PHP FILTER_VALIDATE_EMAIL 无法正常工作

Posted 2023-02-22

【中文标题】PHP FILTER_VALIDATE_EMAIL 无法正常工作

【英文标题】：PHP FILTER_VALIDATE_EMAIL does not work correctly

【发布时间】：2013-10-13 18:00:14

【问题描述】：

我使用的是 php 5.3.10。这是代码：

<?php
$email = "test@example.c";
if (filter_var($email, FILTER_VALIDATE_EMAIL))
        echo "Email: ".$email." correct";
else
        echo "email not correct";
?>

它返回："Email: test@example.c 正确。

我认为只有一个字符的***域是不正确的（根据此列表，我不知道一个字符长度的 TLD：http://data.iana.org/TLD/tlds-alpha-by-domain.txt）。

那么，FILTER_VALIDATE_EMAIL 过滤器是否正常工作？

【问题讨论】：

@ 之前的第一部分不能超过 64 个字符...在我的情况下，这导致了几个小时的调试，但 FILTER_VALIDATE_EMAIL 是正确的...

【参考方案1】：

FILTER_VALIDATE_EMAIL只能告诉你地址格式是否正确。

考虑这些例子

// "not an email" is invalid so its false.
php > var_export(filter_var("not an email", FILTER_VALIDATE_EMAIL));
false
// "[e-mail]" looks like an email, so it passes even though its not real.
php > var_export(filter_var("[e-mail]", FILTER_VALIDATE_EMAIL));
'[e-mail]'
// "[e-mail]" passes, gmail is a valid email server,
//  but gmail require more than 3 letters for the address.
var_export(filter_var("[e-mail]", FILTER_VALIDATE_EMAIL));
'[e-mail]'

所以FILTER_VALIDATE_EMAIL 只擅长在完全错误的时候告诉你，而不是在正确的时候告诉你。

您将需要使用像Real Email 这样可以进行深入的电子邮件地址验证的服务。

// [e-mail] is invalid because gmail require more than 3 letters for the address.
var_export(file_get_contents("https://isitarealemail.com/api/email/validate?email=[e-mail]"));
'"status":"invalid"'

// [e-mail] is valid
var_export(file_get_contents("https://isitarealemail.com/api/email/validate?email=[e-mail]"));
'"status":"valid"'

更多信息请参见https://docs.isitarealemail.com/how-to-validate-email-addresses-in-php

【参考方案2】：

验证电子邮件地址有点复杂。 看看这个列表：

有效的电子邮件地址

[e-mail] [e-mail] [e-mail] [e-mail] user@[IPv6:2001:db8:1ff::a0b:dbd0] “非常不寻常”@example.com "very.unusual.@.unusual.com"@example.com "非常.(),:;[]".非常."非常@\ "非常".unusual"@strange.example.com postbox@com（***域是有效的主机名） admin@mailserver1（没有 TLD 的本地域名） !#$%&'*+-/=?^_`|~@example.org "()[]:,;@\"!#$%&'*+-/=?^_`| ~.a"@example.org " "@example.org（引号之间的空格） üñîçøðé​​@example.com（本地部分的 Unicode 字符）

电子邮件地址无效

Abc.example.com（@ 字符必须分隔本地和域 部分） A@b@[e-mail]（引号外只允许有一个@） a"b(c)d,e:f;gi[j\k][e-mail]（没有特殊字符 在此本地部分中允许在引号之外） just"not"[e-mail]（引用的字符串必须用点分隔，或者 构成本地部分的唯一元素） this is"not\[e-mail]（空格、引号和反斜杠可能 仅存在于带引号的字符串中并以反斜杠开头） this\ still"not\[e-mail]（即使转义（前面 反斜杠）、空格、引号和反斜杠仍然必须是 包含在引号中）

来源http://en.wikipedia.org/wiki/Email_address

几乎所有的电子邮件验证实现都是“错误的”，但 php 实现很好用，因为它接受所有常见的电子邮件地址

更新：

发现于http://www.php.net/manual/en/filter.filters.validate.php

关于没有 .在域部分，源代码中的注释（在 ext/filter/logical_filters.c 中）证明了这种拒绝：

 * The regex below is based on a regex by Michael Rushton.
 * However, it is not identical.  I changed it to only consider routeable
 * addresses as valid.  Michael's regex considers a@b a valid address
 * which conflicts with section 2.3.5 of RFC 5321 which states that:
 *
 *   Only resolvable, fully-qualified domain names (FQDNs) are permitted
 *   when domain names are used in SMTP.  In other words, names that can
 *   be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed
 *   in Section 5) are permitted, as are CNAME RRs whose targets can be
 *   resolved, in turn, to MX or address RRs.  Local nicknames or
 *   unqualified names MUST NOT be used.

