Java tutorial
/* * Copyright 2013-2015 MongoDB Inc. * * 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.techngage.smartbin; import com.mongodb.ErrorCategory; import com.mongodb.MongoWriteException; import com.mongodb.client.MongoDatabase; import com.mongodb.client.MongoCollection; import sun.misc.BASE64Encoder; import org.bson.Document; import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.Random; import static com.mongodb.client.model.Filters.eq; public class UserDAO { private final MongoCollection<Document> usersCollection; private final ThreadLocal<Random> random = new ThreadLocal<Random>(); public UserDAO(final MongoDatabase smartbinDatabase) { usersCollection = smartbinDatabase.getCollection("users"); } // validates that username is unique and insert into db public boolean addUser(String username, String password, String email) { String passwordHash = makePasswordHash(password, Integer.toString(getRandom().nextInt())); Document user = new Document(); user.append("_id", username).append("password", passwordHash); if (email != null && !email.equals("")) { // the provided email address user.append("email", email); } try { usersCollection.insertOne(user); return true; } catch (MongoWriteException e) { if (e.getError().getCategory().equals(ErrorCategory.DUPLICATE_KEY)) { System.out.println("Username already in use: " + username); return false; } throw e; } } public Document validateLogin(String username, String password) { Document user; user = usersCollection.find(eq("_id", username)).first(); if (user == null) { 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); } } private Random getRandom() { Random result = random.get(); if (result == null) { result = new Random(); random.set(result); } return result; } }