I use powershell to convert string
$Text = 'ouser:v3$34##85b&g%fD79a3nf'
$Bytes = [System.Text.Encoding]::Unicode.GetBytes($Text)
$EncodedText =[Convert]::ToBase64String($Bytes)
$EncodedText
However when using https://www.base64decode.org/, or some java libraries for base64 encoding I get a different, shorter version.
Sample string:
This is a secret and should be hiden
powershell result:
VABoAGkAcwAgAGkAcwAgAGEAIABzAGUAYwByAGUAdAAgAGEAbgBkACAAcwBoAG8AdQBsAGQAIABiAGUAIABoAGkAZABlAG4A
normal base64 result:
VGhpcyBpcyBhIHNlY3JldCBhbmQgc2hvdWxkIGJlIGhpZGVu
While using the website I am able to decode both versions, however using my java code I am only able to decode the latter. Why is that? Is there more than one version of base64? Where those differences come from?
Adding the comment from #Raziel as an answer for better discoverability of this question.
[System.Text.Encoding]::Unicode] is UTF-16, the later is UTF-8. There's [System.Text.Encoding]::UTF8 that you can use.
Related
I'm currently working on something that requires me to pass a Base64 string to a PowerShell script. But while decoding the string back to the original I'm getting some unexpected results as I need to use UTF-7 during decoding and I don't understand why. Would someone know why?
The Mozilla documentation would suggest that it's insufficient to use Base64 if you have Unicode characters in your string. Thus you need to use a workaround that consists of using encodeURIComponent and a replace. I don't really get why the replace is needed and shortened it to btoa(escape('✓ à la mode')) to encode the string. The result of that operation would be JXUyNzEzJTIwJUUwJTIwbGElMjBtb2Rl.
Using PowerShell to decode the string back to the original, I need to first undo the Base64 encoding. In order to do System.Convert can be used (which results in a byte array) and its output can be converted to a UTF-8 string using System.Text.Encoding. Together this would look like the following:
$bytes = [System.Convert]::FromBase64String($inputstring)
$utf8string = [System.Text.Encoding]::UTF8.GetString($bytes)
What's left to do is URL decode the whole thing. As it is a UTF-8 string I'd expect only to need to run the URL decode without any further parameters. But if you do that you end up with a accented a that looks like � in a file or ? on the console. To get the actual original string it's necessary to tell the URL decode to use UTF-7 as the character set. It's nice that this works but I don't really get why it's necessary since the string should be UTF-8 and UTF-8 certainly supports an accented a. See the last two lines of the entire script for what I mean. With those two lines you will end up with one line that has the garbled text and one which has the original text in the same file encoded as UTF-8
Entire PowerShell script:
Add-Type -AssemblyName System.Web
$inputstring = "JXUyNzEzJTIwJUUwJTIwbGElMjBtb2Rl"
$bytes = [System.Convert]::FromBase64String($inputstring)
$utf8string = [System.Text.Encoding]::UTF8.GetString($bytes)
[System.Web.HttpUtility]::UrlDecode($utf8string) | Out-File -Encoding utf8 C:\temp\output.txt
[System.Web.HttpUtility]::UrlDecode($utf8string, [System.Text.UnicodeEncoding]::UTF7) | Out-File -Append -Encoding utf8 C:\temp\output.txt
Clarification:
The problem isn't the conversion of the Base64 to UTF-8. The problem is some inconsistent behavior of the UrlDecode of C#. If you run escape('✓ à la mode') in your browser you will end up with the following string %u2713%20%E0%20la%20mode. So we have a Unicode representation of the check mark and a HTML entity for the á. If we use this directly in UrlDecode we end up with the same error. My current assumption would be that it's an issue with the encoding of the PowerShell window and pasting characters into it.
Turns out it actually isn't all that strange. It's just for what I want to do it's advantages to use a newer function. I'm still not sure why it works if you use the UTF-7 encoding. But anyways, as an explanation:
... The hexadecimal form for characters, whose code unit value is 0xFF or less, is a two-digit escape sequence: %xx. For characters with a greater code unit, the four-digit format %uxxxx is used.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/escape
As TesselatingHecksler pointed out What is the proper way to URL encode Unicode characters? would indicate that the %u format wasn't formerly standardized. A newer version to escape characters exists though, which is encodeURIComponent.
The encodeURIComponent() function encodes a Uniform Resource Identifier (URI) component by replacing each instance of certain characters by one, two, three, or four escape sequences representing the UTF-8 encoding of the character (will only be four escape sequences for characters composed of two "surrogate" characters).
