error in file_get_content() in php - php

Question

I m trying to generate a QR code with form values my problem is it's showing some error like:
Warning: file_get_contents(http://www.test.com/chart?chs=100x100&cht=qr&chl=test1,test2 , test3): failed to open stream: HTTP request failed! HTTP/1.0 400 Bad Request in local path.
When I m running this code it will generate a QR-code with no data.
So far I have done this:
$datas = $_POST['data'];
$width = $height = 100;
$url = implode(", ",$datas);
$qr_img = "<img src=\"http://www.test.com/chart?chs={$width}x{$height}&cht=qr&chl=$url\" />";
$filename = "images/qr-code/qr-code.png";
$qr = file_get_contents("http://www.test.com/chart?chs={$width}x{$height}&cht=qr&chl=$url");
file_put_contents($filename, $qr);
Please help me to solve this.

Answer 1

I assume that this line:
$url = implode(", ",$datas);
is generating an invalid url. URLs passed as argument to another URL must be url-encoded:
$datas = $_POST['data'];
$width = $height = 100;
$url = urlencode(implode(", ",$datas)); // encode invalid chars
$qr_img = "<img src=\"http://www.test.com/chart?chs={$width}x{$height}&cht=qr&chl=$url\" />";
$qr = file_get_contents("http://www.test.com/chart?chs={$width}x{$height}&cht=qr&chl=$url");
$filename = "images/qr-code/qr-code.png";
file_put_contents($filename, $qr);
see also here: urlencode in PHP