#
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
Validate E-mail Address with PHP the Right Way
Listing 1: Shows an example code that contains 3 errors. First, it fails to recognize many valid e-mail address characters, such as %. Secondly, it splits the e-mail address into username and domain parts at the sign @. E-mail addresses that contain a quoted @ sign, such as koko@koko@domain.com will break this code. Lastly, it fails to check for host address DNS records.
function validateEmail($email_add) {
if (preg_match(”/^([a-zA-Z0-9])+([a-zA-Z0-9._-])*@([a-zA-Z0-9_-])+( [a-zA-Z0-9._-]+)+$/”, $email_add))
{
list ($username, $domain)=split(‘@’,$email_add);
if (!checkdnsrr($domain, ‘MX’)) {
return false;
}
return true;
}
return false;
}
Listing 2: Shows a better way to develop an E-mail validator as it satisfy the following requirements:
-An e-mail address consists of local part and domain seperated by an at sign (@) character (RFC 2822 3.4.1)/
-The local part may consist of alphabet and numeric characters, and the following characters: !#$%&’*+-/=?^_`{|}~, possibly with dot seperators (.), inside, but not at the start, end or next to another dot seperator (RFC 2822 3.2.4)
-The local part may consist of a quoted string - i.e. anything within quotes (”), including spaces (RFC 2822 3.2.5)
-Quoted pairs (such as @) are valid components of a local part, though an obsolete form from RFC 822 (RFC 2822 4.4)
-The maximum length of a local part is 64 characters (RFC 2821 4.5.3.1)
-A domain consists of labels seperated by dot seperators (RFC 1035 2.3.1)
-Domain labels start with an alphabet character followed by 0 or more alphabet characters, numeric characters or hyphen (-), ending with an alphabetic or numeric character (RFC 1035 2.3.1)
-The maximum length of a label is 63 characters (RFC 1035 2.3.1)
-The maximum lenght of a domain is 255 characters (RFC 2821 4.5.3.1)
-The domain must be fully qualified and resolvable to a type A or type MX DNS address record (RFC 2821 3.6)
function validateEmail($email_add) {
$isValid = true;
$atIndex = strrpos($email_add, “@”);
if (is_bool($atIndex) && !$atIndex) {
$isValid = false;
}
else {
$domain = substr($email_add, $atIndex+1);
$local = substr($email_add, 0, $atIndex);
$localLen = strlen($local);
$domainLen = strlen($domain);
if ($localLen 64) {
$isValid = false; // local part lenght exceeded
}
else if ($domainLen 255) {
$isValid = false; // domain part lenght exceeded
}
else if ($local[0] == ‘.’ || $local[$localLen-1] == ‘.’) {
$isValid = false; // local part starts or ends with ‘.’
}
else if (preg_match(’/../’, $local)) {
$isValid = false; // local part has 2 consecutive dots
}
else if (!preg_match(’/^[A-Za-z0-9-.]+$/’, $domain)) {
$isValid = false; // character not valid in domain part
}
else if (preg_match(’/../’, $domain)) {
$isValid = false; // domain part has 2 consecutive dots
}
else if (!preg_match(’/^(.|[A-Za-z0-9!#%&`_=/$’*+?^{}|~.-])+$/’ . str_replace(””.”",$local))) {
if (!preg_match(’/^”(”|[^”])+”$/’, $str_replace(””,”", $local))) {
$isValid = false; //character not valid in local part unless local part is quoted
}
}
if ($isValid && !(checkdnsrr($domain, “MX”) || checkdnsrr($domain, “A”))) {
$isValid = false; // domain not found in DNS
}
}
return $isValid;
}
#
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
y
z
|
|
 | ImVajra Password Manager | 
ImVajra Password
Manager is an
outstanding
password manager to
store accounts,
passwords, logins,
cr... |
| iOrgSoft MOV Converter | 
The best MOV
Converter designed
for Video
fans.
iOrgSo
ft MOV Converter is
a powerful Video Co... |
| iOrgSoft AVI Converter | 
The best AVI
Converter designed
for Video
fans.
iOrgSo
ft AVI Converter is
an easy-to-use vide... |
| MP3 File Renamer | 
MP3 File Renamer:
How to Rename MP3
Files - easily? You
need MP3 File
Renamer.
This
automa... |
| iOrgSoft FLV Converter | 
The best FLV
Converter designed
for Flash Video
fans.
iOrgSo
ft FLV Converter is
a perfect sol... |
|
You can get our free e-mail newsletter that highlights the latest software news and updates enter your email address and hit OK.
|
|
|
|
