我在其他地方找不到这个问题的答案，我希望这里的人可能知道。我已经连续花了9个小时试图让它发挥作用，我一直在不停地寻找。
我有三个PHP文件。第三个文件包含我的PHP函数，用于检查现有用户并将用户添加到数据库
user.inc.php
<?php
//checks if given username exists in database
function user_exists($user){
$user = mysqli_real_escape_string($user);
$sql= "SELECT COUNT(`user_id`) FROM `users` WHERE `user_name` = '{$user}'";
$result = mysqli_query($con,$sql);
if ($result == 1){
return true;
}
else {
return false;
}
}
function email_exists($email){
$user = mysqli_real_escape_string($email);
$sql="SELECT COUNT(`user_id`) FROM `users` WHERE `user_email` = '{$email}'";
$result = mysqli_query($con,$sql);
// $row = mysqli_fetch_assoc($total);
if ($result == 1){
return true;
}
else {
return false;
}
}
//checks if given username/password is valid
function valid_credentials($user,$pass){
$user = mysqli_real_escape_string(htmlentities($user));
$pass = sha1($pass);
$sql= "SELECT COUNT(`user_id`) FROM `users` WHERE `user_name` = '{$user}'AND `user_password` ='{$pass}'";
$result = mysqli_query($con,$sql);
if ($result == 1){
return true;
}
else {
return false;
}
}
//adds a user to the database
function add_user($user,$pass,$email){
mysqli_query($con,"INSERT INTO`users` (`user_name`,`user_password`,`user_email`) VALUES ('a','b','c')");
$user = mysqli_real_escape_string(htmlentities($user));
$pass = sha1($_REQUEST[$pass]);
mysqli_query($con,"INSERT INTO`users` (`user_name`,`user_password`,`user_email`) VALUES ('{$user}','{$pass}','{email}')");
}
?>
第二个PHP文件启动与数据库的连接，并在底部包含上一个文件。
init.inc.php
<?php
session_start();
$exceptions = array('registerPage','login');
$page = substr(end(explode('/',$_SERVER['SCRIPT_NAME'])), 0, -4);
if (in_array($page, $exceptions)=== false){
if (isset($_SESSION['username'])=== false ){
header('Location: login.php');
die();
}
}
$con = mysqli_connect('127.0.0.1','root','','yingyujiaocheng');
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
mysqli_query($con,"INSERT INTO `users` (`user_name`,`user_password`) VALUES ('user','pass')");
$path = dirname(__FILE__);
include("{$path}/inc/user.inc.php");
?>
第三个PHP文件包括顶部的第二个文件，还包含HTML和表单。当第3页上的表单填写并提交时，它会将信息发送到第3页顶部的PHP脚本。这是针对从第一个文件调用函数的错误进行处理的。数据库工作正常，我在每个地方都执行了MYSQLI命令，唯一不工作的是从第三个PHP文件调用第一个PHP文件。函数user_exists、email_exists和add_user不能正确调用。
这是第三个文件：
registerPage.php
<?php error_reporting(E_ALL);
include('core/init.inc.php');
$errors = array();
if(isset($_POST['username'],$_POST['password'],$_POST['email'])){
$username = $_POST['username'];
$password = $_POST['password'];
$email = $_POST['email'];
if (empty($username)){
$errors[] = 'The username cannot be empty.';
}
if (empty($password)){
$errors[] = 'The password cannot be empty.';
}
if (empty($email)){
$errors[] = 'The email field cannot be empty.';
}
if (user_exists($username)){
$errors[] = 'The username is already taken';
}
if (email_exists($email)){
$errors[] = 'The email already taken';
}
if (empty($errors)){
add_user($username,$password,$email);
//$_SESSION['username'] = htmlentities($username);
//header('Location: protected.php');
// die();
}
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<link href="ext/Styles/styleSheet.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div class="header" align="centre">
<img src="ext/Images/Logo.png" width="150" height="80" style="float:left;" />
<h2 class="headerFontClickedSmall" style="float: right; margin-top:36px; margin-right: 60px"> </h2>
<h2 class="headerFontUnclickedSmall" style="float: right; margin-top:36px; margin-right: 10px"> / </h2>
<h2 class="headerFontUnclickedSmall" style="float: right; margin-top:36px; margin-right: 10px"> </h2>
<h2 class="cornerBox1" style="float: right; margin-top:20px; margin-right: 50px"> </h2>
</div>
<div class="content">
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<?php echo "Username is :" . $username . "<br>";
echo "Password is :" . $password;
?>
<br />
<h1 class="contentHeader" style=""> </h1>
<div>
<?php
if (empty($errors) === false){
?>
<ul>
<?php
foreach ($errors as $error){
echo "<li>{$error}</li>";
}
?>
</ul>
<?php
}
?>
</div>
<form action="registerPage.php" method="POST">
<h1 class="contentRegisterText" style=""> : <input class="inputbox" style="margin-left:30px" type="text"
name = "username" id="username"/> </h1>
<br />
<h1 class="contentRegisterText" style=""> : <input class="inputbox" style="margin-left:30px" type="text"
name = "email" id="email"/> </h1>
<br />
<h1 class="contentRegisterText" style="">: <input class="inputbox" style="margin-left:30px" type="password"
name = "password" id="password"/> </h1>
<br /><br /><br /><br /><br /><br />
<input style="margin-left:30px" type="submit" value = "" id="Register"/> </form>
</div>
<div class="footer" align="center" >
<div class="floating-box" style="margin-top:40px" >
<dl>
<dt><h1 class="footerTitle">社交媒体</h1></dt>
<br />
<dd><a href="http://www.huya.com/lucio">
<img src="ext/Images/HuyaLogo.png" alt=" " width="42" height="42" outline="none">
</a>
<img src="ext/Images/weixinLogo.png" width="40" height="40" style="margin-left:3;"/><img src="ext/Images/logo-qq.png" width="40" height="40" /></dd>
</dl>
</div>
<div class="floatingboxFooter1" style="margin-top:40px">
<dl>
<dt><h1 class="footerTitle"></h1> </dt>
<br />
<dd><h1 class="footerSmall">:</h1></dd>
<dd><h1 class="footerSmall">Weixin: </h1></dd>
<dd><h1 class="footerSmall">QQ: </h1></dd>
</dl>
</div>
<div class="floating-box" style="margin-top:64px">
<dl>
<br />
<dd><h1 class="footerSmall">bangzhu@yingyujiaocheng.com</h1></dd>
<dd><h1 class="footerSmall">yingyujiaocheng</h1></dd>
<dd><h1 class="footerSmall">yingyujiaocheng</h1></dd>
</dl>
</div>
<div class="floatingboxFooter1" style="margin-top:40px">
<dl>
<dt><h1 class="footerTitle"></h1> </dt>
<br />
<dd><h1 class="footerSmall"></h1></dd>
<dd><h1 class="footerSmall"></h1></dd>
<dd><h1 class="footerSmall"></h1></dd>
</dl>
</div>
</body>
</html>
感谢您的关注，如有帮助，我们将不胜感激，
干杯
Lucio
尝试调试$path变量，我认为问题出在您此行中包含的路径上。
include("{$path}/inc/user.inc.php");或者尝试在user.inc.php中的每个函数上插入global $con，如下所示：
function user_exists($user) {
global $con;
// rest of the code...
}