PHP email validation class
This here is the best email validation class that I've ever seen. It checks for every official requirement I know about. Unfortunetly the class can`t validate corectly email addresses from cyrillic and other non ASCII domains if they are presented in unicode but it works fine if the emails are converted to IDNA ASCII form. For example:
The validation of example@россия.рф would not work properly but example@xn--h1alffa9f.xn--p1ai is just fine.
So thanks
Cal Henderson
<?php
class EmailValidation {
#
# RFC3696 Email Parser
#
# By Cal Henderson <cal@iamcal.com>
#
# This code is dual licensed:
# CC Attribution-ShareAlike 2.5 - http://creativecommons.org/licenses/by-sa/2.5/
# GPLv3 - http://www.gnu.org/copyleft/gpl.html
#
# $Revision: 5039 $
#
##################################################################################
function email_validate($email){
####################################################################################
#
# NO-WS-CTL = %d1-8 / ; US-ASCII control characters
# %d11 / ; that do not include the
# %d12 / ; carriage return, line feed,
# %d14-31 / ; and white space characters
# %d127
# ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
# DIGIT = %x30-39
$no_ws_ctl = "[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x7f]";
$alpha = "[\\x41-\\x5a\\x61-\\x7a]";
$digit = "[\\x30-\\x39]";
$cr = "\\x0d";
$lf = "\\x0a";
$crlf = "(?:$cr$lf)";
####################################################################################
#
# obs-char = %d0-9 / %d11 / ; %d0-127 except CR and
# %d12 / %d14-127 ; LF
# obs-text = *LF *CR *(obs-char *LF *CR)
# text = %d1-9 / ; Characters excluding CR and LF
# %d11 /
# %d12 /
# %d14-127 /
# obs-text
# obs-qp = "\" (%d0-127)
# quoted-pair = ("\" text) / obs-qp
$obs_char = "[\\x00-\\x09\\x0b\\x0c\\x0e-\\x7f]";
$obs_text = "(?:$lf*$cr*(?:$obs_char$lf*$cr*)*)";
$text = "(?:[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f]|$obs_text)";
#
# there's an issue with the definition of 'text', since 'obs_text' can
# be blank and that allows qp's with no character after the slash. we're
# treating that as bad, so this just checks we have at least one
# (non-CRLF) character
#
$text = "(?:$lf*$cr*$obs_char$lf*$cr*)";
$obs_qp = "(?:\\x5c[\\x00-\\x7f])";
$quoted_pair = "(?:\\x5c$text|$obs_qp)";
####################################################################################
#
# obs-FWS = 1*WSP *(CRLF 1*WSP)
# FWS = ([*WSP CRLF] 1*WSP) / ; Folding white space
# obs-FWS
# ctext = NO-WS-CTL / ; Non white space controls
# %d33-39 / ; The rest of the US-ASCII
# %d42-91 / ; characters not including "(",
# %d93-126 ; ")", or "\"
# ccontent = ctext / quoted-pair / comment
# comment = "(" *([FWS] ccontent) [FWS] ")"
# CFWS = *([FWS] comment) (([FWS] comment) / FWS)
#
# note: we translate ccontent only partially to avoid an infinite loop
# instead, we'll recursively strip *nested* comments before processing
# the input. that will leave 'plain old comments' to be matched during
# the main parse.
#
$wsp = "[\\x20\\x09]";
$obs_fws = "(?:$wsp+(?:$crlf$wsp+)*)";
$fws = "(?:(?:(?:$wsp*$crlf)?$wsp+)|$obs_fws)";
$ctext = "(?:$no_ws_ctl|[\\x21-\\x27\\x2A-\\x5b\\x5d-\\x7e])";
$ccontent = "(?:$ctext|$quoted_pair)";
$comment = "(?:\\x28(?:$fws?$ccontent)*$fws?\\x29)";
$cfws = "(?:(?:$fws?$comment)*(?:$fws?$comment|$fws))";
