Re: Email Verfication Regular Expression

# bnichols(at)ca(dot)afilias(dot)info / 2005-09-07 11:17:10 -0400:
> Does anybody have regular expression handy to verfiy email addresses?

This is what I have. The comment notes the caveats.

-- CREATE FUNCTION IS_EMAILADDRESS {{{
-- returns TRUE if $1 matches the rules for RFC2822 addr-spec token,
-- ignoring CFWS in atoms, obs- versions of everything, !dot-atom
-- versions of local-part, and quoted-pairs in domain-literal (IOW,
-- this function doesn't allow backslashes after the "@")
-- FIXME: locale-dependent (relies on ranges [x-y])
/*
atext = ALPHA / DIGIT / ; Any character except controls,
"!" / "#" / ; SP, and specials.
"$" / "%" / ; Used for atoms
"&" / "'" /
"*" / "+" /
"-" / "/" /
"=" / "?" /
"^" / "_" /
"`" / "{" /
"|" / "}" /
"~"
dot-atom-text = 1*atext *("." 1*atext)
dot-atom = [CFWS] dot-atom-text [CFWS]
addr-spec = local-part "@" domain
local-part = dot-atom / quoted-string / obs-local-part
domain = dot-atom / domain-literal / obs-domain
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 "\"
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
*/
CREATE OR REPLACE FUNCTION IS_EMAILADDRESS(VARCHAR)
RETURNS BOOL
IMMUTABLE
RETURNS NULL ON NULL INPUT
LANGUAGE plpgsql
AS '
BEGIN
RETURN $1 ~ ''(?x) # this is an ARE
# local-part dot-atom-text (1*atext)
^[-!#$%&''''*+/=?^_`{|}~[:alnum:]]+
# local-part dot-atom-text (*("." 1*atext))
(?:\.[-!#$%&''''*+/=?^_`{|}~[:alnum:]]+)*
# literal "@"
@
(?:
# domain (dom-atom or domain-literal)
(?:
# domain dot-atom (1*atext)
[-!#$%&''''*+/=?^_`{|}~[:alnum:]]+
# domain dot-atom (*("." 1*atext))
\.[-!#$%&''''*+/=?^_`{|}~[:alnum:]]+
)*
|
# domain domain-literal ("[")
[[]
# domain domain-literal (dcontent)
# ^@ - ^H ^K ^L ^N ^_ "!" - "Z" "^" - DEL
[\\\\x01-\\\\x08\\\\x0B\\\\x0C\\\\x0E-\\\\x1F\\\\x21-\\\\x5A\\\\x5E-\\\\x7F]*
# domain domain-literal ("]")
[]]
)
$'';
END;
';
-- }}}

-- CREATE DOMAIN emailaddrspec {{{
CREATE DOMAIN emailaddrspec AS VARCHAR
CONSTRAINT dom_emailaddrspec CHECK (
VALUE = ''
OR IS_EMAILADDRESS(VALUE)
);
-- }}}

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