聊一聊 各類驗證郵件地址的正則表達式

用正則表達式驗證郵件地址彷佛是一件簡單的事情，可是若是要完美的驗證一個合規的郵件地址，其實也許很複雜。郵件地址的規範來自於 RFC 5322 。

 

郵件地址的規範來自於 RFC 5322 。有一個網站 emailregex.com 專門列出各類編程語言下的驗證郵件地址的正則表達式，其中不少正則表達式都是我據說過而從未見過的複雜——我想說，作這個網站的程序員是被郵件驗證這件事傷害了多深啊！

其實，在產品環境中，通常來講並不須要這麼複雜的正則表達式來作到99.99%正確。通常來講，從執行效率和測試覆蓋率來講，只須要一個簡單的版本便可：

/^[A-Z0-9._%+-]+@[A-Z0-9.-]+/.[A-Z]{2,4}$/i

那麼下面咱們來看看這些更嚴謹、更復雜的正則表達式吧：

驗證郵件地址的通用正則表達式（符合 RFC 5322 標準）

(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:/.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[/x01-/x08/x0b/x0c/x0e-/x1f/x21/x23-/x5b/x5d-/x7f]|//[/x01-/x09/x0b/x0c/x0e-/x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?/.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|/[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)/.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[/x01-/x08/x0b/x0c/x0e-/x1f/x21-/x5a/x53-/x7f]|//[/x01-/x09/x0b/x0c/x0e-/x7f])+)/])

因爲各類語言對正則表達式的支持不一樣、語法差別和覆蓋率不一樣，因此，不一樣語言裏面的正則表達式也不一樣：

Python

這個是個簡單的版本：

r"(^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+/.[a-zA-Z0-9-.]+$)"

Javascript

這個有點複雜了：

/^[-a-z0-9~!$%^&*_=+}{/'?]+(/.[-a-z0-9~!$%^&*_=+}{/'?]+)*@([a-z0-9_][-a-z0-9_]*(/.[-a-z0-9_]+)*/.(aero|arpa|biz|com|coop|edu|gov|info|int|mil|museum|name|net|org|pro|travel|mobi|[a-z][a-z])|([0-9]{1,3}/.[0-9]{1,3}/.[0-9]{1,3}/.[0-9]{1,3}))(:[0-9]{1,5})?$/i

Swift

[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+//.[A-Za-z]{2,6}

PHP

PHP 的這個版本就更復雜了，覆蓋率就更大一些：

/^(?!(?:(?:/x22?/x5C[/x00-/x7E]/x22?)|(?:/x22?[^/x5C/x22]/x22?)){255,})(?!(?:(?:/x22?/x5C[/x00-/x7E]/x22?)|(?:/x22?[^/x5C/x22]/x22?)){65,}@)(?:(?:[/x21/x23-/x27/x2A/x2B/x2D/x2F-/x39/x3D/x3F/x5E-/x7E]+)|(?:/x22(?:[/x01-/x08/x0B/x0C/x0E-/x1F/x21/x23-/x5B/x5D-/x7F]|(?:/x5C[/x00-/x7F]))*/x22))(?:/.(?:(?:[/x21/x23-/x27/x2A/x2B/x2D/x2F-/x39/x3D/x3F/x5E-/x7E]+)|(?:/x22(?:[/x01-/x08/x0B/x0C/x0E-/x1F/x21/x23-/x5B/x5D-/x7F]|(?:/x5C[/x00-/x7F]))*/x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-[a-z0-9]+)*/.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-[a-z0-9]+)*)|(?:/[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:/]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:/.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))/]))$/iD

Perl / Ruby

對與 PHP 的版本，Perl 和 Ruby 表示不服，能夠更嚴謹：

(?:(?:/r/n)?[ /t])*(?:(?:(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[/t]))*"(?:(?:/r/n)?[ /t])*))*@(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*|(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)*/<(?:(?:/r/n)?[ /t])*(?:@(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[/t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*(?:,@(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[/t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*)*:(?:(?:/r/n)?[ /t])*)?(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*))*@(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*/>(?:(?:/r/n)?[ /t])*)|(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)*:(?:(?:/r/n)?[ /t])*(?:(?:(?:[^()<>@,;://"./[/]/000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*))*@(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*|(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)*/<(?:(?:/r/n)?[ /t])*(?:@(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*(?:,@(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/]/000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*)*:(?:(?:/r/n)?[ /t])*)?(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*))*@(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*/>(?:(?:/r/n)?[ /t])*)(?:,/s*(?:(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*))*@(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*|(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)*/<(?:(?:/r/n)?[ /t])*(?:@(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*(?:,@(?:(?:/r/n)?[/t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*)*:(?:(?:/r/n)?[ /t])*)?(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|"(?:[^/"/r//]|//.|(?:(?:/r/n)?[ /t]))*"(?:(?:/r/n)?[ /t])*))*@(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*)(?:/.(?:(?:/r/n)?[ /t])*(?:[^()<>@,;://"./[/] /000-/031]+(?:(?:(?:/r/n)?[ /t])+|/Z|(?=[/["()<>@,;://"./[/]]))|/[([^/[/]/r//]|//.)*/](?:(?:/r/n)?[ /t])*))*/>(?:(?:/r/n)?[ /t])*))*)?;/s

