Simple bearychat image robot in world's best language

imagebot.php

<?php
$post = json_decode(file_get_contents("php://input"));
if (!$post) {
    die('Hello world!');
}
$text = trim(substr($post->text, strlen($post->trigger_word)));
if (!$text) {
    die('{ "text": "what?" }');
}
$ret = json_decode(file_get_contents('http://ajax.googleapis.com/ajax/services/search/images?v=1.0&rsz=8&imgsz=small|medium|large&q=' . urlencode($text)));

if (!count($ret->responseData->results)) {
    die('{ "text": "404" }');
}

$rand = array_rand($ret->responseData->results);
$image_url = $ret->responseData->results[$rand]->url;

echo json_encode([
    'attachments' => array([
#       'text' => $image_url,
        'images' => array([
            'url' => $image_url
        ])
    ])], JSON_UNESCAPED_SLASHES);