URL Encoding using C#
I've been experimenting with the various methods .NET provide for URL encoding. Perhaps the following table will be useful (as output from a test app I wrote):
Unencoded UrlEncoded UrlEncodedUnicode UrlPathEncoded EscapedDataString EscapedUriString HtmlEncoded HtmlAttributeEncoded HexEscaped
A A A A A A A A %41
B B B B B B B B %42
a a a a a a a a %61
b b b b b b b b %62
0 0 0 0 0 0 0 0 %30
1 1 1 1 1 1 1 1 %31
[space] + + %20 %20 %20 [space] [space] %20
! ! ! ! ! ! ! ! %21
" %22 %22 " %22 %22 " " %22
# %23 %23 # %23 # # # %23
$ %24 %24 $ %24 $ $ $ %24
% %25 %25 % %25 %25 % % %25
& %26 %26 & %26 & & & %26
' %27 %27 ' ' ' ' ' %27
( ( ( ( ( ( ( ( %28
) ) ) ) ) ) ) ) %29
* * * * %2A * * * %2A
+ %2b %2b + %2B + + + %2B
, %2c %2c , %2C , , , %2C
- - - - - - - - %2D
. . . . . . . . %2E
/ %2f %2f / %2F / / / %2F
: %3a %3a : %3A : : : %3A
; %3b %3b ; %3B ; ; ; %3B
< %3c %3c < %3C %3C < < %3C
= %3d %3d = %3D = = = %3D
> %3e %3e > %3E %3E > > %3E
? %3f %3f ? %3F ? ? ? %3F
@ %40 %40 @ %40 @ @ @ %40
[ %5b %5b [ %5B %5B [ [ %5B
\ %5c %5c \ %5C %5C \ \ %5C
] %5d %5d ] %5D %5D ] ] %5D
^ %5e %5e ^ %5E %5E ^ ^ %5E
_ _ _ _ _ _ _ _ %5F
` %60 %60 ` %60 %60 ` ` %60
{ %7b %7b { %7B %7B { { %7B
| %7c %7c | %7C %7C | | %7C
} %7d %7d } %7D %7D } } %7D
~ %7e %7e ~ ~ ~ ~ ~ %7E
Ā %c4%80 %u0100 %c4%80 %C4%80 %C4%80 Ā Ā [OoR]
ā %c4%81 %u0101 %c4%81 %C4%81 %C4%81 ā ā [OoR]
Ē %c4%92 %u0112 %c4%92 %C4%92 %C4%92 Ē Ē [OoR]
ē %c4%93 %u0113 %c4%93 %C4%93 %C4%93 ē ē [OoR]
Ī %c4%aa %u012a %c4%aa %C4%AA %C4%AA Ī Ī [OoR]
ī %c4%ab %u012b %c4%ab %C4%AB %C4%AB ī ī [OoR]
Ō %c5%8c %u014c %c5%8c %C5%8C %C5%8C Ō Ō [OoR]
ō %c5%8d %u014d %c5%8d %C5%8D %C5%8D ō ō [OoR]
Ū %c5%aa %u016a %c5%aa %C5%AA %C5%AA Ū Ū [OoR]
ū %c5%ab %u016b %c5%ab %C5%AB %C5%AB ū ū [OoR]
The columns represent encodings as follows:
UrlEncoded:
HttpUtility.UrlEncodeUrlEncodedUnicode:
HttpUtility.UrlEncodeUnicodeUrlPathEncoded:
HttpUtility.UrlPathEncodeEscapedDataString:
Uri.EscapeDataStringEscapedUriString:
Uri.EscapeUriStringHtmlEncoded:
HttpUtility.HtmlEncodeHtmlAttributeEncoded:
HttpUtility.HtmlAttributeEncodeHexEscaped:
Uri.HexEscape
NOTES:
HexEscapecan only handle the first 255 characters. Therefore it throws anArgumentOutOfRangeexception for the Latin A-Extended characters (eg Ā).This table was generated in .NET 4.0 (see Levi Botelho's comment below that says the encoding in .NET 4.5 is slightly different).
