Zoltan Hudak
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.
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.
 |  |
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:
- For a Web Switch using a WIZ550io or W5500 Ethernet module see WebSwitch_Wiz550io.
- For a Web Switch using mbed's built in Ethernet PHY see WebSwitch_mbed-dev or WebSwitch_mbed-os .
Diff: main.cpp
- Revision:
- 15:9beb9b99695d
- Parent:
- 14:810ac368dd6e
--- a/main.cpp Sat Sep 07 17:53:02 2019 +0000
+++ b/main.cpp Fri Jun 05 15:15:01 2020 +0000
@@ -4,28 +4,23 @@
#include "TcpServer.h"
#include "TcpClient.h"
-using namespace std;
-
//#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 receiveBuf[1024];
+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 = 21.8; // A temperature sensor output
-const string PASSWORD = "secret"; // Change as you like
-string httpHeader; // HTTP header
-string httpContent; // HTTP content
+float roomTemp = 21.8f; // A temperature sensor output
+const char PASSWORD[] = "secret"; // Change as you like
/**
* @brief Analyses the received URL
@@ -42,30 +37,33 @@
* 0 switch off
* 1 switch on
*/
-int8_t analyseURL(string& url)
+int8_t analyseURL(char* url)
{
- if (url.length() < 5 + PASSWORD.size() + 1)
+ if (strlen(url) < (5 + strlen(PASSWORD) + 1))
return(-1);
- if (url.substr(5, PASSWORD.size()) != PASSWORD)
+ //if (url.substr(5, PASSWORD.size()) != PASSWORD)
+ if (strncmp(url + 5, PASSWORD, strlen(PASSWORD)) != 0)
return(-1);
- uint8_t pos = 5 + PASSWORD.size();
+ uint8_t pos = 5 + strlen(PASSWORD);
- if (url.substr(pos, 1) != "/")
+ //if (url.substr(pos, 1) != "/")
+
+ if (*(url + pos) != '/')
return(-1);
- if (url.substr(pos++, 1) == " ")
+ //if (url.substr(pos++, 1) == " ")
+ if (*(url + pos++) == ' ')
return(-2);
- string cmd(url.substr(pos, 5));
-
- if (cmd == "?sw=0")
+ //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 (cmd == "?sw=1")
+ if (strcmp(cmd, "?sw=1") == 0)
return(1);
-
return(-3);
}
@@ -75,16 +73,17 @@
* @param
* @retval
*/
-string& movedPermanently(uint8_t flag)
+char* movedPermanently(uint8_t flag)
{
- if (flag == 1)
- httpContent = "/" + PASSWORD + "/";
- else
- httpContent = "";
+ memset(httpBuf, 0, sizeof(httpBuf));
+ if (flag == 1) {
+ strcpy(httpBuf, "/");
+ strcat(httpBuf, PASSWORD);
+ strcat(httpBuf, "/");
+ }
- httpContent += "<h1>301 Moved Permanently</h1>\r\n";
-
- return(httpContent);
+ strcat(httpBuf, "<h1>301 Moved Permanently</h1>\r\n");
+ return(httpBuf);
}
/**
@@ -93,92 +92,108 @@
* @param
* @retval
*/
-string& showWebPage(int status)
+char* showWebPage(int status)
{
- char roomTempStr[5];
+ char roomTempStr[10] = { };
//roomTemp = ds1820.read();
+
sprintf(roomTempStr, "%3.1f", roomTemp);
-
+ memset(httpBuf, 0, sizeof(httpBuf));
/*$off*/
- httpContent =
+ 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>"
+ "<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" + string(roomTempStr) + "°C</pre>"
- "<pre>Heating:\t";
-
+ "<h2><a href=\".\" title=\"Click to refresh the page\">Smart Home</a></h2>"
+ "<pre>Temperature:\t"
+ );
+ strcat(httpBuf, roomTempStr);
+ strcat(httpBuf, "°C</pre>");
+ strcat
+ (
+ httpBuf,
+ "<pre>Heating:\t"
+ );
if(status == ON) {
- httpContent +=
- "<a href=\"./?sw=0\" class=\"switch\"> "
- "<input type=\"checkbox\" checked>";
+ strcat
+ (
+ httpBuf,
+ "<a href=\"./?sw=0\" class=\"switch\"> "
+ "<input type=\"checkbox\" checked>"
+ );
}
else {
- httpContent +=
- "<a href=\"./?sw=1\" class=\"switch\"> "
- "<input type=\"checkbox\">";
+ strcat
+ (
+ httpBuf,
+ "<a href=\"./?sw=1\" class=\"switch\"> "
+ "<input type=\"checkbox\">"
+ );
}
