魁！小野の塾　PHPで簡単なプログラムを作ってみようの巻　第９話

<?php
	// db resource
	$db	= new mysqli('localhost', 'root', '', 'pjin');
	$db->set_charset("utf8");

	// $_POST -> $request
	$request	= [
		'author'	=> $_POST['author'] ?? '',
		'content'	=> $_POST['content'] ?? '',
		'action'	=> $_POST['action'] ?? ''
	];

	// create or delete
	$errors	= [];
	switch($request['action']){
	case 'create':
		// error check
		if(empty($request['author'])){
			$errors['author'][]	= '名前を入力して下さい。';
		}
		if(mb_strlen($request['author']) > 128){
			$errors['author'][]	= '名前は128文字以内で入力して下さい。';
		}
		if(empty($request['content'])){
			$errors['content'][]	= '内容を入力して下さい。';
		}
		if(mb_strlen($request['content']) > 65535){
			$errors['content'][]	= '名前は65,535文字以内で入力して下さい。';
		}

		if(count($errors) > 0){
			// エラーがあれば終了
			break;
		}

		// 登録処理
		$sql	= "insert into board(author, content) values (?, ?)";
		if($stmt = $db->prepare($sql)){
			$stmt->bind_param("ss", $request['author'], $request['content']);
			$stmt->execute();
			$stmt->close();
			// 登録後に空にします。
			$request	= [
				'author'	=> '',
				'content'	=> ''
			];
		}
		break;

	case 'delete';
		// 削除処理
		$sql	= "delete from board where id = ?";
		if($stmt = $db->prepare($sql)){
			$stmt->bind_param("i", $_POST['id']);
			$stmt->execute();
			$stmt->close();
		}
		break;
	}

	// 検索処理
	$rs	= [];
	$sql	= "select * from board order by id desc";
	if($stmt = $db->prepare($sql)){
		$stmt->execute();
		$stmt->bind_result($id, $createdAt, $author, $content);
		while($stmt->fetch()){
			$rs[]	= [
				'id'		=> $id,
				'createdAt'	=> $createdAt,
				'author'	=> $author,
				'content'	=> $content
			];
		}
		$stmt->close();
	}

	// db resource close
	$db->close();
?>

<?php foreach($rs as $row){ ?>
	<div class="card">
		<div class="card-header">
			<div class="row">
				<div class="col-sm-6">
					<strong><?php echo htmlentities($row['author']) ?></strong>
				</div>
				<div class="col-sm-6 text-right">
					<small><?php echo date('Y-m-d H:i:s ', strtotime($row['createdAt'])) ?></small>
				</div>
			</div>
		</div>
		<div class="card-body">
			<form action="<?php echo $_SERVER['SCRIPT_NAME'] ?>" method="POST">
				<p class="float-right">
					<input type="hidden" name="action" value="delete">
					<input type="hidden" name="id" value="<?php echo htmlentities($row['id']) ?>">
					<button type="submit" class="btn btn-outline-danger btn-sm">
						<i class="far fa-trash-alt"></i> 削除
					</button>
				</p>
			</form>
			<p class="card-text">
				<?php echo nl2br(htmlentities($row['content'])) ?>
			</p>
		</div>
	</div>

	<div class="mt-3"></div>
<?php } ?>

<form action="<?php echo $_SERVER['SCRIPT_NAME'] ?>" method="POST">
	<input type="hidden" name="action" value="create">
	<input type="hidden" name="id" value="">

[省略]

<div class="card-body">
	<p class="float-right">
		<button class="btn btn-outline-danger btn-sm" data-id="<?php echo htmlentities($row['id']) ?>">
			<i class="far fa-trash-alt"></i> 削除
		</button>
	</p>
	<p class="card-text">
		<?php echo nl2br(htmlentities($row['content'])) ?>
	</p>
</div>

[省略]

<script>
$(function(){
	$('[data-id]').on('click', function(){
		var id = $(this).data('id');
		var $form = $('form:first');
		$form.find('[name=action]').val('delete');
		$form.find('[name=id]').val(id);
		$form.submit();
	});
});
</script>