com.goodow.realtime.server.rpc.PollHandler.java Source code

Introduction

Here is the source code for com.goodow.realtime.server.rpc.PollHandler.java

Source

/*
 * Copyright 2012 Goodow.com
 * 
 * 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.goodow.realtime.server.rpc;

import com.goodow.realtime.channel.constant.Constants.Params;
import com.goodow.realtime.server.auth.AccountContext;
import com.goodow.realtime.server.model.ObjectId;
import com.goodow.realtime.server.model.Session;

import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.walkaround.slob.server.AccessDeniedException;
import com.google.walkaround.slob.server.SlobFacilities;
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.util.server.servlet.AbstractHandler;
import com.google.walkaround.util.server.servlet.BadRequestException;

import java.io.IOException;

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

public class PollHandler extends AbstractHandler {

    @Inject
    SlobFacilities slobFacilities;
    @Inject
    DeltaHandler deltaHandler;
    @Inject
    Provider<AccountContext> context;

    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
        JsonObject payload = new JsonParser().parse(RpcUtil.readRequestBody(req)).getAsJsonObject();
        String sessionId = requireParameter(req, Params.SESSION_ID);
        JsonArray toRtn;
        try {
            toRtn = fetchDeltas(payload.get(Params.IDS).getAsJsonArray(), sessionId);
        } 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);
        }

        RpcUtil.writeJsonResult(req, resp, toRtn.toString());
    }

    private JsonArray fetchDeltas(JsonArray ids, String sessionId)
            throws IOException, SlobNotFoundException, AccessDeniedException {
        JsonArray msgs = new JsonArray();
        SlobStore store = slobFacilities.getSlobStore();
        String token = null;
        for (JsonElement elem : ids) {
            JsonArray array = elem.getAsJsonArray();
            ObjectId key = new ObjectId(array.get(0).getAsString());
            long startRev = array.get(1).getAsLong();
            Long endVersion = array.size() >= 3 ? array.get(2).getAsLong() : null;

            ConnectResult r = null;
            try {
                r = store.reconnect(key, new Session(context.get().getAccountInfo().getUserId(), sessionId));
            } catch (SlobNotFoundException e) {
                if (startRev == 1) {
                    continue;
                }
                throw e;
            }
            if (r.getChannelToken() != null) {
                assert token == null || token.equals(r.getChannelToken());
                token = r.getChannelToken();
            }
            JsonObject msg = new JsonObject();
            msg.addProperty(Params.ID, key.toString());
            boolean isEmpty = deltaHandler.fetchDeltas(msg, key, startRev - 1, endVersion);
            if (!isEmpty) {
                msgs.add(msg);
            }
        }
        if (token != null) {
            JsonObject tokenMsg = new JsonObject();
            tokenMsg.addProperty(Params.ID, Params.TOKEN);
            tokenMsg.addProperty(Params.TOKEN, token);
            msgs.add(tokenMsg);
        }
        return msgs;
    }
}