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Diffstat (limited to 'includes/is_email.php')
| -rw-r--r-- | includes/is_email.php | 529 |
1 files changed, 529 insertions, 0 deletions
diff --git a/includes/is_email.php b/includes/is_email.php new file mode 100644 index 0000000..3a29fbb --- /dev/null +++ b/includes/is_email.php @@ -0,0 +1,529 @@ +<?php
+/**
+ * To validate an email address according to RFCs 5321, 5322 and others
+ *
+ * Copyright © 2008-2010, Dominic Sayers <br>
+ * Test schema documentation Copyright © 2010, Daniel Marschall <br>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * - Neither the name of Dominic Sayers nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package is_email
+ * @author Dominic Sayers <dominic@sayers.cc>
+ * @copyright 2008-2010 Dominic Sayers
+ * @license http://www.opensource.org/licenses/bsd-license.php BSD License
+ * @link http://www.dominicsayers.com/isemail
+ * @version 2.10.1 - Amended DNS lookup logic. Also, in is_email_statustext.php, changed $type to integer to allow for additional types (starting with SMTP codes)
+ */
+
+// The quality of this code has been improved greatly by using PHPLint
+// Copyright (c) 2010 Umberto Salsi
+// This is free software; see the license for copying conditions.
+// More info: http://www.icosaedro.it/phplint/
+/*.
+ require_module 'standard';
+ require_module 'pcre';
+.*/
+/**
+ * Check that an email address conforms to RFCs 5321, 5322 and others
+ *
+ * @param string $email The email address to check
+ * @param boolean $checkDNS If true then a DNS check for A and MX records will be made
+ * @param mixed $errorlevel If true then return an integer error or warning number rather than true or false
+ */
+/*.mixed.*/ function is_email ($email, $checkDNS = false, $errorlevel = false) {
+ // Check that $email is a valid address. Read the following RFCs to understand the constraints:
+ // (http://tools.ietf.org/html/rfc5321)
+ // (http://tools.ietf.org/html/rfc5322)
+ // (http://tools.ietf.org/html/rfc4291#section-2.2)
+ // (http://tools.ietf.org/html/rfc1123#section-2.1)
+ // (http://tools.ietf.org/html/rfc3696) (guidance only)
+
+ // $errorlevel Behaviour
+ // --------------- ---------------------------------------------------------------------------
+ // E_ERROR Return validation failures only. For technically valid addresses return
+ // ISEMAIL_VALID
+ // E_WARNING Return warnings for unlikely but technically valid addresses. This includes
+ // addresses at TLDs (e.g. johndoe@com), addresses with FWS and comments,
+ // addresses that are quoted and addresses that contain no alphabetic or
+ // numeric characters.
+ // true Same as E_ERROR
+ // false Return true for valid addresses, false for invalid ones. No warnings.
+ //
+ // Errors can be distinguished from warnings if ($return_value > ISEMAIL_ERROR)
+// version 2.0: Enhance $diagnose parameter to $errorlevel
+// revision 2.5: some syntax changes to make it more PHPLint-friendly. Should be functionally identical.
