Zoltan Hudak / Mbed OS WebSwitch_mbed-os

HTTP Server serving a simple webpage which enables to remotely turn LED1 on/off. Compile, download, run and type 'IP_address/secret/' (don't forget the last '/') into your web browser and hit ENTER.

Fork of WebSwitch_mbed-os by Zoltan Hudak

Turn LED1, or other digital output, on/off using a web browser.

In this example we create a HTTP server that will serve a simple Web page to remotely turn LED1, or other digital output, on/off by using a web browser.

/media/uploads/hudakz/webswitch03.png/media/uploads/hudakz/webswitch_mobile01.jpg

Notice that DHCP is turned on by default. The IP address assigned to the WebSwitch server along with an instruction how to use it is printed to the connected PC's serial terminal window during program start up.
To use static IP address uncomment and adjust line #221 in main.cpp.

The project was inspired by the Tuxgraphics Web Switch. Thank you Guido!

For a Web Switch using

main.cpp

Committer:
hudakz
Date:
2020-10-27
Revision:
12:138b2b3d041a
Parent:
11:101be77aa5db

File content as of revision 12:138b2b3d041a:

#include "mbed.h"
#include "EthernetInterface.h"
#include "TCPSocket.h"
#include <stdio.h>
#include <string>
using namespace std;

#define IP      "192.168.1.181"
#define GATEWAY "192.168.1.1"
#define NETMASK "255.255.255.0"

#define PORT    80
/* */
EthernetInterface*  net;
TCPSocket           server;
TCPSocket*          client;
char                httpBuf[1500];
char                httpHeader[256];
const int           OFF = 0;
const int           ON = 1;
const char          PASSWORD[] = "secret";  // Change as you like
DigitalOut          output(LED1);
float               roomTemp = 21.8;        // A temperature sensor output

/**
 * @brief   Analyses the received URL
 * @note    The string passed to this function will look like this:
 *          GET /password HTTP/1.....
 *          GET /password/ HTTP/1.....
 *          GET /password/?sw=1 HTTP/1.....
 *          GET /password/?sw=0 HTTP/1.....
 * @param   url URL string
 * @retval -1 invalid password
 *         -2 no command given but password valid
 *         -3 just refresh page
 *          0 switch off
 *          1 switch on
 */
int8_t analyseURL(char* url)
{
    if (strlen(url) < (5 + strlen(PASSWORD) + 1))
        return(-1);

    //if (url.substr(5, PASSWORD.size()) != PASSWORD)
    if (strncmp(url + 5, PASSWORD, strlen(PASSWORD)) != 0)
        return(-1);

    uint8_t pos = 5 + strlen(PASSWORD);

    //if (url.substr(pos, 1) != "/")

    if (*(url + pos) != '/')
        return(-1);

    //if (url.substr(pos++, 1) == " ")
    if (*(url + pos++) == ' ')
        return(-2);

    //string  cmd(url.substr(pos, 5));
    *(url + pos + 5) = '\0';    // terminate the cmd string
    char*   cmd = ((url + pos));
    if (strcmp(cmd, "?sw=0") == 0)
        return(0);
    if (strcmp(cmd, "?sw=1") == 0)
        return(1);
    return(-3);
}

/**
 * @brief
 * @note
 * @param
 * @retval
 */
char* movedPermanently(uint8_t flag)
{
    memset(httpBuf, 0, sizeof(httpBuf));
    if (flag == 1) {
        strcpy(httpBuf, "/");
        strcat(httpBuf, PASSWORD);
        strcat(httpBuf, "/");
    }

    strcat(httpBuf, "<h1>301 Moved Permanently</h1>\r\n");
    return(httpBuf);
}

/**
 * @brief
 * @note
 * @param
 * @retval
 */
char* showWebPage(int status)
{
    char    roomTempStr[10] = { };

    //roomTemp = ds1820.read();

    sprintf(roomTempStr, "%3.1f", roomTemp);
    memset(httpBuf, 0, sizeof(httpBuf));

    /*$off*/
    strcat
    (
        httpBuf,
        "<head>"
            "<meta charset=\"utf-8\">"
            "<meta name=\"viewport\" content=\" initial-scale=1.0; maximum-scale=1.0; minimum-scale=1.0; user-scalable=0;\"/>"
            "<title>Smart Home</title>"
            "<link href='http://fonts.googleapis.com/css?family=Droid+Sans&v1' rel='stylesheet' type='text/css'>"
            "<style>"
            ".switch {"
                "position: relative;"
                "display: inline-block;"
                "width: 60px;"
                "height: 34px;"
            "}"
            ".switch input {display:none;}"
            ".slider {"
                "position: absolute;"
                "cursor: pointer;"
                "top: 0;"
                "left: 0;"
                "right: 0;"
                "bottom: 0;"
                "border-radius: 34px;"
                "background-color: #ccc;"
                "-webkit-transition: .4s;"
                "transition: .4s;"
            "}"
            ".slider:before {"
                "position: absolute;"
                "content: \"\";"
                "height: 26px;"
                "width: 26px;"
                "left: 4px;"
                "bottom: 4px;"
                "border-radius: 50%;"
                "background-color: white;"
                "-webkit-transition: .4s;"
                "transition: .4s;"
            "}"
            "input:checked + .slider {"
                "background-color: #8ce196;"
            "}"
            "input:focus + .slider {"
                "box-shadow: 0 0 1px #8ce196;"
            "}"
            "input:checked + .slider:before {"
                "-webkit-transform: translateX(26px);"
                "-ms-transform: translateX(26px);"
                "transform: translateX(26px);"
            "}"
            "</style>"
        "</head>"

