<?php

try {

    if (!isset($_GET['no'])) {
        throw new RuntimeException('生徒番号が指定されていません', 400);
    }
    $pdo = new PDO(
        'mysql:dbname=school;host=localhost;charset=utf8',
        'username',
        'password',
        array(
            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
            PDO::ATTR_EMULATE_PREPARES => false,
            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
        )
    );
    $stmt = $pdo->prepare('SELECT * FROM student WHERE no = ? LIMIT 1');
    $stmt->bindValue(1, $_GET['no'], PDO::PARAM_INT);
    $stmt->execute();
    if (!$result = $stmt->fetch()) {
        throw new RuntimeException('番号に一致する生徒は見つかりませんでした', 404);
    }
    header('Content-Type: application/json; charset=utf-8');
    echo json_encode(compact('result'));

} catch (PDOException $e) {

    header('Content-Type: application/json; charset=utf-8', true, 500);
    $error = 'データベースでエラーが発生しました';
    echo json_encode(compact('error'));

} catch (RuntimeException $e) {

    header('Content-Type: application/json; charset=utf-8', true, $e->getCode());
    $error = $e->getMessage();
    echo json_encode(compact('error'));

}