+
+ if (!defined('ISEMAIL_VALID')) {
+ // No errors
+ define('ISEMAIL_VALID' , 0);
+ // Warnings (valid address but unlikely in the real world)
+ define('ISEMAIL_WARNING' , 64);
+ define('ISEMAIL_TLD' , 65);
+ define('ISEMAIL_TLDNUMERIC' , 66);
+ define('ISEMAIL_QUOTEDSTRING' , 67);
+ define('ISEMAIL_COMMENTS' , 68);
+ define('ISEMAIL_FWS' , 69);
+ define('ISEMAIL_ADDRESSLITERAL' , 70);
+ define('ISEMAIL_UNLIKELYINITIAL' , 71);
+ define('ISEMAIL_SINGLEGROUPELISION' , 72);
+ define('ISEMAIL_DOMAINNOTFOUND' , 73);
+ define('ISEMAIL_MXNOTFOUND' , 74);
+ // Errors (invalid address)
+ define('ISEMAIL_ERROR' , 128);
+ define('ISEMAIL_TOOLONG' , 129);
+ define('ISEMAIL_NOAT' , 130);
+ define('ISEMAIL_NOLOCALPART' , 131);
+ define('ISEMAIL_NODOMAIN' , 132);
+ define('ISEMAIL_ZEROLENGTHELEMENT' , 133);
+ define('ISEMAIL_BADCOMMENT_START' , 134);
+ define('ISEMAIL_BADCOMMENT_END' , 135);
+ define('ISEMAIL_UNESCAPEDDELIM' , 136);
+ define('ISEMAIL_EMPTYELEMENT' , 137);
+ define('ISEMAIL_UNESCAPEDSPECIAL' , 138);
+ define('ISEMAIL_LOCALTOOLONG' , 139);
+// define('ISEMAIL_IPV4BADPREFIX' , 140);
+ define('ISEMAIL_IPV6BADPREFIXMIXED' , 141);
+ define('ISEMAIL_IPV6BADPREFIX' , 142);
+ define('ISEMAIL_IPV6GROUPCOUNT' , 143);
+ define('ISEMAIL_IPV6DOUBLEDOUBLECOLON' , 144);
+ define('ISEMAIL_IPV6BADCHAR' , 145);
+ define('ISEMAIL_IPV6TOOMANYGROUPS' , 146);
+ define('ISEMAIL_DOMAINEMPTYELEMENT' , 147);
+ define('ISEMAIL_DOMAINELEMENTTOOLONG' , 148);
+ define('ISEMAIL_DOMAINBADCHAR' , 149);
+ define('ISEMAIL_DOMAINTOOLONG' , 150);
+ define('ISEMAIL_IPV6SINGLECOLONSTART' , 151);
+ define('ISEMAIL_IPV6SINGLECOLONEND' , 152);
+ // Unexpected errors
+// define('ISEMAIL_BADPARAMETER' , 190);
+// define('ISEMAIL_NOTDEFINED' , 191);
+// revision 2.1: Redefined unexpected error constants so they don't clash with the ISEMAIL_WARNING bit
+// revision 2.5: Undefined unused constants
+ }
+
+ if (is_bool($errorlevel)) {
+ if ((bool) $errorlevel) {
+ $diagnose = true;
+ $warn = false;
+ } else {
+ $diagnose = false;
+ $warn = false;
+ }
+ } else {
+ switch ((int) $errorlevel) {
+ case E_WARNING:
+ $diagnose = true;
+ $warn = true;
+ break;
+ case E_ERROR:
+ $diagnose = true;
+ $warn = false;
+ break;
+ default:
+ $diagnose = false;
+ $warn = false;
+ }
+ }
+
+ if ($diagnose) /*.mixed.*/ $return_status = ISEMAIL_VALID; else $return_status = true;
+// version 2.0: Enhance $diagnose parameter to $errorlevel
+
+ // the upper limit on address lengths should normally be considered to be 254
+ // (http://www.rfc-editor.org/errata_search.php?rfc=3696)
+ // NB My erratum has now been verified by the IETF so the correct answer is 254
+ //
+ // The maximum total length of a reverse-path or forward-path is 256
+ // characters (including the punctuation and element separators)
+ // (http://tools.ietf.org/html/rfc5321#section-4.5.3.1.3)
+ // NB There is a mandatory 2-character wrapper round the actual address
+ $emailLength = strlen($email);
+// revision 1.17: Max length reduced to 254 (see above)
+ if ($emailLength > 254) if ($diagnose) return ISEMAIL_TOOLONG; else return false; // Too long
+
+ // Contemporary email addresses consist of a "local part" separated from
+ // a "domain part" (a fully-qualified domain name) by an at-sign ("@").
+ // (http://tools.ietf.org/html/rfc3696#section-3)
+ $atIndex = strrpos($email,'@');
+
+ if ($atIndex === false) if ($diagnose) return ISEMAIL_NOAT; else return false; // No at-sign
+ if ($atIndex === 0) if ($diagnose) return ISEMAIL_NOLOCALPART; else return false; // No local part
+ if ($atIndex === $emailLength - 1) if ($diagnose) return ISEMAIL_NODOMAIN; else return false; // No domain part
+// revision 1.14: Length test bug suggested by Andrew Campbell of Gloucester, MA
+
+ // Sanitize comments
+ // - remove nested comments, quotes and dots in comments
+ // - remove parentheses and dots from quoted strings
+ $braceDepth = 0;
+ $inQuote = false;
+ $escapeThisChar = false;
+
+ for ($i = 0; $i < $emailLength; ++$i) {
+ $char = $email[$i];
+ $replaceChar = false;
+
+ if ($char === '\\') $escapeThisChar = !$escapeThisChar; // Escape the next character?
