ISS Spotter Script

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<head><title>ISS Spotter</title></head>

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<?php

/*
Title: ISS Spotter Script

Abstract: This PHP script is designed to track the International Space
Station (ISS) using NASA's Spot the Station data. It fetches XML data
from NASA's specified URL, which contains information about the ISS's
passing times over a specific location (in this case, Remscheid, Germany).
The script uses cURL to retrieve this data and then parses it using
SimpleXMLElement. It extracts and formats relevant information such as
passing date, time, duration, and maximum elevation of the ISS. The script
then calculates the timestamp for the next ISS pass and sets up a shell
command to trigger an external script ('iss-fader.sh') that will execute
corresponding actions (e.g., lighting control) at the right time. This
setup provides a user-friendly interface to display the next ISS passing
time and other details on a web page. It's a unique way to engage with
space through web technology.
*/


$url = "https://spotthestation.nasa.gov/sightings/xml_files.cfm?filename=Germany_None_Remscheid.xml";

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "$url");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$output = curl_exec($ch);
curl_close($ch);

$jetzt = time();

$iss = new SimpleXMLElement($output);

foreach ($iss->channel->item as $flug) {
    $desc = $flug->description;
        $zeilen = explode("<br/>", $flug->description);

        $zeilen[0] = str_replace("Date: ", "", $zeilen[0]);
        $zeilen[1] = str_replace("Time: ", "", $zeilen[1]);

        $zeit = "$zeilen[0] $zeilen[1]";
        $dauer = $zeilen[2];
        $max = $zeilen[3];

        $timestamp = strtotime($zeit);
        if ($timestamp > $jetzt) {break;}
}


if ($timestamp < $jetzt) {echo "Kein ISS Pass in der Zukunft gefunden. <a href=\"$url\">NASA</a>"; die;}

$dauer = preg_replace("/[^0-9]/","",$dauer);
$dauer = $dauer * 60;

$max = str_replace("Maximum Elevation: ", "", $max);
$max = substr($max, 0, -3);

// DEBUG
//$dauer = 10;
//$timestamp = $jetzt + $dauer;
// DEBUG

$output = shell_exec("nohup /bin/bash /path/to/iss-fader.sh $dauer $timestamp > /dev/null 2>&1 &");


echo "iss-fader.sh f&uuml;r <b>$zeit</b> ($timestamp).<br><a href=\"$url\">Dauer $dauer s, maximale H&ouml;he $max&deg;</a><br><br>";
echo "$desc<br><br>";

//$output = shell_exec("ps aux | grep '[iss]-fader' | wc -l");
// 2 Zeilen bedeutet, dass diese Instanz läuft UND eine andere. Abbrechen!
//if ($output >= 1) {
//  echo '<b>Abbruch! Programm wartet bereits.</b><br>';
    $countdown = ($timestamp - $jetzt) / 60;
    $countdown = round($countdown, 1);
    echo "<br>T-$countdown min";
    $countdown = $countdown / 60;
    $countdown = round($countdown, 1);
    echo "/$countdown h";


        ob_flush();
        flush();
    sleep(1);
    $output = shell_exec("ps aux | grep '[iss]-fader'");
    echo "<pre>USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND\n$output</pre>";
//  }


?>
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