如何使用PHP开发微信小程序的医疗咨询功能？

<?php
  
  // 获取用户openid
  function getUserOpenid($code, $appid, $appsecret) {
    $url = "https://api.weixin.qq.com/sns/jscode2session?appid=".$appid."&secret=".$appsecret."&js_code=".$code."&grant_type=authorization_code";
    $result = file_get_contents($url);
    $data = json_decode($result, true);
    return $data['openid'];
  }
  
  // 用户咨询接口
  function userConsult($question, $openid) {
    // 连接数据库并插入数据
    $conn = new mysqli("localhost", "username", "password", "consultation");
    if ($conn->connect_error) {
      die("Connection failed: " . $conn->connect_error);
    }
  
    $sql = "INSERT INTO consultations (user_id, question) VALUES ('$openid', '$question')";
    if ($conn->query($sql) === TRUE) {
      echo "Consultation saved successfully";
    } else {
      echo "Error: " . $sql . "<br>" . $conn->error;
    }
  
    $conn->close();
  }
  
  // 医生回复接口
  function doctorReply($reply, $record_id) {
    // 连接数据库并更新数据
    $conn = new mysqli("localhost", "username", "password", "consultation");
    if ($conn->connect_error) {
      die("Connection failed: " . $conn->connect_error);
    }
  
    $sql = "UPDATE consultations SET reply='$reply' WHERE id='$record_id'";
    if ($conn->query($sql) === TRUE) {
      echo "Reply saved successfully";
    } else {
      echo "Error: " . $sql . "<br>" . $conn->error;
    }
  
    $conn->close();
  }
  
?>