Decode json base64 file string.

base64FileDecode.php

<?php

/**
 * Takes a base64 encoded file string and returns usable information, including the re-encoded file.
 * Very useful for absorbing files over JSON.
 * @param $str
 * @return array
 * @throws Exception
 */
function base64FileDecode($str)
{
    $file_parts     = explode(',', $str);
    $file_encoding  = explode(';',$file_parts[0])[1];
    $file_type      = explode(':', explode(';',$file_parts[0])[0])[1];
    $file           = $file_parts[1];
    $file           = str_replace(' ','+',$file);
    $file_decoded   = base64_decode($file);

    if($file_encoding != 'base64'){
        throw new Exception('Did not detect a base64 encoded string');
    }

    return array(
        "file"     => $file_decoded,
        "type"     => $file_type,
        "string"   => $file
    );
}
?>