Download images from SLSA (State Library of South Australia) collections

download-slsa.php

<?php

/**
 * Download large size images from SLSA Library
 * (State Library of South Australia)
 * Copyleft (C) 2015-2017 BohwaZ http://bohwaz.net/
 * GNU AGPL license
 */

if (empty($argv[1]))
{
	die('Usage: ' . $arrgv[0] . ' http://collections.slsa.sa.gov.au/resource/B+61438' . PHP_EOL);
}

$url = $argv[1];

// Normalize URL
$url = preg_replace('!/continue$!', '', $url);

$url = rtrim($url, '/');

// Get the unique ID
$id = str_replace('http://collections.slsa.sa.gov.au/resource/', '', $url);
$id = preg_replace('/[^\w_]+/i', '_', $id);

// Skip if file has already been fetched
if (count(glob('SLSA_' . $id . '*')) > 0)
{
	die('Already found' . PHP_EOL);
}

// Fetch page title
$page = file_get_contents($url);
$title = '';

if (preg_match('!<title>(.*?)(?:•.*?)?</title>!is', $page, $match))
{
	$title = trim($match[1]);
}

// Fetch tiles index
$url .= '/tiles.json';

$json = json_decode(file_get_contents($url));

if (empty($json))
{
	die('Invalid json' . PHP_EOL);
}

$tiles = [];
$w = $h = null;

// Look up for zoom level 0
foreach ($json->levels as $level)
{
	if ($level->name == 'z0')
	{
		$tiles = $level->tiles;
		$w = $level->width;
		$h = $level->height;
		break;
	}
}

if (empty($tiles))
{
	die('No tiles found' . PHP_EOL);
}

// Download tiles
$max_x = 0;
$max_y = 0;

foreach ($tiles as $tile)
{
	$filename = sprintf('tile-y%02d-x%02d.jpg', $tile->y, $tile->x);
	echo '.';

	if (!file_exists($filename))
	{
		copy($tile->url, $filename);
	}

	$max_x = max($max_x, $tile->x);
	$max_y = max($max_y, $tile->y);
}

echo " $w x $h / $max_x, $max_y" . PHP_EOL;

// Create filename
$name = preg_replace('/[^\w_]+/i', '_', $id . '_' . $title);
$name = 'SLSA_' . $name . '.jpg';

// Assemble tiles with imagemagick
$command = sprintf('montage tile*.jpg -quality 95 -tile %dx%d -geometry %dx%d+0+0 -mode Concatenate %s', $max_x+1, $max_y+1, 512, 512, escapeshellarg($name));
echo $command;

shell_exec($command);

// Cleanup
shell_exec('rm -f tile-*.jpg');

echo PHP_EOL;