        "<body>"
            "<h2><a href=\".\" title=\"Click to refresh the page\">Smart Home</a></h2>"
            "<pre>Temperature:\t"
    );
    strcat(httpBuf, roomTempStr);
    strcat(httpBuf, "&deg;C</pre>");
    strcat
    (
       httpBuf,
       "<pre>Heating:\t"
    );
    if(status == ON) {
       strcat
       (
           httpBuf,
           "<a href=\"./?sw=0\" class=\"switch\"> "
           "<input type=\"checkbox\" checked>"
       );
    }
    else {
       strcat
       (
           httpBuf,
           "<a href=\"./?sw=1\" class=\"switch\"> "
           "<input type=\"checkbox\">"
       );
    }
    strcat
    (
       httpBuf,
           "<div class=\"slider\"></div>"
           "</a>"
           "</pre>"
           "<hr>"
           "<pre>2017 ARMmbed</pre>"
       "</body>"
    );
    /*$on*/
    return httpBuf;
}

/**
 * @brief
 * @note
 * @param
 * @retval
 */
void sendHTTP(TCPSocket* client, char* header, char* content)
{
    char    content_length[10] = { };
    sprintf(content_length, "%u\r\n", strlen(content));
    strcat(header, "\r\nContent-Type: text/html\r\n");
    strcat(header, "Content-Length: ");
    strcat(header, content_length);
    strcat(header, "Pragma: no-cache\r\n");
    strcat(header, "Connection: About to close\r\n\r\n");

    char    c = content[0];
    memmove(httpBuf + strlen(header), httpBuf, strlen(content));    // make room for the header
    strcpy(httpBuf, header);                                        // copy the header on front of the content
    httpBuf[strlen(header)] = c;
    client->send((uint8_t*)httpBuf, strlen(httpBuf));
}

/**
 * @brief
 * @note
 * @param
 * @retval
 */
int main(void)
{
    printf("\r\n Starting \r\n");

    //ethLed.start(eth_led);
    //net = NetworkInterface::get_default_instance();
    net = new EthernetInterface();

    //net->set_network("192.168.1.181","255.255.255.0","192.168.1.1");  // use static IP address, netmask, gateway
    if (!net) {
        printf("Error! No network inteface found.\n");
        return 0;
    }

    //net->set_network (IP, NETMASK, GATEWAY);  // include this for using static IP address
    nsapi_size_or_error_t   r = net->connect();
    if (r != NSAPI_ERROR_OK) {
        printf("Error! net->connect() returned: %d\n", r);
        return r;
    }

    // Show the network address
    SocketAddress   addr;
    net->get_ip_address(&addr);
    printf("IP address: %s\n", addr.get_ip_address() ? addr.get_ip_address() : "None");
    net->get_netmask(&addr);
    printf("Netmask: %s\n", addr.get_ip_address() ? addr.get_ip_address() : "None");
    net->get_gateway(&addr);
    printf("Gateway: %s\n", addr.get_ip_address() ? addr.get_ip_address() : "None");

    /* Open the server on ethernet stack */
    server.open(net);

    /* Bind the HTTP port (TCP 80) to the server */
    server.bind(PORT);

    /* Listen for clients */
    server.listen();

    printf("=========================================\r\n");
    printf("Ready to serve clients.\r\n");
    net->get_ip_address(&addr);
    printf("Usage: Type http:\/\/%s\/%s\/  into your web browser and hit ENTER\r\n", addr.get_ip_address(), PASSWORD);
    while (true) {
        //listening for http GET request
        client = server.accept();
        if (client) {
            client->getpeername(&addr);
            printf("Connection succeeded!\n\rIP: %s\n\r", addr.get_ip_address());
            client->recv(httpBuf, 1500);
            if (strncmp(httpBuf, "GET", 3) != 0) {
                strcpy(httpHeader, "HTTP/1.0 200 OK");
                strcpy(httpBuf, "<h1>200 OK</h1>");
                sendHTTP(client, httpHeader, httpBuf);
            }
            else
            if ((strncmp(httpBuf, "GET", 3) == 0) && (strncmp(httpBuf + 3, " / ", 3 == 0))) {
                strcpy(httpHeader, "HTTP/1.0 200 OK");
                strcpy(httpBuf, "<p>Usage: http://host_or_ip/password</p>\r\n");
                sendHTTP(client, httpHeader, httpBuf);
            }
            else {
                int cmd = analyseURL(httpBuf);
                switch (cmd) {
                    case -3:
                        // update webpage
                        strcpy(httpHeader, "HTTP/1.0 200 OK");
                        sendHTTP(client, httpHeader, showWebPage(output));
                        break;

                    case -2:
                        // redirect to the right base url
                        strcpy(httpHeader, "HTTP/1.0 301 Moved Permanently\r\nLocation: ");
                        sendHTTP(client, httpHeader, movedPermanently(1));
                        break;

                    case -1:
                        strcpy(httpHeader, "HTTP/1.0 401 Unauthorized");
                        strcpy(httpBuf, "<h1>401 Unauthorized</h1>");
                        sendHTTP(client, httpHeader, httpBuf);
                        break;

                    case 0:
                        output = OFF;   // output off
                        strcpy(httpHeader, "HTTP/1.0 200 OK");
                        sendHTTP(client, httpHeader, showWebPage(output));
                        break;

                    case 1:
                        output = ON;    // output on
                        strcpy(httpHeader, "HTTP/1.0 200 OK");
                        sendHTTP(client, httpHeader, showWebPage(output));
                        break;
                }
            }

            client->close();
        }
    }
}