How can I strip the data:image part from a base64 string of any image type in PHP

Question

I am currently doing the following to decode base64 images in PHP:

   $img = str_replace('data:image/jpeg;base64,', '', $s['image']);
   $img = str_replace('data:image/png;base64,', '', $s['image']);
   $img = str_replace('data:image/gif;base64,', '', $s['image']);
   $img = str_replace('data:image/bmp;base64,', '', $s['image']);
   $img = str_replace(' ', '+', $img);
   $data = base64_decode($img);

As you can see above we are accepting the four most standard image types (jpeg, png, gif, bmp);

However, some of these images are very large and scanning through each one 4-5 times with str_replace seems a dreadful waste and terribly inefficient.

Is there a way I could reliably strip the data:image part of a base64 image string in a single pass? Perhaps by detecting the first comma in the string?

My apologies if this is a simple problem, PHP is not my forte. Thanks in advance.

Answer 1

You can use a regular expression:

$img = preg_replace('#data:image/[^;]+;base64,#', '', $s['image']);

if the text you are replacing is the first text in the image, adding ^ at the beginning of the regexp will make it much faster, because it won't analyze the entire image, just the first few characters:

$img = preg_replace('#^data:image/[^;]+;base64,#', '', $s['image']);

Answer 2

Function file_get_contents remove header and use base64_decode function, so you get clear content image.

Try this code:

$img = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAA0gA...';
$imageContent = file_get_contents($img);