+ else {
+ switch ($char) {
+ case '(':
+ if ($escapeThisChar) $replaceChar = true;
+ else if ($inQuote) $replaceChar = true;
+ else if ($braceDepth++ > 0) $replaceChar = true; // Increment brace depth
+
+ break;
+ case ')':
+ if ($escapeThisChar) $replaceChar = true;
+ else if ($inQuote) $replaceChar = true;
+ else {
+ if (--$braceDepth > 0) $replaceChar = true; // Decrement brace depth
+ if ($braceDepth < 0) $braceDepth = 0;
+ }
+
+ break;
+ case '"':
+ if ($escapeThisChar) $replaceChar = true;
+ else if ($braceDepth === 0) $inQuote = !$inQuote; // Are we inside a quoted string?
+ else $replaceChar = true;
+
+ break;
+ case '.':
+ if ($escapeThisChar) $replaceChar = true; // Dots don't help us either
+ else if ($braceDepth > 0) $replaceChar = true;
+
+ break;
+ default:
+ }
+
+ $escapeThisChar = false;
+// if ($replaceChar) $email[$i] = 'x'; // Replace the offending character with something harmless
+// revision 1.12: Line above replaced because PHPLint doesn't like that syntax
+ if ($replaceChar) $email = (string) substr_replace($email, 'x', $i, 1); // Replace the offending character with something harmless
+ }
+ }
+
+ $localPart = substr($email, 0, $atIndex);
+ $domain = substr($email, $atIndex + 1);
+ $FWS = "(?:(?:(?:[ \\t]*(?:\\r\\n))?[ \\t]+)|(?:[ \\t]+(?:(?:\\r\\n)[ \\t]+)*))"; // Folding white space
+ $dotArray = /*. (array[]) .*/ array();
+
+ // Let's check the local part for RFC compliance...
+ //
+ // local-part = dot-atom / quoted-string / obs-local-part
+ // obs-local-part = word *("." word)
+ // (http://tools.ietf.org/html/rfc5322#section-3.4.1)
+ //
+ // Problem: need to distinguish between "first.last" and "first"."last"
+ // (i.e. one element or two). And I suck at regular expressions.
+ $dotArray = preg_split('/\\.(?=(?:[^\\"]*\\"[^\\"]*\\")*(?![^\\"]*\\"))/m', $localPart);
+ $partLength = 0;
+
+ foreach ($dotArray as $arrayMember) {
+ $element = (string) $arrayMember;
+ // Remove any leading or trailing FWS
+ $new_element = preg_replace("/^$FWS|$FWS\$/", '', $element);
+ if ($warn && ($element !== $new_element)) $return_status = ISEMAIL_FWS; // FWS is unlikely in the real world
+ $element = $new_element;
+// version 2.3: Warning condition added
+ $elementLength = strlen($element);
+
+ if ($elementLength === 0) if ($diagnose) return ISEMAIL_ZEROLENGTHELEMENT; else return false; // Can't have empty element (consecutive dots or dots at the start or end)
+// revision 1.15: Speed up the test and get rid of "uninitialized string offset" notices from PHP
+
+ // We need to remove any valid comments (i.e. those at the start or end of the element)
+ if ($element[0] === '(') {
+ if ($warn) $return_status = ISEMAIL_COMMENTS; // Comments are unlikely in the real world
+// version 2.0: Warning condition added
+ $indexBrace = strpos($element, ')');
+ if ($indexBrace !== false) {
+ if (preg_match('/(?<!\\\\)[\\(\\)]/', substr($element, 1, $indexBrace - 1)) > 0)
+ if ($diagnose) return ISEMAIL_BADCOMMENT_START; else return false; // Illegal characters in comment
+ $element = substr($element, $indexBrace + 1, $elementLength - $indexBrace - 1);
+ $elementLength = strlen($element);
+ }
+ }
+
+ if ($element[$elementLength - 1] === ')') {
+ if ($warn) $return_status = ISEMAIL_COMMENTS; // Comments are unlikely in the real world
