Principes de conception et pratique du système de blog PHP

CREATE TABLE `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) NOT NULL,
  `password` varchar(255) NOT NULL,
  `email` varchar(255) NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `username` (`username`),
  UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `articles` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(255) NOT NULL,
  `content` text NOT NULL,
  `user_id` int(11) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `user_id` (`user_id`),
  CONSTRAINT `articles_user_id_foreign` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

CREATE TABLE `comments` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `content` text NOT NULL,
  `user_id` int(11) NOT NULL,
  `article_id` int(11) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `user_id` (`user_id`),
  KEY `article_id` (`article_id`),
  CONSTRAINT `comments_user_id_foreign` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE,
  CONSTRAINT `comments_article_id_foreign` FOREIGN KEY (`article_id`) REFERENCES `articles` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

// 用户登录
session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // 验证用户名和密码
    if (验证用户名和密码通过) {
        // 认证通过，保存用户信息到Session
        $_SESSION['user_id'] = $user_id;
        // 跳转至博客主页
        header('Location: index.php');
        exit;
    } else {
        // 认证失败，显示错误消息
        $error_msg = '用户名或密码错误！';
    }
}

// 用户退出
session_start();
unset($_SESSION['user_id']);
session_destroy();
// 跳转至登录页
header('Location: login.php');
exit;

// 鉴权检查
session_start();
if (!isset($_SESSION['user_id'])) {
    // 未登录，跳转至登录页
    header('Location: login.php');
    exit;
}

// 发布文章
session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // 鉴权检查
    if (!isset($_SESSION['user_id'])) {
        // 未登录，跳转至登录页
        header('Location: login.php');
        exit;
    }
    // 获取表单数据
    $title = $_POST['title'];
    $content = $_POST['content'];

    // 保存到数据库
    $user_id = $_SESSION['user_id'];
    $sql = "INSERT INTO articles (title, content, user_id) VALUES ('$title', '$content', $user_id)";
    // 执行SQL语句
    // 跳转至文章详情页
    header('Location: article.php?id=' . $article_id);
    exit;
}

// 编辑文章
session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // 鉴权检查
    if (!isset($_SESSION['user_id'])) {
        // 未登录，跳转至登录页
        header('Location: login.php');
        exit;
    }
    // 获取表单数据
    $title = $_POST['title'];
    $content = $_POST['content'];

    // 更新数据库
    $user_id = $_SESSION['user_id'];
    $sql = "UPDATE articles SET title = '$title', content = '$content' WHERE id = $article_id AND user_id = $user_id";
    // 执行SQL语句
    // 跳转至文章详情页
    header('Location: article.php?id=' . $article_id);
    exit;
}

// 删除文章
session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // 鉴权检查
    if (!isset($_SESSION['user_id'])) {
        // 未登录，跳转至登录页
        header('Location: login.php');
        exit;
    }
    // 删除数据库中的文章
    $user_id = $_SESSION['user_id'];
    $sql = "DELETE FROM articles WHERE id = $article_id AND user_id = $user_id";
    // 执行SQL语句
    // 跳转至博客主页
    header('Location: index.php');
    exit;
}

// 发表评论
session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // 鉴权检查
    if (!isset($_SESSION['user_id'])) {
        // 未登录，跳转至登录页
        header('Location: login.php');
        exit;
    }
    // 获取表单数据
    $content = $_POST['content'];
    // 保存到数据库
    $user_id = $_SESSION['user_id'];
    $sql = "INSERT INTO comments (content, user_id, article_id) VALUES ('$content', $user_id, $article_id)";
    // 执行SQL语句
    // 刷新页面
    header('Location: article.php?id=' . $article_id);
    exit;
}

// 删除评论
session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // 鉴权检查
    if (!isset($_SESSION['user_id'])) {
        // 未登录，跳转至登录页
        header('Location: login.php');
        exit;
    }
    // 获取评论ID
    $comment_id = $_POST['comment_id'];
    // 删除数据库中的评论
    $user_id = $_SESSION['user_id'];
    $sql = "DELETE FROM comments WHERE id = $comment_id AND user_id = $user_id";
    // 执行SQL语句
    // 刷新页面
    header('Location: article.php?id=' . $article_id);
    exit;
}