97 lines
4 KiB
C
97 lines
4 KiB
C
/*
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* Copyright (c) 2014, Nimbus Centre for Embedded Systems Research, Cork Institute of Technology.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*/
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/**
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* \file
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* SHT11 Sensor Resource
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*
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* This is a simple GET resource that returns the temperature in Celsius
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* and the humidity reading from the SHT11.
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* \author
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* Pablo Corbalan <paul.corbalan@gmail.com>
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*/
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#include "contiki.h"
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#if PLATFORM_HAS_SHT11
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#include <string.h>
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#include "rest-engine.h"
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#include "dev/sht11/sht11-sensor.h"
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static void res_get_handler(void *request, void *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset);
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/* Get Method Example. Returns the reading from temperature and humidity sensors. */
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RESOURCE(res_sht11,
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"title=\"Temperature and Humidity\";rt=\"Sht11\"",
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res_get_handler,
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NULL,
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NULL,
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NULL);
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static void
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res_get_handler(void *request, void *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset)
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{
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/* Temperature in Celsius (t in 14 bits resolution at 3 Volts)
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* T = -39.60 + 0.01*t
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*/
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uint16_t temperature = ((sht11_sensor.value(SHT11_SENSOR_TEMP) / 10) - 396) / 10;
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/* Relative Humidity in percent (h in 12 bits resolution)
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* RH = -4 + 0.0405*h - 2.8e-6*(h*h)
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*/
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uint16_t rh = sht11_sensor.value(SHT11_SENSOR_HUMIDITY);
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unsigned int accept = -1;
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REST.get_header_accept(request, &accept);
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if(accept == -1 || accept == REST.type.TEXT_PLAIN) {
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REST.set_header_content_type(response, REST.type.TEXT_PLAIN);
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snprintf((char *)buffer, REST_MAX_CHUNK_SIZE, "%u;%u", temperature, rh);
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REST.set_response_payload(response, (uint8_t *)buffer, strlen((char *)buffer));
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} else if(accept == REST.type.APPLICATION_XML) {
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REST.set_header_content_type(response, REST.type.APPLICATION_XML);
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snprintf((char *)buffer, REST_MAX_CHUNK_SIZE, "<Temperature =\"%u\" Humidity=\"%u\"/>", temperature, rh);
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REST.set_response_payload(response, buffer, strlen((char *)buffer));
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} else if(accept == REST.type.APPLICATION_JSON) {
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REST.set_header_content_type(response, REST.type.APPLICATION_JSON);
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snprintf((char *)buffer, REST_MAX_CHUNK_SIZE, "{'Sht11':{'Temperature':%u,'Humidity':%u}}", temperature, rh);
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REST.set_response_payload(response, buffer, strlen((char *)buffer));
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} else {
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REST.set_response_status(response, REST.status.NOT_ACCEPTABLE);
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const char *msg = "Supporting content-types text/plain, application/xml, and application/json";
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REST.set_response_payload(response, msg, strlen(msg));
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}
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}
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#endif /* PLATFORM_HAS_SHT11 */
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