com.bosch.cr.integration.helloworld.ProxyServlet.java Source code

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/*
 *                                            Bosch SI Example Code License
 *                                              Version 1.0, January 2016
 *
 * Copyright 2016 Bosch Software Innovations GmbH ("Bosch SI"). All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following
 * disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 * following disclaimer in the documentation and/or other materials provided with the distribution.
 *
 * BOSCH SI PROVIDES THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO
 * THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
 * ALL NECESSARY SERVICING, REPAIR OR CORRECTION. THIS SHALL NOT APPLY TO MATERIAL DEFECTS AND DEFECTS OF TITLE WHICH
 * BOSCH SI HAS FRAUDULENTLY CONCEALED. APART FROM THE CASES STIPULATED ABOVE, BOSCH SI SHALL BE LIABLE WITHOUT
 * LIMITATION FOR INTENT OR GROSS NEGLIGENCE, FOR INJURIES TO LIFE, BODY OR HEALTH AND ACCORDING TO THE PROVISIONS OF
 * THE GERMAN PRODUCT LIABILITY ACT (PRODUKTHAFTUNGSGESETZ). THE SCOPE OF A GUARANTEE GRANTED BY BOSCH SI SHALL REMAIN
 * UNAFFECTED BY LIMITATIONS OF LIABILITY. IN ALL OTHER CASES, LIABILITY OF BOSCH SI IS EXCLUDED. THESE LIMITATIONS OF
 * LIABILITY ALSO APPLY IN REGARD TO THE FAULT OF VICARIOUS AGENTS OF BOSCH SI AND THE PERSONAL LIABILITY OF BOSCH SI'S
 * EMPLOYEES, REPRESENTATIVES AND ORGANS.
 */
package com.bosch.cr.integration.helloworld;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.util.Properties;

import javax.net.ssl.SSLContext;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.http.HttpHost;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.AuthenticationException;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.impl.auth.BasicScheme;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.message.BasicHttpRequest;
import org.apache.http.ssl.SSLContextBuilder;

/**
 * ProxyServlet to forward all requests to target service required as replacement for for cross domain requests.
 */
@WebServlet(ProxyServlet.URL_PATTERN)
public class ProxyServlet extends HttpServlet {

    private static final String URL_PREFIX = "/cr";
    static final String URL_PATTERN = URL_PREFIX + "/*";

    private HttpHost targetHost;
    private CloseableHttpClient httpClient;
    private Properties props;

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        props = new Properties(System.getProperties());
        if (new File("config.properties").exists()) {
            try (FileReader reader = new FileReader("config.properties")) {
                props.load(reader);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        } else {
            try (InputStream is = Thread.currentThread().getContextClassLoader()
                    .getResourceAsStream("config.properties")) {
                props.load(is);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        System.out.println("Config: " + props);
        targetHost = HttpHost
                .create(props.getProperty("thingsServiceEndpointUrl", "https://things.apps.bosch-iot-cloud.com"));
    }

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String auth = req.getHeader("Authorization");
        if (auth == null) {
            resp.setHeader("WWW-Authenticate", "BASIC realm=\"Proxy for Bosch IoT Things\"");
            resp.sendError(HttpServletResponse.SC_UNAUTHORIZED);
            return;
        }

        try {
            long time = System.currentTimeMillis();
            CloseableHttpClient c = getHttpClient();

            String targetUrl = URL_PREFIX + req.getPathInfo()
                    + (req.getQueryString() != null ? ("?" + req.getQueryString()) : "");
            BasicHttpRequest targetReq = new BasicHttpRequest(req.getMethod(), targetUrl);

            String user = "";
            if (auth.toUpperCase().startsWith("BASIC ")) {
                String userpassDecoded = new String(
                        new sun.misc.BASE64Decoder().decodeBuffer(auth.substring("BASIC ".length())));
                user = userpassDecoded.substring(0, userpassDecoded.indexOf(':'));
                String pass = userpassDecoded.substring(userpassDecoded.indexOf(':') + 1);
                UsernamePasswordCredentials creds = new UsernamePasswordCredentials(user, pass);
                targetReq.addHeader(new BasicScheme().authenticate(creds, targetReq, null));
            }

            targetReq.addHeader("x-cr-api-token", req.getHeader("x-cr-api-token"));
            CloseableHttpResponse targetResp = c.execute(targetHost, targetReq);

            System.out.println("Request: " + targetHost + targetUrl + ", user " + user + " -> "
                    + (System.currentTimeMillis() - time) + " msec: " + targetResp.getStatusLine());

            resp.setStatus(targetResp.getStatusLine().getStatusCode());
            targetResp.getEntity().writeTo(resp.getOutputStream());
        } catch (IOException | AuthenticationException ex) {
            throw new RuntimeException(ex);
        }
    }

    /**
     * Create http client
     */
    private synchronized CloseableHttpClient getHttpClient() {
        if (httpClient == null) {
            HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();

            if (props.getProperty("http.proxyHost") != null) {
                httpClientBuilder.setProxy(new HttpHost(props.getProperty("http.proxyHost"),
                        Integer.parseInt(props.getProperty("http.proxyPort"))));
            }

            if (props.getProperty("http.proxyUser") != null) {
                CredentialsProvider credsProvider = new BasicCredentialsProvider();
                credsProvider.setCredentials(new AuthScope(targetHost), new UsernamePasswordCredentials(
                        props.getProperty("http.proxyUser"), props.getProperty("http.proxyPwd")));
                httpClientBuilder.setDefaultCredentialsProvider(credsProvider);
            }

            httpClient = httpClientBuilder.build();
        }

        return httpClient;
    }
}