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LightSail Upstream Error 515

If you use LightSail, AWS provides an easy way for you to connect to LightSail instances via Web SSH. I normally use a terminal (ssh client) to connect to LightSail instances, but using Web SSH is very convenient. If you try to do an OS upgrade, for example from Ubuntu 18.04 LTS to Ubuntu 20.04 LTS, you will break Web SSH. AWS has added a special Web SSH configuration on LightSail base images. The error you’ll get is “Upstream Error 515.” The only way to fix this is to get AWS Support to help you apply the fix. It’s not a make or break it deal, but it can be a nuisance if you prefer to use AWS Web SSH instead of a terminal. If you need a more secure SSH connection, consider uploading your ssh-key to the server, and disable password login.

Detect Device, OS, Browser

If you like to deliver specific content to a certain device type, you can use PHP’s server environment settings to know what type of device, operating systems, and browser type is being used. The server environment setting we are interested in is ‘HTTP_USER_AGENT.’ This index contains a string that is given off by the user agent, the browser in this case. All devices pass down pieces of information identifying themselves, including the type of device, operating system, and browser that is being used.

If we were to look for an iPad for example, we need to perform the following commands:

$iPad   = stripos($_SERVER['HTTP_USER_AGENT'],"iPad");
if ($iPad) { 
  echo 'This is an iPad'; 
} else { 
  echo 'This is not'; 
}

Other Devices

$user_agent = $_SERVER['HTTP_USER_AGENT'];
 
$iPad   = stripos($user_agent,"iPad");
$iPod   = stripos($user_agent,"iPod");
$iPhone = stripos($user_agent,"iPhone");
$webOS  = stripos($user_agent,"webOS");
$BlackBerry = stripos($user_agent,"BlackBerry");
$RimTablet= stripos($user_agent,"RIM Tablet");
 
if (stripos($user_agent,"Android") && stripos($user_agent,"mobile")) { 
  $Android = true;
} elseif(stripos($user_agent,"Android")){
  $AndroidTablet = true;
}
 
if ($AndroidTablet) {
  echo 'This is an Android Tablet';
} else {
  echo 'This is not an Android Tablet';
}

Detect OS Type

$user_agent = $_SERVER['HTTP_USER_AGENT'];
 
if (preg_match('/linux/i', $user_agent)) { $platform = 'linux'; }
if (preg_match('/macintosh|mac os x/i', $user_agent)) { $platform = 'mac'; }
if (preg_match('/windows|win32/i', $user_agent)) { $platform = 'windows'; }
 
if ($platform == 'windows') {
  // do something
}

Detect Browser Type

$user_agent = $_SERVER['HTTP_USER_AGENT'];
 
if (preg_match('/MSIE/i',$user_agent)) { $browser = 'Internet Explorer'; }
if (preg_match('/Firefox/i',$user_agent)) { $browser = 'Mozilla Firefox'; }
if (preg_match('/Chrome/i',$user_agent)) { $browser = 'Google Chrome'; }
if (preg_match('/Safari/i',$user_agent)) { $browser = 'Apple Safari'; }
if (preg_match('/Opera/i',$user_agent)) { $browser = 'Opera'; }
if (preg_match('/Netscape/i',$user_agent)) { $browser = 'Netscape'; }
 
if ($browser == 'Google Chrome') {
  // do something
}

With the sample code above, you can pretty much single out any device and deliver specific content to it.