+// version 2.0: Warning condition added
+ $indexBrace = strrpos($element, '(');
+ if ($indexBrace !== false) {
+ if (preg_match('/(?<!\\\\)(?:[\\(\\)])/', substr($element, $indexBrace + 1, $elementLength - $indexBrace - 2)) > 0)
+ if ($diagnose) return ISEMAIL_BADCOMMENT_END; else return false; // Illegal characters in comment
+ $element = substr($element, 0, $indexBrace);
+ $elementLength = strlen($element);
+ }
+ }
+
+ // Remove any remaining leading or trailing FWS around the element (having removed any comments)
+ $new_element = preg_replace("/^$FWS|$FWS\$/", '', $element);
+ if ($warn && ($element !== $new_element)) $return_status = ISEMAIL_FWS; // FWS is unlikely in the real world
+ $element = $new_element;
+// version 2.0: Warning condition added
+
+ // What's left counts towards the maximum length for this part
+ if ($partLength > 0) $partLength++; // for the dot
+ $partLength += strlen($element);
+
+ // Each dot-delimited component can be an atom or a quoted string
+ // (because of the obs-local-part provision)
+ if (preg_match('/^"(?:.)*"$/s', $element) > 0) {
+ // Quoted-string tests:
+ if ($warn) $return_status = ISEMAIL_QUOTEDSTRING; // Quoted string is unlikely in the real world
+// version 2.0: Warning condition added
+ // Remove any FWS
+ $element = preg_replace("/(?<!\\\\)$FWS/", '', $element); // A warning condition, but we've already raised ISEMAIL_QUOTEDSTRING
+ // My regular expression skills aren't up to distinguishing between \" \\" \\\" \\\\" etc.
+ // So remove all \\ from the string first...
+ $element = preg_replace('/\\\\\\\\/', ' ', $element);
+ if (preg_match('/(?<!\\\\|^)["\\r\\n\\x00](?!$)|\\\\"$|""/', $element) > 0) if ($diagnose) return ISEMAIL_UNESCAPEDDELIM; else return false; // ", CR, LF and NUL must be escaped
+// version 2.0: allow ""@example.com because it's technically valid
+ } else {
+ // Unquoted string tests:
+ //
+ // Period (".") may...appear, but may not be used to start or end the
+ // local part, nor may two or more consecutive periods appear.
+ // (http://tools.ietf.org/html/rfc3696#section-3)
+ //
+ // A zero-length element implies a period at the beginning or end of the
+ // local part, or two periods together. Either way it's not allowed.
+ if ($element === '') if ($diagnose) return ISEMAIL_EMPTYELEMENT; else return false; // Dots in wrong place
+
+ // Any ASCII graphic (printing) character other than the
+ // at-sign ("@"), backslash, double quote, comma, or square brackets may
+ // appear without quoting. If any of that list of excluded characters
+ // are to appear, they must be quoted
+ // (http://tools.ietf.org/html/rfc3696#section-3)
+ //
+ // Any excluded characters? i.e. 0x00-0x20, (, ), <, >, [, ], :, ;, @, \, comma, period, "
+ if (preg_match('/[\\x00-\\x20\\(\\)<>\\[\\]:;@\\\\,\\."]/', $element) > 0) if ($diagnose) return ISEMAIL_UNESCAPEDSPECIAL; else return false; // These characters must be in a quoted string
+ if ($warn && (preg_match('/^\\w+/', $element) === 0)) $return_status = ISEMAIL_UNLIKELYINITIAL; // First character is an odd one
+ }
+ }
+
+ if ($partLength > 64) if ($diagnose) return ISEMAIL_LOCALTOOLONG; else return false; // Local part must be 64 characters or less
+
+ // Now let's check the domain part...
