Zoltan Hudak / Mbed OS STM32F407VET6_WebSwitch-os

Tiny HTTP server controlling a DigitalOutput.

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

In this example we create a HTTP server for the STM32F407VET6 black board 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.

A DP83848 module is used as Ethernet interface.

/media/uploads/hudakz/dp83848_01.jpg

Wiring

DP83848 moduleSTM32F407VET6 board
VCC<=>+3.3V
GND<=>GND
MDIO<=>PA_2
MDC<=>PC_1
OSCIN<=>PA_1
CRS<=>PA_7
RX0<=>PC_4
RX1<=>PC_5
TX_EN<=>PB_11
TX0<=>PB_12
TX1<=>PB_13

Notice that because the RX_ER line is not used the DP83848 module doesn't have to be modified.

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

main.cpp

Committer:
hudakz
Date:
2020-10-29
Revision:
10:6860e839277e
Parent:
9:3716ffcf2f27

File content as of revision 10:6860e839277e:

#include "mbed.h"
#include "EthernetInterface.h"
#include "TCPSocket.h"
#include <stdio.h>
#include <string>

DigitalOut led(PA_6);

FileHandle* mbed::mbed_override_console(int)
{
    static BufferedSerial   arch_max_serial1(PA_9, PA_10, 9600);
    return &arch_max_serial1;
}

#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

FileHandle* mbed_override_console(int)
{
    static BufferedSerial   arch_max_serial1(PA_9, PA_10, 9600);
    return &arch_max_serial1;
}

/**
 * @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()
{
    printf("starting\r\n");

    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();

    //listening for http GET request
    while (true) {
        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);
        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();
        }
    }
}