nominatim.php

<?php

// where $app is a silex/pimple container — this could easily be rewritten as an ordinary function though

// example usage: list($location, $err) = $app['nominatim.reverse']([-1.125, 3.526])

function nameForLocation(array $location, $fallback='Unknown Location') {
	if (isset($location['name'])) return $location['name'];
	if (isset($location['street-address']) and isset($location['region']))
		return "{$location['street-address']}, {$location['region']}";
	if (isset($location['latitude']) and isset($location['longitude']))
		return round($location['latitude'], 2) . ', ' . round($location['longitude'], 2);
	return $fallback;
}

$app['nominatim.reverse'] = $app->share(function () use ($app) {
	return function (array $coordinates) use ($app) {
		$client = new Guzzle\Http\Client(isset($app['nominatim.server']) ? $app['nominatim.server'] : 'http://nominatim.openstreetmap.org/');
		
		$query = [
			'lat' => $coordinates[0],
			'lon' => $coordinates[1],
			'email' => $app['nominatim.email'],
			'format' => 'json',
			'zoom' => isset($app['nominatim.zoom']) ? $app['nominatim.zoom'] : 17,
			'addressdetails' => '1'
		];
		
		$cacheKey = 'nominatim.reverse.'.implode(',', $coordinates);
		if ($app['cache']->contains($cacheKey)) {
			return [$app['cache']->fetch($cacheKey), null];
		}
		
		try {
			// figure out if we need to sleep for a short while for Nominatim
			if ($app['cache']->contains('nominatim.last-query-time')) {
				$nextQueryTime = 1 + $app['cache']->fetch('nominatim.last-query-time');
				if (microtime(true) < $nextQueryTime) {
					time_sleep_until($nextQueryTime);
				}
			}
			
			$data = $client->get([
				'reverse{?data*}',
				['data' => $query]
			])->send()->json();
			$app['cache']->save('nominatim.last-query-time', microtime(true));
			
			$adr = $data['address'];
			$region = function ($g) {
				if ($g['country_code'] == 'us')
					return @($g['state'] ?: $g['county']);
				else
					return @($g['county'] ?: $g['state']);
			};
			$location = @([
				'street-address' => $adr['road'] ?: null,
				'extended-address' => $adr['suburb'] ?: null,
				'locality' => $adr['hamlet'] ?: $adr['village'] ?: $adr['town'] ?: $adr['city'] ?: null,
				'region' => $region($adr),
				'country-name' => $adr['country'] ?: null,
				'postal-code' => $adr['postcode'] ?: null,
				'country-code' => $adr['country_code'] ?: null,
				'latitude' => $coordinate
				s[0],
				'longitude' => $coordinates[1]
			]);
			$location['name'] = nameForLocation($location);
			$app['cache']->save($cacheKey, $location);
			return [$location, null];
		} catch (Guzzle\Common\Exception\GuzzleException $e) {
			return [null, $e];
		}
	};
});