The output of this function actually works with the C# implementation of UrlDecode without supplying an additional encoding of UTF-7.
The original linked Mozilla article about a Base64 encode for an UTF-8 strings modifies the whole process in a way to allows you to just call the Base64 decode function in order to get the whole string. This is realized by converting the URL encode version of the string to bytes.
I have a normal string in Powershell that is from a text file containing Base64 text; it is stored in $x. I am trying to decode it as such:
$z = [System.Text.Encoding]::Unicode.GetString([System.Convert]::FromBase64String($x));
This works if $x was a Base64 string created in Powershell (but it's not). And this does not work on the $x Base64 string that came from a file, $z simply ends up as something like 䐲券.
What am I missing? For example, $x could be YmxhaGJsYWg= which is Base64 for blahblah.
In a nutshell, YmxhaGJsYWg= is in a text file then put into a string in this Powershell code and I try to decode it but end up with 䐲券 etc.
Isn't encoding taking the text TO base64 and decoding taking base64 BACK to text? You seem be mixing them up here. When I decode using this online decoder I get:
BASE64: blahblah
UTF8: nVnV
not the other way around. I can't reproduce it completely in PS though. See sample below:
PS > [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String("blahblah"))
nV�nV�
PS > [System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes("nVnV"))
blZuVg==
EDIT I believe you're using the wrong encoder for your text. The encoded base64 string is encoded from UTF8(or ASCII) string.
PS > [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String("YmxhaGJsYWg="))
blahblah
PS > [System.Text.Encoding]::Unicode.GetString([System.Convert]::FromBase64String("YmxhaGJsYWg="))
汢桡汢桡
PS > [System.Text.Encoding]::ASCII.GetString([System.Convert]::FromBase64String("YmxhaGJsYWg="))
blahblah
There are no PowerShell-native commands for Base64 conversion - yet (as of PowerShell [Core] 7.1), but adding dedicated cmdlets has been suggested in GitHub issue #8620.
For now, direct use of .NET is needed.
Important:
Base64 encoding is an encoding of binary data using bytes whose values are constrained to a well-defined 64-character subrange of the ASCII character set representing printable characters, devised at a time when sending arbitrary bytes was problematic, especially with the high bit set (byte values > 0x7f).
Therefore, you must always specify explicitly what character encoding the Base64 bytes do / should represent.
Ergo:
on converting TO Base64, you must first obtain a byte representation of the string you're trying to encode using the character encoding the consumer of the Base64 string expects.
on converting FROM Base64, you must interpret the resultant array of bytes as a string using the same encoding that was used to create the Base64 representation.
Examples:
Note:
The following examples convert to and from UTF-8 encoded strings:
To convert to and from UTF-16LE ("Unicode") instead, substitute [Text.Encoding]::Unicode for [Text.Encoding]::UTF8
Convert TO Base64:
PS> [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes('Motörhead'))
TW90w7ZyaGVhZA==
Convert FROM Base64:
PS> [Text.Encoding]::Utf8.GetString([Convert]::FromBase64String('TW90w7ZyaGVhZA=='))
Motörhead
This page shows up when you google how to convert to base64, so for completeness:
$b = [System.Text.Encoding]::UTF8.GetBytes("blahblah")
[System.Convert]::ToBase64String($b)
Base64 encoding converts three 8-bit bytes (0-255) into four 6-bit bytes (0-63 aka base64). Each of the four bytes indexes an ASCII string which represents the final output as four 8-bit ASCII characters. The indexed string is typically 'A-Za-z0-9+/' with '=' used as padding. This is why encoded data is 4/3 longer.
Base64 decoding is the inverse process. And as one would expect, the decoded data is 3/4 as long.
While base64 encoding can encode plain text, its real benefit is encoding non-printable characters which may be interpreted by transmitting systems as control characters.
I suggest the original poster render $z as bytes with each bit having meaning to the application. Rendering non-printable characters as text typically invokes Unicode which produces glyphs based on your system's localization.
Base64decode("the answer to life the universe and everything") = 00101010
If anyone would like to do it with a pipe in Powershell (like a filter) (e.g. read file contents and decode it), it can be achieved with a one-liner like that:
Get-Content base64.txt | %{[Text.Encoding]::UTF8.GetString([Convert]::FromBase64String($_))}
I had issues with spaces showing in between my output and there was no answer online at all to fix this issue. I literally spend many hours trying to find a solution and found one from playing around with the code to the point that I almost did not even know what I typed in at the time that I got it to work. Here is my fix for the issue: [System.Text.Encoding]::UTF8.GetString(([System.Convert]::FromBase64String($base64string)|?{$_}))
Still not a "built-in", but published to gallery, authored by MS:
https://github.com/powershell/textutility
TextUtility
ConvertFrom-Base64
Return a string decoded from base64.
