PHP中AJAX请求触发无关控制器方法的问题排查

我正在实现点赞按钮的更新功能，已在Posts控制器中创建likepost()方法，同时编写了对应的Model、View及AJAX代码。但点击按钮时控制台出现报错，错误指向原本运行正常的show()方法，相关代码如下：

控制器likepost()代码 #

public function likepost() 
{
  if (IsloggedIn()) {
      // 检查是否为POST请求
      if ($_SERVER['REQUEST_METHOD'] == 'POST') {
          $post_id = $_POST['post_id'];
          $user_id = $_SESSION['user_id']; // 假设用户已登录，用户ID存储在session中
  
          // 检查用户是否已点赞该帖子
          if ($this->postModel->hasUserLikedPost($post_id, $user_id)) {
              // 用户已点赞，取消点赞
              if ($this->postModel->removeLike($post_id, $user_id)) {
                  // 减少帖子表中的点赞数
                  $this->postModel->decrementLikeCount($post_id);
                  echo json_encode(['status' => 'unliked', 'likes_count' => $this->postModel->getLikesCount($post_id)]);
              }
          } else {
              // 用户未点赞，添加点赞
              if ($this->postModel->addLike($post_id, $user_id)) {
                  // 增加帖子表中的点赞数
                  $this->postModel->incrementLikeCount($post_id);
                  echo json_encode(['status' => 'liked', 'likes_count' => $this->postModel->getLikesCount($post_id)]);
              }
          }
      } else {
          echo json_encode(['status' => 'error', 'message' => '无效请求']);
      }
  } else {
      echo json_encode(['status' => 'error', 'message' => '用户未登录']);
  }
}

模型（Model）代码 #

public function hasUserLikedPost($user_id, $post_id) {
    echo $this->db->query('SELECT * FROM post_likes WHERE user_id = :user_id AND post_id = :post_id');
    $this->db->bind(':user_id', $user_id);
    $this->db->bind(':post_id', $post_id);
    $row = $this->db->single();
    
    return $row ? true : false;
}

public function addLike($post_id, $user_id) {
    $this->db->query('INSERT INTO post_likes (post_id, user_id) VALUES (:post_id, :user_id)');
    $this->db->bind(':post_id', $post_id);
    $this->db->bind(':user_id', $user_id);
    return $this->db->execute();
}

public function removeLike($post_id, $user_id) {
    $this->db->query('DELETE FROM post_likes WHERE post_id = :post_id AND user_id = :user_id');
    $this->db->bind(':post_id', $post_id);
    $this->db->bind(':user_id', $user_id);
    return $this->db->execute();
}

public function incrementLikeCount($post_id) {
    $this->db->query('UPDATE posts SET likes_count = likes_count + 1 WHERE id = :post_id');
    $this->db->bind(':post_id', $post_id);
    return $this->db->execute();
}

public function decrementLikeCount($post_id) {
    $this->db->query('UPDATE posts SET likes_count = likes_count - 1 WHERE id = :post_id');
    $this->db->bind(':post_id', $post_id);
    return $this->db->execute();
}

public function getLikesCount($post_id) {
    $this->db->query('SELECT likes_count FROM posts WHERE id = :post_id');
    $this->db->bind(':post_id', $post_id);
    return $this->db->single()->likes_count;
}

视图（View）代码 #

<button class="btn btn-success" id="upvote" data-post-id='<?php echo $data['post']->id; ?>'>
    <i class="fa fa-thumbs-up"></i> Upvote <span id="display"><?php echo $data['post']->likes_count; ?></span>
</button>

AJAX代码 #

document.addEventListener("DOMContentLoaded", function () {
    let btn = document.getElementById("upvote");
    if (!btn) {
        console.error('未找到ID为"upvote"的元素');
        return;
    }
    let disp = document.getElementById("display");
    let post_id = btn.getAttribute("data-post-id");

    btn.onclick = function () {
        // 创建AJAX请求将post_id发送到PHP
        let xhr = new XMLHttpRequest();
        xhr.open("POST", "<?php echo URLROOT;?>/posts/likepost", true);
        xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");

        xhr.onreadystatechange = function () {
            if (xhr.readyState === 4 && xhr.status === 200) {
                // 处理PHP返回的响应
                let response = JSON.parse(xhr.responseText);
                if (response.status === 'liked') {
                    disp.innerHTML = response.likes_count; // 更新点赞数
                } else if (response.status === 'unliked') {
                    disp.innerHTML = response.likes_count; // 更新点赞数
                }
            }
        };

        // 发送包含post_id的请求
        xhr.send("post_id=" + post_id);
    }
});

报错指向的show()方法（原正常运行） #

public function show($id)
{
    $post = $this->postModel->getPostById($id);
    $user = $this->userModel->getUserById($post->userid);
    $data = [
        'post' => $post,
        'user' => $user,   
    ];
    $this->view('posts/show',$data);
}

内容的提问来源于stack exchange，提问作者santosh bawari