other:vicinity_php_code [Playgrounds Wiki]

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<title>Swarm - Vicinity Testing</title>
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<?php
 
/* Tarim / April 2008 / for Swarm MediaSandbox Project */
 
 
 
/* Tweak these to get the desired effects... */
 
// Read in $db, $dbuser, $dbpasswd
include 'consts.php';
 
// These are the boundaries on the range _squared_
$InnerRangeSquared = 3;
$OuterRangeSquared = 4;
 
// The root and data elements around nearby output
$Root = 'document';
$Nearby = 'nearby';
$Device = 'device';
$Time = 'time';
 
// Uncomment this to see the XML
// header("Content-Type: Text/Plain;");
 
 
 
/* Define a few functions */
 
// Return a get option if it exists, else null
function get_opt($key) {
  return array_key_exists($key, $_GET) ? $_GET[$key] : null;
}
 
// Output the results of a query as XML
function xml_query($query, $element, $root) {
 
  ($result = mysql_query($query)) || die("Select $element: " . mysql_error());
  if ($root) echo "<${root}>\n";
 
  while ($line = mysql_fetch_array($result, MYSQL_ASSOC)) {
    echo "  <${element}> ";
    foreach ($line as $name=>$value) {
      echo " <${name}>${value}</${name}>";
    }
    echo "  </${element}>\n";
  }
 
  if ($root) echo "</${root}>\n";
  mysql_free_result($result);
}
 
 
/* Start the code for real */
 
// Connect to database
mysql_connect(null, $dbuser, $dbpasswd) || die('Connect database: ' . mysql_error());
mysql_select_db($db) || die('Select database: ' . mysql_error());
 
// if we are adding a player then insert row into Players and Connections
if($player = get_opt('add')) {
  $name = get_opt('name');
  $xpos = get_opt('x');
  $ypos = get_opt('y');
 
  mysql_query("
    INSERT INTO Players ( Player, Name, Xpos, Ypos )
    VALUES (${player}, '${name}', ${xpos}, ${ypos})
  ") || die('Add player: ' . mysql_error());
 
  mysql_query("
    INSERT INTO Connections ( Player1, Player2 )
    SELECT ${player} AS NewPlayer, Players.Player
    FROM Players
    WHERE Players.Player <> ${player}
  ") || die('Add connection: ' . mysql_error());
}
 
// Delete player from players and connections tables
if ($player = get_opt('delete')) {
  mysql_query("
    DELETE FROM Players
    WHERE Players.Player = ${player}
  ") || die('Delete player: ' . mysql_error());
 
  mysql_query("
    DELETE FROM Connections
    WHERE Connections.Player1 = ${player} OR
      Connections.Player2 = ${player}
  ") || die('Delete connection: ' . mysql_error());
}
 
// Update connections table when there are new co-ordinates from a player
if (($player = get_opt('update')) || ($player = get_opt('add'))) {
  $xpos = get_opt('x');
  $ypos = get_opt('y');
 
  mysql_query("
    UPDATE Players
    SET Xpos = ${xpos}, Ypos = ${ypos}
    WHERE Player = $player
  ") || die('Update player: ' . mysql_error());
 
 
  mysql_query("
    UPDATE (Connections
      INNER JOIN Players AS Players_1 ON
        Connections.Player1 = Players_1.Player)
      INNER JOIN Players AS Players_2 ON
        Connections.Player2 = Players_2.Player
      SET
        Connections.FirstContact = if(isnull(FirstContact), now(), null)
      WHERE
        (${player} = Connections.Player1 Or
         ${player} = Connections.Player2)
      AND
        ( (Players_1.Xpos - Players_2.Xpos)*(Players_1.Xpos - Players_2.Xpos)
        + (Players_1.Ypos - Players_2.Ypos)*(Players_1.Ypos - Players_2.Ypos)
        < if(isnull(FirstContact), ${InnerRangeSquared}, ${OuterRangeSquared}))
          = isnull(FirstContact)
    ") || die('Update connection: ' . mysql_error());
}
 
if ($player = get_opt('update')) {
  xml_query("
    SELECT
      if($player = Player2, Player1, Player2) AS $Device,
      FirstContact AS $Time
    FROM Connections
    WHERE ($player = Player1 or $player = Player2) and not isnull(FirstContact)
    ORDER BY Player1, Player2
  ", $Nearby, $Root);
} else {
 
  // Display the complete players table
  xml_query("SELECT * from Players ORDER BY Player", 'playerdata', 'pre');
 
  // Display the complete connections table
  xml_query("SELECT * from Connections ORDER BY Player1, Player2", 'connections', 'pre');
}
 
?>
 
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<address>Tarim / Vicinity for Swarm</address>
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