check_email_address('test@example.org')) { // Email address is technically valid } */ class EmailAddressValidator { /** * Check email address validity * @param strEmailAddress Email address to be checked * @return True if email is valid, false if not */ public function check_email_address($strEmailAddress) { // If magic quotes is "on", email addresses with quote marks will // fail validation because of added escape characters. Uncommenting // the next three lines will allow for this issue. //if (get_magic_quotes_gpc()) { // $strEmailAddress = stripslashes($strEmailAddress); //} // Control characters are not allowed if (preg_match('/[\x00-\x1F\x7F-\xFF]/', $strEmailAddress)) { return false; } // Split it into sections using last instance of "@" $intAtSymbol = strrpos($strEmailAddress, '@'); if ($intAtSymbol === false) { // No "@" symbol in email. return false; } $arrEmailAddress[0] = substr($strEmailAddress, 0, $intAtSymbol); $arrEmailAddress[1] = substr($strEmailAddress, $intAtSymbol + 1); // Count the "@" symbols. Only one is allowed, except where // contained in quote marks in the local part. Quickest way to // check this is to remove anything in quotes. $arrTempAddress[0] = preg_replace('/"[^"]+"/', '', $arrEmailAddress[0]); $arrTempAddress[1] = $arrEmailAddress[1]; $strTempAddress = $arrTempAddress[0] . $arrTempAddress[1]; // Then check - should be no "@" symbols. if (strrpos($strTempAddress, '@') !== false) { // "@" symbol found return false; } // Check local portion if (!$this->check_local_portion($arrEmailAddress[0])) { return false; } // Check domain portion if (!$this->check_domain_portion($arrEmailAddress[1])) { return false; } // If we're still here, all checks above passed. Email is valid. return true; } /** * Checks email section before "@" symbol for validity * @param strLocalPortion Text to be checked * @return True if local portion is valid, false if not */ protected function check_local_portion($strLocalPortion) { // Local portion can only be from 1 to 64 characters, inclusive. // Please note that servers are encouraged to accept longer local // parts than 64 characters. if (!$this->check_text_length($strLocalPortion, 1, 64)) { return false; } // Local portion must be: // 1) a dot-atom (strings separated by periods) // 2) a quoted string // 3) an obsolete format string (combination of the above) $arrLocalPortion = explode('.', $strLocalPortion); for ($i = 0, $max = sizeof($arrLocalPortion); $i < $max; $i++) { if (!preg_match('.^(' . '([A-Za-z0-9!#$%&\'*+/=?^_`{|}~-]' . '[A-Za-z0-9!#$%&\'*+/=?^_`{|}~-]{0,63})' .'|' . '("[^\\\"]{0,62}")' .')$.', $arrLocalPortion[$i])) { return false; } } return true; } /** * Checks email section after "@" symbol for validity * @param strDomainPortion Text to be checked * @return True if domain portion is valid, false if not */ protected function check_domain_portion($strDomainPortion) { // Total domain can only be from 1 to 255 characters, inclusive if (!$this->check_text_length($strDomainPortion, 1, 255)) { return false; } // Check if domain is IP, possibly enclosed in square brackets. if (preg_match('/^(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])' .'(\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])){3}$/', $strDomainPortion) || preg_match('/^\[(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])' .'(\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])){3}\]$/', $strDomainPortion)) { return true; } else { $arrDomainPortion = explode('.', $strDomainPortion); if (sizeof($arrDomainPortion) < 2) { return false; // Not enough parts to domain } for ($i = 0, $max = sizeof($arrDomainPortion); $i < $max; $i++) { // Each portion must be between 1 and 63 characters, inclusive if (!$this->check_text_length($arrDomainPortion[$i], 1, 63)) { return false; } if (!preg_match('/^(([A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])|' .'([A-Za-z0-9]+))$/', $arrDomainPortion[$i])) { return false; } } } return true; } /** * Check given text length is between defined bounds * @param strText Text to be checked * @param intMinimum Minimum acceptable length * @param intMaximum Maximum acceptable length * @return True if string is within bounds (inclusive), false if not */ protected function check_text_length($strText, $intMinimum, $intMaximum) { // Minimum and maximum are both inclusive $intTextLength = strlen($strText); if (($intTextLength < $intMinimum) || ($intTextLength > $intMaximum)) { return false; } else { return true; } } }