#
# these are the rules for removing *nested* comments. we'll just detect
# outer comment and replace it with an empty comment, and recurse until
# we stop.
#
$outer_ccontent_dull = "(?:$fws?$ctext|$quoted_pair)";
$outer_ccontent_nest = "(?:$fws?$comment)";
$outer_comment = "(?:\\x28$outer_ccontent_dull*(?:$outer_ccontent_nest$outer_ccontent_dull*)+$fws?\\x29)";
####################################################################################
#
# atext = ALPHA / DIGIT / ; Any character except controls,
# "!" / "#" / ; SP, and specials.
# "$" / "%" / ; Used for atoms
# "&" / "'" /
# "*" / "+" /
# "-" / "/" /
# "=" / "?" /
# "^" / "_" /
# "`" / "{" /
# "|" / "}" /
# "~"
# atom = [CFWS] 1*atext [CFWS]
$atext = "(?:$alpha|$digit|[\\x21\\x23-\\x27\\x2a\\x2b\\x2d\\x2f\\x3d\\x3f\\x5e\\x5f\\x60\\x7b-\\x7e])";
$atom = "(?:$cfws?(?:$atext)+$cfws?)";
####################################################################################
#
# qtext = NO-WS-CTL / ; Non white space controls
# %d33 / ; The rest of the US-ASCII
# %d35-91 / ; characters not including "\"
# %d93-126 ; or the quote character
# qcontent = qtext / quoted-pair
# quoted-string = [CFWS]
# DQUOTE *([FWS] qcontent) [FWS] DQUOTE
# [CFWS]
# word = atom / quoted-string
$qtext = "(?:$no_ws_ctl|[\\x21\\x23-\\x5b\\x5d-\\x7e])";
$qcontent = "(?:$qtext|$quoted_pair)";
$quoted_string = "(?:$cfws?\\x22(?:$fws?$qcontent)*$fws?\\x22$cfws?)";
#
# changed the '*' to a '+' to require that quoted strings are not empty
#
$quoted_string = "(?:$cfws?\\x22(?:$fws?$qcontent)+$fws?\\x22$cfws?)";
$word = "(?:$atom|$quoted_string)";
####################################################################################
#
# obs-local-part = word *("." word)
# obs-domain = atom *("." atom)
$obs_local_part = "(?:$word(?:\\x2e$word)*)";
$obs_domain = "(?:$atom(?:\\x2e$atom)*)";
####################################################################################
#
# dot-atom-text = 1*atext *("." 1*atext)
# dot-atom = [CFWS] dot-atom-text [CFWS]
$dot_atom_text = "(?:$atext+(?:\\x2e$atext+)*)";
$dot_atom = "(?:$cfws?$dot_atom_text$cfws?)";
####################################################################################
#
# domain-literal = [CFWS] "[" *([FWS] dcontent) [FWS] "]" [CFWS]
# dcontent = dtext / quoted-pair
# dtext = NO-WS-CTL / ; Non white space controls
#
# %d33-90 / ; The rest of the US-ASCII
# %d94-126 ; characters not including "[",
# ; "]", or "\"
$dtext = "(?:$no_ws_ctl|[\\x21-\\x5a\\x5e-\\x7e])";
$dcontent = "(?:$dtext|$quoted_pair)";
$domain_literal = "(?:$cfws?\\x5b(?:$fws?$dcontent)*$fws?\\x5d$cfws?)";
####################################################################################
#
# local-part = dot-atom / quoted-string / obs-local-part
# domain = dot-atom / domain-literal / obs-domain
# addr-spec = local-part "@" domain
$local_part = "(($dot_atom)|($quoted_string)|($obs_local_part))";
$domain = "(($dot_atom)|($domain_literal)|($obs_domain))";
$addr_spec = "$local_part\\x40$domain";
#
# see http://www.dominicsayers.com/isemail/ for details, but this should probably be 254
#
if (strlen($email) > 256) return 0;
#
# we need to strip nested comments first - we replace them with a simple comment
#
$email = $this->rfc3696_strip_comments($outer_comment, $email, "(x)");
#
# now match what's left
#
if (!preg_match("!^$addr_spec$!", $email, $m)){
return 0;
}
$bits = array(
'local' => isset($m[1]) ? $m[1] : '',
'local-atom' => isset($m[2]) ? $m[2] : '',
'local-quoted' => isset($m[3]) ? $m[3] : '',
