CODEWITHSUNDEEP
javascriptphpcharacter-encodingbase64
juanjo75es
juanjo75es

Reputation: 262

base64 encoding in javascript decoding in php

I am trying to encode a string in javascript and decode it in php.

I use this code to put the string in a inputbox and then send it via form PUT.

document.getElementById('signature').value= b64EncodeUnicode(ab2str(signature));

And this code to decode

$signature=base64_decode($signature);

Here there is a jsfiddle for the encoding page: https://jsfiddle.net/okaea662/

The problem is that I always get a string 98% correct but with some different characters. For example: (the first string is the string printed in the inputbox)

¦S÷ä½m0×C|u>£áWÅàUù»¥ïs7Dþ1Ji%ýÊ{\ö°(úýýÁñxçO9Ù¡ö}XÇIWçβÆü8ú²ðÑOA¤nì6S+̽ i¼?¼ºNËÒo·a©8»eO|PPþBE=HèÑqaX©$Ì磰©b2(Ðç.$nÈR,ä_OX¾xè¥3éÂòkå¾ N,sáW§ÝáV:ö~Å×à<4)íÇKo¡L¤<Í»äA(!xón#WÙÕGù¾g!)ùC)]Q(*}?­Ìp

¦S÷ ä½m0×C|u>£áWÅàUù»¥ïs7Dþ1Ji%ýÊ{\ö°(úýýÁñxçO9Ù¡ö}XÇIWçβÆü8ú²ðÑOA¤nì6S+̽ i¼?¼ºNËÒo·a©8»eO|PPþBE=HèÑ qaX©$Ì磰©b2(Ðç.$nÈR,ä_OX¾xè¥3éÂòkå¾ N ,sá W§ÝáV:ö~Å×à<4)íÇKo¡L¤<Í»äA(!xón#WÙÕGù¾g!)ùC)]Q(*}?­Ìp

Note that the 4th character is distinct and then there is one or two more somewhere. The string corresponds to a digital signature so these characters make the signature to be invalid.

I have no idea what is happening here. Any idea? I use Chrome browser and utf-8 encoding in header and metas (Firefox seems to use a different encoding in the inputbox but I will look that problem later)

EDIT:

The encoding to base64 apparently is not the problem. The base64 encoded string is the same in the browser than in the server. If I base64-decode it in javascript I get the original string but if I decode it in PHP I get a slightly different string.

EDIT2: I still don't know what the problem is but I have avoided it sending the data in a blob with ajax.

Upvotes: 5

Views: 10939

Answers (1)

James111
James111

Reputation: 15903

Try using this command to encode your string with js:

var signature = document.getElementById('signature');
var base64 = window.btoa(signature);

Now with php, you simply use: base64_decode($signature)

If that doesn't work (I haven't tested it) there may be something wrong with the btoa func. So checkout this link here:

https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding

There is a function in there that should work (if the above does not)

function b64EncodeUnicode(str) {
    return btoa(encodeURIComponent(str).replace(/%([0-9A-F]{2})/g, function(match, p1) {
        return String.fromCharCode('0x' + p1);
    }));
}

b64EncodeUnicode(signature); // "4pyTIMOgIGxhIG1vZGU="

Upvotes: 5

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