HTTP_USER_AGENT on the fingerprint function

This is somewhat related to my earlier problem, “Trying to get property of non-object” error
Just to summarize:
I’ve got this route

array(
    "pattern" => "api/yt",
    "method" => "GET",
    "action" => function() {
        $api_src        = c::get("api.youtube.channel.src") . c::get("api.youtube.key");
        $api_src_alt    = c::get("api.youtube.channel2.src") . c::get("api.youtube.key");

        $api_alt        = json_decode(file_get_contents($api_src_alt));
        $api            = json_decode(file_get_contents($api_src));

        $views          = $api->items[0]->statistics->viewCount + $api_alt->items[0]->statistics->viewCount;
        $videos         = $api->items[0]->statistics->videoCount + $api_alt->items[0]->statistics->videoCount;
        $subscribers    = $api->items[0]->statistics->subscriberCount + $api_alt->items[0]->statistics->subscriberCount;
        return response::json(array(
            "views" => array(
                "main" => $api->items[0]->statistics->viewCount,
                "services" => $api_alt->items[0]->statistics->viewCount,
                "total" => $api->items[0]->statistics->viewCount + $api_alt->items[0]->statistics->viewCount
            ),
            "videos" => array(
                "main" => $api->items[0]->statistics->videoCount,
                "services" => $api_alt->items[0]->statistics->videoCount,
                "total" => $api->items[0]->statistics->videoCount + $api_alt->items[0]->statistics->videoCount
            ),
            "subscribers" => array(
                "main" => $api->items[0]->statistics->subscriberCount,
                "services" => $api_alt->items[0]->statistics->subscriberCount,
                "total" => $api->items[0]->statistics->subscriberCount + $api_alt->items[0]->statistics->subscriberCount
            )
        ));
    }
),

which generates this json

{
    "views": {
        "main": "37519",
        "services": "7208",
        "total": 44727
    },
    "videos": {
        "main": "48",
        "services": "22",
        "total": 70
    },
    "subscribers": {
        "main": "184",
        "services": "35",
        "total": 219
    }
}

and is called with this

$api = json_decode(file_get_contents($site->url()."/api/yt"), TRUE);

It was working fine when I tested it, but I don’t think I edited anything related to that, but it then started to show blank, so I tried to just echo the file contents, without decoding the json, and I then got this error up (both dev and production server)

Notice: Undefined index: HTTP_USER_AGENT in /home/nginx/gsponsor.com/public/kirby/toolkit/lib/s.php on line 113
// and the json response

To solve this I had to add a UA string to to file_get_contents()
So now to call the api out I have to do this

$context = stream_context_create(['http' => ['user_agent' => 'PHP 7.0.2 file_get_contents()']]);
$api = json_decode(file_get_contents($site->url()."/api/yt", false, $context), TRUE);

This is the snippet it’s complaining about, $_SERVER[“HTTP_USER_AGENT”] is the undefined index

public static function fingerprint() {
  if(!r::cli()) {
    return sha1($_SERVER['HTTP_USER_AGENT'] . (ip2long($_SERVER['REMOTE_ADDR']) & ip2long('255.255.0.0')));
  } else {
    return '';
  }
}

I know it has worked before, it worked before I turned on debug mode, which threw me the “Trying to get property of non-object” error, and when I solved that thanks to @jbeyerstedt, it was working.
All I did was install the Pear Mail function, but I removed the function, and it was still not working. Also tried with a backup server without the Pear Mail, and it too was reporting the undefined index.

I tried to go back to the functions, which reported the “Trying to get property of non-object” error, and it’s working again. With debug turned off.

I did some testing, with just echoing out the

file_get_contents($site->url()."/api/yt")

And when debug is off, everything works.
But when I turn debug on, it notices me about the undefined index

Notice: Undefined index: HTTP_USER_AGENT in /home/nginx/gsponsor.com/public/kirby/toolkit/lib/s.php on line 113

Testing again, this time with node.js, trying to pull the same JSON data from $site->url()."/api/yt" and it also throws me the Undefined index: HTTP_USER_AGENT.
And I also tried to just get the content of the main page too, still throws me the same Undefined index: HTTP_USER_AGENT
I can’t remember this happening before, as I’ve used the exact same JSON data in other sites

Found how to solve it, and created a pull request on Toolkit dev branch (#146)

-    return sha1($_SERVER['HTTP_USER_AGENT'] . (ip2long($_SERVER['REMOTE_ADDR']) & ip2long('255.255.0.0')));      
+    return sha1(Visitor::ua() . (ip2long($_SERVER['REMOTE_ADDR']) & ip2long('255.255.0.0')));