Async.fi

Gone static

Update 2: Looks like page load times, at least as reported by Pingdom, went up from what they initially were. In my own testing cached pages still load in something like 150 to 250 milliseconds but Pingdom disagees. I don't know if this is regular CloudFront performance fluctuation, some kind of impedance mismatch between Pingdom and CloudFront or "something else".

Update: That really did the trick and the estimated -90% page load time wasn't that far off:

Having been fed up with wastefulness (resource wise) and general slowness of the MySQL/PHP/WordPress/CloudFlare setup for some time, I have now moved this site to S3/CloudFront. Site is generated from an XML file (which I derived from a WordPress export dump) with a Python script that is hosted here. Commenting is obviously impossible but if you for some reason need to contact me you'll find contact details on your left.

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Verifying Amazon SNS Messages with PHP

Messages sent by Amazon Simple Notification Service are signed, and checking that any received message is indeed from AWS and not from some douche trying to outsmart you is not very hard (nor should it be optional, for that matter): sns-verify.php The verify_sns() function expects the message in JSON format, plus region (e.g. "eu-west-1"), numerical account ID without dashes and an array containing the topics you're interested in. The code will verify both SubscriptionConfirmation and Notification messages. It loads the certificate from the address in SigningCertURL field to check against for each message separately because the certificate changes over time, as described here. It is also checked that the host where the certificate is loaded from is in the amazonaws.com domain. Example usage where subscriptions are automatically confirmed: 
require_once('sns-verify.php');

if($_SERVER['REQUEST_METHOD'] != 'POST') {
    logger('Not POST request, quitting');
    exit();
}

$post = file_get_contents('php://input');

if(!verify_sns($post, 'REGION', 'ACCOUNT', array('TOPIC 1', 'TOPIC 2'))) {
    exit;
}

$msg = json_decode($post);


if($msg->Type == 'SubscriptionConfirmation') {
    logger('SNS SubscriptionConfirmation received);
    file_get_contents($msg->SubscribeURL);
} elseif($msg->Type == 'Notification') {
    logger('SNS Notification received);
    process_message($msg);
}

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Visitor Locator, Take Two

The new version that I hacked together stores number of visits per country and shows the totals when a user clicks a countrys' marker. Visits are stored in an SQLite database, which, as you may know, makes things very easy as there is no server to look after etc. I was thinking of using Berkeley DB, because in an app like this, all that SQL is simply unnecessary sugar, but was lazy in the end (as usual). Update: Added country flags in place of the same default icon for every country (see: Custom Icons section in Google Maps API). Update 2: Added tooltip-like functionality, which shows country details in a transient window (label) instead of the default info window. See GxMarker for additional info. Continuing here from where last nights' script ended. This is just the PHP side of things; Google Maps API examples can be found elsewhere. First we open an SQLite database and create a table for our visitor data if table does not exist: 
try {
        $db = new PDO('sqlite:' . $_SERVER['DOCUMENT_ROOT'] . '/../db/visitor-locator.sqlite3');
} catch(PDOException $exception) {
        die($exception->getMessage());
}

$stmt = $db->query('SELECT name FROM sqlite_master WHERE type = 'table'');
$result = $stmt->fetchAll();
if(sizeof($result) == 0) {
        $db->beginTransaction();
        $db->exec('CREATE TABLE visits (country TEXT, visits INTEGER, lat TEXT, lng TEXT);');
        $db->commit();
}
Next, check if the country is already in the table and if it is, increment the 'visits' field: 
$stmt = $db->query('SELECT country, visits FROM visits WHERE country = '' . $countryname . ''');
$result = $stmt->fetch();

if($result['country']) {
        $db->beginTransaction();
        $stmt = $db->prepare('UPDATE visits SET visits=:visits, lat=:lat, lng=:lng WHERE country=:country');
        $stmt->bindParam(':country', $countryname, PDO::PARAM_STR);
        $visits = $result['visits'] + 1;
        $stmt->bindParam(':visits', $visits, PDO::PARAM_INT);
        $stmt->bindParam(':lat', $lat, PDO::PARAM_STR);
        $stmt->bindParam(':lng', $lng, PDO::PARAM_STR);
        $stmt->execute();
        $db->commit();
}
If country was not in the table, create a row for it: 
else {
        $db->beginTransaction();
        $stmt = $db->prepare('INSERT INTO visits (country, visits, lat, lng) VALUES (:country, :visits, :lat, :lng)');
        $stmt->bindParam(':country', $countryname, PDO::PARAM_STR);
        $visits = 1;
        $stmt->bindParam(':visits', $visits, PDO::PARAM_INT);
        $stmt->bindParam(':lat', $lat, PDO::PARAM_STR);
        $stmt->bindParam(':lng', $lng, PDO::PARAM_STR);
        $stmt->execute();
        $db->commit();
}
And lastly, fetch all rows and form a Javascript array for our client-side script to use: 
$result = $db->query('SELECT country, visits, lat, lng FROM visits');

echo "<script type=\"text/javascript\">\n";
echo "//<![CDATA[\n";
echo "var tbl_country = []; var tbl_visits = []; var tbl_lat = []; var tbl_lng = []; var count = 0;\n";
foreach($result->fetchAll() as $row) {
        echo 'tbl_country[count] = \'' . $row['country'] . '\'; ';
        echo 'tbl_visits[count] = \'' . $row['visits'] . '\'; ';
        echo 'tbl_lat[count] = \'' . $row['lat'] . '\'; ';
        echo 'tbl_lng[count] = \'' . $row['lng'] . '\';';
        echo " count++;\n";
}
echo "//]]>\n";
echo "</script>\n";

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