org.n52.v3d.terraintools.auth.ConnectServlet.java Source code

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Here is the source code for org.n52.v3d.terraintools.auth.ConnectServlet.java

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/**
 * Copyright (C) 2016-2016 52North Initiative for Geospatial Open Source
 * Software GmbH
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the Free
 * Software Foundation.
 *
 * If the program is linked with libraries which are licensed under one of the
 * following licenses, the combination of the program with the linked library is
 * not considered a "derivative work" of the program:
 *
 *     - Apache License, version 2.0
 *     - Apache Software License, version 1.0
 *     - GNU Lesser General Public License, version 3
 *     - Mozilla Public License, versions 1.0, 1.1 and 2.0
 *     - Common Development and Distribution License (CDDL), version 1.0
 *
 * Therefore the distribution of the program linked with libraries licensed under
 * the aforementioned licenses, is permitted by the copyright holders if the
 * distribution is compliant with both the GNU General Public License version 2
 * and the aforementioned licenses.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU General Public License for more details.
 */
package org.n52.v3d.terraintools.auth;

import com.google.api.client.auth.oauth2.TokenResponseException;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeTokenRequest;
import com.google.api.client.googleapis.auth.oauth2.GoogleIdToken;
import com.google.api.client.googleapis.auth.oauth2.GoogleTokenResponse;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import static org.n52.v3d.terraintools.auth.Signin.CLIENT_ID;
import static org.n52.v3d.terraintools.auth.Signin.CLIENT_SECRET;
import static org.n52.v3d.terraintools.auth.Signin.GSON;
import static org.n52.v3d.terraintools.auth.Signin.JSON_FACTORY;
import static org.n52.v3d.terraintools.auth.Signin.TRANSPORT;
import org.n52.v3d.terraintools.drive.DriveSample;

/**
 * Upgrade given auth code to token, and store it in the session. POST body of
 * request should be the authorization code. Example URI:
 * /connect?state=...&gplus_id=...
 */
public class ConnectServlet extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("application/json");

        // Only connect a user that is not already connected.
        String tokenData = (String) request.getSession().getAttribute("token");
        if (tokenData != null) {
            response.setStatus(HttpServletResponse.SC_OK);
            System.out.println("Current user is already connected");
            response.getWriter().print(GSON.toJson("Current user is already connected."));
            DriveSample.init(tokenData);
            return;
        }

        // Normally the state would be a one-time use token, however in our
        // simple case, we want a user to be able to connect and disconnect
        // without reloading the page.  Thus, for demonstration, we don't
        // implement this best practice.
        //request.getSession().removeAttribute("state");
        ByteArrayOutputStream resultStream = new ByteArrayOutputStream();
        getContent(request.getInputStream(), resultStream);
        String code = new String(resultStream.toByteArray(), "UTF-8");

        try {
            // Upgrade the authorization code into an access and refresh token.
            GoogleTokenResponse tokenResponse = new GoogleAuthorizationCodeTokenRequest(TRANSPORT, JSON_FACTORY,
                    CLIENT_ID, CLIENT_SECRET, code, "postmessage").execute();

            // You can read the Google user ID in the ID token.
            // This sample does not use the user ID.
            GoogleIdToken idToken = tokenResponse.parseIdToken();
            String gplusId = idToken.getPayload().getSubject();

            // Store the token in the session for later use.
            request.getSession().setAttribute("token", tokenResponse.toString());
            response.setStatus(HttpServletResponse.SC_OK);
            response.getWriter().print(GSON.toJson("Successfully connected user."));

            tokenData = (String) request.getSession().getAttribute("token");
            DriveSample.init(tokenData);
        } catch (TokenResponseException e) {
            response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            response.getWriter().print(GSON.toJson("Failed to upgrade the authorization code."));
        } catch (IOException e) {
            response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            response.getWriter().print(GSON.toJson("Failed to read token data from Google. " + e.getMessage()));
        }
    }

    /*
     * Read the content of an InputStream.
     *
     * @param inputStream the InputStream to be read.
     * @return the content of the InputStream as a ByteArrayOutputStream.
     * @throws IOException
     */
    static void getContent(InputStream inputStream, ByteArrayOutputStream outputStream) throws IOException {
        // Read the response into a buffered stream
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        int readChar;
        while ((readChar = reader.read()) != -1) {
            outputStream.write(readChar);
        }
        reader.close();
    }
}