PHP Data-URI to file - php

Question

I have a data URI I am getting from javascript and trying to save via php. I use the following code which gives a apparently corrupt image file:
$data = $_POST['logoImage'];
$uri = substr($data,strpos($data,",")+1);
file_put_contents($_POST['logoFilename'], base64_decode($uri));
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs 9AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAxklEQVQYlYWQMW7CUBBE33yITYUUmwbOkBtEcgUlTa7COXIVV5RUkXKC5AxU EdyZVD4kyKxkwIrr9vd0c7Oih aopinLNsF6Qkg2XW4XJ7LGFsAAcTV6lF5/jLdbALA9XDAXYfthFQVx OrmqKYK88/7rbbMFksALieTnzu9wDYTj6f70PKsp2kwAiSvjXNcvkWpAfNZkzWa/5a9yT7fdoX7rrB7hYh2fXo9HdjPYQZu3MIU8bYIlW20y0RUlXG2Kpv/vfwLxhTaSQwWqwhAAAAAElFTkSuQmCC
Below the code is the actual image as a Data-URI. 'logoImage' is the string above, and $uri is the string minus 'image/jpeg;base64,'.

Answer 1

A quick look at the PHP manual yields the following:
If you want to save data that is derived from a Javascript
canvas.toDataURL() function, you have to convert blanks into plusses.
If you do not do that, the decoded data is corrupted:
$encodedData = str_replace(' ','+',$encodedData);
$decodedData = base64_decode($encodedData);

Answer 2

The data URI you have in your example is not a valid PNG image. This will never work and is unrelated to the code, it's related to the data.
Does not apply but might be of interest:
file_put_contents($_POST['logoFilename'], file_get_contents($data));
The idea behind: PHP itself can read the contents of data URIs (data://) so you don't need to decode it on your own.
Note that the official data URI scheme (ref: The "data" URL scheme RFC 2397) does not include a double slash ("//") after the colon (":"). PHP supports with or without the two slashes.
# RFC 2397 conform
$binary = file_get_contents($uri);
# with two slashes
$uriPhp = 'data://' . substr($uri, 5);
$binary = file_get_contents($uriPhp);

Answer 3

The all code that works :
$imgData = str_replace(' ','+',$_POST['image']);
$imgData = substr($imgData,strpos($imgData,",")+1);
$imgData = base64_decode($imgData);
// Path where the image is going to be saved
$filePath = $_SERVER['DOCUMENT_ROOT']. '/ima/temp2.png';
// Write $imgData into the image file
$file = fopen($filePath, 'w');
fwrite($file, $imgData);
fclose($file);

Answer 4

I have another way to do this with PHP.
$img = str_replace(' ','+',$img);
$i = explode(',', $img);
$imgData = array_pop($i);
$newName = 'digital_file/'. rand(10, 16) . '.' . str_replace('/', '.', mime_content_type($img) );
// data:image/png;base64
$imgData = base64_decode($imgData);
Now you can use file_put_contents($newName) to create the image file.
Produces a file with a random numerical name (e.g. "123123.image.png"). And of course it has correct mime type.