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:
2015-02-04
Revision:
4:d34811deedab
Parent:
3:0133517ba02d
Child:
5:0ab8292e37da

File content as of revision 4:d34811deedab:

/* In this example LED1 is switched on/off using a web browser connected to this HTTP server.
 * The example is based on the Tuxgraphics Web Switch <http://www.tuxgraphics.org/>.
 * This HTTP server is built around the the ENC28J60 chip 
 * driven by the UIPEthernet library <https://github.com/ntruchsess/arduino_uip>
 * ported to mbed.
 */

#include <mbed.h>
#include <UIPEthernet.h>
#include <UIPServer.h>
#include <UIPClient.h>
#include <string>

using namespace std;

// UIPEthernet is the name of a global instance of UIPEthernetClass.
// Do not change the name! It is used within the UIPEthernet library.
#if defined(TARGET_LPC1768)
UIPEthernetClass UIPEthernet(p11, p12, p13, p8);        // mosi, miso, sck, cs
#elif defined(TARGET_LPC1114)
UIPEthernetClass UIPEthernet(dp2, dp1, dp6, dp25);      // mosi, miso, sck, cs
#elif defined(TARGET_LPC11U68)
UIPEthernetClass UIPEthernet(P0_9, P0_8, P1_29, P0_2);  // mosi, miso, sck, cs
#elif defined (TARGET_NUCLEO_F103RB)
UIPEthernetClass UIPEthernet(PB_5, PB_4, PB_3, PB_6);   // mosi, miso, sck, cs
#elif defined (TARGET_NUCLEO_F401RE)
UIPEthernetClass UIPEthernet(PB_5, PB_4, PB_3, PB_6);   // mosi, miso, sck, cs
#elif defined (TARGET_NUCLEO_F411RE)
UIPEthernetClass UIPEthernet(PB_5, PB_4, PB_3, PB_6);   // mosi, miso, sck, cs

// If your board/plaform is not present yet then uncomment the following two lines and replace TARGET_YOUR_BOARD as appropriate.

//#elif defined (TARGET_YOUR_BOARD)
//UIPEthernetClass UIPEthernet(SPI_MOSI, SPI_MISO, SPI_SCK, SPI_CS);   // mosi, miso, sck, cs

#endif

// Note:
// If it happends that any of the SPI_MOSI, SPI_MISO, SPI_SCK, SPI_CS pins collide with LED1 pin
// then either use different SPI port (if available on the board) and change the pin names in the constructor UIPEthernet(...) accordingly
// or instead of using LED1 pin, select a free pin (not used by SPI port) and connect to it an external LED which is connected to a resitor that is connected to the groud.
// In the second case remember to replace LED1 in sw(LED1) constructor (see below).


// MAC number must be unique within the connected network. Modify as appropriate.
const uint8_t    MY_MAC[6] = {0x00,0x01,0x02,0x03,0x04,0x06};
// IP address must be also unique and compatible with your network. Change as appropriate.
const IPAddress  MY_IP(192,168,1,181);
const uint16_t   MY_PORT = 80;      // for HTTP connection
EthernetServer   myServer = EthernetServer(MY_PORT);
// In this example we are turning on/off LED1.
DigitalOut       sw(LED1);  // Change LED1 to a pin of your choice. However, make sure that it does not collide with any of the SPI pins already used in the UIPEthernet(...) constructor above!

const string PASSWORD     = "secret";   // change as you like
const string HTTP_OK      = "HTTP/1.0 200 OK";
const string MOVED_PERM   = "HTTP/1.0 301 Moved Permanently\r\nLocation: ";
const string UNAUTHORIZED = "HTTP/1.0 401 Unauthorized";
string       httpHeader;     // HTTP header
string       httpContent;    // HTTP content


// analyse the url given
// return values: -1 invalid password
//                -2 no command given but password valid
//                -3 just refresh page
//                 0 switch off
//                 1 switch on
//
//                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.....

int8_t analyse_get_url(string& str)
{
    if(str.substr(5, PASSWORD.size()) != PASSWORD)
        return(-1);

    uint8_t pos = 5 + PASSWORD.size();

    if(str.substr(pos, 1) == " ")
        return(-2);

    if(str.substr(pos, 1) != "/")
        return(-1);

    pos++;

    string cmd(str.substr(pos, 5));

    if(cmd == "?sw=0")
        return(0);

    if(cmd == "?sw=1")
        return(1);

    return(-3);
}

string& moved_perm(uint8_t flag)
{
    if(flag == 1)
        httpContent = "/" +  PASSWORD + "/";
    else
        httpContent = "";

    httpContent += "<h1>301 Moved Permanently</h1>\r\n";

    return (httpContent);
}

string& page(uint8_t status)
{
    httpContent = "<h2>Web Switch</h2>\r\n";

    if(status == 1) {
        httpContent += "<pre>\r\n  <font color=#FF0000>ON</font>";
        httpContent += " <a href=\"./?sw=0\">[switch off]</a>\r\n";
    } else {
        httpContent += "<pre>\r\n  <font color=#00FF00>OFF</font>";
        httpContent += " <a href=\"./?sw=1\">[switch on]</a>\r\n";
    }

    httpContent += "  <a href=\".\">[refresh status]</a>\r\n";
    httpContent += "</pre>\r\n";
    httpContent += "<hr>\r\n";
    return httpContent;
}

void http_send(EthernetClient& client, string& header, string& content)
{
    char content_length[5] = {};

    header += "\r\nContent-Type: text/html\r\n";
    header += "Content-Length: ";
    sprintf(content_length, "%d", content.length());
    header += string(content_length) + "\r\n";
    header += "Pragma: no-cache\r\n";
    header += "Connection: About to close\r\n";
    header += "\r\n";
    string webpage = header + content;
    client.write((uint8_t*)webpage.c_str(),webpage.length());
}

int main()
{
    UIPEthernet.begin(MY_MAC,MY_IP);
    myServer.begin();
    while(1) {
        EthernetClient client = myServer.available();
        if (client) {
            size_t size = client.available();
            if(size > 0) {
                uint8_t* buf = (uint8_t*)malloc(size);
                size = client.read(buf, size);
                string received((char*)buf);
                free(buf);
                if(received.substr(0, 3) != "GET") {
                    // head, post or other method
                    // for possible status codes see:
                    // http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
                    httpHeader = HTTP_OK;
                    httpContent = "<h1>200 OK</h1>";
                    http_send(client, httpHeader, httpContent);
                    continue;
                }

                if(received.substr(0, 6) == "GET / ") {
                    httpHeader = HTTP_OK;
                    httpContent = "<p>Usage: http://host_or_ip/password</p>\r\n";
                    http_send(client, httpHeader, httpContent);
                    continue;
                }

                int cmd = analyse_get_url(received);

                if(cmd == -2) {
                    // redirect to the right base url
                    httpHeader = MOVED_PERM;
                    http_send(client, httpHeader, moved_perm(1));
                    continue;
                }

                if(cmd == -1) {
                    httpHeader = UNAUTHORIZED;
                    httpContent = "<h1>401 Unauthorized</h1>";
                    http_send(client, httpHeader, httpContent);
                    continue;
                }

                if(cmd == 1) {
                    sw = 1;     // switch on
                }

                if(cmd == 0) {
                    sw = 0;    // switch off
                }

                httpHeader = HTTP_OK;
                http_send(client, httpHeader, page(sw));
            }
        }
    }
}