/*
* Copyright 2011 Google Inc. All Rights Reserved.
*
* 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.google.walkaround.wave.server.rpc;
import com.google.inject.Inject;
import com.google.walkaround.slob.server.AccessDeniedException;
import com.google.walkaround.slob.server.SlobStoreSelector;
import com.google.walkaround.slob.server.SlobNotFoundException;
import com.google.walkaround.slob.server.SlobStore;
import com.google.walkaround.slob.server.SlobStore.ConnectResult;
import com.google.walkaround.slob.server.SlobStore.HistoryResult;
import com.google.walkaround.util.server.servlet.AbstractHandler;
import com.google.walkaround.util.server.servlet.BadRequestException;
import com.google.walkaround.wave.server.ObjectSession;
import com.google.walkaround.wave.server.servlet.ServletUtil;
import com.google.walkaround.wave.shared.SharedConstants.Params;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.util.logging.Logger;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Used by the client to notify the server of connection to an object at a
* specific revision, or to refresh a channel.
*
* @author danilatos@google.com (Daniel Danilatos)
*/
public class ChannelHandler extends AbstractHandler {
@SuppressWarnings("unused")
private static final Logger log = Logger.getLogger(ChannelHandler.class.getName());
@Inject SlobStoreSelector storeSelector;
@Inject ObjectSession session;
@Override
public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
try {
inner(req, resp);
} catch (JSONException e) {
throw new Error(e);
}
}
private void inner(HttpServletRequest req, HttpServletResponse resp)
throws IOException, JSONException {
JSONObject result = new JSONObject();
SlobStore store = storeSelector.get(session.getStoreType()).getSlobStore();
try {
int revision = Integer.parseInt(requireParameter(req, Params.REVISION));
ConnectResult r = store.reconnect(session.getObjectId(), session.getClientId());
if (r.getChannelToken() != null) {
result.put("token", r.getChannelToken());
HistoryResult history = store.loadHistory(session.getObjectId(), revision, null);
result.put("history", HistoryHandler.serializeHistory(revision, history.getData()));
result.put("head", r.getVersion());
} else {
// TODO(ohler): Figure out and document how the client-server protocol
// works and what the different endpoints do. It's not clear to me why
// the above case returns history and head version (even though the
// javadoc doesn't mention this) and this case doesn't (even though it
// could).
result.put("error", "Too many concurrent connections");
}
} catch (SlobNotFoundException e) {
throw new BadRequestException("Object not found or access denied", e);
} catch (AccessDeniedException e) {
throw new BadRequestException("Object not found or access denied", e);
} catch (NumberFormatException nfe) {
throw new BadRequestException("Parse error", nfe);
}
resp.setContentType("application/json");
ServletUtil.writeJsonResult(resp.getWriter(), result.toString());
}
}