contiki/examples/er-rest-example/resources/res-push.c

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/*
* Copyright (c) 2013, 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 Contiki operating system.
*/
/**
* \file
* Example resource
* \author
* Matthias Kovatsch <kovatsch@inf.ethz.ch>
*/
#include <string.h>
#include "rest-engine.h"
#include "er-coap.h"
static void res_get_handler(void *request, void *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset);
static void res_periodic_handler(void);
PERIODIC_RESOURCE(res_push,
"title=\"Periodic demo\";obs",
res_get_handler,
NULL,
NULL,
NULL,
5 * CLOCK_SECOND,
res_periodic_handler);
/*
* Use local resource state that is accessed by res_get_handler() and altered by res_periodic_handler() or PUT or POST.
*/
static int32_t event_counter = 0;
static void
res_get_handler(void *request, void *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset)
{
/*
* For minimal complexity, request query and options should be ignored for GET on observable resources.
* Otherwise the requests must be stored with the observer list and passed by REST.notify_subscribers().
* This would be a TODO in the corresponding files in contiki/apps/erbium/!
*/
REST.set_header_content_type(response, REST.type.TEXT_PLAIN);
REST.set_header_max_age(response, res_push.periodic->period / CLOCK_SECOND);
REST.set_response_payload(response, buffer, snprintf((char *)buffer, preferred_size, "VERY LONG EVENT %lu", event_counter));
/* The REST.subscription_handler() will be called for observable resources by the REST framework. */
}
/*
* Additionally, a handler function named [resource name]_handler must be implemented for each PERIODIC_RESOURCE.
* It will be called by the REST manager process with the defined period.
*/
static void
res_periodic_handler()
{
/* Do a periodic task here, e.g., sampling a sensor. */
++event_counter;
/* Usually a condition is defined under with subscribers are notified, e.g., large enough delta in sensor reading. */
if(1) {
/* Notify the registered observers which will trigger the res_get_handler to create the response. */
REST.notify_subscribers(&res_push);
}
}