Zoltan Hudak / Mbed OS WebSwitch_ENC28J60 Featured

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

Dependencies:   UIPEthernet

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 the mbed board, on/off by using a web browser. An inexpensive ENC28J60 Ethernet module is used to assure connection between the mbed board and the Ethernet network (Internet). The ENC28J60 Ethernet module is driven by the UIPEthernet library.

Needed parts:

  • mbed board
  • ENC28J60 Ethernet module
  • Wires
  • Web browser (Internet Explorer, Safari, Firefox, Chrome ...) running on Windows, Mac, Linux, iPhone or Android device.
/media/uploads/hudakz/webswitch_enc.jpg/media/uploads/hudakz/webswitch_mobile01.jpg

Notice that DHCP is turned on by default. If you prefer to use static IP address then uncomment line 234

The IP address assigned to the WebSwitch server along with an instruction how to use it is printed in the connected PC's serial terminal window during program start up.

Warning

Please notice that the 3.3V power supply chip (RT8183-B) installed on an STM32F103C8T6 board is not rated to power also the ENC28J60 board.


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

NOTE:

main.cpp

Committer:
hudakz
Date:
2020-06-05
Revision:
16:f348413be13e
Parent:
15:9beb9b99695d

File content as of revision 16:f348413be13e:

#include "mbed.h"
#include <string>
#include "UipEthernet.h"
#include "TcpServer.h"
#include "TcpClient.h"

//#define DEBUG
// Static IP address must be unique and compatible with your network.
#define IP      "192.168.1.35"
#define GATEWAY "192.168.1.1"
#define NETMASK "255.255.255.0"
#define PORT    80
const uint8_t   MAC[6] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x06 };
UipEthernet     net(MAC, D11, D12, D13, D10);   // mosi, miso, sck, cs
TcpServer       server;                         // Ethernet server
TcpClient*      client;
char            httpBuf[1500];
char            httpHeader[256];
const int       OFF = 0;
const int       ON = 1;
DigitalOut      output(D3);                     // A digital output to be switched on/off
float           roomTemp = 21.8f;               // A temperature sensor output
const char      PASSWORD[] = "secret";          // Change as you like

/**
 * @brief   Analyses the received URL
 * @note    The string passed to this function will look like this:
 *          GET /HTTP/1.....
 *          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 -3 just refresh page
 *         -2 no command given but password valid
 *         -1 invalid password
 *          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(TcpClient* 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("Starting ...\r\n");

    //net.set_network(IP, NETMASK, GATEWAY);  // include this for using static IP address
    if (net.connect(30) != 0) {

        // 'connect' timeout in seconds (defaults to 60 sec)
        printf("Unable to connet.\r\n");
        return -1;
    }

    // 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);

    /* Can handle 4 simultaneous connections */
    server.listen(4);

    while (true) {
        client = server.accept();
        if (client) {
            switch (client->recv((uint8_t*)httpBuf, client->available())) {
                case 0:
                    printf("recieved buffer is empty.\n\r");
                    break;

                case -1:
                    printf("failed to read data from client.\n\r");
                    break;

                default:
    #ifdef DEBUG
                    printf("Client with IP address %s connected.\r\n\r\n", client->getpeername());
                    printf("Data received:\r\n%s\n\r", receiveBuf);
    #endif
                    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();
        }
    }
}