Raphael Jeger Raphael Jeger - 6 months ago 44
Javascript Question

Save base64-encoded image with AJAX request in PHP

I encoded a canvas-image to base64 which gives me this:

data:image/jpeg;base64,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


which seems like a valid base64-image (decoded it with an online-decoder).

I send this with other (form-) variables with jquery ajax like this:

$.ajax({
type: "POST",
url: "index.php?action=saveNewPost",
data: {text: text, img: encodeURIComponent(base64img)},
contentType: "application/x-www-form-urlencoded;charset=UTF-8",
success: function(){
//...
}
});


on the server this goes to this line:

saveImage(utf8_decode($_POST['img']));


which calls:

function saveImage($base64img){
define('UPLOAD_DIR', '../uploads/');
$base64img = str_replace('data:image/jpeg;base64,', '', $base64img);
$data = base64_decode($base64img);
$file = UPLOAD_DIR . uniqid() . '.jpg';
file_put_contents($file, $data);
}


However, the file isn't saved. What could be wrong?

Answer

Lets try to create file test.php in same folder with single function and call, check output errors in browser or /var/log/httpd/error_log

<?php

function saveImage($base64img){
    define('UPLOAD_DIR', '../uploads/');
    $base64img = str_replace('data:image/jpeg;base64,', '', $base64img);
    $data = base64_decode($base64img);
    $file = UPLOAD_DIR . '123123123.jpg';
    file_put_contents($file, $data);
}

saveImage('data:image/jpeg;base64,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');

That mean that troubles in part AJAX => php script. Now, we try to compare what we recieve from ajax and original string, just change your function to this and look at test.txt:

function saveImage($base64img){
    define('UPLOAD_DIR', '../uploads/');

    $file = UPLOAD_DIR . 'test.txt';
    file_put_contents($file, 'ORIG:'.'data:image/jpeg;base64,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'."\n".'AJAX:'.$base64img);
}
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