Spark Core Code

/*This is the code that will be on the Spark Core*/

#define NUM_TRIES 2
#define MAXLINE 1024
TCPClient client;
byte server[] = { 10,0,0,18 }; // Rpi server
int port = 17060;

char *connect_and_send(char* message);
void *get_response(char *response);
char *response_buf = (char*)malloc(sizeof(char) * MAXLINE/4);;

void setup()
{
    pinMode(D7, OUTPUT);
    Spark.variable("response", response_buf, STRING);
}

void loop()
{
    char *response = connect_and_send("GET pi.txt");
    if(response == NULL)
    {
        return;
    }
    strcpy(response_buf, response);
    digitalWrite(D7, HIGH);
    delay(5000);
    if(response != NULL)
        free(response);
    digitalWrite(D7, LOW);
}


//Call this function to connect and send a message. Returns the message it received
//TODO: make it return an array and make verbose mode where it will echo the response
inline char *connect_and_send(char *message)
{
    bool connected = false;
    char *response = (char*)malloc(sizeof(char) * MAXLINE/4);
    if(response == NULL)
        return response;


    // Tries to connect to server multiple times
    for(int i = 0; i < NUM_TRIES; i++)
    {
        if(client.connect(server,port)) //if connected, send message
        {
            connected = true;
            client.println(message);
            break;
        }
    }

    if(connected)   //if connection succeeded, get the file
    {
        get_response(response);
    }

    delay(100);
    client.flush();
    client.stop();
    return response;
}

//Gets the file response from the Raspberry Pi and modifies pointer response
void *get_response(char *response)
{
    int count = 0;
    if (client.connected())
    {
        // echo all available bytes back to the client
        while (client.available())
        {
            char c = client.read();
            response[count] = c;
            count += 1;
        }
    }
    else
    {
        digitalWrite(D7, HIGH);
        delay(500);
        digitalWrite(D7, LOW);
    }
}