这是 Michael Rushton 的课程链接（链接已断开，请参阅下面的源代码） 支持 RFC 5321/5322

<?php
  /**
   * Squiloople Framework
   *
   * LICENSE: Feel free to use and redistribute this code.
   *
   * @author Michael Rushton <[e-mail]>
   * @link http://squiloople.com/
   * @package Squiloople
   * @version 1.0
   * @copyright © 2012 Michael Rushton
   */
  /**
   * Email Address Validator
   *
   * Validate email addresses according to the relevant standards
   */
  final class EmailAddressValidator
  
    // The RFC 5321 constant
    const RFC_5321 = 5321;
    // The RFC 5322 constant
    const RFC_5322 = 5322;
    /**
     * The email address
     *
     * @access private
     * @var string $_email_address
     */
    private $_email_address;
    /**
     * A quoted string local part is either allowed (true) or not (false)
     *
     * @access private
     * @var boolean $_quoted_string
     */
    private $_quoted_string = FALSE;
    /**
     * An obsolete local part is either allowed (true) or not (false)
     *
     * @access private
     * @var boolean $_obsolete
     */
    private $_obsolete = FALSE;
    /**
     * A basic domain name is either required (true) or not (false)
     *
     * @access private
     * @var boolean $_basic_domain_name
     */
    private $_basic_domain_name = TRUE;
    /**
     * A domain literal domain is either allowed (true) or not (false)
     *
     * @access private
     * @var boolean $_domain_literal
     */
    private $_domain_literal = FALSE;
   /**
     * Comments and folding white spaces are either allowed (true) or not (false)
     *
     * @access private
     * @var boolean $_cfws
     */
    private $_cfws = FALSE;
    /**
     * Set the email address and turn on the relevant standard if required
     *
     * @access public
     * @param string $email_address
     * @param null|integer $standard
     */
    public function __construct($email_address, $standard = NULL)
    
      // Set the email address
      $this->_email_address = $email_address;
      // Set the relevant standard or throw an exception if an unknown is requested
      switch ($standard)
      
        // Do nothing if no standard requested
        case NULL:
          break;
        // Otherwise if RFC 5321 requested
        case self::RFC_5321:
          $this->setStandard5321();
          break;
        // Otherwise if RFC 5322 requested
        case self::RFC_5322:
          $this->setStandard5322();
          break;
        // Otherwise throw an exception
        default:
          throw new Exception('Unknown RFC standard for email address validation.');
      
    
    /**
     * Call the constructor fluently
     *
     * @access public
     * @static
     * @param string $email_address
     * @param null|integer $standard
     * @return EmailAddressValidator
     */
    public static function setEmailAddress($email_address, $standard = NULL)
    
      return new self($email_address, $standard);
    
    /**
     * Validate the email address using a basic standard
     *
     * @access public
     * @return EmailAddressValidator
     */
    public function setStandardBasic()
    
      // A quoted string local part is not allowed
      $this->_quoted_string = FALSE;
      // An obsolete local part is not allowed
      $this->_obsolete = FALSE;
      // A basic domain name is required
      $this->_basic_domain_name = TRUE;
      // A domain literal domain is not allowed
      $this->_domain_literal = FALSE;
      // Comments and folding white spaces are not allowed
      $this->_cfws = FALSE;
      // Return the EmailAddressValidator object
      return $this;
    
    /**
     * Validate the email address using RFC 5321
     *
     * @access public
     * @return EmailAddressValidator
     */
    public function setStandard5321()
    
      // A quoted string local part is allowed
      $this->_quoted_string = TRUE;
      // An obsolete local part is not allowed
      $this->_obsolete = FALSE;
      // Only a basic domain name is not required
      $this->_basic_domain_name = FALSE;
      // A domain literal domain is allowed
      $this->_domain_literal = TRUE;
      // Comments and folding white spaces are not allowed
      $this->_cfws = FALSE;
      // Return the EmailAddressValidator object
      return $this;
    
    /**
     * Validate the email address using RFC 5322
     *
     * @access public
     * @return EmailAddressValidator
     */
    public function setStandard5322()
    
