This document contains an example of calling the service and receiving a result using the REST ThingWorx. Example Arduino sketch in C language.
#include <SPI.h>
#include <Ethernet.h>
#include <ArduinoJson.h>
// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x03};
char server[] = "tvsn.cloud.thingworx.com";
EthernetClient client;
//ThingWorx App key which replaces login credentials)
char appKey[] = "b0b54023-3977-4670-8a0a-671ef412fe30";
// ThingWorx Thing name for which you want to set properties values
char thingName[] = "ExamleThing";
//Interval of time at which you want the properties values to be sent to TWX server
int timeBetweenRefresh = 5000;
// ThingWorx service that will set values for the properties you need
// See the documentation for this tutorial for more information
char serviceName[] = "ExampleService";
//How many values you will be pushing to ThingWorx
#define propertyCount 2
//Initialize Properties Names and Values Arrays
const char* propertyNames[] = {"Example1", "Example2"};
double propertyValues[propertyCount];
// last time you connected to the server, in milliseconds
unsigned long lastConnectionTime = 0;
// timer waiting for the arrival of characters from the server
unsigned long timer_iot_timeout = 0;
// Receive buffer size
#define BUFF_LENGTH 64
void setup() {
//shut down the SD Card pins
pinMode(4, OUTPUT);
digitalWrite(4, HIGH);
// start serial port:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
// start the Ethernet connection:
Serial.println("Trying to get an IP address using DHCP");
Ethernet.begin(mac);
Serial.print("My IP address: ");
Serial.print(Ethernet.localIP());
Serial.println();
}
void loop() {
// wait the established interval of time before
// reading values from the sensor
// and sending them to the TWX server again
// delay(timeBetweenRefresh);
if (millis() - lastConnectionTime > timeBetweenRefresh)
updateServiceValues();
else
updateSensorsData();
}
void updateSensorsData()
{
// Aquire sensor values
propertyValues[0] = 0;
}
void updateServiceValues()
{
// Connection to server Thingworx
Serial.println("Connecting to IoT server...");
if (client.connect(server, 80))
{
// Check connection
if (client.connected())
{
// Sending a header of a network packet
Serial.println("Sending data to IoT server...\n");
Serial.print("POST /Thingworx/Things/");
client.print("POST /Thingworx/Things/");
Serial.print(thingName);
client.print(thingName);
Serial.print("/Services/");
client.print("/Services/");
Serial.print(serviceName);
client.print(serviceName);
Serial.print("?appKey=");
client.print("?appKey=");
Serial.print(appKey);
client.print(appKey);
Serial.print("&method=post&x-thingworx-session=true");
client.print("&method=post&x-thingworx-session=true");
// Sending data from sensors
for (int idx = 0; idx < propertyCount; idx ++)
{
Serial.print("&");
client.print("&");
Serial.print(propertyNames[idx]);
client.print(propertyNames[idx]);
Serial.print("=");
client.print("=");
Serial.print(propertyValues[idx]);
client.print(propertyValues[idx]);
}
// Close package
Serial.println(" HTTP/1.1");
client.println(" HTTP/1.1");
Serial.println("Accept: application/json");
client.println("Accept: application/json");
Serial.print("Host: ");
client.print("Host: ");
Serial.println(server);
client.println(server);
Serial.println("Content-Type: application/json");
client.println("Content-Type: application/json");
Serial.println();
client.println();
// Waiting for a response from the server
timer_iot_timeout = millis();
while ((client.available() == 0) && (millis() < timer_iot_timeout + 5000));
// Display the response on the server, and if a slow connection, wait for the timeout
char buff[BUFF_LENGTH] = "";
int iii = 0;
bool flagJSON = false;
timer_iot_timeout = millis();
while ((millis() < timer_iot_timeout + 100) && (client.connected()))
{
while (client.available() > 0)
{
char symb = client.read();
Serial.print(symb);
if (symb == '{')
{
flagJSON = true;
}
else if (symb == '}')
{
flagJSON = false;
}
if (flagJSON == true)
{
buff[iii] = symb;
iii ++;
}
timer_iot_timeout = millis();
}
}
buff[iii] = '}';
buff[iii + 1] = '\0';
Serial.println(buff);
// Close connection
client.stop();
// Decrypted parameters
StaticJsonBuffer<BUFF_LENGTH> jsonBuffer;
JsonObject& json_array = jsonBuffer.parseObject(buff);
//Service result variable (return JSON)
int result = json_array["result"];
Serial.println("Result state: " + String(result));
Serial.println();
// Device control
//controlDevices();
Serial.println("Packet successfully sent!");
Serial.println();
lastConnectionTime = millis();
}
}
else {
// if you didn't get a connection to the server:
Serial.println("Connection could not be established");
client.stop();
}
}
Many thanks to the company MGBOT for the idea of this example.
