/*
* 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.tuscany.sca.binding.comet.runtime.handler;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletContext;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import org.apache.tuscany.sca.binding.comet.runtime.ServletFactory;
import org.apache.tuscany.sca.interfacedef.DataType;
import org.apache.tuscany.sca.interfacedef.Operation;
import org.apache.tuscany.sca.runtime.RuntimeEndpoint;
import org.atmosphere.annotation.Broadcast;
import org.atmosphere.cpr.Broadcaster;
import org.atmosphere.cpr.DefaultBroadcaster;
import org.atmosphere.jersey.Broadcastable;
import org.atmosphere.jersey.SuspendResponse;
import com.google.gson.Gson;
import com.sun.jersey.spi.container.servlet.PerSession;
/**
* Class serving calls coming for comet services and operations.
*/
@Path("/")
@Produces("text/html;charset=ISO-8859-1")
@PerSession
public class CometBindingHandler {
/**
* The object used to suspend the response and send async responses back to
* client.
*/
private Broadcaster broadcaster;
/**
* The service endpoints corresponding to each operation.
*/
private Map<String, RuntimeEndpoint> endpoints;
/**
* The comet operations.
*/
private Map<String, Operation> operations;
/**
* JSON converter.
*/
private Gson gson;
/**
* The underlying servlet context.
*/
@Context
private ServletContext sc;
/**
* Method called at comet connect time. This suspends the response and keeps
* the connection opened.
*
* @return the suspended response
*/
@GET
public SuspendResponse<String> connect() {
this.broadcaster = new DefaultBroadcaster();
this.endpoints = (Map<String, RuntimeEndpoint>)this.sc.getAttribute(ServletFactory.ENDPOINTS_KEY);
this.operations = (Map<String, Operation>)this.sc.getAttribute(ServletFactory.OPERATIONS_KEY);
this.gson = new Gson();
return new SuspendResponse.SuspendResponseBuilder<String>().broadcaster(this.broadcaster).outputComments(true)
.build();
}
/**
* Method called on service calls.
*
* @param service service called
* @param method operation called
* @param callbackMethod the callback method from Javascript
* @param jsonData arguments for the method sent as JSON array
* @return object used by the Broadcaster to send response through the
* persisted connection
* @throws InvocationTargetException if problems occur at service invocation
*/
@POST
@Path("/{service}/{method}")
@Broadcast
public Broadcastable callAndRespond(@PathParam("service") final String service,
@PathParam("method") final String method,
@FormParam("callback") final String callbackMethod,
@FormParam("params") final String jsonData) throws InvocationTargetException {
final String url = "/" + service + "/" + method;
final RuntimeEndpoint wire = this.endpoints.get(url);
final Operation operation = this.operations.get(url);
final Object[] args = new Object[operation.getInputType().getLogical().size()];
final String[] json = this.parseArray(jsonData);
int index = 0;
// convert each argument to the corresponding class
for (final DataType<?> dataType : operation.getInputType().getLogical()) {
args[index] = this.gson.fromJson(json[index], dataType.getPhysical());
index++;
}
// invoke the service operation
final Object response = wire.invoke(operation, args);
return new Broadcastable(callbackMethod + "($.secureEvalJSON('" + this.gson.toJson(response) + "'))", "",
this.broadcaster);
}
/**
* Parse the JSON array containing the arguments for the method call in
* order to avoid converting JSON to Object[]. Converting each object
* separately to it's corresponding type avoids type mismatch problems at
* service invocation.
*
* @param jsonArray the JSON array
* @return an array of JSON formatted objects
*/
private String[] parseArray(final String jsonArray) {
final List<String> objects = new ArrayList<String>();
int bracketNum = 0;
int parNum = 0;
int startPos = 1;
for (int i = 0; i < jsonArray.length(); i++) {
switch (jsonArray.charAt(i)) {
case '{':
bracketNum++;
break;
case '}':
bracketNum--;
break;
case '[':
parNum++;
break;
case ']':
parNum--;
break;
case ',':
if ((bracketNum == 0) && (parNum == 1)) {
objects.add(jsonArray.substring(startPos, i));
startPos = i + 1;
}
}
}
// add last object
objects.add(jsonArray.substring(startPos, jsonArray.length() - 1));
return objects.toArray(new String[] {});
}
}