/* * [EmailSyntaxValidator.java] * * Summary: Validate syntax of email addresses. * * Copyright: (c) 2002-2017 Roedy Green, Canadian Mind Products, http://mindprod.com * * Licence: This software may be copied and used freely for any purpose but military. * http://mindprod.com/contact/nonmil.html * * Requires: JDK 1.8+ * * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/ * * Version History: * 1.7 2007-08-21 */ package com.mindprod.bulk; import javax.mail.internet.AddressException; import javax.mail.internet.InternetAddress; import java.util.Arrays; import java.util.HashSet; import java.util.Locale; import java.util.regex.Matcher; import java.util.regex.Pattern; import static java.lang.System.*; // TODO: @version check validity of & in first part of email address. Appears in practice. /** * Validate syntax of email addresses. *

* Does not probe to see if mailserver exists in DNS or online. See MailProber for * that. See ValidateEmailFile for an example of how to use this class. * * @author Roedy Green, Canadian Mind Products * @version 1.7 2007-08-21 * @since 2002 */ public final class EmailSyntaxValidator { /** * True if want extra debugging output. */ @SuppressWarnings( { "UnusedDeclaration" } ) private static final boolean DEBUGGING = false; /** * Country where this program is running. */ private static final String THIS_COUNTRY = Locale.getDefault().getCountry().toLowerCase(); /** * Bad top level domains -- ones never valid. */ private static final HashSet BAD_TLDS = hmaker( new String[] { "invalid", "nowhere", "noone", } ); /** * Top level domains for countries. */ private static final HashSet NATIONAL_TLDS = hmaker( new String[] { "ac", "ad", "ae", "af", "ag", "ai", "al", "am", "an", "ao", "aq", "ar", "as", "at", "au", "aw", "az", "ba", "bb", "bd", "be", "bf", "bg", "bh", "bi", "bj", "bm", "bn", "bo", "br", "bs", "bt", "bv", "bw", "by", "bz", "ca", "cc", "cd", "cf", "cg", "ch", "ci", "ck", "cl", "cm", "cn", "co", "cr", "cu", "cv", "cx", "cy", "cz", "de", "dj", "dk", "dm", "do", "dz", "ec", "ee", "eg", "eh", "er", "es", "et", "fi", "fj", "fk", "fm", "fo", "fr", "fx", "ga", "gb", "gd", "ge", "gf", "gg", "gh", "gi", "gl", "gm", "gn", "gp", "gq", "gr", "gs", "gt", "gu", "gw", "gy", "hk", "hm", "hn", "hr", "ht", "hu", "id", "ie", "il", "im", "in", "io", "iq", "ir", "is", "it", "je", "jm", "jo", "jp", "ke", "kg", "kh", "ki", "km", "kn", "kp", "kr", "kw", "ky", "kz", "la", "lb", "lc", "li", "lk", "lr", "ls", "lt", "lu", "lv", "ly", "ma", "mc", "md", "mg", "mh", "mk", "ml", "mm", "mn", "mo", "mp", "mq", "mr", "ms", "mt", "mu", "mv", "mw", "mx", "my", "mz", "na", "nc", "ne", "nf", "ng", "ni", "nl", "no", "np", "nr", "nu", "nz", "om", "pa", "pe", "pf", "pg", "ph", "pk", "pl", "pm", "pn", "pr", "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", "sv", "sy", "sz", "tc", "td", "tf", "tg", "th", "tj", "tk", "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", } ); /** * Official top level domains. */ private static final HashSet OFFICIAL_TLDS = hmaker( new String[] { "aero", "biz", "coop", "com", "edu", "gov", "info", "mil", "museum", "name", "net", "org", "pro", } ); /** * Rarely used top level domains */ private static final HashSet RARE_TLDS = hmaker( new String[] { "cam", "mp3", "agent", "art", "arts", "asia", "auction", "aus", "bank", "cam", "chat", "church", "club", "corp", "dds", "design", "dns2go", "e", "email", "exp", "fam", "family", "faq", "fed", "film", "firm", "free", "fun", "g", "game", "games", "gay", "ger", "globe", "gmbh", "golf", "gov", "help", "hola", "i", "inc", "int", "jpn", "k12", "kids", "law", "learn", "llb", "llc", "llp", "lnx", "love", "ltd", "mag", "mail", "med", "media", "mp3", "netz", "nic", "nom", "npo", "per", "pol", "prices", "radio", "rsc", "school", "scifi", "sea", "service", "sex", "shop", "sky", "soc", "space", "sport", "tech", "tour", "travel", "usvi", "video", "web", "wine", "wir", "wired", "zine", "zoo", } ); /** * regex to allow dots anywhere, but not at start of domain name, no + */ private static final Pattern P3 = Pattern.compile( "[\\d\\p{Lower}\\-_\\.]