How to save a PNG image server-side, from a base64 data string

Question

I\'m using Nihilogic\'s \"Canvas2Image\" JavaScript tool to convert canvas drawings to PNG images. What I need now is to turn those base64 strings that this tool generates,

Answer 1

This code works for me check below code:

<?php
define('UPLOAD_DIR', 'images/');
$image_parts = explode(";base64,", $_POST['image']);
$image_type_aux = explode("image/", $image_parts[0]);
$image_type = $image_type_aux[1];
$image_base64 = base64_decode($image_parts[1]);
$file = UPLOAD_DIR . uniqid() . '.png';
file_put_contents($file, $image_base64);
?>

Answer 2

This function should work. this has the photo parameter that holds the base64 string and also path to an existing image directory should you already have an existing image you want to unlink while you save the new one.

 public function convertBase64ToImage($photo = null, $path = null) {
    if (!empty($photo)) {
        $photo = str_replace('data:image/png;base64,', '', $photo);
        $photo = str_replace(' ', '+', $photo);
        $photo = str_replace('data:image/jpeg;base64,', '', $photo);
        $photo = str_replace('data:image/gif;base64,', '', $photo);
        $entry = base64_decode($photo);
        $image = imagecreatefromstring($entry);

        $fileName = time() . ".jpeg";
        $directory = "uploads/customer/" . $fileName;

        header('Content-type:image/jpeg');

        if (!empty($path)) {
            if (file_exists($path)) {
                unlink($path);
            }
        }

        $saveImage = imagejpeg($image, $directory);

        imagedestroy($image);

        if ($saveImage) {
            return $fileName;
        } else {
            return false; // image not saved
        }
    }
}

Answer 3

PHP has already a fair treatment base64 -> file transform

I use to get it done using this way:

$blob=$_POST['blob']; // base64 coming from an url, for example
$blob=file_get_contents($blob);
$fh=fopen("myfile.png",'w'); // be aware, it'll overwrite!
fwrite($fh,$blob);
fclose($fh);
echo '<img src=myfile.png>'; // just for the check

Answer 4

Well your solution above depends on the image being a jpeg file. For a general solution i used

$img = $_POST['image'];
$img = substr(explode(";",$img)[1], 7);
file_put_contents('img.png', base64_decode($img));

Answer 5

Total concerns:

$data = 'data:image/png;base64,AAAFBfj42Pj4';

// Extract base64 file for standard data
$fileBin = file_get_contents($data);
$mimeType = mime_content_type($data);

// Check allowed mime type
if ('image/png'==$mimeType) {
    file_put_contents('name.png', $fileBin);
}

http://php.net/manual/en/wrappers.data.php

http://php.net/manual/en/function.mime-content-type.php

Answer 6

Taken the @dre010 idea, I have extended it to another function that works with any image type: PNG, JPG, JPEG or GIF and gives a unique name to the filename

The function separate image data and image type

function base64ToImage($imageData){
    $data = 'data:image/png;base64,AAAFBfj42Pj4';
    list($type, $imageData) = explode(';', $imageData);
    list(,$extension) = explode('/',$type);
    list(,$imageData)      = explode(',', $imageData);
    $fileName = uniqid().'.'.$extension;
    $imageData = base64_decode($imageData);
    file_put_contents($fileName, $imageData);
}