com.squarecash4glass.servlet.OAuth2AuthorizationServlet.java Source code

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Here is the source code for com.squarecash4glass.servlet.OAuth2AuthorizationServlet.java

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/*
 * Copyright (C) 2013 Google 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.squarecash4glass.servlet;

import static com.googlecode.objectify.ObjectifyService.ofy;

import java.io.IOException;
import java.util.logging.Logger;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;

import com.google.api.client.auth.oauth2.AuthorizationCodeFlow;
import com.google.api.client.auth.oauth2.TokenResponse;
import com.google.api.client.auth.oauth2.TokenResponseException;
import com.google.api.client.googleapis.auth.oauth2.GoogleIdToken.Payload;
import com.google.api.client.googleapis.auth.oauth2.GoogleTokenResponse;
import com.google.api.client.http.GenericUrl;
import com.squarecash4glass.dto.User;
import com.squarecash4glass.util.OAuth2Util;
import com.squarecash4glass.util.Oauth2Factory;

/**
 * This servlet manages the OAuth 2.0 dance
 * 
 * @author Jenny Murphy - http://google.com/+JennyMurphy
 */
@SuppressWarnings("serial")
public class OAuth2AuthorizationServlet extends HttpServlet {
    private static final Logger LOG = Logger.getLogger(OAuth2AuthorizationServlet.class.getSimpleName());

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException, ServletException {
        String provider = getProvider(req);
        LOG.info("in oauth flow for: " + provider);
        Configuration oauthConfiguration;
        try {
            oauthConfiguration = Oauth2Factory.getOauth2Configuration(provider, "sandbox");
        } catch (ConfigurationException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
            throw new ServletException(e1);
        }
        OAuth2Util oAuth2Util = Oauth2Factory.getOauth2Util(oauthConfiguration);
        if (req.getParameter("error") != null) {
            LOG.severe("Something went wrong during auth: " + req.getParameter("error"));
            res.setContentType("text/plain");
            res.getWriter().write("Something went wrong during auth. Please check your log for details");
            return;
        }

        // If we have a code, finish the OAuth 2.0 dance
        if (req.getParameter("code") != null) {
            LOG.info("Got a code. Attempting to exchange for access token.");

            TokenResponse tokenResponse = null;
            AuthorizationCodeFlow flow = oAuth2Util.newAuthorizationCodeFlow();

            try {

                tokenResponse = flow.newTokenRequest(req.getParameter("code"))
                        .setRedirectUri(WebUtil.buildUrl(req, oauthConfiguration.getString("oauthcallback")))
                        .execute();

            } catch (TokenResponseException e) {
                LOG.severe("exception getting token: " + e.getMessage());
                throw e;
            }

            LOG.info("tokenResponse: " + tokenResponse);

            if ("google".equals(provider)) {
                // Extract the Google User ID from the ID token in the auth response
                Payload googlePayload = ((GoogleTokenResponse) tokenResponse).parseIdToken().getPayload();
                String userId = googlePayload.getSubject();
                String email = googlePayload.getEmail();
                req.getSession().setAttribute("userId", userId);
                User user = new User(userId, email);
                ofy().save().entities(user).now();
                LOG.info("Code exchange worked. User " + userId + " logged in.");
            }

            String userid = OAuth2Util.getUserId(req);
            flow.createAndStoreCredential(tokenResponse, userid + oauthConfiguration.getString("useridPostfix"));

            // Redirect back to index
            res.sendRedirect(WebUtil.buildUrl(req, "/main"));
            return;
        }

        // Else, we have a new flow. Initiate a new flow.
        LOG.info("No auth context found. Kicking off a new dwolla auth flow.");

        AuthorizationCodeFlow flow = oAuth2Util.newAuthorizationCodeFlow();
        GenericUrl url = flow.newAuthorizationUrl()
                .setRedirectUri(WebUtil.buildUrl(req, oauthConfiguration.getString("oauthcallback")));
        adjustURL(provider, url);
        LOG.info("redirecting to URL: " + url.build());
        res.sendRedirect(url.build());
    }

    /**
     * @param provider
     * @param url
     */
    private void adjustURL(String provider, GenericUrl url) {
        // manage some specific configuration settings
        if ("dwolla".equals(provider)) {
            url.set("request_type", "code");
            url.set("scope", "send");
        }
        if ("google".equals(provider)) {
            url.set("approval_prompt", "force");
        }
        if ("square".equals(provider)) {
            url.set("request_type", "code");
            url.set("state", "ciao");
        }
    }

    /**
     * @param req
     * @param provider
     * @return
     */
    private String getProvider(HttpServletRequest req) {
        LOG.info("getServletPath: " + req.getServletPath());
        if ("/oauth2callbackdwolla".equals(req.getServletPath())) {
            return "dwolla";
        }
        if ("/oauth2callbacksquare".equals(req.getServletPath())) {
            return "square";
        }
        if ("/oauth2callbackvenmo".equals(req.getServletPath())) {
            return "venmo";
        }
        if ("/oauth2callback".equals(req.getServletPath())) {
            return "google";
        }
        return null;
    }
}