ConvertTo-Base64
Return a base64 encoded representation of a string.
I decided to use Python 3 for making my website, but I encountered a problem with Unicode output.
It seems like plain print(html) #html is astr should be working, but it's not. I get UnicodeEncodeError: 'ascii' codec can't encode characters[...]: ordinal not in range(128). This must be because the webserver doesn't support unicode output.
The next thing I tried was print(html.encode('utf-8')), but I got something like repr output of the byte string: it is placed inside b'...' and all the escape characters are in raw form (e.g. \n and \xd0\x9c)
Please show me the correct way to output a Unicode (str) string as a raw UTF-8 encoded bytes string in Python 3.1
The problem here is that you stdout isn't attached to an actual terminal and will use the ASCII encoding by default. Therefore you need to write to sys.stdout.buffer, which is the "raw" binary output of sys.stdout. This can be done in various ways, the most common one seems to be:
import codecs, sys
writer = codecs.getwriter('utf8')(sys.stdout.buffer)
And the use writer. In a CGI script you may be able to replace sys.stdout with the writer so:
sys.stdout = codecs.getwriter('utf8')(sys.stdout.buffer)
Might actually work so you can print normally. Try that!
I've tried everything Google and StackOverflow have recommended (that I could find) including using Encode. My code works but it just uses UTF8 and I get the wide character warnings. I know how to work around those warnings but I'm not using UTF8 for anything else so I'd like to just convert it and not have to adapt the rest of my code to deal with it. Here's my code:
my $xml = XMLin($content);
# Populate the #titles array with each item title.
my #titles;
for my $item (#{$xml->{channel}->{item}}) {
my $title = Encode::decode_utf8($item->{title});
#my $title = $item->{title};
#utf8::downgrade($title, 1);
Encode::from_to($title, 'utf8', 'iso-8859-1');
push #titles, $title;
}
return #titles;
Commented out you can see some of the other things I've tried. I'm well aware that I don't know what I'm doing here. I just want to end up with a plain old ASCII string though. Any ideas would be greatly appreciated. Thanks.
The answer depends on how you want to use the title. There are 3 basic ways to go:
Bytes that represent a UTF-8 encoded string.
This is the format that should be used if you want to store the UTF-8 encoded string outside your application, be it on disk or sending it over the network or anything outside the scope of your program.
A string of Unicode characters.
The concept of characters is internal to Perl. When you perform Encode::decode_utf8, then a bunch of bytes is attempted to be converted to a string of characters, as seen by Perl. The Perl VM (and the programmer writing Perl code) cannot externalize that concept except through decoding UTF-8 bytes on input and encoding them to UTF-8 bytes on output. For example, your program receives two bytes as input that you know they represent UTF-8 encoded character(s), let's say 0xC3 0xB6. In that case decode_utf8 returns a representation that instead of two bytes, sees one character: ö.
You can then proceed to manipulate that string in Perl. To illustrate the difference further, consider the following code:
my $bytes = "\xC3\xB6";
say length($bytes); # prints "2"
my $string = decode_utf8($bytes);
say length($string); # prints "1"
The special case of ASCII, a subset of UTF-8.
ASCII is a very small subset of Unicode, where characters in that range are represented by a single byte. Converting Unicode into ASCII is an inherently lossy operation, as most of the Unicode characters are not ASCII characters. You're either forced to drop every character in your string which is not in ASCII or try to map from a Unicode character to their closest ASCII equivalents (which isn't possible in the vast majority of cases), when trying to coerce a Unicode string to ASCII.
Since you have wide character warnings, it means that you're trying to manipulate (possibly output) Unicode characters that cannot be represented as ASCII or ISO-8859-1.
If you do not need to manipulate the title from your XML document as a string, I'd suggest you leave it as UTF-8 bytes (I'd mention that you should be careful not to mix bytes and characters in strings). If you do need to manipulate it, then decode, manipulate, and on output encode it in UTF-8.
For further reading, please use perldoc to study perlunitut, perlunifaq, perlunicode, perluniintro, and Encode.
Although this is an old question, I just spent several hours (!) trying to do more or less the same thing! That is: read data from a UTF-8 XML file, and convert that data into the Windows-1252 codepage (I could also have used Latin1, ISO-8859-1 etc.) in order to be able to create filenames with accented letters.
