Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.apache.shindig.social.opensocial.service; import org.apache.shindig.auth.SecurityToken; import org.apache.shindig.common.util.JsonConversionUtil; import org.apache.shindig.social.ResponseError; import org.apache.shindig.social.opensocial.spi.DataCollection; import org.apache.shindig.social.opensocial.spi.RestfulCollection; import com.google.common.collect.Lists; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.StringUtils; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.IOException; import java.util.List; import java.util.concurrent.Future; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * JSON-RPC handler servlet. */ public class JsonRpcServlet extends ApiServlet { @Override protected void doGet(HttpServletRequest servletRequest, HttpServletResponse servletResponse) throws ServletException, IOException { SecurityToken token = getSecurityToken(servletRequest); if (token == null) { sendSecurityError(servletResponse); return; } try { setCharacterEncodings(servletRequest, servletResponse); JSONObject request = JsonConversionUtil.fromRequest(servletRequest); dispatch(request, servletRequest, servletResponse, token); } catch (JSONException je) { // FIXME } } @Override protected void doPost(HttpServletRequest servletRequest, HttpServletResponse servletResponse) throws ServletException, IOException { SecurityToken token = getSecurityToken(servletRequest); if (token == null) { sendSecurityError(servletResponse); return; } setCharacterEncodings(servletRequest, servletResponse); servletResponse.setContentType("application/json"); try { String content = IOUtils.toString(servletRequest.getInputStream(), servletRequest.getCharacterEncoding()); if ((content.indexOf('[') != -1) && content.indexOf('[') < content.indexOf('{')) { // Is a batch JSONArray batch = new JSONArray(content); dispatchBatch(batch, servletRequest, servletResponse, token); } else { JSONObject request = new JSONObject(content); dispatch(request, servletRequest, servletResponse, token); } } catch (JSONException je) { sendBadRequest(je, servletResponse); } } protected void dispatchBatch(JSONArray batch, HttpServletRequest servletRequest, HttpServletResponse servletResponse, SecurityToken token) throws JSONException, IOException { // Use linked hash map to preserve order List<Future<?>> responses = Lists.newArrayListWithExpectedSize(batch.length()); // Gather all Futures. We do this up front so that // the first call to get() comes after all futures are created, // which allows for implementations that batch multiple Futures // into single requests. for (int i = 0; i < batch.length(); i++) { JSONObject batchObj = batch.getJSONObject(i); RpcRequestItem requestItem = new RpcRequestItem(batchObj, token, jsonConverter); responses.add(handleRequestItem(requestItem, servletRequest)); } // Resolve each Future into a response. // TODO: should use shared deadline across each request JSONArray result = new JSONArray(); for (int i = 0; i < batch.length(); i++) { JSONObject batchObj = batch.getJSONObject(i); String key = null; if (batchObj.has("id")) { key = batchObj.getString("id"); } result.put(getJSONResponse(key, getResponseItem(responses.get(i)))); } servletResponse.getWriter().write(result.toString()); } protected void dispatch(JSONObject request, HttpServletRequest servletRequest, HttpServletResponse servletResponse, SecurityToken token) throws JSONException, IOException { String key = null; if (request.has("id")) { key = request.getString("id"); } RpcRequestItem requestItem = new RpcRequestItem(request, token, jsonConverter); // Resolve each Future into a response. // TODO: should use shared deadline across each request ResponseItem response = getResponseItem(handleRequestItem(requestItem, servletRequest)); JSONObject result = getJSONResponse(key, response); servletResponse.getWriter().write(result.toString()); } private JSONObject getJSONResponse(String key, ResponseItem responseItem) throws JSONException { JSONObject result = new JSONObject(); if (key != null) { result.put("id", key); } if (responseItem.getError() != null) { result.put("error", getErrorJson(responseItem)); } else { Object response = responseItem.getResponse(); JSONObject converted = (JSONObject) jsonConverter.convertToJson(response); if (response instanceof RestfulCollection) { // FIXME this is a little hacky because of the field names in the RestfulCollection converted.put("list", converted.remove("entry")); result.put("data", converted); } else if (response instanceof DataCollection) { if (converted.has("entry")) { result.put("data", converted.get("entry")); } } else { result.put("data", converted); } } return result; } // TODO(doll): Refactor the responseItem so that the fields on it line up with this format. // Then we can use the general converter to output the response to the client and we won't // be harcoded to json. private JSONObject getErrorJson(ResponseItem responseItem) throws JSONException { JSONObject error = new JSONObject(); error.put("code", responseItem.getError().getHttpErrorCode()); String message = responseItem.getError().toString(); if (StringUtils.isNotBlank(responseItem.getErrorMessage())) { message += ": " + responseItem.getErrorMessage(); } error.put("message", message); return error; } @Override protected void sendError(HttpServletResponse servletResponse, ResponseItem responseItem) throws IOException { try { JSONObject error = getErrorJson(responseItem); servletResponse.getWriter().write(error.toString()); } catch (JSONException je) { // This really shouldn't ever happen servletResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Error generating error response " + je.getMessage()); } } private void sendBadRequest(Throwable t, HttpServletResponse response) throws IOException { sendError(response, new ResponseItem(ResponseError.BAD_REQUEST, "Invalid batch - " + t.getMessage())); } }