/**
* 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.camel.component.gae.task;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.appengine.api.labs.taskqueue.TaskOptions;
import org.apache.camel.Exchange;
import org.apache.camel.Message;
import org.apache.camel.component.gae.bind.InboundBinding;
import org.apache.camel.component.gae.bind.OutboundBinding;
import org.apache.camel.component.http.DefaultHttpBinding;
import org.apache.camel.component.http.HttpMessage;
import org.apache.camel.spi.HeaderFilterStrategy;
/**
* Binds the {@link TaskOptions} of the task queueing service to a Camel
* {@link Exchange} for outbound communication. For inbound communication a
* {@link HttpMessage} is bound to {@link Exchange}.
*/
public class GTaskBinding implements
OutboundBinding <GTaskEndpoint, TaskOptions, Void>,
InboundBinding <GTaskEndpoint, HttpServletRequest, HttpServletResponse> {
/**
* Camel header name corresponding to <code>X-AppEngine-QueueName</code>
* header created by task queueing service.
*/
public static final String GTASK_QUEUE_NAME = "CamelGtaskQueueName";
/**
* Camel header name corresponding to <code>X-AppEngine-TaskName</code>
* header created by task queueing service.
*/
public static final String GTASK_TASK_NAME = "CamelGtaskTaskName";
/**
* Camel header name corresponding to <code>X-AppEngine-TaskRetryCount</code>
* header created by task queueing service.
*/
public static final String GTASK_RETRY_COUNT = "CamelGtaskRetryCount";
static final String GAE_QUEUE_NAME = "X-AppEngine-QueueName";
static final String GAE_TASK_NAME = "X-AppEngine-TaskName";
static final String GAE_RETRY_COUNT = "X-AppEngine-TaskRetryCount";
// ----------------------------------------------------------------
// Outbound binding
// ----------------------------------------------------------------
/**
* Reads data from <code>exchange</code> and writes it to a newly created
* {@link TaskOptions} instance. The <code>request</code> parameter is
* ignored.
*
* @param endpoint
* @param exchange
* @param request
* ignored.
* @return a newly created {@link TaskOptions} instance containing data from
* <code>exchange</code>.
*/
public TaskOptions writeRequest(GTaskEndpoint endpoint, Exchange exchange, TaskOptions request) {
TaskOptions answer = TaskOptions.Builder.url(getWorkerRoot(endpoint) + endpoint.getPath());
writeRequestHeaders(endpoint, exchange, answer);
writeRequestBody(endpoint, exchange, answer);
// TODO: consider TaskOptions method (POST, GET, ...)
return answer;
}
/**
* @throws UnsupportedOperationException.
*/
public Exchange readResponse(GTaskEndpoint endpoint, Exchange exchange, Void response) {
throw new UnsupportedOperationException("gtask responses not supported");
}
// ----------------------------------------------------------------
// Inbound binding
// ----------------------------------------------------------------
/**
* Replaces the task service-specific headers (<code>X-AppEngine-*</code>)
* with Camel-specific headers.
*
* @see GTaskBinding#GTASK_QUEUE_NAME
* @see GTaskBinding#GTASK_TASK_NAME
* @see GTaskBinding#GTASK_RETRY_COUNT
* @see DefaultHttpBinding#readRequest(HttpServletRequest, HttpMessage)
*/
public Exchange readRequest(GTaskEndpoint endpoint, Exchange exchange, HttpServletRequest request) {
readRequestHeaders(endpoint, exchange, request);
return exchange;
}
/**
* @throws UnsupportedOperationException.
*/
public HttpServletResponse writeResponse(GTaskEndpoint endpoint, Exchange exchange, HttpServletResponse response) {
throw new UnsupportedOperationException("gtask responses not supported");
}
// ----------------------------------------------------------------
// Customization points
// ----------------------------------------------------------------
protected void writeRequestHeaders(GTaskEndpoint endpoint, Exchange exchange, TaskOptions request) {
HeaderFilterStrategy strategy = endpoint.getHeaderFilterStrategy();
for (String headerName : exchange.getIn().getHeaders().keySet()) {
String headerValue = exchange.getIn().getHeader(headerName, String.class);
if (strategy != null && !strategy.applyFilterToCamelHeaders(headerName, headerValue, exchange)) {
request.header(headerName, headerValue);
}
}
}
protected void readRequestHeaders(GTaskEndpoint endpoint, Exchange exchange, HttpServletRequest request) {
Message message = exchange.getIn();
String key = GAE_QUEUE_NAME;
Object val = message.getHeader(key);
if (val != null) {
message.getHeaders().put(GTASK_QUEUE_NAME, val);
message.getHeaders().remove(key);
}
key = GAE_TASK_NAME;
val = message.getHeader(key);
if (val != null) {
message.getHeaders().put(GTASK_TASK_NAME, val);
message.getHeaders().remove(key);
}
key = GAE_RETRY_COUNT;
val = message.getHeader(key);
if (val != null) {
message.getHeaders().put(GTASK_RETRY_COUNT, Integer.parseInt(val.toString()));
message.getHeaders().remove(key);
}
// EXPERIMENTAL // TODO: resolve gzip encoding issues
exchange.getIn().removeHeader("Accept-Encoding");
exchange.getIn().removeHeader("Content-Encoding");
}
protected void writeRequestBody(GTaskEndpoint endpoint, Exchange exchange, TaskOptions request) {
// TODO: allow message header or endpoint uri to configure character encoding and content type
request.payload(exchange.getIn().getBody(byte[].class), "application/octet-stream");
}
protected String getWorkerRoot(GTaskEndpoint endpoint) {
return "/" + endpoint.getWorkerRoot();
}
}