FacebookInviteController.java

/*
 * Copyright 2010 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.invite;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.inject.Inject;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.social.connect.UsersConnectionRepository;
import org.springframework.social.facebook.api.Facebook;
import org.springframework.social.facebook.api.Reference;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import com.springsource.greenhouse.account.Account;
import com.springsource.greenhouse.account.AccountRepository;
import com.springsource.greenhouse.account.ProfileReference;
import com.springsource.greenhouse.utils.Message;

/**
 * UI Controller for inviting Facebook friends to join our community.
 * @author Keith Donald
 */
@Controller
public class FacebookInviteController {

	private final Facebook facebook;
	
	private final UsersConnectionRepository connectionRepository;
	
	private final AccountRepository accountRepository;
	
	/**
	 * Construct the FacebookInviteController.
	 * The Facebook ServiceProvider is injected for obtaining the client-side proxy to Facebook's REST API.
	 * It is also used to lookup which of a member's Facebook friends have already joined our community.
	 */
	@Inject
	public FacebookInviteController(Facebook facebook, UsersConnectionRepository connectionRepository, AccountRepository accountRepository) {
		this.facebook = facebook;
		this.connectionRepository = connectionRepository;
		this.accountRepository = accountRepository;
	}
	
	/**
	 * Renders the Facebook friend-finder page as HTML in the web browser.
	 * If the member's account is connected to Facebook, adds his or her Facebook friends who are already members to the model.
	 * Supports distinguishing between those Facebook friends who have already joined and those who haven't.
	 */
	@RequestMapping(value="/invite/facebook", method=RequestMethod.GET)
	public void friendFinder(Model model, Account account) {
		if (facebook.isAuthorized()) {
			List<ProfileReference> profileReferences = accountRepository.findProfileReferencesByIds(friendAccountIds(account.getId(), facebook));
			model.addAttribute("friends", profileReferences);
		} else {
			model.addAttribute("friends", Collections.emptySet());
		}
		model.addAttribute("facebookAppId", facebookAppId);
	}
	
	/**
	 * Called by the Facebook multi-friend-selector form after sending invitations.
	 * Redirects the user back to the invite page and renders a success message.
	 * @param inviteIds the invitation ids assigned by Facebook, one for each invitation sent
	 */
	@RequestMapping(value="/invite/facebook/request-form", method=RequestMethod.POST)
	public String invitationsSent(@RequestParam("ids[]") String[] inviteIds, RedirectAttributes redirectAttrs) {
		redirectAttrs.addFlashAttribute(Message.success("Your invitations have been sent"));
		return "redirect:/invite";
	}

	/**
	 * Called by the Facebook multi-friend-selector form after choosing to cancel the sending of one or more invites.
	 * Redirects the user back to the main invite page.
	 */
	@RequestMapping(value="/invite/facebook/request-form", method=RequestMethod.GET)
	public String invitationsCancelled() {
		return "redirect:/invite";
	}

	// internal helpers
	
	private List<Long> friendAccountIds(Long accountId, Facebook facebook) {
		List<Reference> friends = facebook.friendOperations().getFriends();
		if (friends.isEmpty()) {
			return Collections.emptyList();
		}
		Set<String> providerUserIds = new HashSet<String>(friends.size());
		for (Reference friend : friends) {
			providerUserIds.add(friend.getId());
		}
		Set<String> userIds = connectionRepository.findUserIdsConnectedTo("facebook", providerUserIds);
		List<Long> friendAccountIds = new ArrayList<Long>(userIds.size());
		for (String localUserId : userIds) {
			friendAccountIds.add(Long.valueOf(localUserId));
		}
		return friendAccountIds;
	}
	
	@Value("#{environment['facebook.appId']}")
	private String facebookAppId;
	
}