osd-contiki/examples/osd/climate2/resources/res-dht11hum.c

/*
 * Copyright (c) 2014, OSDomotics, Institute of Technology.
 * 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
 *      dht11hum Sensor Resource
 *
 *      This is a simple GET resource that returns the humidity in % rel.
 *
 * \author
 *      Harald Pichler <harald@the-develop.net>
 */

#include "contiki.h"

#if PLATFORM_HAS_DHT11HUM

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <math.h>
#include "rest-engine.h"
#include "dev/dht11.h"

/*A simple getter example. Returns the reading from dhtxx sensor*/
static void res_get_dht11hum_handler(void *request, void *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset);

RESOURCE(res_dht11hum,
         "title=\"Humidity DHTxx\";rt=\"humidity %\"",
         res_get_dht11hum_handler,
         NULL,
         NULL,
         NULL);
         
uint16_t dht11_hum=0;

static void
res_get_dht11hum_handler(void* request, void* response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset)
{
  char message[100];
  int length = 0; /*           |<-------->| */

  unsigned int accept = -1;
  REST.get_header_accept(request, &accept);

  if(accept == -1 || accept == REST.type.TEXT_PLAIN)
  {
    REST.set_header_content_type(response, REST.type.TEXT_PLAIN);
    snprintf(message, REST_MAX_CHUNK_SIZE, "%d.%02d",dht11_hum/100, dht11_hum % 100);

    length = strlen(message);
    memcpy(buffer, message,length );

    REST.set_response_payload(response, buffer, length);
  }
  else if (accept == REST.type.APPLICATION_JSON)
  {
    REST.set_header_content_type(response, REST.type.APPLICATION_JSON);
    snprintf(message, REST_MAX_CHUNK_SIZE, "{\"hum\":\"%d.%02d\"}",dht11_hum/100, dht11_hum % 100);

    length = strlen(message);
    memcpy(buffer, message,length );

    REST.set_response_payload(response, buffer, length);
  }
  else
  {
    REST.set_response_status(response, REST.status.NOT_ACCEPTABLE);
    REST.set_response_payload(response, (uint8_t *)"Supporting content-types text/plain and application/json", 56);
  }
}
#endif /* PLATFORM_HAS_DHT11HUM */