text: /*
   * 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 <stdlib.h>
  #include <string.h>
  #include "coap-engine.h"
  #include "stdio.h"
  
  static void res_put_handler(coap_message_t *request, coap_message_t *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset);
  
  /*
   * A handler function named [resource name]_handler must be implemented for each RESOURCE.
   * A buffer for the response payload is provided through the buffer pointer. Simple resources can ignore
   * preferred_size and offset, but must respect the REST_MAX_CHUNK_SIZE limit for the buffer.
   * If a smaller block size is requested for CoAP, the REST framework automatically splits the data.
   */
  RESOURCE(res_hello7,
           "title=\"Hello world: ?len=0..\";rt=\"Text\"",
           NULL,
           NULL,
  	 res_put_handler,
  	 NULL);
  
  static int value_len = 0;
  static uint8_t value[20];
  
  static void res_put_handler(coap_message_t *request, coap_message_t *response, uint8_t *buffer, uint16_t preferred_size, int32_t *offset)
  {
  
    const uint8_t *payload = NULL;
    int payload_len = coap_get_payload(request, &payload);
    if ( payload_len  > 0 && payload != NULL) {
  	memcpy(value, payload, payload_len);
          value_len = payload_len;
    }
    if (coap_get_header_if_none_match(request)){
          printf("if none match found\n");
    	coap_set_status_code(response, PRECONDITION_FAILED_4_12);
    } else {
  	coap_set_status_code(response, CHANGED_2_04);
          coap_set_payload(response, value, value_len);
          coap_set_header_content_format(response, TEXT_PLAIN); /* text/plain is the default, hence this option could be omitted. */
    }
     
  
  }
  
  
  