Perl 5.10 及之後版本

上面的版本，嗯，我能夠說是天書嗎？反正我是沒有解讀的想法了。固然，新版本的 Perl 語言還有一個更易讀的版本（你是說真的麼？）

/(?(DEFINE)
(?<address> (?&mailbox) | (?&group))
(?<mailbox> (?&name_addr) | (?&addr_spec))
(?<name_addr> (?&display_name)? (?&angle_addr))
(?<angle_addr> (?&CFWS)? < (?&addr_spec) > (?&CFWS)?)
(?<group> (?&display_name) : (?:(?&mailbox_list) | (?&CFWS))? ;
(?&CFWS)?)
(?<display_name> (?&phrase))
(?<mailbox_list> (?&mailbox) (?: , (?&mailbox))*)

(?<addr_spec> (?&local_part) /@ (?&domain))
(?<local_part> (?&dot_atom) | (?&quoted_string))
(?<domain> (?&dot_atom) | (?&domain_literal))
(?<domain_literal> (?&CFWS)? /[ (?: (?&FWS)? (?&dcontent))* (?&FWS)?
/] (?&CFWS)?)
(?<dcontent> (?&dtext) | (?&quoted_pair))
(?<dtext> (?&NO_WS_CTL) | [/x21-/x5a/x5e-/x7e])

(?<atext> (?&ALPHA) | (?&DIGIT) | [!#/$%&'*+-/=?^_`{|}~])
(?<atom> (?&CFWS)? (?&atext)+ (?&CFWS)?)
(?<dot_atom> (?&CFWS)? (?&dot_atom_text) (?&CFWS)?)
(?<dot_atom_text> (?&atext)+ (?: /. (?&atext)+)*)

(?<text> [/x01-/x09/x0b/x0c/x0e-/x7f])
(?<quoted_pair> // (?&text))

(?<qtext> (?&NO_WS_CTL) | [/x21/x23-/x5b/x5d-/x7e])
(?<qcontent> (?&qtext) | (?&quoted_pair))
(?<quoted_string> (?&CFWS)? (?&DQUOTE) (?:(?&FWS)? (?&qcontent))*
(?&FWS)? (?&DQUOTE) (?&CFWS)?)

(?<word> (?&atom) | (?&quoted_string))
(?<phrase> (?&word)+)

# Folding white space
(?<FWS> (?: (?&WSP)* (?&CRLF))? (?&WSP)+)
(?<ctext> (?&NO_WS_CTL) | [/x21-/x27/x2a-/x5b/x5d-/x7e])
(?<ccontent> (?&ctext) | (?&quoted_pair) | (?&comment))
(?<comment> /( (?: (?&FWS)? (?&ccontent))* (?&FWS)? /) )
(?<CFWS> (?: (?&FWS)? (?&comment))*
(?: (?:(?&FWS)? (?&comment)) | (?&FWS)))

# No whitespace control
(?<NO_WS_CTL> [/x01-/x08/x0b/x0c/x0e-/x1f/x7f])

(?<ALPHA> [A-Za-z])
(?<DIGIT> [0-9])
(?<CRLF> /x0d /x0a)
(?<DQUOTE> ")
(?<WSP> [/x20/x09])
)

(?&address)/x

Ruby (簡單版)

Ruby 表示，其實人家還有個簡單版本：

//A([/w+/-].?)+@[a-z/d/-]+(/.[a-z]+)*/.[a-z]+/z/i

.NET

這樣的版本誰沒有啊——.NET 說：

^/w+([-+.']/w+)*@/w+([-.]/w+)*/./w+([-.]/w+)*$

grep 命令

用 grep 命令在文件中查找郵件地址，我想你不會寫個若干行的正則表達式吧，意思一下就好了：

$ grep -E -o "/b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+/.[A-Za-z]{2,6}/b" filename.txt

SQL Server

在 SQL Server 中也是能夠用正則表達式的，不過這個代碼片斷應該是來自某個產品環境中的，因此，還體貼的照顧了那些把郵件地址寫錯的人：

select email 
 from table_name where 
 patindex ('%[ &'',":;!+=//()<>]%', email) > 0 -- Invalid characters
 or patindex ('[@.-_]%', email) > 0 -- Valid but cannot be starting character
 or patindex ('%[@.-_]', email) > 0 -- Valid but cannot be ending character
 or email not like '%@%.%' -- Must contain at least one @ and one .
 or email like '%..%' -- Cannot have two periods in a row
 or email like '%@%@%' -- Cannot have two @ anywhere
 or email like '%.@%' or email like '%@.%' -- Cannot have @ and . next to each other
 or email like '%.cm' or email like '%.co' -- Camaroon or Colombia? Typos. 
 or email like '%.or' or email like '%.ne' -- Missing last letter

Oracle PL/SQL

這個是否是有點偷懶？尤爲是在那些「複雜」的正則表達式以後：

SELECT email 
FROM table_name
WHERE REGEXP_LIKE (email, '[A-Z0-9._%-]+@[A-Z0-9._%-]+/.[A-Z]{2,4}');

MySQL

好吧，看來最後也同樣懶：

SELECT * FROM `users` WHERE `email` NOT REGEXP '^[A-Z0-9._%-]+@[A-Z0-9.-]+/.[A-Z]{2,4}$';

那麼，你有沒有關於驗證郵件地址的正則表達式分享給你們？