gas_sensor.cpp

00001 // IPSO Prototype gas sensor resource implementation
00002 
00003 #include "mbed.h"
00004 #include "nsdl_support.h"
00005 
00006 #define GAS_RES_ID    "3300/0/5700"
00007 #define GAS_RES_RT    "urn:X-mbed:gas-sensor"
00008 
00009 extern Serial pc;
00010 uint8_t gas_max_age = 0; 
00011 uint8_t gas_content_type = 50;
00012 
00013 AnalogIn gasSensor(A0);
00014 int gas_percent;
00015 char gasPctString[5];
00016 
00017 /* Only GET method allowed */
00018 static uint8_t gas_sensor_resource_cb(sn_coap_hdr_s *received_coap_ptr, sn_nsdl_addr_s *address, sn_proto_info_s * proto)
00019 {
00020     sn_coap_hdr_s *coap_res_ptr = 0;
00021 
00022     if(received_coap_ptr->msg_code == COAP_MSG_CODE_REQUEST_GET)
00023     {
00024         gas_percent = gasSensor.read() * 100;
00025         sprintf(gasPctString,"%d", gas_percent);
00026         pc.printf("gas percent %s\r\n", gasPctString);
00027 
00028         coap_res_ptr = sn_coap_build_response(received_coap_ptr, COAP_MSG_CODE_RESPONSE_CONTENT);
00029 
00030         coap_res_ptr->payload_len = strlen(gasPctString);
00031         coap_res_ptr->payload_ptr = (uint8_t*)gasPctString;
00032         
00033         coap_res_ptr->content_type_ptr = &gas_content_type;
00034         coap_res_ptr->content_type_len = sizeof(gas_content_type);
00035         
00036         coap_res_ptr->options_list_ptr = (sn_coap_options_list_s*)nsdl_alloc(sizeof(sn_coap_options_list_s));
00037         if(!coap_res_ptr->options_list_ptr)
00038             {
00039             pc.printf("cant alloc option list for max-age\r\n");
00040             coap_res_ptr->options_list_ptr = NULL; //FIXME report error and recover
00041             }
00042         memset(coap_res_ptr->options_list_ptr, 0, sizeof(sn_coap_options_list_s));
00043         coap_res_ptr->options_list_ptr->max_age_ptr = &gas_max_age;
00044         coap_res_ptr->options_list_ptr->max_age_len = sizeof(gas_max_age);
00045 
00046         sn_nsdl_send_coap_message(address, coap_res_ptr);
00047         nsdl_free(coap_res_ptr->options_list_ptr);
00048         coap_res_ptr->options_list_ptr = NULL;
00049         coap_res_ptr->content_type_ptr = NULL;// parser_release below tries to free this memory
00050 
00051     }
00052 
00053     sn_coap_parser_release_allocated_coap_msg_mem(coap_res_ptr);
00054 
00055     return 0;
00056 }
00057 
00058 int create_gas_sensor_resource(sn_nsdl_resource_info_s *resource_ptr)
00059 {
00060     nsdl_create_dynamic_resource(resource_ptr, sizeof(GAS_RES_ID)-1, (uint8_t*)GAS_RES_ID, sizeof(GAS_RES_RT)-1, (uint8_t*)GAS_RES_RT, 0, &gas_sensor_resource_cb, (SN_GRS_GET_ALLOWED));
00061     return 0;
00062 }