      // A quoted string local part is disallowed
      $this->_quoted_string = FALSE;
      // An obsolete local part is allowed
      $this->_obsolete = TRUE;
      // Only a basic domain name is not required
      $this->_basic_domain_name = FALSE;
      // A domain literal domain is allowed
      $this->_domain_literal = TRUE;
      // Comments and folding white spaces are allowed
      $this->_cfws = TRUE;
      // Return the EmailAddressValidator object
      return $this;
    
    /**
     * Either allow (true) or do not allow (false) a quoted string local part
     *
     * @access public
     * @param boolean $allow
     * @return EmailAddressValidator
     */
    public function setQuotedString($allow = TRUE)
    
      // Either allow (true) or do not allow (false) a quoted string local part
      $this->_quoted_string = $allow;
      // Return the EmailAddressValidator object
      return $this;
    
    /**
     * Either allow (true) or do not allow (false) an obsolete local part
     *
     * @access public
     * @param boolean $allow
     * @return EmailAddressValidator
     */
    public function setObsolete($allow = TRUE)
    
      // Either allow (true) or do not allow (false) an obsolete local part
      $this->_obsolete = $allow;
      // Return the EmailAddressValidator object
      return $this;
    
    /**
     * Either require (true) or do not require (false) a basic domain name
     *
     * @access public
     * @param boolean $allow
     * @return EmailAddressValidator
     */
    public function setBasicDomainName($allow = TRUE)
    
      // Either require (true) or do not require (false) a basic domain name
      $this->_basic_domain_name = $allow;
      // Return the EmailAddressValidator object
      return $this;
    
    /**
     * Either allow (true) or do not allow (false) a domain literal domain
     *
     * @access public
     * @param boolean $allow
     * @return EmailAddressValidator
     */
    public function setDomainLiteral($allow = TRUE)
    
      // Either allow (true) or do not allow (false) a domain literal domain
      $this->_domain_literal = $allow;
      // Return the EmailAddressValidator object
      return $this;
    
    /**
     * Either allow (true) or do not allow (false) comments and folding white spaces
     *
     * @access public
     * @param boolean $allow
     * @return EmailAddressValidator
     */
    public function setCFWS($allow = TRUE)
    
      // Either allow (true) or do not allow (false) comments and folding white spaces
      $this->_cfws = $allow;
      // Return the EmailAddressValidator object
      return $this;
    
    /**
     * Return the regular expression for a dot atom local part
     *
     * @access private
     * @return string
     */
    private function _getDotAtom()
    
      return "([!#-'*+\/-9=?^-~-]+)(?>\.(?1))*";
    
    /**
     * Return the regular expression for a quoted string local part
     *
     * @access private
     * @return string
     */
    private function _getQuotedString()
    
      return '"(?>[ !#-\[\]-~]|\\\[ -~])*"';
    
    /**
     * Return the regular expression for an obsolete local part
     *
     * @access private
     * @return string
     */
    private function _getObsolete()
    
      return '([!#-\'*+\/-9=?^-~-]+|"(?>'
        . $this->_getFWS()
        . '(?>[\x01-\x08\x0B\x0C\x0E-!#-\[\]-\x7F]|\\\[\x00-\xFF]))*'
        . $this->_getFWS()
        . '")(?>'
        . $this->_getCFWS()
        . '\.'
        . $this->_getCFWS()
        . '(?1))*';
    
    /**
     * Return the regular expression for a domain name domain
     *
     * @access private
     * @return string
     */
    private function _getDomainName()
    
      // Return the basic domain name format if required
      if ($this->_basic_domain_name)
      
        return '(?>' . $this->_getDomainNameLengthLimit()
          . '[a-z\d](?>[a-z\d-]*[a-z\d])?'
          . $this->_getCFWS()
          . '\.'
          . $this->_getCFWS()
          . ')1,126[a-z]2,6';
      
      // Otherwise return the full domain name format
      return $this->_getDomainNameLengthLimit()
        . '([a-z\d](?>[a-z\d-]*[a-z\d])?)(?>'
        . $this->_getCFWS()
        . '\.'
        . $this->_getDomainNameLengthLimit()
        . $this->_getCFWS()
        . '(?2))0,126';
    
    /**
     * Return the regular expression for an IPv6 address
     *
     * @access private
     * @return string
     */
    private function _getIPv6()
    
      return '([a-f\d]1,4)(?>:(?3))7|(?!(?:.*[a-f\d][:\]])8,)((?3)(?>:(?3))0,6)?::(?4)?';
    