EDIT:
I've added a second table with the encodings for .NET 4.5. See this answer: https://stackoverflow.com/a/21771206/216440
EDIT 2:
Since people seem to appreciate these tables, I thought you might like the source code that generates the table, so you can play around yourselves. It's a simple C# console application, which can target either .NET 4.0 or 4.5:
using System;
using System.Collections.Generic;
using System.Text;
// Need to add a Reference to the System.Web assembly.
using System.Web;
namespace UriEncodingDEMO2
{
class Program
{
static void Main(string[] args)
{
EncodeStrings();
Console.WriteLine();
Console.WriteLine("Press any key to continue...");
Console.Read();
}
public static void EncodeStrings()
{
string stringToEncode = "ABCD" + "abcd"
+ "0123" + " !\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~" + "ĀāĒēĪīŌōŪū";
// Need to set the console encoding to display non-ASCII characters correctly (eg the
// Latin A-Extended characters such as ĀāĒē...).
Console.OutputEncoding = Encoding.UTF8;
// Will also need to set the console font (in the console Properties dialog) to a font
// that displays the extended character set correctly.
// The following fonts all display the extended characters correctly:
// Consolas
// DejaVu Sana Mono
// Lucida Console
// Also, in the console Properties, set the Screen Buffer Size and the Window Size
// Width properties to at least 140 characters, to display the full width of the
// table that is generated.
Dictionary<string, Func<string, string>> columnDetails =
new Dictionary<string, Func<string, string>>();
columnDetails.Add("Unencoded", (unencodedString => unencodedString));
columnDetails.Add("UrlEncoded",
(unencodedString => HttpUtility.UrlEncode(unencodedString)));
columnDetails.Add("UrlEncodedUnicode",
(unencodedString => HttpUtility.UrlEncodeUnicode(unencodedString)));
columnDetails.Add("UrlPathEncoded",
(unencodedString => HttpUtility.UrlPathEncode(unencodedString)));
columnDetails.Add("EscapedDataString",
(unencodedString => Uri.EscapeDataString(unencodedString)));
columnDetails.Add("EscapedUriString",
(unencodedString => Uri.EscapeUriString(unencodedString)));
columnDetails.Add("HtmlEncoded",
(unencodedString => HttpUtility.HtmlEncode(unencodedString)));
columnDetails.Add("HtmlAttributeEncoded",
(unencodedString => HttpUtility.HtmlAttributeEncode(unencodedString)));
columnDetails.Add("HexEscaped",
(unencodedString
=>
{
// Uri.HexEscape can only handle the first 255 characters so for the
// Latin A-Extended characters, such as A, it will throw an
// ArgumentOutOfRange exception.
try
{
return Uri.HexEscape(unencodedString.ToCharArray()[0]);
}
catch
{
return "[OoR]";
}
}));
char[] charactersToEncode = stringToEncode.ToCharArray();
string[] stringCharactersToEncode = Array.ConvertAll<char, string>(charactersToEncode,
(character => character.ToString()));
DisplayCharacterTable<string>(stringCharactersToEncode, columnDetails);
}
private static void DisplayCharacterTable<TUnencoded>(TUnencoded[] unencodedArray,
Dictionary<string, Func<TUnencoded, string>> mappings)
{
foreach (string key in mappings.Keys)
{
Console.Write(key.Replace(" ", "[space]") + " ");
}
Console.WriteLine();
foreach (TUnencoded unencodedObject in unencodedArray)
{
string stringCharToEncode = unencodedObject.ToString();
foreach (string columnHeader in mappings.Keys)
{
int columnWidth = columnHeader.Length + 1;
Func<TUnencoded, string> encoder = mappings[columnHeader];
string encodedString = encoder(unencodedObject);
// ASSUMPTION: Column header will always be wider than encoded string.
Console.Write(encodedString.Replace(" ", "[space]").PadRight(columnWidth));
}
Console.WriteLine();
}
}
}
}
You should encode only the user name or other part of the URL that could be invalid. URL encoding a URL can lead to problems since something like this:
string url = HttpUtility.UrlEncode("http://www.google.com/search?q=Example");
Will yield
http%3a%2f%2fwww.google.com%2fsearch%3fq%3dExample
This is obviously not going to work well. Instead, you should encode ONLY the value of the key/value pair in the query string, like this:
string url = "http://www.google.com/search?q=" + HttpUtility.UrlEncode("Example");
Hopefully that helps. Also, as teedyay mentioned, you'll still need to make sure illegal file-name characters are removed or else the file system won't like the path.
Better way is to use
Uri.EscapeUriString
to not reference Full Profile of .net 4.