++@[\\d\\p{Lower}\\-_]++(\\.[\\d\\p{Lower}\\-_]++)++" ); /** * regex IP style names, no + */ private static final Pattern P4 = Pattern.compile( "[\\d\\p{Lower}\\-_]++(\\.[\\d\\p{Lower}\\-_]++)*@\\[(\\d{1,3}\\.){3}\\d{1,3}\\]" ); /** * regex to allow - _ dots in name, no + */ private static final Pattern P5 = Pattern.compile( "[\\d\\p{Lower}\\-_]++(\\.[\\d\\p{Lower}\\-_]++)*@[\\d\\p{Lower}\\-_]++(\\.[\\d\\p{Lower}\\-_]++)" + "++" ); /** * regex to allow _ - in name, lead and trailing ones are filtered later, no +. */ private static final Pattern P9 = Pattern.compile( "[\\d\\p{Lower}\\-_]++@[\\d\\p{Lower}\\-_]++(\\.[\\d\\p{Lower}\\-_]++)++" ); /** * regex to split into fields */ private static final Pattern SPLIT_ON_PUNCT = Pattern.compile( "[@\\.]" ); /** * build a HashSet from an array of String literals. * * @param list array of strings * * @return HashSet you can use to test if a string is in the set. */ private static HashSet hmaker( String[] list ) { HashSet map = new HashSet<>( Math.max( ( int ) ( list.length / .75f ) + 1, 16 ) ); map.addAll( Arrays.asList( list ) ); return map; } /** * Check how likely an email address is to be valid. The higher the number returned, the more likely the address is * valid. This method does not probe the Internet in any way to see if the corresponding mail server or domain * exists. * * @param email bare computer email address. e.g. roedyg@mindprod.com No "Roedy Green" style * addresses. No local addresses, e.g. roedy. * * @return

*/ public static int howValid( String email ) { if ( email == null ) { return 0; } email = email.trim().toLowerCase(); int dotPlace = email.lastIndexOf( '.' ); if ( 0 < dotPlace && dotPlace < email.length() - 1 ) { String tld = email.substring( dotPlace + 1 ); if ( BAD_TLDS.contains( tld ) ) { /* deliberate invalid address */ return 0; } // make sure none of fragments start or end in _ or - String[] fragments = SPLIT_ON_PUNCT.split( email ); boolean clean = true; for ( String fragment : fragments ) { if ( fragment.startsWith( "_" ) || fragment.endsWith( "_" ) || fragment.startsWith( "-" ) || fragment.endsWith( "-" ) ) { clean = false; break; } } // end for if ( clean ) { Matcher m9 = P9.matcher( email ); if ( m9.matches() ) { if ( OFFICIAL_TLDS.contains( tld ) ) { return 9; } else if ( THIS_COUNTRY.equals( tld ) ) { return 8; } else if ( NATIONAL_TLDS.contains( tld ) ) { return 7; } else if ( RARE_TLDS.contains( tld ) ) { return 6; } else { return 3;/* unknown tld */ } } // allow dots in name Matcher m5 = P5.matcher( email ); if ( m5.matches() ) { if ( OFFICIAL_TLDS.contains( tld ) ) { return 5; } else if ( THIS_COUNTRY.equals( tld ) ) { return 5; } else if ( NATIONAL_TLDS.contains( tld ) ) { return 5; } else if ( RARE_TLDS.contains( tld ) ) { return 5; } else { return 2;/* unknown tld */ } } // IP Matcher m4 = P4.matcher( email ); if ( m4.matches() ) { return 4;/* can't tell TLD */ } // allow even lead/trail dots in name, except at start of domain Matcher m3 = P3.matcher( email ); if ( m3.matches() ) { if ( OFFICIAL_TLDS.contains( tld ) ) { return 3; } else if ( THIS_COUNTRY.equals( tld ) ) { return 3; } else if ( NATIONAL_TLDS.contains( tld ) ) { return 3; } else if ( RARE_TLDS.contains( tld ) ) { return 3; } else { return 2;/* unknown domain */ } } } // end if clean } // allow even unclean addresses, and addresses without a TLD to have a whack at passing RFC:822 try { /* see if InternetAddress likes it, it follows RFC:822. It will names without domains though. */ InternetAddress.parse( email, true/* strict */ ); // it liked it, no exception happened. Seems very sloppy. return 1; } catch ( AddressException e ) { // it did not like it return 0; } } /** * main debugging harness. * * @param args not used */ public static void main( String[] args ) { out.println( howValid( "kellizer@.hotmail.com" ) ); } }