请帮助，初学者在php努力将数据库连接到我的项目[重复]

Question

This question already has an answer here:

• PHP parse/syntax errors; and how to solve them? 17 answers

I'm working on a login system and I keep getting this error

"The requested URL was not found on this server. The link on the referring page seems to be wrong or outdated. Please inform the author of that page about the error. If you think this is a server error, please contact the webmaster."

when I execute the code below:

<?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();
}
}   

the below error message comes up also when I execute just the php script

Parse error: syntax error, unexpected ';' in C:\xampp\htdocs\signup.php on line 17

</div>

Answer 1

You have several errors here:

• Your if statement when you check for empty variables have extra ( at the begining
• Your if else have some missing brackets so you need to be careful when you create them. I would suggest to use an IDE like PhpStorm or text editor like Sublime Text with PHPSyntaxChecker extention

I have made some fixes to your code so it doesn't have syntax problems but you must check the logic and I would suggest to start using Prepared Statements for mysql queries to add more security to you application.

    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();
    }