+
+ // The domain name can also be replaced by an IP address in square brackets
+ // (http://tools.ietf.org/html/rfc3696#section-3)
+ // (http://tools.ietf.org/html/rfc5321#section-4.1.3)
+ // (http://tools.ietf.org/html/rfc4291#section-2.2)
+ if (preg_match('/^\\[(.)+]$/', $domain) === 1) {
+ // It's an address-literal
+ if ($warn) $return_status = ISEMAIL_ADDRESSLITERAL; // Quoted string is unlikely in the real world
+// version 2.0: Warning condition added
+ $addressLiteral = substr($domain, 1, strlen($domain) - 2);
+ $groupMax = 8;
+// revision 2.1: new IPv6 testing strategy
+ $matchesIP = array();
+ $colon = ':'; // Revision 2.7: Daniel Marschall's new IPv6 testing strategy
+ $double_colon = '::';
+
+ // Extract IPv4 part from the end of the address-literal (if there is one)
+ if (preg_match('/\\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/', $addressLiteral, $matchesIP) > 0) {
+ $index = strrpos($addressLiteral, $matchesIP[0]);
+
+ if ($index === 0) {
+ // Nothing there except a valid IPv4 address, so...
+ if ($diagnose) return $return_status; else return true;
+// version 2.0: return warning if one is set
+ } else {
+//- // Assume it's an attempt at a mixed address (IPv6 + IPv4)
+//- if ($addressLiteral[$index - 1] !== $colon) if ($diagnose) return ISEMAIL_IPV4BADPREFIX; else return false; // Character preceding IPv4 address must be ':'
+// revision 2.1: new IPv6 testing strategy
+ if (substr($addressLiteral, 0, 5) !== 'IPv6:') if ($diagnose) return ISEMAIL_IPV6BADPREFIXMIXED; else return false; // RFC5321 section 4.1.3
+//-
+//- $IPv6 = substr($addressLiteral, 5, ($index === 7) ? 2 : $index - 6);
+//- $groupMax = 6;
+// revision 2.1: new IPv6 testing strategy
+ $IPv6 = substr($addressLiteral, 5, $index - 5) . '0000:0000'; // Convert IPv4 part to IPv6 format
+ }
+ } else {
+ // It must be an attempt at pure IPv6
+ if (substr($addressLiteral, 0, 5) !== 'IPv6:') if ($diagnose) return ISEMAIL_IPV6BADPREFIX; else return false; // RFC5321 section 4.1.3
+ $IPv6 = substr($addressLiteral, 5);
+//- $groupMax = 8;
+// revision 2.1: new IPv6 testing strategy
+ }
+
+ $matchesIP = explode($colon, $IPv6); // Revision 2.7: Daniel Marschall's new IPv6 testing strategy
+ $groupCount = count($matchesIP);
+ $index = strpos($IPv6,$double_colon);
+
+ if ($index === false) {
+ // We need exactly the right number of groups
+ if ($groupCount !== $groupMax) if ($diagnose) return ISEMAIL_IPV6GROUPCOUNT; else return false; // RFC5321 section 4.1.3
+ } else {
+ if ($index !== strrpos($IPv6,$double_colon)) if ($diagnose) return ISEMAIL_IPV6DOUBLEDOUBLECOLON; else return false; // More than one '::'
+ if ($index === 0 || $index === (strlen($IPv6) - 2)) $groupMax++; // RFC 4291 allows :: at the start or end of an address with 7 other groups in addition
+ if ($groupCount > $groupMax) if ($diagnose) return ISEMAIL_IPV6TOOMANYGROUPS; else return false; // Too many IPv6 groups in address
+ if ($groupCount === $groupMax) $return_status = ISEMAIL_SINGLEGROUPELISION; // Eliding a single group with :: is deprecated by RFCs 5321 & 5952
+ }
+
+ // Check for single : at start and end of address
+ // Revision 2.7: Daniel Marschall's new IPv6 testing strategy
+ if ((substr($IPv6, 0, 1) === $colon) && (substr($IPv6, 1, 1) !== $colon)) if ($diagnose) return ISEMAIL_IPV6SINGLECOLONSTART; else return false; // Address starts with a single colon
+ if ((substr($IPv6, -1) === $colon) && (substr($IPv6, -2, 1) !== $colon)) if ($diagnose) return ISEMAIL_IPV6SINGLECOLONEND; else return false; // Address ends with a single colon
+
+ // Check for unmatched characters
+ if (count(preg_grep('/^[0-9A-Fa-f]{0,4}$/', $matchesIP, PREG_GREP_INVERT)) !== 0) if ($diagnose) return ISEMAIL_IPV6BADCHAR; else return false; // Illegal characters in address
+ // It's a valid IPv6 address, so...