    /**
     * Return the regular expression for an IPv4-mapped IPv6 address
     *
     * @access private
     * @return string
     */
    private function _getIPv4MappedIPv6()
    
      return '(?3)(?>:(?3))5:|(?!(?:.*[a-f\d]:)6,)(?5)?::(?>((?3)(?>:(?3))0,4):)?';
    
    /**
     * Return the regular expression for an IPv4 address
     *
     * @access private
     * @return string
     */
    private function _getIPv4()
    
      return '(25[0-5]|2[0-4]\d|1\d2|[1-9]?\d)(?>\.(?6))3';
    
    /**
     * Return the regular expression for a domain literal domain
     *
     * @access private
     * @return string
     */
    private function _getDomainLiteral()
    
      return '\[(?:(?>IPv6:(?>'
        . $this->_getIPv6()
        . '))|(?>(?>IPv6:(?>'
        . $this->_getIPv4MappedIPv6()
        . '))?'
        . $this->_getIPv4()
        . '))\]';
    
    /**
     * Return either the regular expression for folding white spaces or its backreference
     *
     * @access private
     * @param boolean $define
     * @return string
     */
    private function _getFWS($define = FALSE)
    
      // Return the backreference if $define is set to FALSE otherwise return the regular expression
      if ($this->_cfws)
      
        return !$define ? '(?P>fws)' : '(?<fws>(?>(?>(?>\x0D\x0A)?[\t ])+|(?>[\t ]*\x0D\x0A)?[\t ]+)?)';
      
    
    /**
     * Return the regular expression for comments
     *
     * @access private
     * @return string
     */
    private function _getComments()
    
      return '(?<comment>\((?>'
        . $this->_getFWS()
        . '(?>[\x01-\x08\x0B\x0C\x0E-\'*-\[\]-\x7F]|\\\[\x00-\x7F]|(?P>comment)))*'
        . $this->_getFWS()
        . '\))';
    
    /**
     * Return either the regular expression for comments and folding white spaces or its backreference
     *
     * @access private
     * @param boolean $define
     * @return string
     */
    private function _getCFWS($define = FALSE)
    
      // Return the backreference if $define is set to FALSE
      if ($this->_cfws && !$define)
      
        return '(?P>cfws)';
      
      // Otherwise return the regular expression
      if ($this->_cfws)
      
        return '(?<cfws>(?>(?>(?>'
          . $this->_getFWS(TRUE)
          . $this->_getComments()
          . ')+'
          . $this->_getFWS()
          . ')|'
          . $this->_getFWS()
          . ')?)';
      
    
    /**
     * Establish and return the valid format for the local part
     *
     * @access private
     * @return string
     */
    private function _getLocalPart()
    
      // The local part may be obsolete if allowed
      if ($this->_obsolete)
      
        return $this->_getObsolete();
      
      // Otherwise the local part must be either a dot atom or a quoted string if the latter is allowed
      if ($this->_quoted_string)
      
        return '(?>' . $this->_getDotAtom() . '|' . $this->_getQuotedString() . ')';
      
      // Otherwise the local part must be a dot atom
      return $this->_getDotAtom();
    
    /**
     * Establish and return the valid format for the domain
     *
     * @access private
     * @return string
     */
    private function _getDomain()
    
      // The domain must be either a domain name or a domain literal if the latter is allowed
      if ($this->_domain_literal)
      
        return '(?>' . $this->_getDomainName() . '|' . $this->_getDomainLiteral() . ')';
      
      // Otherwise the domain must be a domain name
      return $this->_getDomainName();
    
    /**
     * Return the email address length limit
     *
     * @access private
     * @return string
     */
    private function _getEmailAddressLengthLimit()
    
      return '(?!(?>' . $this->_getCFWS() . '"?(?>\\\[ -~]|[^"])"?' . $this->_getCFWS() . ')255,)';
    
    /**
     * Return the local part length limit
     *
     * @access private
     * @return string
     */
    private function _getLocalPartLengthLimit()
    
      return '(?!(?>' . $this->_getCFWS() . '"?(?>\\\[ -~]|[^"])"?' . $this->_getCFWS() . ')65,@)';
    
    /**
     * Establish and return the domain name length limit
     *
     * @access private
     * @return string
     */
    private function _getDomainNameLengthLimit()
    
      return '(?!' . $this->_getCFWS() . '[a-z\d-]64,)';
    
    /**
     * Check to see if the domain can be resolved to MX RRs
     *
     * @access private
     * @param array $domain
     * @return integer|boolean
     */
    private function _verifyDomain($domain)
    
      // Return 0 if the domain cannot be resolved to MX RRs
      if (!checkdnsrr(end($domain), 'MX'))
      
        return 0;
      