'local-obs' => isset($m[4]) ? $m[4] : '',
'domain' => isset($m[5]) ? $m[5] : '',
'domain-atom' => isset($m[6]) ? $m[6] : '',
'domain-literal' => isset($m[7]) ? $m[7] : '',
'domain-obs' => isset($m[8]) ? $m[8] : '',
);
#
# we need to now strip comments from $bits[local] and $bits[domain],
# since we know they're i the right place and we want them out of the
# way for checking IPs, label sizes, etc
#
$bits['local'] = $this->rfc3696_strip_comments($comment, $bits['local']);
$bits['domain'] = $this->rfc3696_strip_comments($comment, $bits['domain']);
#
# length limits on segments
#
if (strlen($bits['local']) > 64) return 0;
if (strlen($bits['domain']) > 255) return 0;
#
# restrictuions on domain-literals from RFC2821 section 4.1.3
#
if (strlen($bits['domain-literal'])){
$Snum = "(\d{1,3})";
$IPv4_address_literal = "$Snum\.$Snum\.$Snum\.$Snum";
$IPv6_hex = "(?:[0-9a-fA-F]{1,4})";
$IPv6_full = "IPv6\:$IPv6_hex(:?\:$IPv6_hex){7}";
$IPv6_comp_part = "(?:$IPv6_hex(?:\:$IPv6_hex){0,5})?";
$IPv6_comp = "IPv6\:($IPv6_comp_part\:\:$IPv6_comp_part)";
$IPv6v4_full = "IPv6\:$IPv6_hex(?:\:$IPv6_hex){5}\:$IPv4_address_literal";
$IPv6v4_comp_part = "$IPv6_hex(?:\:$IPv6_hex){0,3}";
$IPv6v4_comp = "IPv6\:((?:$IPv6v4_comp_part)?\:\:(?:$IPv6v4_comp_part\:)?)$IPv4_address_literal";
#
# IPv4 is simple
#
if (preg_match("!^\[$IPv4_address_literal\]$!", $bits['domain'], $m)){
if (intval($m[1]) > 255) return 0;
if (intval($m[2]) > 255) return 0;
if (intval($m[3]) > 255) return 0;
if (intval($m[4]) > 255) return 0;
}else{
#
# this should be IPv6 - a bunch of tests are needed here :)
#
while (1){
if (preg_match("!^\[$IPv6_full\]$!", $bits['domain'])){
break;
}
if (preg_match("!^\[$IPv6_comp\]$!", $bits['domain'], $m)){
list($a, $b) = explode('::', $m[1]);
$folded = (strlen($a) && strlen($b)) ? "$a:$b" : "$a$b";
$groups = explode(':', $folded);
if (count($groups) > 6) return 0;
break;
}
if (preg_match("!^\[$IPv6v4_full\]$!", $bits['domain'], $m)){
if (intval($m[1]) > 255) return 0;
if (intval($m[2]) > 255) return 0;
if (intval($m[3]) > 255) return 0;
if (intval($m[4]) > 255) return 0;
break;
}
if (preg_match("!^\[$IPv6v4_comp\]$!", $bits['domain'], $m)){
list($a, $b) = explode('::', $m[1]);
$b = substr($b, 0, -1); # remove the trailing colon before the IPv4 address
$folded = (strlen($a) && strlen($b)) ? "$a:$b" : "$a$b";
$groups = explode(':', $folded);
if (count($groups) > 4) return 0;
break;
}
return 0;
}
}
}else{
#
# the domain is either dot-atom or obs-domain - either way, it's
# made up of simple labels and we split on dots
#
$labels = explode('.', $bits['domain']);
#
# this is allowed by both dot-atom and obs-domain, but is un-routeable on the
# public internet, so we'll fail it (e.g. user@localhost)
#
if (count($labels) == 1) return 0;
#
# checks on each label
#
foreach ($labels as $label){
if (strlen($label) > 63) return 0;
if (substr($label, 0, 1) == '-') return 0;
if (substr($label, -1) == '-') return 0;
}
#
# last label can't be all numeric
#
if (preg_match('!^[0-9]+$!', array_pop($labels))) return 0;
}
return 1;
}
##################################################################################
function rfc3696_strip_comments($comment, $email, $replace=''){
while (1){
$new = preg_replace("!$comment!", $replace, $email);
if (strlen($new) == strlen($email)){
return $email;
}
$email = $new;
}
}
##################################################################################
}
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