I keep getting a Base64 invalid character error even though I shouldn't.
The program takes an XML file and exports it to a document. If the user wants, it will compress the file as well. The compression works fine and returns a Base64 String which is encoded into UTF-8 and written to a file.
When its time to reload the document into the program I have to check whether its compressed or not, the code is simply:
byte[] gzBuffer = System.Convert.FromBase64String(text);
return "1F-8B-08" == BitConverter.ToString(new List<Byte>(gzBuffer).GetRange(4, 3).ToArray());
It checks the beginning of the string to see if it has GZips code in it.
Now the thing is, all my tests work. I take a string, compress it, decompress it, and compare it to the original. The problem is when I get the string returned from an ADO Recordset. The string is exactly what was written to the file (with the addition of a "\0" at the end, but I don't think that even does anything, even trimmed off it still throws). I even copy and pasted the entire string into a test method and compress/decompress that. Works fine.
The tests will pass but the code will fail using the exact same string? The only difference is instead of just declaring a regular string and passing it in I'm getting one returned from a recordset.
Any ideas on what am I doing wrong?
This question is related to
c#
string
ado.net
base64
invalid-characters
One gotcha to do with converting Base64 from a string is that some conversion functions use the preceding "data:image/jpg;base64," and others only accept the actual data.
If removing \0 from the end of string is impossible, you can add your own character for each string you encode, and remove it on decode.
string stringToDecrypt = HttpContext.Current.Request.QueryString.ToString()
//change to string stringToDecrypt = HttpUtility.UrlDecode(HttpContext.Current.Request.QueryString.ToString())
Whether null char is allowed or not really depends on base64 codec in question. Given vagueness of Base64 standard (there is no authoritative exact specification), many implementations would just ignore it as white space. And then others can flag it as a problem. And buggiest ones wouldn't notice and would happily try decoding it... :-/
But it sounds c# implementation does not like it (which is one valid approach) so if removing it helps, that should be done.
One minor additional comment: UTF-8 is not a requirement, ISO-8859-x aka Latin-x, and 7-bit Ascii would work as well. This because Base64 was specifically designed to only use 7-bit subset which works with all 7-bit ascii compatible encodings.
Source: Stackoverflow.com