      // Otherwise return true
      return TRUE;
    
    /**
     * Perform the validation check on the email address's syntax and, if required, call _verifyDomain()
     *
     * @access public
     * @param boolean $verify
     * @return boolean|integer
     */
    public function isValid($verify = FALSE)
    
      // Return false if the email address has an incorrect syntax
      if (!preg_match(
          '/^'
        . $this->_getEmailAddressLengthLimit()
        . $this->_getLocalPartLengthLimit()
        . $this->_getCFWS()
        . $this->_getLocalPart()
        . $this->_getCFWS()
        . '@'
        . $this->_getCFWS()
        . $this->_getDomain()
        . $this->_getCFWS(TRUE)
        . '$/isD'
        , $this->_email_address
      ))
      
        return FALSE;
      
      // Otherwise check to see if the domain can be resolved to MX RRs if required
      if ($verify)
      
        return $this->_verifyDomain(explode('@', $this->_email_address));
      
      // Otherwise return 1
      return 1;
    
  

2016 年编辑： 在 PHP 7.1 beta 中，我注意到以下内容：

根据 RFC 6531 实施电子邮件验证。（Leo Feyer，Anatol）。

参见第 3.3 节 https://www.rfc-editor.org/rfc/rfc6531#section-3.3

https://en.wikipedia.org/wiki/International_email

还有一些不错的额外示例

用户@例子.广告                 (Chinese, Unicode)
उपयोगकर्ता@उदाहरण.कॉम           (Hindi, Unicode)
юзер@екзампл.ком             (Ukrainian, Unicode)
θσερ@εχαμπλε.ψομ             (Greek, Unicode)
Dörte@Sörensen.example.com   (German, Unicode)

【讨论】：

您说： 9. postbox@com（***域是有效的主机名），但该地址上的 FILTER_VALIDATE_EMAIL 过滤器返回 false！那么，过滤器是否只接受某些电子邮件地址（包括“joe@example.c”）而不接受其他电子邮件地址（无论如何，像“postbox@com”一样有效）？这是一种奇怪的行为！

@visserSander: filter_var('"very.(),:;<>[]\".VERY.\"very@\\ \"very\".unusual"@strange.example.com',FILTER_VALIDATE_EMAIL) 被接受，但postbox@com 不被接受。我称之为错误

@aaron：我完全不同意您所说的everything：您声明PHP 实现是正确的，但官方RFC 规范不是？我是说……真的吗？！自从更新以来，我有点明白为什么a@b 被认为是无效的，尽管我不禁将其视为一个决定，至少部分是出于懒惰的动机……在一个测试环境mail('root@localhost'); 看起来不会太古怪吧？

是的，PHP 支持新的更长的顶层。但我注意到 php7.1 中的 filter_var 不认为 उपयोगकर्ता@उदाहरण.कॉम 是有效的电子邮件地址

FILTER_VALIDATE_EMAIL 不处理国际电子邮件地址。这种格式会导致错误，我几乎每天都通过电子邮件发送它。 [e-mail]

【参考方案3】：

google 代码上有一个用于验证电子邮件地址的 PHP 类：

http://code.google.com/p/php-email-address-validation

你可以像这样使用它

include('EmailAddressValidator.php');
$validator = new EmailAddressValidator;
if ($validator->check_email_address('[e-mail]'))  
    // Email address is technically valid 
 else 
    // Email not valid

【讨论】：

已弃用...坚持使用 PHP 的 php.net/manual/en/filter.filters.validate.php，它根据 RFC 822 涵盖了几乎所有用例

【参考方案4】：

我选择使用：

<?php
$email =$argv[1];$result= is_valid_email($email); echo $result;
function is_valid_email($email)  return preg_match('/^(([^<>()[\]\\.,;:\s@"\']+(\.[^<>()[\]\\.,;:\s@"\']+)*)|("[^"\']+"))@((\[\d1,3\.\d1,3\.\d1,3\.\d1,3\])|(([a-zA-Z\d\-]+\.)+[a-zA-Z]2,))$/', $email); 
?>

在我的论坛软件中 https://github.com/neofutur/MyBestBB/blob/master/include/email.php#L39

但官方是这样的： http://www.ex-parrot.com/pdw/Mail-RFC822-Address.html （也更长）

【参考方案5】：

FILTER_VALIDATE_EMAIL 不支持 PHP 5.2.14

【讨论】：

我注意到了这一点，因为它在我的机器上本地运行，但当我将代码上传到托管服务器时却没有。