PHP Data-URI to file

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);