email-validation/lib/email-validation.js

Email validation that follows the specs.

var util = require('util');
var email = module.exports = function() {};

var strToObj = function(str) {
  var obj = {};
  for(var i = 0; i < str.length; i++) {
    obj[str[i]] = str.charCodeAt(i);
  }
  return obj;
};

var chars = strToObj("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!#$%&'*+-/=?^_`{|}~.");
var specialchars = strToObj("\\\"(),:;<>@[\] ");
var escapers = strToObj('\\"');
var hostchars = strToObj("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789.-");

email.parse = function(address, dothrow, callback) {
  callback = (typeof callback == 'undefined' && typeof dothrow == 'function') ? dothrow : null;
  var userland = true;
  var quotation = false;
  var escaped = false;
  var _user = "", _domain = "";
  var hostisip = false;
  var hoststartpos = 0;
  try {
    if(address.length >= 254) throw util.format("[Error parsing email address: address is longer than 253, actual]", address.length);
    for(var i = 0; i < address.length; i++) {
      //console.log(i, address[i])
      if(userland) {
        if(address[i] == '"' && i == 0) { quotation = true; _user += address[i]; continue; }
        if(typeof chars[address[i]] != 'undefined') { //needed I'm sure.
          _user += address[i]; continue;
        } else if(typeof specialchars[address[i]] != 'undefined') {
          if(quotation) {
            if(!escaped && address[i] == "\\") { escaped = true; _user += address[i]; continue; }
            if(!escaped && address[i] == '"' && address[i+1] == "@") { userland = false; hoststartpos = i+2; _user += address[i]; i+=1; continue; }
            if(escaped && typeof escapers[address[i]] != 'undefined') { escaped = false; _user += address[i]; continue; }
            if(!escaped && typeof escapers[address[i]] != 'undefined') throw util.format("[Error parsing email address: invalid use of %s (pos: %s)]", address[i], i, address);
          } else if(address[i] == "@" && !quotation) {
            userland = false;
            hoststartpos = i+1;
            continue;
          } else {
            throw util.format("[Error parsing email address: special character '%s' (pos: %s) used without quotation marks]", address[i], i);
          }
        } else {
          throw util.format("[Error parsing email address: character '%s' (pos: %s) is not allowed in an email address user space.]", address[i], i, address);
        }
        _user += address[i];
      } else { //parsing hostname. Probably could be done with regex.
        if(i == hoststartpos && address[i] == '[') { hostisip = true; hostchars['['] = '['; hostchars[']'] = ']'; hostchars[':'] = ':'; _domain += address[i]; continue; }
        if(typeof hostchars[address[i]] == 'undefined') throw util.format("[Error parsing email address: character '%s' (pos: %s) is not allowed in the hostname section]", address[i], i);
        if(i >= hoststartpos && /[@\.]/.test(address[i - 1]) && !/[a-z0-9]/i.test(address[i])) throw util.format("[Error parsing email address: All domain segments must start with a letter or number, never a symbol like '%s'.")
        _domain += address[i];
      }
    }
    if(_domain === '') throw util.format("[Error parseing email address: no domain part]", address);
    if(hostisip && !require('net').isIP(address.substring(hoststartpos+1,address.length-1))) throw util.format("[Error parsing email address: invalid IP address]");
    if(hostisip && address[address.length-1] != "]") throw util.format("[Error parsing email address: IP address notation must end with a ']']");
    if(!hostisip && (/^.+@([a-z0-9]{64,}(|\.))/i).test(address)) throw util.format("[Error parsing email address: hostname has elements greater than 63 characters]");
    if(userland) throw util.format("[Error parsing email address: quotation mark not closed]" , address);
  } catch (err) {
    if(callback) callback(err);
    if(typeof dothrow != 'undefined' && typeof dothrow != 'function') throw err;
    return false; //redundant?
  }
  if(callback) callback(null, {user: _user, domain: _domain});
  else return {user: _user, domain: _domain};
}

email.valid = function(address, dothrow, callback) {
  return !!email.parse(address, dothrow, callback);
}