/*******************************************************************************
* Copyright (c) 2014, Institute for Pervasive Computing, ETH Zurich.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This file is part of the Californium (Cf) CoAP framework.
******************************************************************************/
package ch.ethz.inf.vs.californium.examples.resources;
import java.util.Arrays;
import java.util.LinkedList;
import ch.ethz.inf.vs.californium.coap.CoAP.ResponseCode;
import ch.ethz.inf.vs.californium.coap.LinkFormat;
import ch.ethz.inf.vs.californium.coap.MediaTypeRegistry;
import ch.ethz.inf.vs.californium.coap.Response;
import ch.ethz.inf.vs.californium.server.resources.CoapExchange;
import ch.ethz.inf.vs.californium.server.resources.Resource;
import ch.ethz.inf.vs.californium.server.resources.ResourceBase;
/**
* This resource allows to store an arbitrary payload in any subresource. If the
* target subresource does not yet exist it will be created. Therefore, such a
* resource can be though off as having all possible children.
* <p>
* <ul>
* <li />A GET request receives the currently stored data within the target
* resource.
* <li />A POST request creates the specified resources from the payload.
* <li />A PUT request stores the payload within the target resource.
* <li />A DELETE request deletes the target resource.
* </ul>
* <p>
* Assume a single instance of this resource called "storage". Assume a client
* sends a PUT request with Payload "foo" to the URI storage/A/B/C. When the
* resource storage receives the request, it creates the resources A, B and C
* and delivers the request to the resource C. Resource C will process the PUT
* request and stare "foo". If the client sends a consecutive GET request to the
* URI storage/A/B/C, resource C will respond with the payload "foo".
*
* @author Martin Lanter
*/
public class StorageResource extends ResourceBase {
private String content;
public StorageResource(String name) {
super(name);
}
@Override
public void handleGET(CoapExchange exchange) {
if (content != null) {
exchange.respond(content);
} else {
String subtree = LinkFormat.serializeTree(this);
exchange.respond(ResponseCode.CONTENT, subtree, MediaTypeRegistry.APPLICATION_LINK_FORMAT);
}
}
@Override
public void handlePOST(CoapExchange exchange) {
String payload = exchange.getRequestText();
String[] parts = payload.split("\\?");
String[] path = parts[0].split("/");
Resource resource = create(new LinkedList<String>(Arrays.asList(path)));
Response response = new Response(ResponseCode.CREATED);
response.getOptions().setLocationPath(resource.getURI());
exchange.respond(response);
}
@Override
public void handlePUT(CoapExchange exchange) {
content = exchange.getRequestText();
exchange.respond(ResponseCode.CHANGED);
}
@Override
public void handleDELETE(CoapExchange exchange) {
this.delete();
exchange.respond(ResponseCode.DELETED);
}
/**
* Find the requested child. If the child does not exist yet, create it.
*/
@Override
public Resource getChild(String name) {
Resource resource = super.getChild(name);
if (resource == null) {
resource = new StorageResource(name);
add(resource);
}
return resource;
}
/**
* Create a resource hierarchy with according to the specified path.
* @param path the path
* @return the lowest resource from the hierarchy
*/
private Resource create(LinkedList<String> path) {
String segment;
do {
if (path.size() == 0)
return this;
segment = path.removeFirst();
} while (segment.isEmpty() || segment.equals("/"));
StorageResource resource = new StorageResource(segment);
add(resource);
return resource.create(path);
}
}