+ if ($diagnose) return $return_status; else return true;
+// revision 2.1: bug fix: now correctly return warning status
+ } else {
+ // It's a domain name...
+
+ // The syntax of a legal Internet host name was specified in RFC-952
+ // One aspect of host name syntax is hereby changed: the
+ // restriction on the first character is relaxed to allow either a
+ // letter or a digit.
+ // (http://tools.ietf.org/html/rfc1123#section-2.1)
+ //
+ // NB RFC 1123 updates RFC 1035, but this is not currently apparent from reading RFC 1035.
+ //
+ // Most common applications, including email and the Web, will generally not
+ // permit...escaped strings
+ // (http://tools.ietf.org/html/rfc3696#section-2)
+ //
+ // the better strategy has now become to make the "at least one period" test,
+ // to verify LDH conformance (including verification that the apparent TLD name
+ // is not all-numeric)
+ // (http://tools.ietf.org/html/rfc3696#section-2)
+ //
+ // Characters outside the set of alphabetic characters, digits, and hyphen MUST NOT appear in domain name
+ // labels for SMTP clients or servers
+ // (http://tools.ietf.org/html/rfc5321#section-4.1.2)
+ //
+ // RFC5321 precludes the use of a trailing dot in a domain name for SMTP purposes
+ // (http://tools.ietf.org/html/rfc5321#section-4.1.2)
+ $dotArray = preg_split('/\\.(?=(?:[^\\"]*\\"[^\\"]*\\")*(?![^\\"]*\\"))/m', $domain);
+ $partLength = 0;
+ $element = ''; // Since we use $element after the foreach loop let's make sure it has a value
+// revision 1.13: Line above added because PHPLint now checks for Definitely Assigned Variables
+
+ if ($warn && (count($dotArray) === 1)) $return_status = ISEMAIL_TLD; // The mail host probably isn't a TLD
+// version 2.0: downgraded to a warning
+
+ foreach ($dotArray as $arrayMember) {
+ $element = (string) $arrayMember;
+ // Remove any leading or trailing FWS
+ $new_element = preg_replace("/^$FWS|$FWS\$/", '', $element);
+ if ($warn && ($element !== $new_element)) $return_status = ISEMAIL_FWS; // FWS is unlikely in the real world
+ $element = $new_element;
+// version 2.0: Warning condition added
+ $elementLength = strlen($element);
+
+ // Each dot-delimited component must be of type atext
+ // A zero-length element implies a period at the beginning or end of the
+ // local part, or two periods together. Either way it's not allowed.
+ if ($elementLength === 0) if ($diagnose) return ISEMAIL_DOMAINEMPTYELEMENT; else return false; // Dots in wrong place
+// revision 1.15: Speed up the test and get rid of "uninitialized string offset" notices from PHP
+
+ // Then we need to remove all valid comments (i.e. those at the start or end of the element
+ if ($element[0] === '(') {
+ if ($warn) $return_status = ISEMAIL_COMMENTS; // Comments are unlikely in the real world
+// version 2.0: Warning condition added
+ $indexBrace = strpos($element, ')');
+ if ($indexBrace !== false) {
+ if (preg_match('/(?<!\\\\)[\\(\\)]/', substr($element, 1, $indexBrace - 1)) > 0)
+ if ($diagnose) return ISEMAIL_BADCOMMENT_START; else return false; // Illegal characters in comment
+// revision 1.17: Fixed name of constant (also spotted by turboflash - thanks!)
