Data bleeds between multiple instances of tileserver.php on same server when same tileset name is used

[bjnsn]

This is the scenario I encountered:

You have two directories A and B each containing the default tileserver.php and a tileset tiles.mbtiles. A/tiles.mbtiles contains different data than B/tiles.mbtiles.

If you request A/tileserver.php?/tiles/7/8/9.pbf and then request B/tileserver.php?/tiles/6/7/8.pbf this second request will sometimes receive data from A/tiles.mbtiles rather than B/tiles.mbtiles.

This appears to be due to persistence within this line from DBConnect that is maintained without regard the tileset's full path:
$this->db = new PDO('sqlite:' . $tileset, '', '', array(PDO::ATTR_PERSISTENT => true));

Changing the dataRoot configuration so that the full path for tiles.mbtiles is passed to DBConnect fixes the issue. I would suggest switching the default configuration from $config['dataRoot'] = ''; to $config['dataRoot'] = __DIR__;.

This fixes the issue in my tests on:
Ubuntu + Nginx + PHP7.0-FPM
Ubutnu + Apache + PHP
OSX + PHP