请帮助，php的初学者正在努力将数据库连接到我的项目[重复]

Question

这个问题已经在这里有了答案：

• PHP解析/语法错误； 以及如何解决它们？ 17个答案

我正在使用登录系统，但不断收到此错误

“在此服务器上找不到请求的URL。引荐页面上的链接似乎有误或已过时。请将该错误告知该页面的作者。如果您认为这是服务器错误，请与网站管理员联系。”

当我执行以下代码时：

<?php

if(isset($POST['submit'])){

    include_once 'dbh.php';

    $first = mysqli_real_escape_string($conn, $POST)['first'];
    $last = mysqli_real_escape_string($conn, $POST)['last'];
    $email = mysqli_real_escape_string($conn, $POST)['email'];
    $uid = mysqli_real_escape_string($conn, $POST)['uid'];
    $pwd = mysqli_real_escape_string($conn, $POST)['pwd'];

    //Error handlers
    //Check for empty fields

    if(empty($first)||(empty($last)||(empty($email)||(empty($uid)||(empty($pwd)){
        header("signup.php?signup=empty");
        exit();     
    }else {
        //Check if input characters are valid
        if(!preg_match("/^[a-zA-Z]*$/", $first)||(!preg_match("/^[a-zA-Z]*$/", $last)){
            header("Location: ../signup.php?signup=invalid");
        }exit();    
        }else{
            //Check if email is valid
            if(!filter_var($email, FILTER_VALIDATE_EMAIL)){
                header("Location: ../signup.php?signup=email");
                exit();
            else{
                $sql = "SELECT * FROM users where user_uid='$uid'";
                $result = mysqli_query($conn, $sql);
                $resultCheck = mysqli_num_rows($result);

                if ($resultCheck > 0) {
                    header("Location: ../signup.php?signup=usertaken");
                    exit();
                else {
                    //hashing the password
                    $hashedPwd = password_hash($pwd, PASSWORD_DEFAULT);

                    //Insert the user into the database
                    $sql = "INSERT INTO users (user_first, user_last, user_email, user_uid, user_pwd) 
                                VALUES('$first', '$last','$email','$uid','$hashedPwd');";
                    mysqli_query($conn, $sql);
                    header("Location: ../signup.php?signup=success");
                    exit();
                }
            }       
        }
    }
} else {
    header("Location: ../signup.php");
    exit();
}
}   

当我仅执行php脚本时，也会出现以下错误消息

解析错误：语法错误，意外的';' 在第17行的C：\\ xampp \\ htdocs \\ signup.php中

Answer 1

您在这里有几个错误：

• 您在检查空变量时的if语句有额外的(开头
• if else您if else缺失的括号，那么创建它们时需要小心。 我建议使用具有PHPSyntaxChecker扩展功能的IDE（如PhpStorm或文本编辑器（如Sublime Text

我已经对您的代码进行了一些修复，因此它没有语法问题，但是您必须检查逻辑，我建议开始对mysql查询使用Prepared Statements以为您的应用程序增加安全性。

    if(isset($POST['submit'])){

        include_once 'dbh.php';

        $first = mysqli_real_escape_string($conn, $POST)['first'];
        $last = mysqli_real_escape_string($conn, $POST)['last'];
        $email = mysqli_real_escape_string($conn, $POST)['email'];
        $uid = mysqli_real_escape_string($conn, $POST)['uid'];
        $pwd = mysqli_real_escape_string($conn, $POST)['pwd'];

        //Error handlers
        //Check for empty fields

        if(empty($first) || empty($last) || empty($email) || empty($uid) || empty($pwd)){
            header("signup.php?signup=empty");
            exit();
        }else {
            //Check if input characters are valid
            if(!preg_match("/^[a-zA-Z]*$/", $first)|| !preg_match("/^[a-zA-Z]*$/", $last)){
                header("Location: ../signup.php?signup=invalid");
                exit();
            }else{
                //Check if email is valid
                if(!filter_var($email, FILTER_VALIDATE_EMAIL)){
                    header("Location: ../signup.php?signup=email");
                    exit();
                }else{
                    $sql = "SELECT * FROM users where user_uid='$uid'";
                    $result = mysqli_query($conn, $sql);
                    $resultCheck = mysqli_num_rows($result);

                    if ($resultCheck > 0) {
                        header("Location: ../signup.php?signup=usertaken");
                        exit();
                    }else {
                        //hashing the password
                        $hashedPwd = password_hash($pwd, PASSWORD_DEFAULT);

                    //Insert the user into the database
                        $sql = "INSERT INTO users (user_first, user_last, user_email, user_uid, user_pwd) VALUES(
                        '$first', '$last','$email','$uid','$hashedPwd');";
                        mysqli_query($conn, $sql);
                        header("Location: ../signup.php?signup=success");
                        exit();
                    }
                }    
            }
        }
    } else {
        header("Location: ../signup.php");
        exit();
    }

Answer 2

存在语法错误。 在所有空白功能之前，您必须有一个额外的方括号。

应该像

if(empty($first)||empty($last)||empty($email)||empty($uid)||empty($pwd)){
    header("Location: ../signup.php?signup=empty");
    exit();     
}

Answer 3

  <?php

    if(isset($POST['submit'])){

        include_once 'dbh.php';

        $first = mysqli_real_escape_string($conn, $POST)['first'];
        $last = mysqli_real_escape_string($conn, $POST)['last'];
        $email = mysqli_real_escape_string($conn, $POST)['email'];
        $uid = mysqli_real_escape_string($conn, $POST)['uid'];
        $pwd = mysqli_real_escape_string($conn, $POST)['pwd'];

        //Error handlers
        //Check for empty fields

        if(empty($first)||empty($last)||empty($email)||empty($uid)||empty($pwd)) {
            header("signup.php?signup=empty");
            exit();     
        }else {
            //Check if input characters are valid
            if(!preg_match("/^[a-zA-Z]*$/", $first)||(!preg_match("/^[a-zA-Z]*$/", $last)))
            {
                header("Location: ../signup.php?signup=invalid");
                exit();
            }else{
                //Check if email is valid
                if(!filter_var($email, FILTER_VALIDATE_EMAIL)){
                    header("Location: ../signup.php?signup=email");
                    exit();
                }
                else{
                    $sql = "SELECT * FROM users where user_uid='$uid'";
                    $result = mysqli_query($conn, $sql);
                    $resultCheck = mysqli_num_rows($result);

                    if ($resultCheck > 0) {
                        header("Location: ../signup.php?signup=usertaken");
                        exit();
                    } else {
                        //hashing the password
                        $hashedPwd = password_hash($pwd, PASSWORD_DEFAULT);

                        //Insert the user into the database
                        $sql = "INSERT INTO users (user_first, user_last, user_email, user_uid, user_pwd) 
                        VALUES('$first', '$last','$email','$uid','$hashedPwd');";
                        mysqli_query($conn, $sql);
                        header("Location: ../signup.php?signup=success");
                        exit();
                    }
                }       
            }
        }
    }