Get file name from URI string in C#
C#StringUriFilenamesC# Problem Overview
I have this method for grabbing the file name from a string URI. What can I do to make it more robust?
private string GetFileName(string hrefLink)
{
string[] parts = hrefLink.Split('/');
string fileName = "";
if (parts.Length > 0)
fileName = parts[parts.Length - 1];
else
fileName = hrefLink;
return fileName;
}
C# Solutions
Solution 1 - C#
You can just make a System.Uri object, and use IsFile to verify it's a file, then Uri.LocalPath to extract the filename.
This is much safer, as it provides you a means to check the validity of the URI as well.
Edit in response to comment:
To get just the full filename, I'd use:
Uri uri = new Uri(hreflink);
if (uri.IsFile) {
string filename = System.IO.Path.GetFileName(uri.LocalPath);
}
This does all of the error checking for you, and is platform-neutral. All of the special cases get handled for you quickly and easily.
Solution 2 - C#
Uri.IsFile doesn't work with http urls. It only works for "file://". From MSDN : "The IsFile property is true when the Scheme property equals UriSchemeFile." So you can't depend on that.
Uri uri = new Uri(hreflink);
string filename = System.IO.Path.GetFileName(uri.LocalPath);
Solution 3 - C#
Most other answers are either incomplete or don't deal with stuff coming after the path (query string/hash).
readonly static Uri SomeBaseUri = new Uri("http://canbeanything");
static string GetFileNameFromUrl(string url)
{
Uri uri;
if (!Uri.TryCreate(url, UriKind.Absolute, out uri))
uri = new Uri(SomeBaseUri, url);
return Path.GetFileName(uri.LocalPath);
}
Test results:
GetFileNameFromUrl(""); // ""
GetFileNameFromUrl("test"); // "test"
GetFileNameFromUrl("test.xml"); // "test.xml"
GetFileNameFromUrl("/test.xml"); // "test.xml"
GetFileNameFromUrl("/test.xml?q=1"); // "test.xml"
GetFileNameFromUrl("/test.xml?q=1&x=3"); // "test.xml"
GetFileNameFromUrl("test.xml?q=1&x=3"); // "test.xml"
GetFileNameFromUrl("http://www.a.com/test.xml?q=1&x=3"); // "test.xml"
GetFileNameFromUrl("http://www.a.com/test.xml?q=1&x=3#aidjsf"); // "test.xml"
GetFileNameFromUrl("http://www.a.com/a/b/c/d"); // "d"
GetFileNameFromUrl("http://www.a.com/a/b/c/d/e/"); // ""
Solution 4 - C#
The accepted answer is problematic for http urls. Moreover Uri.LocalPath
does Windows specific conversions, and as someone pointed out leaves query strings in there. A better way is to use Uri.AbsolutePath
The correct way to do this for http urls is:
Uri uri = new Uri(hreflink);
string filename = System.IO.Path.GetFileName(uri.AbsolutePath);
Solution 5 - C#
I think this will do what you need:
var uri = new Uri(hreflink);
var filename = uri.Segments.Last();
Solution 6 - C#
using System.IO;
private String GetFileName(String hrefLink)
{
return Path.GetFileName(hrefLink.Replace("/", "\\"));
}
THis assumes, of course, that you've parsed out the file name.
EDIT #2:
using System.IO;
private String GetFileName(String hrefLink)
{
return Path.GetFileName(Uri.UnescapeDataString(hrefLink).Replace("/", "\\"));
}
This should handle spaces and the like in the file name.
Solution 7 - C#
this is my sample you can use:
public static string GetFileNameValidChar(string fileName)
{
foreach (var item in System.IO.Path.GetInvalidFileNameChars())
{
fileName = fileName.Replace(item.ToString(), "");
}
return fileName;
}
public static string GetFileNameFromUrl(string url)
{
string fileName = "";
if (Uri.TryCreate(url, UriKind.Absolute, out Uri uri))
{
fileName = GetFileNameValidChar(Path.GetFileName(uri.AbsolutePath));
}
string ext = "";
if (!string.IsNullOrEmpty(fileName))
{
ext = Path.GetExtension(fileName);
if (string.IsNullOrEmpty(ext))
ext = ".html";
else
ext = "";
return GetFileNameValidChar(fileName + ext);
}
fileName = Path.GetFileName(url);
if (string.IsNullOrEmpty(fileName))
{
fileName = "noName";
}
ext = Path.GetExtension(fileName);
if (string.IsNullOrEmpty(ext))
ext = ".html";
else
ext = "";
fileName = fileName + ext;
if (!fileName.StartsWith("?"))
fileName = fileName.Split('?').FirstOrDefault();
fileName = fileName.Split('&').LastOrDefault().Split('=').LastOrDefault();
return GetFileNameValidChar(fileName);
}
Usage:
var fileName = GetFileNameFromUrl("http://cdn.p30download.com/?b=p30dl-software&f=Mozilla.Firefox.v58.0.x86_p30download.com.zip");
Solution 8 - C#
Simple and straight forward:
Uri uri = new Uri(documentAttachment.DocumentAttachment.PreSignedUrl);
fileName = Path.GetFileName(uri.LocalPath);
Solution 9 - C#
As of 2020, handles query strings & encoded URLs
public static string GetFileNameFromUrl (string url)
{
var decoded = HttpUtility.UrlDecode(url);
if (decoded.IndexOf("?") is {} queryIndex && queryIndex != -1)
{
decoded = decoded.Substring(0, queryIndex);
}
return Path.GetFileName(decoded);
}