File content as of revision 1:feb9f603f054:

#include "mbed.h"
#include "EthernetInterface.h"
#include "Adafruit_SSD1306.h"
   
// W7500 onboard LED & Init
DigitalOut gled(LED2,0);


// I2C Class
I2C i2c(PA_10,PA_9);

// OLED Class   
Adafruit_SSD1306_I2c gOled(i2c,NC,0x78,64,128);

// Declare Ethernet Class
EthernetInterface eth;

// Declare TCP Connection Class
TCPSocketConnection sock;



int main() {
      
    int phy_link;
    printf("Wait a second...\r\n");
    
    //--------- Have to modify the mac address-------------
    uint8_t mac_addr[6] = {0x00, 0x08, 0xDC, 0xff, 0xff, 0x25};   
    
    eth.init(mac_addr);     //Use DHCP
        
    // phy link 
    do{
        phy_link = eth.ethernet_link();
        printf("...");
        wait(2);
    }while(!phy_link);
    printf("\r\n");
        
    eth.connect();
         
    printf("IP Address is %s\r\n\r\n", eth.getIPAddress());
    printf("MASK Address is %s\r\n\r\n", eth.getNetworkMask());
    printf("GATEWAY Address is %s\r\n\r\n", eth.getGateway());
    printf("MAC Address is %s\r\n\r\n", eth.getMACAddress());
    
    while(1){
        // TCP socket connect to openweather server 
        //TCPSocketConnection sock;
        char http_addr[]="api.openweathermap.org";
        int port=80;
        
        //connect
        ///////////////////////////////////////////////////////////
        sock.connect(http_addr, port);
        ////////////////////////////////////////////////////////////
        
        // GET method, to request weather forecast  
        char http_cmd[] = "GET /data/2.5/weather?q=London,uk&appid=a0ca47dd7f6066404629b3e1ad728981 HTTP/1.0\n\n";
        
        
        //send data
        ///////////////////////////////////////////////////////
        sock.send(http_cmd, sizeof(http_cmd)-1);
        ///////////////////////////////////////////////////////
        
        // get data into buffer
        char buffer[2048];
        int ret;
        while (true) {
            // break the while(), when don't received tha data
            // save the data to buffer
            // save the return value to ret
            //receive data
            //////////////////////////////////////////////////////
            ret = sock.receive(buffer, sizeof(buffer)-1);
            if (ret <= 0)
                break;
            ////////////////////////////////////////////////////
            buffer[ret] = '\0';
            printf("Received %d chars from server: %s\n", ret, buffer);     
        }
        printf("\r\n\r\n");
        
        // parsing current date, weather, city, tempurature 
        char *date;
        char *weather;
        char *city;
        char *temper;
        
        char cur_date[17] = {0};
        char weather_con[15] = {0};
        char city_name[10] = {0};
        char temper_data[3] = {0};
    
        int temp;
        int num100, num10, num1;
        
        //parding date
        date = strstr(buffer, "Date");
        for(int x=0;x<17;x++){
            cur_date[x] = date[x+6];
        }
            
        // parsing weather condition
        weather = strstr(buffer, "main");
        for(int i=0; i<15;i++){
            weather_con[i] = weather[i+7];
            if(weather_con[i] == 34){
                weather_con[i] = 0;
                break;
            }
        }
        
        // parsing city name
        city = strstr(buffer, "name");
        for(int j=0; j<10;j++){
            city_name[j] = city[j+7];
            if(city_name[j] == 34){
                city_name[j] = 0;
                break;
            }
        }
     
        //parsing current tempurature
        temper = strstr(buffer, "temp");
        for(int k=0; k<3;k++){
            temper_data[k] = temper[k+6];
        }
           
        //kelvin to celius converter
        num100 = temper_data[0]- 48;
        num10 = temper_data[1] - 48;
        num1 = temper_data[2]- 48;
        temp = (num100*100 + num10*10 + num1) - 273;
        
        // Debug message
        printf("city name   :  %s\r\n",  city_name);
        printf("weather     :  %s\r\n",  weather_con);
        printf("temperature :  %d\r\n\r\n",  temp);
        
        // OLED Display
        gOled.begin();
        gOled.clearDisplay();
        gOled.printf("%s\n\n", cur_date);
        gOled.printf("City    : %s\n", city_name);
        gOled.printf("Weather : %s\n", weather_con);
        gOled.printf("Temper  : %d\n", temp);
        gOled.display();
        gOled.setTextCursor(0,0);
        

    
        //close 
        //////////////////////////////////////////////////
        sock.close();
        eth.disconnect();
        //////////////////////////////////////////////////
        /* 
         *    everytime in delay, request weather forecast 
         */
        wait(20.0);
    
   };

}