After much experimentation, and even more searching, I finally managed to get the conversion working. The "trick" is to use Encode::encode instead of Encode::decode.
For example, given the code in the original question, the correct (or at least one :-) way to convert from UTF-8 would be:
my $title = Encode::encode("Windows-1252", $item->{title});
or
my $title = Encode::encode("ISO-8859-1", $item->{title});
or
my $title = Encode::encode("<your-favourite-codepage-here>", $item->{title});
I hope this helps others having similar problems!
You can use the following line to simply get rid of the warning. This assumes that you want to use UTF8, which shouldn't normally be a problem.
binmode(STDOUT, ":encoding(utf8)");
Lets say i have this code:
use strict;
use LWP qw ( get );
my $content = get ( "http://www.msn.co.il" );
print STDERR $content;
The error log shows something like "\xd7\x9c\xd7\x94\xd7\x93\xd7\xa4\xd7\xa1\xd7\x94"
which i'm guessing it's utf-16 ?
The website's encoding is with
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=windows-1255">
so why these characters appear and not the windows-1255 chars ?
And, another weird thing is that i have two servers:
the first server returning CP1255 chars and i can simply convert it to utf8,
and the current server gives me these chars and i can't do anything with it ...
is there any configuration file in apache/perl/module that is messing up the encoding ?
forcing something ... ?
The result in my website at the second server, is that the perl file and the headers are all utf8, so when i write text that aren't english chars, the content from the example above is showing ok ( even though it's weird utf chars ) but my own static text are look like "×ס'××ר××:"
One more thing that i tested is ...
Through perl:
my $content = `curl "http://www.anglo-saxon.co.il"`;
I get utf8 encoding.
Through Bash:
curl "http://www.anglo-saxon.co.il"
and here i get CP1255 ( Windows-1255 ) encoding ...
Also,
when i run the script in bash - it gives CP1255, and when run it through the web - then it's utf8 again ...
fixed the problem by changin the content from utf8 - to what is supposed to, and then back to utf8:
use Text::Iconv;
my $converter = Text::Iconv->new("utf8", "CP1255");
$content=$converter->convert($content);
my $converter = Text::Iconv->new("CP1255", "utf8");
$content=$converter->convert($content);
All of this manual encoding and decoding is unnecessary. The HTML is lying to you when it says that the page is encoded in windows-1255; the server says it's serving UTF-8, and it is. Blame Microsoft HTML-generation tools.
Anyway, since the server does return the correct encoding, this works:
my $response = LWP::UserAgent->new->get("http://www.msn.co.il/");
my $content = $res->decoded_content;
$content is now a perl character string, ready to do whatever you need. If you want to convert it to some other encoding, then calling Encode::encode on it is appropriate; do not use Encode::decode as it's already been decoded once.
http://www.msn.co.il is in UTF-8, and indicates that properly. The string "\xd7\x9c\xd7\x94\xd7\x93\xd7\xa4\xd7\xa1\xd7\x94" is also proper UTF-8 (להדפסה). I don't see the problem.
I think your second problem is due to you mixing different encodings (UTF-8 and Windows-1252). You might want to encode/decode your strings properly.
First, note that you should import get from LWP::Simple. Second, everything works fine with:
#!/usr/bin/perl
use strict; use warnings;
use LWP::Simple qw ( getstore );
getstore 'http://www.msn.co.il', 'test.html';
which indicates to me that the problem is the encoding of the filehandle to which you are sending the output.
The string with the hex values that you gave appears to be a UTF-8 encoding. You are getting this because Perl ‘likes to’ use UTF-8 when it deals with strings. The LWP::Simple->get() method automatically decodes the content from the server which includes undoing any Content-Encoding as well as converting to UTF-8.
You could dig into the internals and get a version that does change the character encoding (see HTTP::Message's decoded_content, which is used by HTTP::Response's decoded_content, which you can get from LWP::UserAgent's get). But it may be easier to re-encode the data in your desired encoding with something like
use Encode;
...;
$cp1255_bytes = encode('CP1255', decode('UTF_8', $utf8_bytes));
The mixed readable/garbage characters you see are due to mixing multiple, incompatible encodings in the same stream. Probably the stream is labeled as UTF-8 but you are putting CP1255 encoded characters into it. You either need to label the stream as CP1255 and put only CP1255-encoded data into it, or label it as UTF-8 and put only UTF-8-encoded data into it. Remind yourself that bytes are not characters and convert between them appropriately.