-
- httpContent +=
- "<div class=\"slider\"></div>"
- "</a>"
- "</pre>"
- "<hr>"
- "<pre>2017 ARMmbed</pre>"
- "</body>";
-
- return httpContent;
+ strcat
+ (
+ httpBuf,
+ "<div class=\"slider\"></div>"
+ "</a>"
+ "</pre>"
+ "<hr>"
+ "<pre>2017 ARMmbed</pre>"
+ "</body>"
+ );
/*$on*/
+ return httpBuf;
}
/**
@@ -187,23 +202,23 @@
* @param
* @retval
*/
-void sendHTTP(TcpClient& client, string& header, string& content)
+void sendHTTP(TcpClient* client, char* header, char* content)
{
- /*$off*/
- char content_length[5] = { };
+ char content_length[10] = { };
+
+ sprintf(content_length, "%u\r\n", strlen(content));
- header +=
- "\r\nContent-Type: text/html\r\n"
- "Content-Length: ";
- sprintf(content_length, "%d", content.length());
- header +=
- string(content_length) + "\r\n"
- "Pragma: no-cache\r\n"
- "Connection: About to close\r\n\r\n";
+ strcat(header, "\r\nContent-Type: text/html\r\n");
+ strcat(header, "Content-Length: ");
+ strcat(header, content_length);
+ strcat(header, "Pragma: no-cache\r\n");
+ strcat(header, "Connection: About to close\r\n\r\n");
- string webpage = header + content;
- client.send((uint8_t*)webpage.c_str(), webpage.length());
- /*$on*/
+ 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));
}
/**
@@ -217,22 +232,21 @@
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)
+ 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
- const char* ip = net.get_ip_address();
- const char* netmask = net.get_netmask();
- const char* gateway = net.get_gateway();
-
- printf("IP address: %s\r\n", ip ? ip : "None");
- printf("Netmask: %s\r\n", netmask ? netmask : "None");
- printf("Gateway: %s\r\n\r\n", gateway ? gateway : "None");
- printf("------------------------------------------------------------------\r\n");
- printf("Usage: Type %s/%s/ into your web browser and hit ENTER\r\n", ip, PASSWORD.c_str());
- printf("------------------------------------------------------------------\r\n");
+ 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);
@@ -245,63 +259,66 @@
while (true) {
client = server.accept();
-
if (client) {
- client->recv((uint8_t*)receiveBuf, client->available());
-#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
- string received(receiveBuf);
-
- if (received.substr(0, 3) != "GET") {
- httpHeader = "HTTP/1.0 200 OK";
- httpContent = "<h1>200 OK</h1>";
- sendHTTP(*client, httpHeader, httpContent);
- client->close();
- continue;
- }
-
- if (received.substr(0, 6) == "GET / ") {
- httpHeader = "HTTP/1.0 200 OK";
- httpContent = "<p>Usage: http://host_or_ip/password</p>\r\n";
- sendHTTP(*client, httpHeader, httpContent);
- client->close();
- continue;
- }
-
- int cmd = analyseURL(received);
-
- switch (cmd) {
- case -3:
- // update webpage
- httpHeader = "HTTP/1.0 200 OK";
- sendHTTP(*client, httpHeader, showWebPage(output));
- break;
-
- case -2:
- // redirect to the right base url
- httpHeader = "HTTP/1.0 301 Moved Permanently\r\nLocation: ";
- sendHTTP(*client, httpHeader, movedPermanently(1));
+ switch (client->recv((uint8_t*)httpBuf, client->available())) {
+ case 0:
+ printf("recieved buffer is empty.\n\r");
break;
case -1:
- httpHeader = "HTTP/1.0 401 Unauthorized";
- httpContent = "<h1>401 Unauthorized</h1>";
- sendHTTP(*client, httpHeader, httpContent);
+ printf("failed to read data from client.\n\r");
break;
- case 0:
- output = OFF; // output off
- httpHeader = "HTTP/1.0 200 OK";
- sendHTTP(*client, httpHeader, showWebPage(output));
- 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 1:
- output = ON; // output on
- 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();