/* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.riotfamily.common.util;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Utility class to perform basic email address syntax checks. The
* implementation is based on the jakarta-commons EmailValidator. Oro-Matcher
* dependencies have been removed (now using java.util.regex) and comments
* are no longer processed, i.e. addresses containing comments will be reported
* as invalid.
*/
public final class EmailValidationUtils {
private static final String SPECIAL_CHARS = "\\(\\)<>@,;:\\\\\\\"\\.\\[\\]";
private static final String VALID_CHARS = "[^\\s" + SPECIAL_CHARS + "]";
private static final String QUOTED_USER = "(\"[^\"]*\")";
private static final String ATOM = VALID_CHARS + '+';
private static final String WORD = "(" + ATOM + "|" + QUOTED_USER + ")";
private static final String LEGAL_ASCII_PATTERN = "^[\\x00-\\x7F]+$";
private static final String EMAIL_PATTERN = "^(.+)@(.+)$";
private static final String IP_DOMAIN_PATTERN =
"^(\\d{1,3})[.](\\d{1,3})[.](\\d{1,3})[.](\\d{1,3})$";
private static final String USER_PATTERN = "^" + WORD + "(\\.|"
+ WORD + ")*$";
private static final String DOMAIN_PATTERN = "^" + ATOM + "(\\."
+ ATOM + ")*$";
private static final String ATOM_PATTERN = "(" + ATOM + ")";
private static final String ADDR_PATTERN = "^[^<]*<([^>]*)>\\s*$";
/* Compiled patterns */
private static Pattern legalAsciiPattern = Pattern.compile(LEGAL_ASCII_PATTERN);
private static Pattern emailPattern = Pattern.compile(EMAIL_PATTERN);
private static Pattern ipDomainPattern = Pattern.compile(IP_DOMAIN_PATTERN);
private static Pattern userPattern = Pattern.compile(USER_PATTERN);
private static Pattern domainPattern = Pattern.compile(DOMAIN_PATTERN);
private static Pattern atomPattern = Pattern.compile(ATOM_PATTERN);
private static Pattern addrPattern = Pattern.compile(ADDR_PATTERN);
private EmailValidationUtils() {
}
private static Logger getLog() {
return LoggerFactory.getLogger(EmailValidationUtils.class);
}
/**
* <p>Checks if a field has a valid e-mail address.</p>
*
* @param email The value validation is being performed on.
* A <code>null</code> value is considered invalid.
*/
public static boolean isValid(String email) {
if (email == null) {
getLog().debug("Address is null");
return false;
}
Matcher addrMatcher = addrPattern.matcher(email);
if (addrMatcher.matches()) {
email = addrMatcher.group(1);
getLog().debug("Extracted machine part from address: " + email);
}
if (!legalAsciiPattern.matcher(email).matches()) {
getLog().debug("Address must only contain ASCII characters");
return false;
}
// Check the whole email address structure
Matcher emailMatcher = emailPattern.matcher(email);
if (!emailMatcher.matches()) {
getLog().debug("Invalid address structure");
return false;
}
if (email.endsWith(".")) {
getLog().debug("Address must not end with a dot");
return false;
}
if (!isValidUser(emailMatcher.group(1))) {
getLog().debug("Invalid user");
return false;
}
if (!isValidDomain(emailMatcher.group(2))) {
getLog().debug("Invalid domain");
return false;
}
getLog().debug("Address is valid");
return true;
}
/**
* Returns true if the domain component of an email address is valid.
* @param domain being validatied.
*/
private static boolean isValidDomain(String domain) {
boolean symbolic = false;
Matcher ipAddressMatcher = ipDomainPattern.matcher(domain);
if (ipAddressMatcher.matches()) {
if (!isValidIpAddress(ipAddressMatcher)) {
return false;
}
}
else {
// Domain is symbolic name
symbolic = domainPattern.matcher(domain).matches();
}
if (symbolic) {
if (!isValidSymbolicDomain(domain)) {
return false;
}
}
else {
return false;
}
return true;
}
/**
* Returns true if the user component of an email address is valid.
* @param user being validated
*/
private static boolean isValidUser(String user) {
return userPattern.matcher(user).matches();
}
/**
* Validates an IP address. Returns true if valid.
* @param ipAddressMatcher Pattren matcher
*/
private static boolean isValidIpAddress(Matcher ipAddressMatcher) {
for (int i = 1; i <= 4; i++) {
String ipSegment = ipAddressMatcher.group(i);
if (ipSegment == null || ipSegment.length() <= 0) {
return false;
}
int iIpSegment = 0;
try {
iIpSegment = Integer.parseInt(ipSegment);
}
catch (NumberFormatException e) {
return false;
}
if (iIpSegment > 255) {
return false;
}
}
return true;
}
/**
* Validates a symbolic domain name. Returns true if it's valid.
* @param domain symbolic domain name
*/
private static boolean isValidSymbolicDomain(String domain) {
String[] domainSegment = new String[10];
boolean match = true;
int i = 0;
Matcher atomMatcher = atomPattern.matcher(domain);
while (match) {
match = atomMatcher.find();
if (match) {
domainSegment[i] = atomMatcher.group(1);
int l = domainSegment[i].length() + 1;
domain =
(l >= domain.length())
? ""
: domain.substring(l);
i++;
}
}
int len = i;
if (domainSegment[len - 1].length() < 2
|| domainSegment[len - 1].length() > 4) {
return false;
}
// Make sure there's a host name preceding the domain.
if (len < 2) {
return false;
}
return true;
}
}