FacebookConnectInterceptor.java

/*
 * Copyright 2012 the original author or authors.
 *
 * 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.springsource.greenhouse.connect;

import java.io.IOException;

import javax.inject.Inject;
import javax.servlet.http.HttpServletRequest;

import org.springframework.social.connect.Connection;
import org.springframework.social.connect.ConnectionFactory;
import org.springframework.social.connect.web.ConnectInterceptor;
import org.springframework.social.facebook.api.Facebook;
import org.springframework.social.facebook.api.FacebookLink;
import org.springframework.util.MultiValueMap;
import org.springframework.util.StringUtils;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.FlashMap;
import org.springframework.web.servlet.support.RequestContextUtils;

import com.springsource.greenhouse.account.Account;
import com.springsource.greenhouse.account.AccountUtils;
import com.springsource.greenhouse.members.ProfilePictureService;
import com.springsource.greenhouse.utils.Message;

/**
 * Supports posting to the wall on behalf of the user after connecting to Facebook.
 * Also supports using the user's Facebook profile picture as their local profile picture.
 * @author Keith Donald
 */
public class FacebookConnectInterceptor implements ConnectInterceptor<Facebook> {

	private final ProfilePictureService profilePictureService;

	@Inject
	public FacebookConnectInterceptor(ProfilePictureService profilePictureService) {
		this.profilePictureService = profilePictureService;
	}

	public void preConnect(ConnectionFactory<Facebook> provider, MultiValueMap<String, String> params, WebRequest request) {
		if (StringUtils.hasText(request.getParameter(POST_TO_WALL_PARAMETER))) {
			request.setAttribute(POST_TO_WALL_ATTRIBUTE, Boolean.TRUE, WebRequest.SCOPE_SESSION);
		}
		if (StringUtils.hasText(request.getParameter(USE_FACEBOOK_IMAGE_PARAMETER))) {
			request.setAttribute(USE_FACEBOOK_IMAGE_ATTRIBUTE, Boolean.TRUE, WebRequest.SCOPE_SESSION);
		}
	}

	public void postConnect(Connection<Facebook> connection, WebRequest request) {
		Account account = AccountUtils.getCurrentAccount();
		postToWall(connection, account, request);
		useFacebookProfileImage(connection, account, request);
	}

	// internal helpers
	
	private void postToWall(Connection<Facebook> connection, Account account, WebRequest request) {
		if (request.getAttribute(POST_TO_WALL_ATTRIBUTE, WebRequest.SCOPE_SESSION) != null) {
			connection.getApi().feedOperations().postLink("Join me at the Greenhouse!", new FacebookLink(account.getProfileUrl(), "Greenhouse", "Where Spring developers hang out.",
				"We help you connect with fellow application developers and take advantage of everything the Spring community has to offer."));
			request.removeAttribute(POST_TO_WALL_ATTRIBUTE, WebRequest.SCOPE_SESSION);
		}
	}

	private void useFacebookProfileImage(Connection<Facebook> connection, Account account, WebRequest request) {
		if (request.getAttribute(USE_FACEBOOK_IMAGE_ATTRIBUTE, WebRequest.SCOPE_SESSION) != null) {
			try {
				profilePictureService.saveProfilePicture(account.getId(), connection.getApi().userOperations().getUserProfileImage());
			} catch (IOException e) {
				NativeWebRequest nativeRequest = (NativeWebRequest) request;
				HttpServletRequest servletRequest = nativeRequest.getNativeRequest(HttpServletRequest.class);
				FlashMap flashMap = RequestContextUtils.getOutputFlashMap(servletRequest);
				flashMap.put("message", Message.warning("Greenhouse was unable to use your Facebook profile picture."));
			}
			request.removeAttribute(USE_FACEBOOK_IMAGE_ATTRIBUTE, WebRequest.SCOPE_SESSION);			
		}
	}

	private static final String POST_TO_WALL_PARAMETER = "postToWall";

	private static final String POST_TO_WALL_ATTRIBUTE = "facebookConnect." + POST_TO_WALL_PARAMETER;

	private static final String USE_FACEBOOK_IMAGE_PARAMETER = "useProfilePicture";

	private static final String USE_FACEBOOK_IMAGE_ATTRIBUTE = "facebookConnect." + USE_FACEBOOK_IMAGE_PARAMETER;

}