jim hamblen / Mbed OS 4180_TCPSocket_Example

Alternative TCPSocket example using an HTTP GET to read a short "helloworld" text web page using a different server

Fork of ARMs demo HTTP socket demo. ARM's server was redirected and the demo was no longer working. An alternative server was setup and the code was modified to display the web page text in addition to just "200 OK". Only works for a very short web page - buffer only 400 characters but RAM is running out on the LPC1768 in the demo! Data read from the web page is read and parsed to control the mbed's 4 LEDs for a basic IoT demo.

main.cpp

Committer:
4180_1
Date:
2021-02-15
Revision:
5:66c4a71d22e9
Parent:
4:d3627ca18f87
Child:
6:9cf6630fa25d

File content as of revision 5:66c4a71d22e9:

#include "mbed.h"
#include "EthernetInterface.h"

// Network interface
EthernetInterface net;

// Socket demo
int main() {
    // Show MAC in case it is needed to enable DHCP on a secure network
    char mac[6];
    mbed_mac_address(mac);
    printf("\r\rmbed's MAC address is %02x:%02x:%02x:%02x:%02x:%02x\n\r", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]); 
    // Bring up the ethernet interface
    printf("Waiting for IP address from DHCP Server\n\r");
    wait(1.0);
    net.connect();
    printf("\n\rEthernet socket example\n\r");

    // Show the network address
    const char *ip = net.get_ip_address();
    printf("IP address is: %s\n\r", ip ? ip : "Timeout - No IP obtained");

    // Open a socket on the network interface, and create a TCP connection to mbed.org
    TCPSocket socket;
    socket.open(&net);
    socket.connect("hamblen.ece.gatech.edu", 80);

    // Send a simple http request
    char sbuffer[] = "GET /hello.txt HTTP/1.1\r\nHost: hamblen.ece.gatech.edu\r\n\r\n";
    int scount = socket.send(sbuffer, sizeof sbuffer);
    //print out packet
    printf("sent %d [%.*s]\n\r", scount, strstr(sbuffer, "\r\n")-sbuffer, sbuffer);

    // Recieve a simple http response and print out the response line and text
    char rbuffer[400]; //enough for a very short text page - almost out of RAM!
    int rcount = socket.recv(rbuffer, sizeof rbuffer);
    rbuffer[rcount] = 0; //terminate to print as a C string;
    printf("recv %d [%.*s]\n\r", rcount, strstr(rbuffer, "\r\n"), rbuffer);

    // Close the socket to return its memory and bring down the network interface
    socket.close();

    // Bring down the ethernet interface
    net.disconnect();
    printf("Done\n\r");
}