+ $element = substr($element, $indexBrace + 1, $elementLength - $indexBrace - 1);
+ $elementLength = strlen($element);
+ }
+ }
+
+ if ($element[$elementLength - 1] === ')') {
+ if ($warn) $return_status = ISEMAIL_COMMENTS; // Comments are unlikely in the real world
+// version 2.0: Warning condition added
+ $indexBrace = strrpos($element, '(');
+ if ($indexBrace !== false) {
+ if (preg_match('/(?<!\\\\)(?:[\\(\\)])/', substr($element, $indexBrace + 1, $elementLength - $indexBrace - 2)) > 0)
+ if ($diagnose) return ISEMAIL_BADCOMMENT_END; else return false; // Illegal characters in comment
+// revision 1.17: Fixed name of constant (also spotted by turboflash - thanks!)
+ $element = substr($element, 0, $indexBrace);
+ $elementLength = strlen($element);
+ }
+ }
+
+ // Remove any leading or trailing FWS around the element (inside any comments)
+ $new_element = preg_replace("/^$FWS|$FWS\$/", '', $element);
+ if ($warn && ($element !== $new_element)) $return_status = ISEMAIL_FWS; // FWS is unlikely in the real world
+ $element = $new_element;
+// version 2.0: Warning condition added
+
+ // What's left counts towards the maximum length for this part
+ if ($partLength > 0) $partLength++; // for the dot
+ $partLength += strlen($element);
+
+ // The DNS defines domain name syntax very generally -- a
+ // string of labels each containing up to 63 8-bit octets,
+ // separated by dots, and with a maximum total of 255
+ // octets.
+ // (http://tools.ietf.org/html/rfc1123#section-6.1.3.5)
+ if ($elementLength > 63) if ($diagnose) return ISEMAIL_DOMAINELEMENTTOOLONG; else return false; // Label must be 63 characters or less
+
+ // Any ASCII graphic (printing) character other than the
+ // at-sign ("@"), backslash, double quote, comma, or square brackets may
+ // appear without quoting. If any of that list of excluded characters
+ // are to appear, they must be quoted
+ // (http://tools.ietf.org/html/rfc3696#section-3)
+ //
+ // If the hyphen is used, it is not permitted to appear at
+ // either the beginning or end of a label.
+ // (http://tools.ietf.org/html/rfc3696#section-2)
+ //
+ // Any excluded characters? i.e. 0x00-0x20, (, ), <, >, [, ], :, ;, @, \, comma, period, "
+ if (preg_match('/[\\x00-\\x20\\(\\)<>\\[\\]:;@\\\\,\\."]|^-|-$/', $element) > 0) if ($diagnose) return ISEMAIL_DOMAINBADCHAR; else return false; // Illegal character in domain name
+ }
+
+ if ($partLength > 255) if ($diagnose) return ISEMAIL_DOMAINTOOLONG; else return false; // Domain part must be 255 characters or less (http://tools.ietf.org/html/rfc1123#section-6.1.3.5)
+
+ if ($warn && (preg_match('/^[0-9]+$/', $element) > 0)) $return_status = ISEMAIL_TLDNUMERIC; // TLD probably isn't all-numeric (http://www.apps.ietf.org/rfc/rfc3696.html#sec-2)
+// version 2.0: Downgraded to a warning
+
+ // Check DNS?
+ if ($diagnose && ($return_status === ISEMAIL_VALID) && $checkDNS && function_exists('checkdnsrr')) {
+ // Revision 2.10: Amended DNS logic
+ // An A-record is not required unless there are no MX-records
+ // for a domain. Obvious when you think about it.
+ // (http://tools.ietf.org/html/rfc5321#section-5)
+ // (http://tools.ietf.org/html/rfc2181#section-10.3)
+ // (http://tools.ietf.org/html/rfc1035)
+ if (!(checkdnsrr($domain, 'MX'))) {
+ $result = @dns_get_record($domain, DNS_A);
+
+ if ((is_bool($result) && !(bool) $result))
+ $return_status = ISEMAIL_DOMAINNOTFOUND; // Neither MX- nor A-record for domain can be found
+ else $return_status = ISEMAIL_MXNOTFOUND; // MX-record for domain can't be found
+ }
+ }
+ }
+
+ // Eliminate all other factors, and the one which remains must be the truth.
+ // (Sherlock Holmes, The Sign of Four)
+ if ($diagnose) return $return_status; else return true;
+// version 2.0: return warning if one is set
+}
+?>
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