POST /register.php HTTP/1.1
Content-Length： 43
Content-type: application/x-www-form-urlencoded

email=xiao@hello.world&password=nihao

<?php
try {
 $email = filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL);
 if (!$email) {
  throw new Exception('Invalid email');
 }
 $password = filter_iput(INPUT_POST, 'password');
 if (!$password || mb_strlen($password) < 8) {
  throw new Exception('Password must contain 8+ characters');
 }
 //创建密码的哈希值
 $passwordHash = password_hash(
  $password,
  PASSWORD_DEFAULT,
  ['cost' => 12]
  );

 if ($passwordHash === false) {
  throw new Exception('Password hash failed');
 }

 //创建用户账户，这里是虚构的代码
 $user = new User();
 $user->email = $email;
 $user->password_hash = $passwordHash;
 $user->save();
 header('HTTP/1.1 302 Redirect');
 header('Location: /login.php');
} catch (Exception $e) {
 header('HTTP1.1 400 Bad Request');
 echo $e->getMessage();
}

POST /login.php HTTP1.1
Content-length: 43
Content-Type: application/x-www-form-urlencoded

email=xiao@hello.wordl&pasword=nihao

session_start();
try {
 $email = filter_input(INPUT_POST, 'email');
 $password = filter_iinput(INPUT_POST, 'password');

 $user = User::findByEmail($email);

 if (password_verify($password, $user->password_hash) === false) {
  throw new Exception(''Invalid password);
 }

 //如果需要的话，重新计算密码的哈希值
 $currentHasAlgorithm = PASSWORD_DEFAULT;
 $currentHashOptions = array('cost' => 15);
 $passwordNeedsRehash = password_needs_rehash(
  $user->password_hash,
  $currentHasAlgorithm,
  $currentHasOptions
 );
 if ($passwordNeedsRehash === true) {
  $user->password_hash = password_hash(
   $password,
   $currentHasAlgorithm,
   $currentHasOptions
  );

  $user->save();
 }

 $_SESSION['user_logged_in'] = 'yes';
 $_SESSION['user_email'] = $email;

 header('HTTP/1.1 302 Redirect');
 header('Location: /user-profile.php');
} catch (Exception) {
 header('HTTP/1.1 401 Unauthorized');
 echo $e->getMessage();
}