Java tutorial
/* * Copyright (c) 2008 - 2013 10gen, Inc. <http://10gen.com> * * 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 com.mongocourse.blog; import com.mongodb.*; import sun.misc.BASE64Encoder; import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import java.util.Random; public class UserDAO { private final DBCollection usersCollection; private Random random = new SecureRandom(); public UserDAO(final DB blogDatabase) { usersCollection = blogDatabase.getCollection("users"); } // validates that username is unique and insert into db public boolean addUser(String username, String password, String email) { BasicDBObject object = new BasicDBObject("_id", username); String passwordHash = makePasswordHash(password, Integer.toString(random.nextInt())); object.append("password", passwordHash); if (email != null && !email.equals("")) { object.append("email", email); } try { WriteResult result = usersCollection.insert(object); return result.getError() == null; } catch (MongoException.DuplicateKey e) { System.out.println("Username already in use: " + username); return false; } } public DBObject validateLogin(String username, String password) { DBObject user = null; DBObject object = new BasicDBObject(); object.put("_id", username); user = usersCollection.findOne(object); if (user == null) { System.out.println("User not in database"); return null; } String hashedAndSalted = user.get("password").toString(); String salt = hashedAndSalted.split(",")[1]; if (!hashedAndSalted.equals(makePasswordHash(password, salt))) { System.out.println("Submitted password is not a match"); return null; } return user; } private String makePasswordHash(String password, String salt) { try { String saltedAndHashed = password + "," + salt; MessageDigest digest = MessageDigest.getInstance("MD5"); digest.update(saltedAndHashed.getBytes()); BASE64Encoder encoder = new BASE64Encoder(); byte hashedBytes[] = (new String(digest.digest(), "UTF-8")).getBytes(); return encoder.encode(hashedBytes) + "," + salt; } catch (NoSuchAlgorithmException e) { throw new RuntimeException("MD5 is not available", e); } catch (UnsupportedEncodingException e) { throw new RuntimeException("UTF-8 unavailable? Not a chance", e); } } }