.IsWellFormedUriString("https://www.google.com", UriKind.Absolute))
MSDN: IsWellFormedUriString
Source: Stackoverflow.com