Re: email validation regex

bruce wrote:

hi.. looking for a good/working/tested php email validation regex that conforms to the rfc2822 standard. a lot of what i've seen from google breaks, or doesn't follow the standard! any ideas/thoughts/sample code/etc...

I use this code to build the regex $tld='[a-z]{2,}'; $regexp='^([_a-z0-9-]+)(\.[_a-z0-9-]+)*'. '@([a-z0-9-]+)(\.[a-z0-9-]+)*(\.'.$tld.')$'; And test it like this: /* BEGIN PHP code*/ if (eregi($regexp, $email)) { list($username,$domaintld) = split("@",$email); // Validate domain if (getmxrr($domaintld,$mxrecords)) { $valid = true; /*print("Domain: $domaintld<br />"); foreach($mxrecords as $mxKey => $mxValue) print("&nbsp;&nbsp;$mxValue<br />");*/ } else { if (checkdnsrr($domaintld, "any")) $valid=true; else $errors.="The domain ('$domaintld') is invalid.". " Please check the email.<br />"; } } else { $errors.="The email ('$email') isn't valid.<br />"; $valid = false; } /* END PHP code*/ I used to get TLD list from http://data.iana.org/TLD/tlds-alpha-by-domain.txt Replacing the above TLD with /*$tld = '(AC|AD|AE|AERO|AF|AG|AI|AL|AM|AN|AO|AQ|AR|ARPA|AS|AT|AU|AW|AZ|'. 'BA|BB|BD|BE|BF|BG|BH|BI|BIZ|BJ|BM|BN|BO|BR|BS|BT|BV|BW|BY|BZ|CA|CC|'. 'CD|CF|CG|CH|CI|CK|CL|CM|CN|CO|COM|COOP|CR|CU|CV|CX|CY|CZ|DE|DJ|DK|DM'. '|DO|DZ|EC|EDU|EE|EG|ER|ES|ET|EU|FI|FJ|FK|FM|FO|FR|GA|GB|GD|GE|GF|GG|GH|'. 'GI|GL|GM|GN|GOV|GP|GQ|GR|GS|GT|GU|GW|GY|HK|HM|HN|HR|HT|HU|ID|IE|IL|'. 'IM|IN|INFO|INT|IO|IQ|IR|IS|IT|JE|JM|JO|JP|KE|KG|KH|KI|KM|KN|KR|KW|KY'. '|KZ|LA|LB|LC|LI|LK|LR|LS|LT|LU|LV|LY|MA|MC|MD|MG|MH|MIL|MK|ML|MM|MN|'. 'MO|MP|MQ|MR|MS|MT|MU|MUSEUM|MV|MW|MX|MY|MZ|NA|NAME|NC|NE|NET|NF|NG|'. 'NI|NL|NO|NP|NR|NU|NZ|OM|ORG|PA|PE|PF|PG|PH|PK|PL|PM|PN|PR|PRO|PS|PT|'. 'PW|PY|QA|RE|RO|RU|RW|SA|SB|SC|SD|SE|SG|SH|SI|SJ|SK|SL|SM|SN|SO|SR|ST'. '|SU|SV|SY|SZ|TC|TD|TF|TG|TH|TJ|TK|TL|TM|TN|TO|TP|TR|TT|TV|TW|TZ|UA|'. 'UG|UK|UM|US|UY|UZ|VA|VC|VE|VG|VI|VN|VU|WF|WS|YE|YT|YU|ZA|ZM|ZW)'; */ But as I check if the email domain part is exists, this is not needed. This is fairly good, and is adapted from a page that i don't have here the reference. I think that it is RFC compatible in the regex, cause I remember to see it to build the regex. The domain check code is adapted as the in the original code it only checks for MX records, but in the RFC says that if no MX records exist (where he should deliver), try to deliver to the machine, e.g., if no mail.isp.com MX records exist, try to deliver the message to the mail.isp.com machine (with SMTP, obviously). PS: your Perl solution can be good, but I think that there exist PHP classes that do it, but I don't know one. -- Nuno Pereira